,,transcriber',s ,,notes      ,italic   
text is denoted by underscores4    ,the 
oe ligature has been expanded to 'oe'4  
,subscripts in chemical formulas are    
denoted by normal numbers2      for     
example ,ca,c#b4      ,obvious          
typographical and punctuation errors    
have been corrected    after careful    
comparison with other occurrences within
 the text    and consultation of        
external sources4      ,more detail can 
be found at the end of the book4        
,illustration3 ,a ,,primitive ,,use ,,of
 ,,the ,,animal ,,machine ,,that ,,is   
,,still ,,in  ,,vogue ,,in ,,many       
,,european ,,countries4    7,from the   
painting by ,j4 ,didier1 in the ,muse du
 ,luxembourg1 ,paris47                  
,,every-,,day ,,science      ,,by       
,,henry ,,smith ,,williams1 ,m4,d41     
,l4,l4,d4      ,,assisted ,,by          
,,edward ,h4 ,,williams1 ,m4,d4         
,,volume ,,vi      ,,the ,,conquest ,,of
 ,,nature      ,,illustrated            
,,new ,,york ,,and ,,london    ,,the    

,,goodhue ,,company    ,,publishers     
,,mdccccix            ,copyright1 #aiaj1
 by ,,the ,,goodhue ,,co4      ,all     
rights reserved          ,,contents     
,,chapter ,i      ,,man ,,and ,,nature  
,the ,conquest of ,nature1 p4 #d--,man's
 use of ,nature's gifts1 p4    #f--,man 
the tool-making animal1 p4 #g--,science 
and ,civilization1    p4 #h--;,clothing 
and artificially heated dwellings of    
primitive man1    p4 #aj--;,early       
domestication of animals1 p4            
#aa--;,early development to    the time 
of gunpowder1 p4 #ab--,the coming of    
steam and electricity1    p4            
#ae--,mechanical aids to the            
agriculturist1 p4 #ai--,the development 
of scientific agriculture1 p4           
#bj--;,difficulties of the early        
manufacturer1 p4 #ba--,the development  
of modern manufacturing1 p4    #bd--,the
 relation of work to human development1 
p4 #be--,the decline of    drudgery and 
the new era of labor-saving devices1 p4 
#bg4        ,,chapter ,,ii      ,,how   

,,work ,,is ,,done      ,primitive man's
 use of the lever1 p4 #bi--,the use of  
the lever as    conceived by            
,archimedes1 p4 #ba--,wheels and        
pulleys1 p4 #cb--,other    means of     
transmitting power1 p4 #ce--;,inclined  
planes and derricks1 p4    #cg--,the    
steam-scoop1 p4 #ch--;,friction1 p4     
#ci--;,available sources of    energy1  
p4 #da4        ,,chapter ,,iii          
,,the ,,animal ,,machine      ,the      
oldest machine in existence1 p4         
#dc--,the relation of muscle    to      
machinery1 p4 #dd--;,how muscular energy
 is applied1 p4 #dd--,the    two types  
of muscles1 p4 #de--;,how the           
nerve-telegraph controls the    muscles1
 p4 #dg--,the nature of muscular action1
 p4 #di--;,applications    of muscular  
energy1 p4 #eb--,the development of the 
knife and saw1 p4    #ec--,the wheel and
 axle1 p4 #ee--,modified levers1 p4     
#eg--;,domesticated    animals1 p4      
#ei--;,early application of horse-power1
 p4 #fj--,the    horse-power as the     

standard of the world's work1 p4 #fa4   
,,chapter ,,iv      ,,the ,,work ,,of   
,,air ,,and ,,water      ,first use of  
sails for propelling boats1 p4 #fb--,the
 fire engine of    ,ctesibius1 p4       
#fc--,suction and pressure as studied by
 the ancients1 p4    #fd--,studies of   
air pressure1 p4 #fe--,the striking     
demonstration of ,von    ,guericke1 p4  
#ff--,the sailing chariot of ,servinus1 
#afjj ,a4,d41    p4 #fh--,the           
development of the windmill1 p4         
#fi--,the development of the            
water-wheel1 p4 #gj--,the invention of  
the turbine1 p4 #gb--;,different        
types of turbines1 p4 #gc--;,hydraulic  
power and its uses1 p4 #gd--,the        
hydraulic elevator1 p4 #gf--,recent     
water motors1 p4 #gg4        ,,chapter  
,v      ,,captive ,,molecules3 ,,the    
,,story ,,of ,,the ,,steam ,,engine     
,the development of the steam engine1 p4
 #gi--,the manner in which    energy is 
generated by steam1 p4 #hj--;,action of 
cylinder and piston1    p4 #ha--;,early 

attempts to utilize steam1 p4           
#hb--;,beginnings of modern             
discovery1 p4 #hc--,the engine of the   
,marquis of ,worcester1 p4              
#hd--,thomas ,savery's steam pump1 p4   
#he--;,denis ,papin invents the piston  
engine1 p4 #hh--,newcomen's improved    
engine1 p4 #hi--,the use of these       
engines in collieries1 p4 #ij--,the     
wastefulness of such engines1 p4        
#ib--,the coming of ,james ,watt1 p4    
#ic--;,early experiments of ,watt1 p4   
#ie--,the final success of ,watt's      
experiments1 p4 #ig--,some of his early 
engines1 p4 #ih--,rotary motion1 p4     
#ii--,watt's engine1 ,old ,bess1    p4  
#aja--;,final improvements and missed   
opportunities1 p4 #ajb--,the            
personality of ,james ,watt1 p4 #ajg4   
,,chapter ,,vi      ,,the ,,master      
,,worker      ,improvements on ,watt's  
engines1 p4 #aaj--;,engines dispensing  
with the    walking beam1 p4 #aaa--,the 
development of high-pressure engines1 p4
    #aab--;,advantages of the           

high-pressure engine1 p4 #aad--;,how    
steam acts    in the high-pressure      
engine1 p4 #aaf--;,compound engines1 p4 
#aag--,rotary    engines1 p4            
#aai--,turbine engines1 p4 #abd--,the   
,turbinia and other    turbine boats1 p4
 #abe--,the action of steam in the      
turbine engine1 p4    #abf--;,advantages
 of the turbine engine1 p4 #abg4        
,,chapter ,,vii      ,,gas ,,and ,,oil  
,,engines      ,some early gas engines1 
p4 #acc--;,dr4 ,stirling's hot-air      
engine1 p4    #acc--;,ericsson's hot-air
 engines1 p4 #acd--,the first practical 
gas    engine1 p4 #ace--,the ,otto gas  
engine1 p4 #acf--,otto's improvement by 
means of compressed gas1 p4 #ach--,the  
,otto cycle1 p4 #aci--;,adaptation    of
 gas engines to automobiles1 p4         
#adj--,rapid increase in the use    of  
gas engines1 p4 #ada--;,defects of the  
older hot-air engines1 p4               
#ade--,recent improvements and          
possibilities in the use of hot-air     
engines1 p4 #adf4        ,,chapter      

,,viii      ,,the ,,smallest ,,workers  
,the relative size of atoms and         
electrons1 p4 #adh--,what is            
electricity8 p4 #adi--;,franklin's      
one-fluid theory1 p4 #aej--,modern      
views1 p4 #aec--;,cathode rays and the  
,x-ray1 p4 #aef--;,how electricity    is
 developed1 p4 #aei--,the work of the   
dynamical current1 p4    #afb--,theories
 of electrical action1 p4               
#afe--,practical uses of    electricity1
 p4 #afh4        ,,chapter ,,ix         
,,man',s ,,newest ,,co-,,laborer3 ,,the 
,,dynamo      ,the mechanism of the     
dynamo1 p4 #agc--,the origin of the     
dynamo1 p4    #agf--,the work of ,ampre1
 ,henry1 and ,faraday1 p4               
#agg--,perfecting the    dynamo1 p4     
#agh--;,a mysterious mechanism1 p4      
#ahj--;,curious relation    between     
magnetism and electricity as exemplified
 in the dynamo1 p4    #ahb4             
,,chapter ,x      ,,niagara ,,in        
,,harness      ,the volume of water at  
the falls1 p4 #ahd--,the point at which 

the falls are harnessed1 p4             
#ahe--,within the power-house1 p4       
#ahf--,penstocks and turbines1 p4       
#ahh--;,a miraculous transformation     
of energy1 p4 #ahi--,subterranean       
tail-races1 p4 #aia--,the effect on     
the falls1 p4 #aib--,the transmission of
 power1 p4 #aid--,step-up and           
step-down transformers1 p4 #aih4        
,,chapter ,,xi      ,,the ,,banishment  
,,of ,,night      ,primitive torch and  
open lamp1 p4 #bjb--,tallow candle and  
perfected    lamp1 p4 #bje--;,gas       
lighting1 p4 #bjg--,the incandescent gas
 mantle1 p4    #bjh--;,early gas        
mantles1 p4 #bji--;,how the incandescent
 gas mantle is    made1 p4 #baa--,the   
introduction of acetylene gas1 p4       
#bab--;,chemistry    of acetylene gas1  
p4 #bad--,practical gas-making1 p4      
#bae--,the triumph    of electricity1 p4
 #bah--;,davy and the first electric    
light1 p4    #bbj--;,helpful discoveries
 in electricity1 p4 #bbb--,the          
,jablochkoff    candle1 p4              

#bbc--;,defects of the ,jablochkoff     
candle1 p4 #bbe--,the    improved arc   
light1 p4 #bbf--;,edison and the        
incandescent lamp1 p4                   
#bbh--;,difficulties encountered in     
finding the proper material for    a    
practical filament1 p4                  
#bcj--,parchmentized thread filament1 p4
    #bcc--,the tungsten lamp1 p4        
#bcd--,the mercury-vapor light of ,peter
    ,cooper ,hewitt1 p4                 
#bcf--;,advantages and peculiarities of 
this light1 p4    #bdj4        ,,chapter
 ,,xii      ,,the ,,mineral ,,depths    
,early mining methods1 p4               
#bdb--,prospecting and locating mines1  
p4    #bdc--;,booming1 p4               
#bdf--;,conditions to be considered in  
mining1    p4 #bdh--;,dangerous gases in
 mines1 p4 #bdi--;,artificial lights and
    lighting1 p4 #bea--,ventilation and 
drainage1 p4 #beb--;,electric           
machinery in mining1 p4 #bec--;,electric
 drills1 p4 #bed--,traction in          
mining1 p4 #bef--,various types of      

electric motors1 p4 #beg--,telphers1    
p4 #bfa--;,electric mining pumps1 p4    
#bfc--,some remarkable demonstrations   
of durability of electric pumps1 p4     
#bfe--;,electricity in coal mining1     
p4 #bff--;,electric lighting in mines1  
p4 #bfi4        ,,chapter ,,xiii        
,,the ,,age ,,of ,,steel      ,rapid    
growth of the iron industry in recent   
years1 p4 #bga--,the ,lake    ,superior 
mines1 p4 #bgb--,methods of mining1 p4  
#bgc--,open-pit mining1    p4           
#bgd--,mining with the steam shovel1 p4 
#bgf--;,from mine to furnace1    p4     
#bgh--,methods of transportation1 p4    
#bgi--,vessels of special               
construction1 p4 #bha--,the conversion  
of iron ore into iron and steel1    p4  
#bhc--;,blast furnaces1 p4              
#bhd--,poisonous gases and their effect 
upon the workmen1 p4 #bhf--;,from pig   
iron to steel1 p4 #bhg--,modern         
methods of producing pig iron1 p4       
#bhh--,the ,bessemer converter1 p4      
#bhi--,sir ,henry ,bessemer1 p4         

#bia--,the ,bessemer-,mushet process1 p4
    #bic--,open-hearth method1 p4       
#bid--;,alloy steels1 p4 #bie4          
,,chapter ,,xiv      ,,some ,,recent    
,,triumphs ,,of ,,applied ,,science     
,the province of electro-chemistry1 p4  
#bih--,linking the laboratory    with   
the workshop1 p4 #bii--,soda            
manufactories at ,niagara ,falls1 p4    
#cjj--,producing aluminum by the        
electrolytic process1 p4 #cjj--,old and 
new methods compared1 p4 #cja--,nitrogen
 from the air1 p4 #cjc--,what    this   
discovery means to the food industries  
of the world1 p4    #cjd--,prof4        
,birkeland's method1 p4 #cjg--;,another 
method of nitrogen    fixation1 p4      
#cji--;,cost of production1 p4          
#cab--;,electrical energy1    p4        
#cac--,production of high temperatures  
with the electric arc1 p4    #cad--,the 
production of artificial diamonds by the
 explosion of    cordite1 p4            
#cae--;,industrial problems of to-day   
and to-morrow1 p4 #caf4                 

,,illustrations        ,a ,,primitive   
,,use ,,of ,,the ,,animal ,,machine     
,,that ,,is    ,,still ,,in ,,vogue ,,in
 ,,many ,,european ,,countries          
,frontispiece      ,,horse ,,and        
,,cattle ,,power                        
,facing p4  #cb      ,,cranes ,,and     
,,derricks                              
#ch      ,a ,,belgian ,,milk-,,wagon    
#ef      ,,two ,,apparatuses ,,for ,,the
 ,,utilization ,,of ,,animal    ,,power 
#fj      ,,windmills ,,of ,,ancient     
,,and ,,modern ,,types                  
#fh      ,,water ,,wheels               
#gb      ,,hydraulic ,,press ,,and      
,,hydraulic ,,capstan                   
#gf      ,,thomas ,,savery',s ,,steam   
,,engine                                
#hf      ,,diagrams ,,of ,,early        
,,attempts ,,to ,,utilize ,,the ,,power 
,,of ,,steam                            
#hh      ,a ,,model ,,of ,,the          
,,newcomen ,,engine                     
#ib      ,,watt',s ,,earliest ,,type    
,,of ,,pumping-,,engine                 

#if      ,,watt',s ,,rotative ,,engine  
#ajj      ,,james ,,watt                
#ajh      ,,old ,,ideas ,,and ,,new     
,,applied ,,to ,,boiler ,,construction  
#aad      ,,compound ,,engines          
#aah      ,,rotary ,,engines            
#abb      ,,the ,,original ,,parsons'   
,,turbine ,,engine ,,and ,,the          
,,record-,,breaking    ,,ship ,,for     
,,which ,,it ,,is ,,responsible         
#abh      ,,gas ,,and ,,oil ,,engines   
#acf      ,,an ,,electric ,,train ,,and 
,,the ,,dynamo ,,that ,,propels ,,it    
#agd      ,,wilde',s ,,separately       
,,excited ,,dynamo                      
#agh      ,,the ,,evolution ,,of ,,the  
,,dynamo                                
#ahj      ,,view ,,in ,,one ,,of ,,the  
,,power ,,houses ,,at ,,niagara         
#ahf      ,,electrical ,,transformers   
#aih      ,,thomas ,a4 ,,edison ,,and   
,,the ,,dynamo ,,that ,,generated       
,,the ,,first ,,commercial              
,,incandescent ,,light                  
#bbh      ,a ,,flint-,,and-,,steel      

,,outfit1 ,,and ,a ,,miner',s ,,steel   
,,mill             #bdh      ,,the      
,,locomotive ,,puffing ,,billy ,,and ,a 
,,modern    ,,colliery ,,trolley        
#beh          ,,the ,,conquest ,,of     
,,nature      ,in the earlier volumes we
 have been concerned with the growth of 
knowledge4 ,for the most part the       
scientific delvers whose efforts have   
held our attention have been tacitly    
unmindful1 or even explicitly           
contemptuous1 of the influence upon     
practical life of the phenomena to  the 
investigation of which they have devoted
 their lives4 ,they were and  are       
obviously seekers of truth for the mere 
love of truth4    ,but the phenomena of 
nature are not dissociated in fact1     
however  much we may attempt to localize
 and classify them4 ,and so it chances  
that even the most visionary devotee of 
abstract science is forever  being      
carried into fields of investigation    
trenching closely upon the              
practicalities of every-day life4 ,a    

,black investigating the laws of  heat  
is preparing the way explicitly1 however
 unconsciously1 for a ,watt  with his   
perfected mechanism of the steam engine4
    ,similarly a ,davy working at the   
,royal ,institution with his newly      
invented batteries1 and intent on the   
discovery of new elements and the       
elucidation of new principles1 is the   
direct forerunner of ,jablochkoff1      
,brush1 and ,edison with their          
commercial revolution in the production 
of  artificial light4    ,again ,oersted
 and ,faraday1 earnestly seeking out the
 fundamental facts  as to the relations 
of electricity and magnetism1 invent    
mechanisms  which1 though they seem but 
laboratory toys1 are the direct         
forerunners  of the modern dynamos that 
take so large a share in the world's    
work4    ,in a word1 all along the line 
there is the closest association        
between what are commonly called the    
theoretical sciences and what  with only
 partial propriety are termed the       

applied sciences4 ,the  linkage of one  
with the other must never be forgotten  
by anyone who  would truly apprehend the
 status of those practical sciences     
which  have revolutionized the          
civilization of the nineteenth and      
twentieth  centuries in its most        
manifest aspects4    ,nevertheless there
 is1 to casual inspection1 a somewhat   
radical  distinction between theoretical
 and practical aspects of science--just 
as there are obvious differences between
 two sides of a shield4  ,and as the    
theoretical aspects of science have     
largely claimed our  attention hitherto1
 so its practical aspects will be       
explicitly  put forward in the pages    
that follow4 ,in the present volume we  
are  concerned with those primitive     
applications of force through which  man
 early learned to add to his working    
efficiency1 and with the  elaborate     
mechanisms--turbine wheels1 steam       
engines1 dynamos--through  which he has 
been enabled to multiply his powers     

until it is scarcely  exaggeration to   
say that he has made all ,nature        
subservient to his  will4 ,it is this   
view which justifies the title of the   
volume1 which  might with equal         
propriety have been termed the ,story of
 the ,world's  ,work4          ,,the    
,,conquest ,,of ,,nature          ,i    
,,man ,,and ,,nature      ,young men1   
said a wise physician in addressing a   
class of graduates  in medicine1 you are
 about to enter the battle of life4     
,note that ,i  say the 'battle' of life4
 ,not a playground1 but a battlefield is
 before  you4 ,it is a hard contest--a  
battle royal4 ,make no mistake as to    
that4  ,your studies here have furnished
 your equipment2 now you must go forth  
each to fight for himself4    ,the same 
words might be said to every neophyte in
 whatever walk of  life4 ,the pursuit of
 every trade1 every profession is a     
battle--a  struggle for existence and   
for supremacy4 ,partly it is a battle   
against  fellow men2 partly against the 

contending powers of ,nature4 ,the      
physician meets rivalry from his        
brothers2 but his chief battle is with  
disease4 ,in the creative and           
manufacturing fields which will chiefly 
concern us in the following volumes1 it 
is the powers of ,nature that  furnish  
an ever-present antagonism4    ,no stone
 can be lifted above another1 to make   
the crudest wall or  dwelling1 but      
,nature--represented by her power of    
gravitation--strives  at once to pull it
 down again4 ,no structure is completed 
before the  elements are at work        
defacing it1 preparing its slow but     
certain ruin4  ,summer heat and winter  
cold expand and contract materials of   
every  kind2 rain and wind wear and warp
 and twist2 the oxygen of the air  gnaws
 into stone and iron alike2--in a word1 
all the elements are at  work undoing   
what man has accomplished4      ,,the   
,,struggle ,,for ,,existence    ,in the 
field of the agriculturist it is the    
same story4 ,the earth which  brings    

forth its crop of unwholesome weeds so  
bountifully1 resists  man's approaches  
when he strives to bring it under       
cultivation4 ,only by  the most careful 
attention can useful grains be made to  
grow where the  wildlings swarmed in    
profusion4 ,not only do wind and rain1  
blighting  heat and withering cold      
menace the crops2 but weeds invade the  
fields1  the germs of fungoid pests lurk
 everywhere2 and myriad insects attack  
orchard and meadow and grain field in   
devastating legions4    ,similarly the  
beasts which were so rugged and         
resistant while in  the wild state1     
become tender and susceptible to disease
 when made  useful by domestication4    
,aforetime they roamed at large1 braving
 every  temperature and thriving in all 
weathers4 ,but now they must be housed  
and cared for so tenderly that they     
become1 as ,thoreau said1 the  keepers  
of men1 rather than kept by men1 so much
 more independent are  they than their  
alleged owners4 ,tender of constitution1

 domesticated  beasts must be housed1 to
 protect them from the blasts in which  
of yore  their forebears revelled2 and  
man must slave day in and day out to    
prepare food to meet the requirements of
 their pampered appetites4    ,he must  
struggle1 too1 to protect them from     
disease1 and must care for  them in time
 of illness as sedulously as he cares   
for his own kith and  kin4 ,truly the ox
 is keeper of the man1 and the seeming  
conquest that  man has wrought has cost 
him dear4    ,but of course the story   
has another side4 ,after all1 ,nature is
 not so  malevolent as at first glance  
she seems4 ,she has opposed man at every
  stage of his attempted progress2 yet  
at the same time she has supplied  him  
all his weapons for waging war upon her4
 ,her great power of  gravitation       
opposes every effort he makes2 yet      
without that same power  he could do    
nothing--he could not walk or stay upon 
the earth even2 and  no structure that  
he builds would hold in place for an    

instant4    ,so1 too1 the wind that     
smites him and tears at his handiwork1  
may be  made to serve the purposes of   
turning his windmills and supplying him 
with power4    ,the water will serve a  
like purpose in turning his mills2 and1 
changed  to steam with the aid of       
,nature's store of coal1 will make his  
steam  engines and dynamos possible4    
,even the lightning he will harness and 
make subject to his will in the         
telegraphic currents and dynamos4       
,and in the fields1 the grains which man
 struggles so arduously to  produce are 
after all no thing of his creating4     
,they are only adopted  products of     
,nature1 which he has striven to make   
serve his purpose by  growing them under
 artificial conditions4 ,so1 too1 the   
domesticated  beasts are creatures that 
belong in the wilds and in distant      
lands4 ,man  has brought them1 in       
defiance of ,nature1 to uncongenial     
climes1 and  made them serve as workers 
and as food-suppliers where ,nature     

alone  could not support them4 ,turn    
loose the cow and the horse to forage   
for  themselves here in the inhospitable
 north1 and they would starve4 ,they    
survive because man helps them to combat
 the adverse conditions imposed  by     
,nature1 yet no one of them could live  
for an hour were not the vital          
capacities supplied by ,nature still in 
control4    ,everywhere1 then1 it is the
 opposing of ,nature1 up to certain     
limits1  with the aid of ,nature's own  
tools1 that constitutes man's work in   
the  world4 ,just in proportion as he   
bends the elements to meet his needs1   
transforms the plants and animals1      
defies and exceeds the limitations  of  
primeval ,nature--just in proportion as 
he conquers ,nature1 in a  word1 is he  
civilized4    ,barbaric man is called a 
child of ,nature with full reason4 ,he  
must  accept what ,nature offers4 ,but  
civilized man is the child grown to     
adult stature1 and able in a manner to  
control1 to dominate--if you  please to 

conquer--the parent4    ,if we were to  
seek the means by which developing man  
has gradually  achieved this conquest1  
we should find it in the single word1   
,tools2  that is to say1 machines for   
utilizing the powers of ,nature1 and1 as
  it were1 multiplying them for man's   
benefit4 ,so unique is the capacity     
that man exerts in this direction1 that 
he has been described as  the           
tool-making animal4 ,the description is 
absolutely accurate2 it  is inclusive   
and exclusive4 ,no non-human animal     
makes any form of  implement to aid it  
in performing its daily work2 and       
contrariwise  every human tribe1 however
 low its stage of savagery1 makes use of
 more  or less crude forms of           
implements4 ,there must have been a     
time1 to be  sure1 when there existed a 
man so low in intelligence that he had  
not  put into execution the idea of     
making even the simplest tool4 ,but the 
period when such a man existed so vastly
 antedates all records that it  need not

 here concern us4 ,for the purpose of   
classifying all existing  men1 and all  
the tribes of men of which history and  
pre-historic  archology give us any     
record1 the definition of man as the    
tool-making  animal is accurate and     
sufficient4    ,at first thought it     
might seem that an equally comprehensive
 definition  might describe man as the  
working animal4 ,but a moment's         
consideration  shows the fallacy of such
 a suggestion4 ,man is1 to be sure1 the 
animal  that works effectively1 thanks  
to the implements with which he has     
learned to provide himself2 but he      
shares with all animate creatures  the  
task of laboring for his daily          
necessities4 ,this is indeed a          
work-a-day world1 and no creature can   
live in it without taking  its share in 
that perpetual conflict which bodily    
necessities make  imperative4 ,most     
lower animals confine their work to the 
mere securing  of food1 and to the      
construction of rude habitations4 ,some1

 indeed1  go a step farther and lay up  
stores of food1 in chance burrows or    
hollow trees2 a few even manufacture    
relatively artistic and highly          
effective receptacles1 as illustrated by
 the honeycomb made by the  bees and    
their allies4 ,again1 certain animals1  
of which the birds  are the best        
representatives1 construct temporary    
structures for the  purpose of rearing  
their young that attain a relatively    
high degree of  artistic perfection4    
,the ,baltimore oriole weaves a cloth of
 vegetable  fibre that is certainly a   
wonderful texture to be made with the   
aid of  claws and bill alone4 ,it may be
 doubted whether human hands1 unaided by
  implements1 could duplicate it4 ,but  
it is crude enough compared with  even  
the coarsest cloth which barbaric races 
manufacture with the aid  of implements4
    ,so it is with any comparison of    
animal work with the work of man1 in    
whatever field4 ,the crudest human      
endeavor is superior to the best        

non-human efforts2 and the explanation  
is found always in the fact that  the   
ingenuity of man has enabled him to find
 artificial aids that add  to his power 
of manipulation4 ,so large a share have 
these artificial  aids taken in man's   
evolution1 that it has long been        
customary1 in  studying the development 
of civilization1 to make the use of     
various  types of implements a test of  
varying stages of human progress4       
,,science ,,and ,,civilization    ,the  
student of primitive life assures us1   
basing his statements on the            
archological records1 that there was a  
time when the most advanced of  mankind 
had no tools made of better material    
than chipped stone4 ,by  common consent 
that time is spoken of as the ,rough    
,stone ,age4    ,we are told that then  
in the course of immeasurable centuries 
man  learned to polish his stone        
implements1 doubtless by rubbing them   
against another stone1 or perhaps with  
the aid of sand1 thus producing  a new  

type of implement which has given its   
name to the ,age of ,smooth  or         
,polished ,stone4    ,then after other  
long centuries came a time when man had 
learned  to smelt the softer metals1 and
 the new civilization which now         
supplanted the old1 and1 thanks to the  
new implements1 advanced upon it        
immeasurably1 is called the ,age of     
,bronze4    ,at last man learned to     
accomplish the wonderful feat of        
smelting the  intractable metal1 iron1  
and in so doing produced implements     
harder1  sharper1 and cheaper than his  
implements of bronze2 and when this     
crowning feat had been accomplished1 the
 ,age of ,iron was ushered in4    ,by   
common consent1 students of the history 
of the evolution of society  accept     
these successive ages1 each designated  
by the type of implements  with which   
the world's work was accomplished1 as   
representing real and  definite stages  
of human progress1 and as needing no    
better definition  than that supplied by

 the different types of implements4     
,could the archologist trace the stream 
of human progress still farther  back   
toward its source1 he would find        
doubtless that there were several  great
 epochal inventions preceding the time  
of the ,rough ,stone ,age1  each of     
which was in its way as definitive and  
as revolutionary in  its effects upon   
society1 as these later inventions which
 we have just  named4 ,to attempt to    
define them clearly is to enter the     
field of  uncertainty1 but two or three 
conjectures may be hazarded that cannot 
be very wide of the truth4    ,it is    
clear1 for example1 that if we go back  
in imagination to the very  remotest    
ancestors of man that can be called     
human1 we must suppose a  vast and      
revolutionary stage of progress to have 
been ushered in by the  first race of   
men that learned to make habitual use of
 the simplest  implement1 such as a mere
 club4 ,when man had learned to wield a 
club  and to throw a stone1 and to use a

 stone held in the hand to break the    
shell of a nut1 he had attained a stage 
of culture which augured great  things  
for the future4 ,out of the idea of     
wielded club and hurled stone  were to  
grow in time the ideas of hammer and axe
 and spear and arrow4    ,then there    
came a time--no one dare guess how many 
thousands of years  later--when man     
learned to cover his body with the skin 
of an animal1  and thus to become in a  
measure freed from the thraldom of the  
weather4  ,he completed his             
enfranchisement by learning to avail    
himself of the  heat provided by an     
artificial fire4 ,equipped with these   
two marvelous  inventions he was able to
 extend the hitherto narrow bounds of   
his  dwelling-place1 passing northward  
to the regions which at an earlier      
stage of his development he dared not   
penetrate4 ,under stress of more        
exhilarating climatic conditions1 he    
developed new ideals and learned  to    
overcome new difficulties2 developing   

both a material civilization  and the   
advanced mentality that is its          
counterpart1 as he doubtless  never     
would have done had he remained subject 
to the more pampering  conditions of the
 tropics4    ,the most important1       
perhaps1 of the new things which he was 
taught  by the seemingly adverse        
conditions of an inhospitable climate1  
was  to provide for the needs of a      
wandering life and of varying seasons   
by domesticating animals that could     
afford him an ever-present food  supply4
 ,in so doing he ceased to be a mere    
fisher and hunter1 and  became a        
herdsman4 ,one other step1 and he had   
conceived the idea of  providing for    
himself a supply of vegetable foods1 to 
take the place  of that which nature had
 provided so bountifully in his old home
 in  the tropics4 ,when this idea was   
put into execution man became an        
agriculturist1 and had entered upon the 
high road to civilization4    ,all these
 stages of progress had been entered    

upon prior to the time of  which the    
oldest known remains of the cave-dweller
 give us knowledge4  ,it were idle to   
conjecture the precise sequence in which
 these earliest  steps toward           
civilization were taken1 and even more  
idle to conjecture  the length of time  
which elapsed between one step and its  
successor4  ,but all questions of       
precise sequence aside1 it is clear that
 here were  four or five great ages     
succeeding one to another1 that marked  
the  onward and upward progress of our  
primeval ancestor before he achieved    
the stage of development that enabled   
him to leave permanent records of  his  
existence4 ,and--what is particularly   
significant from our present            
standpoint--it is equally clear that    
each of the great ages thus  vaguely    
outlined was dependent upon an          
achievement or an invention  that       
facilitated the carrying out of that    
scheme of never-ending work  which from 
first to last has been man's portion4   

,how to labor more  efficiently1 more   
productively2 how to produce more of the
 necessaries  and of the luxuries that  
man's physical and mental being demands1
  with less expenditure of toil--that   
from first to last has been the         
ever-insistent problem4 ,and the answer 
has been found always through  the      
development of some new species of      
mechanism1 some new labor-saving        
device1 some ingenious manipulation of  
the powers of ,nature4    ,if1 turning  
from the hypothetical period of our     
primitive ancestor1  we consider the    
sweep of secure and relatively recent   
history1 we  shall find that precisely  
the same thing holds4 ,if we contrast   
the  civilization of ,old ,egypt and    
,babylonia--the oldest civilizations of 
which we have any secure record--with   
the civilization of to-day1 we  shall   
find that the differences between the   
one and the other are such  as are due  
to new and improved methods of          
accomplishing the world's  work4        

,indeed1 if we view the subject         
carefully1 it will become more and  more
 evident that the only real progress    
that the historic period has  to show is
 such as has grown directly from the    
development of new  mechanical          
inventions4 ,the more we study the      
ancient civilizations  the more we shall
 be struck with their marvelous         
resemblance1 as  regards mental life1 to
 the civilization of to-day4 ,in their  
moral  and spiritual ideals1 the ancient
 ,egyptians were as brothers to the     
modern ,europeans4 ,in philosophy1 in   
art1 in literature1 the ,age of         
,pericles established standards that    
still remain unexcelled4 ,in all the    
subtleties of thought1 we feel that the 
,greeks had reached intellectual  bounds
 that we have not been able to extend4  
,but when1 on the other hand1 we        
consider the material civilization of   
the two epochs1 we find contrasts that  
are altogether startling4 ,the  little  
world of the ,greeks nestled about the  

,mediterranean1 bounded  on every side  
at a distance of a few hundred leagues  
by a terra  incognita4 ,the philosophers
 who had reached the confines of the    
field of thought1 had but the narrowest 
knowledge of the geography of  our      
globe4 ,they traversed at best a few    
petty miles of its surface  on foot or  
in carts2 and they navigated the        
,mediterranean ,sea1 or at  most coasted
 out a little way beyond the ,pillars of
 ,hercules in boats  chiefly propelled  
by oars4 ,by dint of great industry they
 produced a  really astonishing number  
of books1 but the production of each one
 was  a long and laborious task1 and the
 aggregate number indited during  the   
,age of ,pericles in all the world was  
perhaps not greater than an  afternoon's
 output of a modern printing press4     
,in a word1 these men of the classical  
period of antiquity1 great as  were     
their mental1 artistic1 and moral       
achievements1 were as children  in those
 matters of practical mechanics upon    

which the outward  evidences of         
civilization depend4 ,should we find a  
race of people  to-day in some hitherto 
unexplored portion of the earth--did    
such  unexplored portions still         
exist--living a life comparable to that 
of the ,age of ,pericles1 we should     
marvel no doubt at their artistic       
achievements1 while at the same time    
regarding them as scarcely better  than 
barbarians4 ,indeed this is more than   
unsupported hypothesis2  for has it not 
been difficult for the ,western world to
 admit the  truly civilized condition of
 the ,chinese1 simply because that      
highly  intellectual race of ,orientals 
has not kept abreast of the ,occidental 
changes in applied mechanics8 ,say what 
we will1 this is the standard  which we 
of the ,western world apply as the test 
of civilization4    ,if1 sweeping over  
in retrospect the history of the world  
since the time  when the ,egyptian and  
,babylonian civilizations were at their 
height1  we attempt some such           

classification of the stages of progress
 as that  which we a moment ago applied 
to pre-historic times1 we shall be led  
to  some rather startling conclusions4  
,in the broadest view1 it will appear   
that the age which ushered in the       
historic period continued unbroken  by  
the advance of any great revolutionary  
invention throughout the  long centuries
 of pre-,christian antiquity1 and well  
into the so-called  ,middle ,ages of our
 newer era4 ,then came the invention of 
gunpowder1 or  at least its introduction
 to the ,western world--since the       
,chinaman here  lays claim to vague     
centuries of precedence4 ,following hard
 upon the  introduction of gunpowder1   
with its capacity to add to the         
destructive  efficiency of man's most   
sinister form of labor1 came a mechanism
 no  less epoch-making in a far         
different field--the printing press4    
,but even these inventions1 great as was
 their influence upon the  progress of  
civilization1 can scarcely be           

considered1 it seems to me1  as taking  
rank with the great epochal discoveries 
that gave their  names to the preceding 
ages4 ,nor can any invention of the     
sixteenth  or seventeenth century be    
hailed as really ushering in a new era4 
,the  invention for which that honor was
 reserved was a development of the      
eighteenth century2 and did not come    
fully to its heritage until the  early  
days of the nineteenth century4 ,the    
invention was the application  of steam 
to the purposes of mechanics4 ,when this
 application was made1  as wide a gap   
was crossed as that which separated the 
,stone ,age from  the ,age of ,metal2   
then the epoch in which the world was   
living when  history begins was brought 
to a close1 and a new era1 the ,age of  
,steam1  was ushered in4    ,scarcely   
had the world begun to adjust itself to 
the new conditions of  the ,age of      
,steam1 when yet another power was made 
subservient to man's  needs1 and the    
,age of ,steam was supplemented1 not to 

say supplanted1 by  the ,age of         
,electricity4 ,of course the new        
progressive movements did not           
necessarily imply elimination of old    
conditions2 they imply merely the       
subordination of old powers to newer and
 better ones4 ,stone implements  by no  
means ceased to have utility at once    
when metal implements came  into vogue4 
,bronze long held its own against iron1 
and still has its  utility4 ,and iron   
itself finds but an added sphere of     
usefulness in the  ,age of ,steam and   
,electricity4    ,all great changes are 
relatively slow4 ,it is only as we look 
back upon  them and view them in        
perspective that they seem cataclysmic4 
,gunpowder  did not at once supplant the
 crossbow1 and the cannon was long held 
to be inferior to the catapult4 ,the    
printed book did not instantly  make its
 way against the work of the scribe4    
,neither did the steam  engine          
immediately supplant water power and the
 direct application of  human labor4    

,but in each case the new invention     
virtually rang the  death knell of the  
old method from the hour of its         
inauguration1 and  the end was no less  
sure because it was delayed4 ,and it    
requires no  great powers of divination 
to foretell that in the coming age1 the 
electric dynamo driven by water power   
may take the place of the steam  engine4
 ,the ,age of ,steam may pass1 with only
 at most a few generations  of          
domination4 ,and it is within the       
possibilities that the ,age of          
,electricity will scarcely come into its
 own before it may be displaced  by an  
,age of ,radio-,activity4 ,to press that
 point1 however1 would be to  enter the 
field of prophecy1 which is no part of  
my present purpose4    ,all that ,i have
 wished to point out is that for some   
thousands of  years after man learned to
 make implements of iron1 the industrial
  world and the human civilization that 
depends upon it1 pursued a  relatively  
static course1 like a broad1 sluggish   

current1 with no  new revolutionary     
discovery to impel it into new channels2
 and that  then one revolutionary       
discovery succeeded another with        
bewildering  suddenness1 so that we of  
the early days of the twentieth century 
are farther removed1 in an industrial   
way1 from our forerunners of  two       
hundred years ago1 than those children  
of the eighteenth century  were from the
 earliest civilization that ever        
developed on our globe4  ,indeed1 this  
startling contrast would still hold     
true1 were we to  consider the newest   
era as compassing only the period of a  
single  life4 ,there are men living     
to-day who were born in that epoch when 
the steam engine was for the first time 
used to turn the wheels of  factories4  
,there are many men who can well        
remember the first practical            
application of steam to railway traffic4
 ,hosts of men can remember when  the   
first commercial message was transmitted
 by electricity along a  wire4 ,even    

middle-aged men recall the first cable  
message that linked  the old world with 
the new4 ,and the application of the    
dynamo to the  purposes of the world's  
work is an affair of but yesterday4     
,the historian of the future1 casting   
his eye back across the long            
perspective of history1 will find       
civilized man pursuing an even and      
unbroken course across the ages from the
 time of the pyramids of ,egypt  to     
about the time of the ,french           
,revolution4 ,there will be no dearth   
of incident to claim his attention in   
the way of wars and conquests1  and     
changing creeds1 and the rise and fall  
of nations1 each pursuing  virtually the
 same course of growth and decay as all 
the others4 ,but  when he comes to the  
close of the eighteenth century1 it will
 not be  the social paroxysm of a       
nation1 or the meteoric career of a     
,napoleon  that will claim his attention
 so much as the introduction of that new
  method of utilizing the powers of     

,nature which found its expression in   
the mechanism called the steam engine4  
,if the name of any individual stands   
out as the great and memorable one  of  
that epoch of transition1 at which the  
static current of previous  civilization
 changed suddenly to a ,niagara-current 
of progress1 it will  be the name of the
 great scientific inventor1 rather than 
that of the  great military             
conqueror--the name of ,james ,watt1    
rather than that of  ,napoleon4    ,the 
military conqueror had his day of       
surpassing glory and departed1  to leave
 the world only a little worse than he  
found it4 ,but the  mechanical inventor 
left a heritage that was to add day by  
day to the  wealth and happiness of     
humanity1 supplying millions of         
artificial  hands1 and making possible  
such beneficent improvements as no      
previous  age had dreamed of4 ,tasks    
that human hands had performed slowly1  
laboriously1 and inadequately1 were now 
to be performed swiftly1 with  ease1 and

 well by the artificial hands provided  
with the aid of the new  power4 ,where  
carts drawn by horses had toiled slowly 
across the land1  and ships driven by   
the wind had drifted slowly through the 
waters1  massive trains of cars were to 
hurtle to the four corners of the earth 
with inconceivable speed1 and floating  
palaces were to course the  waters with 
almost equal defiance to the limitations
 of time and space4    ,and then there  
came that still weirder conquest of time
 and space1  wrought by the electric    
current4 ,the moment when man first     
spoke with  man from continent to       
continent in defiance of the oceans1    
marked  the dawning of that larger day  
when all mankind shall constitute one   
brotherhood and all peoples but a single
 nation4 ,within a half century  the sun
 of that new day has risen well above   
the horizon1 and far  sooner than even  
the optimist of to-day dare predict with
 certainty1 it  seems destined to reach 
its zenith4    ,but here again we verge 

upon the dangerous field of prophecy4   
,let  us turn from it and cast an eye   
back across the most wonderful of       
centuries1 contrasting the conditions of
 to-day in each of a half-dozen  fields 
of the world's work1 with the conditions
 that obtained at the  close of the     
eighteenth century4 ,such a brief survey
 will show us  perhaps more vividly than
 we could otherwise be shown1 how vast  
has  been the progress1 how marvelous   
the development of civilization1 in  the
 short decades that have elapsed since  
the coming of the ,age of  ,steam4      
,let us pay heed first to the world of  
the agriculturist4 ,could we  turn back 
to the days of our grandparents1 we     
should find farming a  very different   
employment from what it is to-day4 ,for 
the most part  the farmer operated but a
 few small fields2 if he had thirty or  
forty  acres of ploughed land1 he found 
ample employment for his capacities4    
,he ploughed his fields with the aid of 
either a yoke of oxen or a  team of     

horses2 he sowed his grain by hand2 he  
cultivated his corn  with a hoe2 he     
reaped his oats and wheat with a        
cradle--a device but  one step removed  
from a sickle2 he threshed his grain    
with a flail2  he ground such portion of
 it as he needed for his own use with   
the  aid of water power at a neighboring
 mill2 and such portion of it as  he    
sold was transported to market1 be it   
far or near1 in wagons that  compassed  
twenty or thirty miles a day at best4   
,as regards live stock1  each farmer    
raised a few cattle1 sheep1 and hogs1   
and butchered them  to supply his own   
needs1 selling the residue to a local   
dealer who  supplied the                
non-agricultural portion of the         
neighborhood4 ,any live  stock intended 
for a distant market was driven on foot 
across the  country to its destination4 
,each town and city1 therefore1 drew    
almost  exclusively for its supply from 
the immediately surrounding country4    
,to-day the small farmer has become     

almost obsolete1 and the farms  of the  
eastern states that were the nation's   
chief source of supply  a century ago   
are largely allowed to lie fallow1 it   
being no longer  possible to cultivate  
them profitably in competition with the 
rich  farm lands of the middle west4 ,in
 that new home of agriculture1 the  farm
 that does not comprise two or three    
hundred acres is considered  small2 and 
large farms are those that number their 
acres by thousands4  ,the soil is turned
 by steam ploughs2 the grain is sown    
with mechanical  seeders and planters2  
the corn is cultivated with a           
horse-drawn  machine1 having blades that
 do the work of a dozen men2 harvesters 
drawn by three or four horses sweep over
 the fields and leave the grain         
mechanically tied in bundles2 the steam 
thresher places the grain in  sacks by  
hundreds of bushels a day2 and this     
grain is hurried off in  steam cars to  
distant mills and yet more distant      
markets4    ,meantime the raising of    

live stock has become a special         
department1  with which the farmer who  
deals in cereals often has no concern4  
,the cattle roam over vast pastures and 
are herded in the winter for  fattening 
in great droves1 and protected from the 
cold in barns  that1 when contrasted    
with the sheds of the old-time farmer1  
seem  almost palatial4 ,when in         
marketable condition1 cattle are no     
longer  slaughtered at the farm1 but are
 transported in cars to one of the  few 
great centres1 chief of which are the   
stock yards of ,chicago and  of ,kansas 
,city4 ,at these centres1 slaughter     
houses and meat-packing  houses of      
stupendous magnitude have been          
developed1 capable of  handling millions
 of animals in a year4 ,from these      
centres the meat is  transported in     
refrigerator cars to the seaboards1 and 
in refrigerator  ships to all parts of  
the world4 ,beef that grew on the ranges
 of the  far west may thus be offered   
for sale in the markets of ,new ,england

  villages1 at a price that prohibits   
local competition4    ,a more radical   
metamorphosis in agricultural conditions
 than all this  implies could not well  
be conceived4 ,and when we recall once  
more that  the agricultural conditions  
that obtained at the beginning of the   
nineteenth century were closely similar 
to those that obtained in each          
successive age for a hundred preceding  
centuries1 we shall gain a vivid  idea  
of the revolutionizing effects of new   
methods of work in the most  important  
of industries4 ,it is little wonder that
 in this short time  the world has not  
solved to the satisfaction of the       
economists all the  new problems thus so
 suddenly developed4    ,turn now to the
 manufacturing world4 ,in the days of   
our  great-grandparents almost every    
household was a miniature factory where 
cotton and wool were spun and the       
products were woven into cloth4  ,it was
 not till toward the close of the       
eighteenth century--just at  the time   

when ,watt was perfecting the steam     
engine--that ,arkwright  developed the  
spinning-frame1 and his successors      
elaborated the  machinery that made     
possible the manufacture of cloth in    
wholesale  quantities2 and the          
nineteenth century was well under way   
before  the household production of     
cloth had been entirely supplanted by   
factory production4 ,it is nothing less 
than pitiful to contemplate in          
imagination our                         
great-great-grandmothers--and all their 
forebears of  the long                  
centuries--drudging away day after day1 
year in and year out1  at the ceaseless 
task of spinning and weaving--only to   
produce1 as the  output of a lifetime of
 labor1 a quantity of cloth equivalent  
perhaps  to what our perfected machine1 
driven by steam1 and manipulated by  a  
factory girl1 produces each working hour
 of every day4 ,similarly1  carpets and 
quilts were of home manufacture2 so were
 coats and dresses2  and shoes were at  

most the product of the local shoemaker 
around the  corner4    ,in the kitchen1 
food was cooked over the coals of a     
great fireplace  or in the brick oven   
connected with that fireplace4 ,meat was
 supplied  from a neighboring farm2 eggs
 were the product of the housewife's own
  poultry yard2 the son or daughter of  
the farmer milked the cow and  drove her
 to and from the pasture2 the milk was  
set in pans in the  cellar--on a        
swinging shelf1 preferably1 to make it  
inaccessible to the  rats2 and twice a  
week the cream was made into butter in a
 primitive  churn1 the dasher of which  
was operated by the vigorous arm of the 
housewife herself1 or by the unwilling  
arms of some one of her numerous        
progeny4    ,to give variety to the     
dietary1 fruits grown in the local      
garden  or orchard were preserved1 each 
in its season1 by the industrious       
housewife1 and stored away in the       
capacious cellar2 where also might be   
found the supply of home-grown potatoes1

 turnips1 carrots1 parsnips1  and       
cabbages to provide for the needs of the
 winter4 ,fuel to supply  the household 
needs1 both for cooking and heating1 was
 cut in the  neighboring woodland1 and  
carefully corded in the door-yard1 where
 it  provided most uncongenial          
employment for the youth of the family  
after  school hours and of a ,saturday  
afternoon4    ,the ashes produced when  
this wood was burned in the various     
fireplaces1  were not wasted1 but were  
carefully deposited in barrels1 from    
which  in due course lye was extracted  
by the simple process of pouring water  
over the contents of the barrel4        
,meantime scraps of fat from the table  
were collected throughout the winter and
 preserved with equal care2 and  in due 
course on some leisure day in the       
springtime--heaven knows how a  leisure 
day was ever found in such a scheme of  
domestic economy6--the  lye drawn from  
the ash-barrels and the scraps of fat   
were put into a  gigantic kettle1       

underneath which a fire was kindled2    
with the result  that ultimately a      
supply of soft soap was provided the    
housewife1 with  which her entire       
establishment1 progeny included1 could  
be kept in a  state of relative         
cleanness4    ,the reader of these pages
 has but to cast his eye about him in   
the  household in which he lives1 and   
contrast the conditions just depicted   
with those of his every-day life1 to    
realize what change has come over  the  
aspects of household economy in the     
course of a short century4  ,nor need he
 be told in each of the various         
departments of which the  activities are
 here outlined1 that the changes which  
he observes have  been due to the       
application of machinery in all the     
essential lines of  work in question4   
,we need not pause to detail the        
multitudinous devices  for the economy  
of household labor which owe their      
origin to the same  agency4 ,there still
 remains1 to be sure1 enough of drudgery

 in the task  of the housewife2 yet her 
most strenuous day seems a mere playtime
 in  comparison with the average day of 
her maternal forebear of three or  four 
generations ago4    ,but we must not    
here pause for further outlines of a    
subject which it  is the purpose of this
 and succeeding volumes to explicate in 
detail4  ,all our succeeding chapters   
will but make it more clear how         
marvelous  are the elaborations of      
method and of mechanism through which   
the  world's work of to-day is          
accomplished4 ,we shall consider first  
the  mechanical principles that underlie
 work in general1 passing on to  some of
 the principal methods of application   
through which the powers  of ,nature are
 made available4 ,we shall then take up 
in succession  the different fields of  
industry4 ,we shall ask how the work of 
the  agriculturist is done in the modern
 world2 how the multitudinous lines  of 
manufacture are carried out2 how        
transportation is effected2 we  shall   

examine the modus operandi of the       
transmission of ideas2 we  shall even   
consider that destructive form of labor 
which manifests  itself in the          
production of mechanisms of warfare4 ,as
 we follow out the  stories of the      
all-essential industries we shall be led
 to realize more  fully perhaps than we 
have done before1 the meaning of work in
 its  relations to human development2   
and in particular the meaning of modern 
work1 as carried out with the aid of    
modern mechanical contrivances1 in  its 
relations to modern civilization4       
,the full force of these relations may  
best be permitted to unfold  itself as  
the story proceeds4 ,there is1 however1 
one fundamental  principle which ,i     
would ask the reader to bear constantly 
in mind1 as  an aid to the full         
appreciation of the importance of our   
subject4 ,it  is that in considering the
 output of the worker we have constantly
 to  do with one form or another of     
property1 and that property is the very 

foundation-stone of civilization4 ,it is
 impossible1 says ,morgan1  in his work 
on ,ancient ,society1 to overestimate   
the influence of  property in the       
civilization of mankind4 ,it was the    
power that brought  the ,aryan and      
,semitic nations out of barbarism into  
civilization4  ,the growth of the idea  
of property in the human mind commenced 
in  feebleness and ended in becoming its
 master passion4 ,governments and  laws 
are instituted with primary reference to
 its creation1 protection1  and         
enjoyment4 ,it introduced human slavery 
in its production2 and1  after the      
experience of several thousand years1 it
 caused the  abolition of slavery upon  
the discovery that the freeman was a    
better  property-making machine4 ,if1   
then1 we recall that without labor there
  is no property1 we shall be in an     
attitude of mind to appreciate the      
importance of our subject2 we shall     
realize1 somewhat beyond the bounds  of 
its more tangible and sordid relations1 

the essential dignity1 the  fundamental 
importance--in a word1 the true         
meaning--of ,work4    ,undoubtedly there
 is a modern tendency to accept this    
view of the  dignity of physical labor4 
,at any rate1 we differ from the savage 
in  thinking it more fitting that man   
should toil than that his wife should   
labor to support him--though it cannot  
be denied that even now the  number of  
physical toilers among women greatly    
exceeds the number of  such toilers     
among men4 ,but in whatever measure we  
admit this attitude  of mind1 there can 
be no question that it is exclusively a 
modern  attitude4 ,time out of mind1    
physical labor has been distasteful to  
mankind1 and it is a later development  
of philosophy that appreciates  the     
beneficence of the task so little       
relished4    ,the barbarian forces his  
wife to do most of the work1 and glories
 in  his own freedom4 ,early            
civilization kept conquered foes in     
thraldom1  developing an hereditary body

 of slaves1 whose function it was to do 
the physical work4    ,the ,hebrew      
explained the necessity for labor as a  
curse imposed upon  ,father ,adam and   
,mother ,eve4 ,plato and ,aristotle1    
voicing the spirit of  the ,greeks1     
considered manual toil as degrading4    
,to-day we hear much of the dignity of  
labor2 but if we would avoid cant  we   
must admit that now--scarcely less than 
in all the olden days--the  physical    
toiler is such because he cannot help   
himself4 ,few indeed are  the manual    
laborers who know any other means of    
getting their daily  bread than that    
which they employ4 ,the most strenuous  
advocates of the  strenuous life are not
 themselves tillers of the soil or      
workers in  factories or machine shops4 
,the farm youth of intelligence does not
 remain a farmer2 he goes to  the city1 
and we find him presently at the head of
 a railroad or a  bank1 or practising   
law or medicine4 ,the more intelligent  
laborer  becomes finally a foreman1 and 

no longer handles the axe or sledge4 ,we
  should think it grotesque were we to  
see a man of intellectual power         
obstinately following a pursuit that    
cost him habitual physical toil4  ,when 
now and then a ,tolstoi offers an       
exception to this rule1 we feel  that he
 is at least eccentric2 and we may be   
excused the doubt whether  he would     
follow the manual task cheerfully if he 
did not know that he  could at any      
moment abandon it4 ,it is because he    
knows that the world  understands him to
 be only a dilettante that he rejoices  
in his task4    ,after all1 then1 judged
 by the modern practice1 rather than by 
the  philosopher's precept1 the old     
,hebrew and ,greek ideas were not so    
far wrong4 ,using the poetical language 
which was so native to them1  it might  
be said that the necessity for physical 
labor is a curse--a  disgrace4    ,a    
partial explanation of this may be found
 in the fact that the most  uncongenial 
tasks are also the worst paid1 while the

 congenial tasks  command the high      
emoluments4 ,generally speaking there is
 no distinction  between one laborer and
 another in the same field--except where
 the  eminently fair method of piece    
work can be employed4 ,even the skilled 
laborer is usually paid by the day1 and 
the amount he is to receive is  commonly
 fixed by a ,union regardless of his    
efficiency as compared with  other      
laborers of the same class4 ,and there  
is no possibility of his  receiving any 
such sums as the man who plans the work1
 but does nothing  with his own hands4  
,it has always been so4 ,just as those  
who think must govern those that  toil1 
so the thinker must command the high    
reward4 ,partly this is  because man1   
considered as a mere toiler1 is so      
relatively inefficient  a worker4 ,when 
he strives to work with his hands1 his  
effort is but a  pitiful one2 he can by 
no possibility compete 7as regards mere 
quantity  of labor7 with the ox and the 
horse4 ,he is impatient of his own      

puerile  efforts4 ,it is only when he   
brings the products of ingenuity to his 
aid that he is able to show his         
superiority1 and to justify his own     
egotism4 ,so it is that in every age he 
has striven to find means of  adding to 
his feeble powers of body through the   
use of his relatively  gigantic powers  
of mind4 ,and in proportion as he thus  
is able to make  his head work for his  
hands as the saying goes1 he verges     
toward the  heights of civilization4 ,to
 accomplish this more and more fully has
  ever been the task of science as      
applied to the industries4    ,it will  
be our object in the ensuing chapters to
 inquire how far  science has           
accomplished the protean task thus set  
for it4 ,we shall see  that much has    
been done2 but that much still remains  
to be done4 ,in  proportion as the      
problems are unsolved1 science is       
reproached for its  shortcomings--and   
stimulated to new efforts4    ,in       
proportion as labor has been minimized  

and production increased--in  just that 
proportion has science justified itself2
 and in the same  proportion has the    
,conquest of ,nature been carried toward
 completion4          ,,ii    ,,how     
,,work ,,is ,,done      ,the word energy
 implies capacity to do work4 ,work1    
considered in  the abstract1 consists in
 the moving of particles of matter      
against  some opposing force1 or in aid 
of previously acting forces4 ,in the    
last analysis1 all energy manifests     
itself either as a push or as a  pull4  
,but there is a modification of push and
 pull which is familiar  to everyone in 
practice under the name of prying4      
,illustrations may  be seen on every    
hand1 as when a workman pries up a      
stone1 or when  a housewife pries up a  
tack with the aid of a hammer4 ,the     
principle  here involved is that of the 
lever--a principle which in its various 
practical modifications is everywhere   
utilized in mechanics4 ,very  seldom    
indeed is the direct push or pull       

utilized2 since the modified  push or   
pull1 as represented by the lever in its
 various modifications  of pulley1      
ratchet-wheel1 and the like1 has long   
been known to meet the  needs of        
practical mechanics4    ,the very       
earliest primitive man who came to use  
any implement whatever1  though it were 
only a broken stick1 must have          
discovered the essential  principle of  
the lever1 though it is hardly necessary
 to add that he  did not know his       
discovery by any such high-sounding     
title4 ,what he  did know1 from         
practical experience1 was that with the 
aid of a stick  he could pry up stones  
or logs that were much too heavy to be  
lifted  without this aid4    ,this      
practical knowledge no doubt sufficed   
for a vast number of  generations of men
 who used the lever habitually1 without 
making  specific study of the relations 
between the force expended1 the lengths 
of the two ends of the lever1 and the   
weight raised4 ,such specific           

experiments were made1 however1 more    
than two thousand years ago by the      
famous ,syracusan1 ,archimedes4 ,he     
discovered--or if some one else had     
discovered it before him1 he at least   
recorded and so gains the credit  of    
discovery--the specific laws of the     
lever1 and he also pointed out  that    
levers1 all acting on the same          
principle1 may be different as to  their
 practical mechanism in three ways4     
,first1 the fulcrum may lie between the 
power and the weight1 as in the  case of
 the balance with which we were just    
experimenting4 ,this is  called a lever 
of the first class1 and familiar        
illustrations of it are  furnished by   
the poker1 steelyard1 or a pair of      
scissors4 ,the so-called  extensor      
muscles of the body--those for example1 
that cause the arm to  extend--act on   
the bones in such a way as to make them 
levers of this  first class4    ,the    
second type of lever is that in which   
the weight lies between the  force and  

the fulcrum1 as illustrated by the      
wheelbarrow1 or by an  ordinary door4   
,in the third class of levers the power 
is applied between weight and  fulcrum1 
as illustrated by a pair of tongs1 the  
treadle of a lathe1  or by the flexor   
muscles of the arm1 operating upon the  
bones of the  forearm4    ,but in each  
case1 let it be repeated1 precisely the 
same principles are  involved1 and the  
same simple law of the relations between
 positions  of power1 weight1 and       
fulcrum are maintained4 ,the practical  
result  is always that a weight of      
indefinite size may be moved by a power 
indefinitely long4 ,if one arm of the   
lever is ten times as long as the       
other1 the power of one pound will lift 
or balance a ten-pound weight2  if the  
one arm is a thousand times as long as  
the other the power of  one pound will  
lift or balance a thousand pounds4 ,if  
the long arm of  the lever could be made
 some millions of miles in length1 the  
power  that a man could exert would     

balance the earth4    ,how fully        
,archimedes realized the possibilities  
of the lever is  illustrated in the     
classical remark attributed to him1     
that1 had he  but a fulcrum on which to 
place his lever1 he could move the      
world4 ,as  otherwise quoted1 the remark
 of ,archimedes was that1 had he a place
  on which to stand1 he could move the  
world1 a remark which even more  than   
the other illustrates the full and acute
 appreciation of the  laws of motion2   
since1 as we have already pointed out1  
action and  reaction being equal1 the   
most infinitesimal push must be         
considered as  disturbing even the      
largest body4    ,tremendous as is the  
pull of gravity by which the earth is   
held in  its orbit1 yet the smallest    
push1 steadily applied from the         
direction  of the sun1 would suffice    
ultimately to disturb the stability of  
our  earth's motion1 and to push it     
gradually through a spiral course       
farther and farther away from its       

present line of elliptical flight4  ,or 
if1 on the other hand1 the persistent   
force were applied from the  side       
opposite the sun1 it would suffice      
ultimately to carry the earth  in a     
spiral course until it plunged into the 
sun itself4 ,indeed it has  been        
questioned in modern times whether it   
may not be possible that  precisely this
 latter effect is gradually being       
accomplished1 through  the action of    
meteorites1 some millions of which fall 
out of space into  the earth's          
atmosphere every day4 ,if these         
meteorites were uniformly  distributed  
through space and flying in every       
direction1 the fact that  the sun       
screens the earth from a certain number 
of them1 would make  the average number 
falling on the side away from the sun   
greater1 and  thus would in the course  
of ages produce the result just         
suggested4 ,all  that could save our    
earth from such a fate would be the     
operation of  some counteracting force4 

,such a counteracting force is perhaps  
found  in solar radiation4 ,it may be   
added that the distribution of          
meteorites  in space is probably too    
irregular to make their influence on the
 earth  predicable in the present state 
of science2 but the principle involved  
is no less sure4      ,,wheels ,,and    
,,pulleys    ,returning from such       
theoretical applications of the         
principle of  motion1 to the            
practicalities of every-day mechanisms1 
we must note  some of the applications  
through which the principle of the lever
 is  made available4 ,of these some of  
the most familiar are wheels1 and the   
various modifications of wheels utilized
 in pulleys and in cogged  and bevelled 
gearings4 ,a moment's reflection will   
make it clear that  the wheel is a lever
 of the first class1 of which the axle  
constitutes  the fulcrum4 ,the spokes of
 the wheel being of equal length1       
weights  and forces applied to opposite 
ends of any diameter are1 of course1  in

 equilibrium4 ,it follows that when a   
wheel is adjusted so that a  rope may be
 run about it1 constituting a simple    
pulley1 a mechanism is  developed which 
gives no gain in power1 but only enables
 the operator  to change the direction  
of application of power4 ,in other      
words1 pound  weights at either end of a
 rope passed about a simple pulley are  
in equilibrium and will balance each    
other1 and move through equal  distances
 in opposite directions4                
,illustration3 ,,horse ,,and ,,cattle   
,,power4    ,the large picture shows a  
model of a familiar mechanism for       
utilizing  horse power4 ,the small      
picture shows a similar apparatus in    
actual  operation1 actuated by cattle1  
in contemporary ,brittany4    ,if1      
however1 two or more pulley wheels are  
connected1 to make the  familiar        
apparatus of a compound pulley1 we have 
accomplished by an  interesting         
mechanism a virtual application of the  
principle of the  long and short arm of 

the lever1 and the relations between the
 weight  at the loose end of the rope   
and the weight attached to the block    
which constitutes virtually the short   
end of the lever1 may be varied         
indefinitely1 according to the number of
 pulley-wheels that are used4  ,a pound 
weight may be made to balance a         
thousand-pound weight2 but1  of course1 
our familiar principle still holding1   
the pound weight  must move through a   
distance of a thousand feet in order to 
move  a thousand-pound weight through a 
distance of one foot4 ,familiar         
illustrations of the application of this
 principle may be seen on every  hand2  
as when1 for example1 a piano or a safe 
is raised to the upper  window of a     
building by the efforts of men whose    
power1 if directly  expended1 would be  
altogether inefficient to stir the      
weight4    ,the pulley was doubtless    
invented at a much later stage of human 
progress than the simple lever4 ,it was1
 however1 well known to the  ancients4  

,it was probably brought to its highest 
state of practical  perfection by       
,archimedes1 whose experiments are      
famous through the  narrative of        
,plutarch4 ,it will be recalled that    
,archimedes amazed  the ,syracusan      
general by constructing an apparatus    
that enabled  him1 sitting on shore1 to 
drag a ponderous galley from the water4 
,plutarch does not describe in detail   
the apparatus with which this  was      
accomplished1 but it is obvious from his
 description of what took  place1 that  
it must have been a system of pulleys4  
,it will be observed that the pulley is 
a mechanism that enables the  user to   
transmit power to a distance4 ,but this 
indeed is true in a  certain sense of   
every form of lever4 ,numberless other  
contrivances  are in use by which power 
is transmitted1 through utilization of  
the  same principle of the lever1 either
 through a short or through a           
relatively long distance4 ,a familiar   
illustration is the windlass1  which    

consists of a cylinder rotating on an   
axis propelled by a long  handle1 a rope
 being wound about the cylinder4 ,this  
is a lever of  the second class1 the    
axis acting as fulcrum1 and the rope    
operating  about the circumference of   
the cylinder typifying the weight1 which
  may be actually at a considerable     
distance1 as in the case of the         
old-fashioned well with its windlass and
 bucket1 or of the simple form  of      
derrick sometimes called a sheerlegs4   
,,other ,,means ,,of ,,transmitting     
,,power    ,power is transmitted        
directly from one part of a machine to  
another1  in the case of a great variety
 of machines1 with the aid of cogged    
gearing wheels of various sizes4 ,the   
modifications of detail in the          
application of these wheels may be      
almost infinite1 but the principle      
involved is always the same4 ,the case  
of two wheels toothed about  the        
circumference1 the teeth of the two     
wheels fitting into one  another1       

illustrates the principle involved4 ,a  
consideration of the  mechanism will    
show that here we have virtually a lever
 fixed at both  ends1 represented by the
 radii of the two wheels1 the power     
being  applied through the axle of one  
wheel1 and the weight1 for purposes  of 
calculation1 being represented by the   
pressure of the teeth of one  wheel upon
 those of the other4 ,so this becomes a 
lever of the second  class1 and the     
relations of power between the two      
wheels are easily  calculated from the  
relative lengths of the radii4 ,if1 for 
example1  one radius is twice as long as
 the other1 the transmission of power   
will be1 obviously1 in the proportion of
 two to one1 and meantime the  distance 
traversed by the circumference of one   
wheel will be twice as  great as that   
traversed by the other4    ,a           
modification of the toothed wheel is    
furnished by wheels which may be        
separated by a considerable distance1   
and the circumferences of which  are    

connected by a belt or by a chain4 ,the 
principle of action here  is precisely  
the same1 the belt or chain serving     
merely as a means of  lengthening out   
our lever4 ,the relative sizes of the   
wheels1 and not  the length of the belt 
or chain1 is the determining factor as  
regards  the relative forces required to
 make the wheels revolve4    ,it is     
obvious all along1 of course1 since     
action and reaction  are equal1 that all
 of the relations in question are       
reciprocal4  ,when1 for example1 we     
speak of a pound weight on the long end 
of a  lever balancing a ten-pound weight
 on the short end1 it is equally        
appropriate to speak of the ten-pound   
weight as balancing the one-pound       
weight4 ,similarly1 when power is       
applied to the lever1 it may be  applied
 at either end4 ,ordinarily1 to be sure1
 the power is applied  at the long end1 
since the object is to lift the heavy   
weight2 but in  complicated machinery it
 quite as often happens that these      

conditions  are reversed1 and then it   
becomes desirable to apply strong power 
to  the short end of the lever1 in order
 that the relatively small weight  may  
be carried through the long distance4   
,in the inter-relations of  gearing     
wheels1 such conditions very frequently 
obtain1 practical ends  being met by a  
series of wheels of different sizes4    
,but the single  rule1 already so often 
outlined1 everywhere holds--wherever    
there is  gain of power there is loss of
 distance1 and we can gain distance only
  by losing power4 ,the words gain and  
loss in this application are in a  sense
 misnomers1 since1 as we have already   
seen1 gain and loss are only  apparent1 
but their convenience of application is 
obvious4    ,a familiar case in which   
there is first loss of speed and gain of
  power1 and then gain of speed at the  
expense of power in the same  mechanism1
 is furnished by the bicycle1 where 7#a7
 the crank shaft  turns the sprocket    
wheel that constitutes a lever of the   

second class  with gain of power2 where 
7#b7 power is further augmented through 
transmission from the relatively large  
sprocket wheel to the small  sprocket of
 the axle2 and where 7#c7 there is great
 loss of power and  corresponding gain  
of speed in transmitting the force from 
the small  sprocket wheel at the axle to
 the rubber rim of the bicycle proper1  
this last transmission representing a   
lever of the third class4 ,the net  gain
 of speed is tangibly represented by the
 difference in distance  traversed by   
the man's feet in revolving the pedals1 
and the actual  distance covered by the 
bicycle4      ,,inclined ,,planes ,,and 
,,derricks    ,a less obvious           
application of the principle of         
reciprocal equivalence  of distance and 
weight is furnished by the inclined     
plane1 a familiar  mechanism with the   
aid of which a great gain of power is   
possible4 ,the  inclined plane1 like the
 lever1 has been known from remotest    
antiquity4  ,its utility was probably   

discovered by almost the earliest       
builders4  ,diodorus ,siculus tells us  
that the great pyramids of ,egypt were  
constructed with the aid of inclined    
planes1 based on a foundation of  earth 
piled about the pyramids4 ,diodorus1    
living at a period removed by  some     
thousands of years from the day of the  
building of the pyramids1  may or may   
not have voiced and recorded an         
authentic tradition1 but we  may well   
believe that the principle of the       
inclined plane was largely  drawn upon  
by the mechanics of old ,egypt1 as by   
later peoples4    ,the law of the       
inclined plane is that in order to      
establish equilibrium  between two      
weights1 the one must be to the other as
 the height of  the inclined plane is to
 its length4 ,the steeper the inclined  
plane1  therefore1 the less will be the 
gain in power2 a mechanical principle   
which familiar experience or the        
simplest experiment will readily        
corroborate4    ,in its elemental form  

the inclined plane is not used very     
largely in  modern machinery1 but its   
modified form of the wedge and the screw
 have  more utility4 ,the screw1 indeed1
 which is obviously an inclined plane   
adjusted spirally about a cylinder or a 
cone1 is familiar to everyone1  and is  
constantly utilized in applying power4  
,the crane or derrick furnishes a       
familiar but relatively elaborate       
illustration of a mechanism for the     
transmission of power1 in which  all the
 various devices hitherto referred to   
are combined1 without the  introduction 
of any new principle4    ,derricks have 
been employed from a very early day4    
,the battering-rams  of the ancient     
,egyptians and ,babylonians1 for        
example1 were virtually  derricks2 and  
no doubt the same people used the device
 in raising  stones to build their      
temples and city walls1 and in putting  
into  position such massive sculptures  
as the obelisks of ,egypt and the       
monster graven bulls and lions of       

,nineveh and ,babylon4    ,illustration3
 ,,cranes ,,and ,,derricks4    ,the     
upper figure shows a floating derrick1  
the lower right-hand figure  a combined 
derrick and weighing machine1 and the   
lower left-hand figure  a so-called     
sheerlegs1 which is a simple derrick and
 windlass operated  by hand or by steam 
power with the aid of compound pulleys4 
,the modern derrick1 made of steel1 and 
operated by steam or  electricity1      
capable of lifting tons1 yet absolutely 
obedient to the  hand of the engineer1  
is a really wonderful piece of          
mechanism4 ,a  steam-scoop1 for example1
 excavating a gravel bank1 seems almost 
a thing of intelligence2 as it gores    
into the bank scooping up  perhaps a    
half ton of earth1 its upward sweeping  
head reminds one of  an angry bull4     
,then as it swings leisurely about and  
discharges its  load at just the right  
spot into an awaiting car1 its hinged   
bottom  swings back and forth two or    
three times before closing1 with curious

  resemblance to the jaw of a dog2 the  
similarity being heightened  by the     
square bull-dog-headed shape of the     
scoop itself4 ,yet this  remarkable     
contrivance1 with all its massive steel 
beams and chains  and cog wheels1       
employs no other principles than the    
simple ones of  lever and pulley and    
inclined plane that we have just        
examined4 ,the  power that must be      
applied to produce a given effect may be
 calculated  to a nicety4 ,the          
capacities of the machine are fully     
predetermined  in advance of its actual 
construction4 ,but of course this is    
equally  true of every other form of    
power-transmitter with which the modern 
mechanical engineer has to deal4        
,,friction    ,in making such           
calculations1 however1 there is an      
additional element  which the engineer  
must consider1 but which we have        
hitherto  disregarded4 ,in all methods  
of transmission of power1 and indeed in 
all  cases of the contact of one        

substance with another1 there is an     
element  of loss through friction4 ,this
 is due to the fact that no substance   
is smooth except in a relative sense4   
,even the most highly polished  glass or
 steel1 when viewed under the           
microscope1 presents a surface  covered 
with indentations and rugosities4 ,this 
granular surface of  even seemingly     
smooth objects1 is easily visualized    
through the analogy  of numberless      
substances that are visibly rough4 ,yet 
the vast practical  importance of this  
roughness is seldom considered by the   
casual  observer4 ,in point of fact1    
were it not for the roughened surface of
  all materials with which we come in   
contact1 it would be impossible for  any
 animal or man to walk1 nor could we    
hold anything in our hands4  ,anyone who
 has attempted to handle a fish1        
particularly an eel1 fresh  from the    
water1 will recall the difficulty with  
which its slippery  surface was held2   
but it may not occur to everyone who has

 had this  experience that all other    
objects would similarly slip from the   
hand1  had their surfaces a similar     
smoothness4 ,the slippery character of  
the  eel is1 of course1 due in large    
part to the relatively smooth surface   
of its skin1 but partly also to the     
lubricant with which it is covered4     
,any substance may be rendered somewhat 
smoother by proper lubrication2  it is  
necessary1 however1 that the lubricant  
should be something  which is not       
absorbed by the substance4 ,thus1 wood  
is given increased  friction by being   
moistened with oil1 but1 on the other   
hand1 is made  slippery if covered with 
graphite1 soap1 or any other fatty      
substances  that it does not absorb4    
,recalling the more or less roughened   
surface of all objects1 the source  of  
friction is readily understood4 ,it     
depends upon the actual jutting  of the 
roughened surfaces1 one upon the other4 
,it virtually constitutes  a force      
acting in opposition to the motion of   

any two surfaces  upon each other4 ,as  
between any different materials1 under  
given  conditions1 it varies with the   
pressure1 in a definite and measurable  
rate1 which is spoken of as the         
coefficient of friction for the         
particular substances4 ,it is very much 
greater where the two substances  slide 
over one another than where the one     
rolls upon the other1 as in  the case of
 the wheel4 ,the latter illustrates what
 is called rolling  friction1 and in    
practical mechanics it is used          
constantly to decrease  the loss--as1   
for example1 in the wheels of wagons and
 cars4 ,the use of  lubricants to       
decrease friction is equally familiar4  
,without them1 as  everyone knows1 it   
would be impossible to run any wheel    
continuously  upon an axle at high speed
 for more than a very brief period1     
owing  to the great heat developed      
through friction4 ,friction is indeed a 
perpetual antagonist of the mechanician1
 and we shall see endless  illustrations

 of the methods he employs to minimize  
its influence4 ,on  the other hand1 we  
must recall that were it rendered       
absolutely nil1  his machinery would all
 be useless4 ,the car wheel1 for        
example1 would  revolve indefinitely    
without stirring the train1 were there  
absolutely  no friction between it and  
the rail4      ,,available ,,sources    
,,of ,,energy    ,we have pointed out   
that every body whatever contains a     
certain store  of energy1 but it has    
equally been called to our attention    
that1 in  the main1 these stores of     
energy are not available for practical  
use4  ,there are1 however1 various great
 natural repositories of energy upon    
which man is able to draw4 ,the chief of
 these are1 first1 the muscular  energy 
of man himself and of animals2 second1  
the energy of air in  motion2 third1 the
 energy of water in motion or at an     
elevation2 and  fourth1 the molecular   
and atomic energies stored in coal1     
wood1 and  other combustible materials4 

,to these we should probably add the    
energy  of radio-active substances--a   
form of energy only recently discovered 
and not as yet available on a large     
scale1 but which may sometime  become   
so1 when new supplies of radio-active   
materials have been  discovered4 ,it    
will be the object of succeeding        
chapters to point out  the practical    
ways in which these various stores of   
energy are drawn  upon and made to do   
work for man's benefit4          ,,iii  
,,the ,,animal ,,machine      ,the      
muscular system is not only the oldest  
machine in existence1  but also the most
 complex4 ,moreover1 it is otherwise    
entitled to  precedence1 for even       
to-day1 in this so-called age of steam  
and  electricity1 the muscular system   
remains by far the most important of    
all machines4 ,in the ,united ,states   
alone there are some twenty million     
horses doing work for man2 and of course
 no machine of any sort is  ever put in 
motion or continues indefinitely in     

operation without  aid supplied by human
 muscles4 ,all in all1 then1 it is      
impossible to  overestimate the         
importance of this muscular machine     
which is at once  the oldest and the    
most lasting of all systems of utilizing
 energy4    ,the physical laws that     
govern the animal machine are precisely 
similar  to those that are applied to   
other mechanisms4 ,all the laws that    
have  been called to our attention must 
therefore be understood as applying     
fully to the muscular mechanism4 ,but in
 addition to these the muscular  system 
has certain laws or methods of action of
 its own1 some of which  are not very   
clearly understood4    ,the prime       
mystery concerning the muscle is its    
wonderful property of  contracting4 ,for
 practical purposes we may say that it  
has no other  property2 the sole        
function of the muscle is to contract4  
,it can1 of  course1 relax1 also1 to    
make ready for another contraction1 but 
this  is the full extent of its         

activities4 ,a microscopic examination  
of  the muscle shows that it is composed
 of minute fibres1 each of which  on    
contraction swells up into a spindle    
shape4 ,a mass of such fibres           
aggregated together constitutes a       
muscle1 and every muscle is attached  at
 either extremity1 by means of a tendon1
 to a bone4 ,both extremities  of a     
muscle are never attached to the same   
bone--otherwise the muscle  would be    
absolutely useless4 ,usually there is   
only a single bone  between the two ends
 of a muscle1 but in exceptional cases  
there may be  more4 ,as a rule1 the main
 body of a muscle lies along the bone to
 which  one end of it is attached1 the  
other end of the muscle being attached  
to the contiguous bone placed not far   
from the point4 ,the first bone1  then1 
serves as a fulcrum on which the second 
bone moves as a lever1  and1 as already 
pointed out1 the familiar laws of the   
lever operate  here as fully as in the  
inanimate world4 ,but a moment's        

reflection  will make it clear that the 
object effected by this mechanism is the
  increase of motion with relative loss 
of energy4 ,in other words1 the         
muscular force is applied to the short  
end of the lever1 and a far  greater    
expenditure of force is required when   
the muscle contracts than  the power    
externally manifested would seem to     
indicate4    ,a moment's consideration  
of the mechanism of the arm1 having     
regard to  the biceps muscle which      
flexes the elbow1 will make this clear4 
,if a  weight is held in the hand it is 
perhaps twelve inches from the elbow4   
,if1 while holding the weight1 you will 
grasp the elbow with the other  hand1   
you will feel the point of attachment of
 the biceps1 and discover  that it does 
not seem to be1 roughly speaking1 more  
than about an inch  from the joint4     
,obviously1 then1 if you are lifting a  
pound weight1 the  actual equivalent of 
energy expended by the contracting      
biceps must  be twelve pounds4 ,but1 in 

the meantime1 when the pound weight in  
your  hand moves through the space of   
one inch1 the muscle has contracted by  
one-twelfth of an inch2 and you may     
sweep the weight through a distance  of 
two feet by utilizing the two-inch      
contraction1 which represents  about the
 capacity of the muscle4    ,a similar  
consideration of the muscles of the legs
 will show how the  muscular system     
which is susceptible of but trifling    
variation in size1  gives to the animal 
great locomotive power4 ,with the aid of
 a series of  levers1 represented by the
 bones of our thighs1 legs1 and feet1 we
 are  able to stride along1 covering    
three or four feet at each step1 while  
no set of the muscles that effect this  
propulsion varies in length by  more    
than two or three inches4 ,it appears1  
then1 that the muscular  system gives a 
marvelous illustration of capacity for  
storing energy in  a compact form and   
utilizing it for the development of     
motion4      ,,the ,,two ,,types ,,of   

,,muscles    ,the muscles of animals and
 men alike are divided into two systems1
  one called voluntary1 the other       
involuntary4 ,the voluntary muscles1  as
 their name implies1 are subject to the 
influence of the will1  and under       
ordinary conditions contract in response
 to the voluntary  nervous impulses4    
,certain sets of them1 indeed1 as those 
having to  do with respiration1 have    
developed a tendency to rhythmical      
action  through long use1 and ordinarily
 perform their functions without        
voluntary guidance4 ,their function may1
 however1 become voluntary  when        
attention is directed toward it1 and is 
then subject to the  action of the will 
within certain bounds4 ,should a        
voluntary attempt  be made1 however1 to 
prevent their action indefinitely1 the  
so-called  reflex mechanism presently   
asserts itself4 ,all of which may be    
easily  attested by anyone who will     
attempt to stop breathing4 ,all systems 
of  voluntary muscles are subject to the

 influence of habit1 and may assume     
activities that are only partially      
recognized by consciousness4 ,as an     
illustration in point1 the muscles      
involved in walking come1 in the  case  
of every adult1 to perform their        
function without direct guidance  of the
 will4 ,such was not the case1 however1 
in the early stage of  their            
development1 as the observation of any  
child learning to walk  will amply      
demonstrate4 ,in the case of animals1   
however1 even those  muscles are so     
under the impress of hereditary         
tendencies as to perform  their         
functions spontaneously almost from the 
moment of birth4 ,these1  however1 are  
physiological details that need not     
concern us here4 ,it  suffices to recall
 that the voluntary muscles may be      
directed by the  will1 and indeed are   
always under what may be termed         
subconscious  direction1 even when the  
conscious attention is not directed to  
them4    ,the strictly involuntary      

muscles1 however1 are placed absolutely 
beyond  control of the will4 ,the most  
important of these muscles are those    
that constitute the heart and the       
diaphragm1 and that enter into the      
substance of the walls of blood vessels1
 and of the abdominal organs4  ,it is   
obvious that the functioning of these   
important organs could not              
advantageously be left to the direction 
of the will2 and so1 in the  long course
 of evolution they have learned1 as it  
were1 to take care  of themselves1 and  
in so doing to take care of the         
organism1 to the  life of which they are
 so absolutely essential4 ,as the       
physiologist  views the matter1 no      
organism could have developed which did 
not  correspondingly develop such       
involuntary action of the vital organs4 
,it will be seen that the involuntary   
muscles differ from the voluntary       
muscles in that they are not connected  
with bones4 ,instead of being  thus     
attached to solid levers1 they are      

annular in structure1 and in            
contracting virtually change the size of
 the ring which their substance         
constitutes4 ,each fibre in contracting 
may be thought of as pulling  against   
other fibres1 instead of against a bony 
surface1 and the joint  action changes  
the size of the organ1 as is obvious in 
the pulsing of  the heart4    ,though   
the rhythmical contractions of the      
involuntary muscles are  independent of 
voluntary control1 it must not be       
supposed that they  are independent of  
the control of the central nervous      
mechanism4 ,on  the contrary1 the nerve 
supply sent out from the brain to the   
heart  and to the abdominal organs is as
 plentiful and as important as that     
sent to the voluntary muscles4 ,there is
 a centre in the brain scarcely  larger 
than the head of a pin1 the destruction 
of which will cause the  heart instantly
 to cease beating forever4 ,from this   
centre1 then1 and  from the other       
centres of the brain1 impulses are      

constantly sent to  the involuntary     
muscles1 which determine the rate of    
activity4 ,nor are  these centres       
absolutely independent of the seat of   
consciousness1 as  anyone will admit who
 recalls the varied changes in the      
heart's action  under stress of varying 
emotions4    ,that the voluntary muscles
 are controlled by the central nervous  
mechanism needs no proof beyond the     
appeal to our personal experiences  of  
every moment4 ,you desire some object   
that lies on the table in front  of you1
 and immediately your hand1 thanks to   
the elaborate muscular  mechanism1      
reaches out and grasps it4 ,and this act
 is but typical of  the thousand        
activities that make up our every-day   
life4 ,everyone is  aware that the      
channel of communication between the    
brain and the  muscular system is found 
in a system of nerves1 which it is      
natural  now-a-days to liken to a system
 of telegraph wires4 ,we speak of the   
impulse generated in the brain as being 

transmitted along the nerves to  the    
muscle1 causing that to contract4 ,we   
are even able to measure the  speed of  
transfer of such an impulse4 ,it is     
found to move with relative  slowness1  
compassing only about one hundred and   
twelve feet per second1  being in this  
regard very unlike the electric current 
with which it is  so often compared4    
,but the precise nature of this impulse 
is unknown4  ,its effect1 however1 is   
made tangible in the muscular           
contraction  which it is its sole       
purpose to produce4 ,the essential      
influence of  the nerve impulse in the  
transaction is easily demonstrable2 for 
if  the nerve cord is severed1 as often 
happens in accidents1 the muscle        
supplied by that nerve immediately loses
 its power of voluntary  contraction4   
,it becomes paralyzed1 as the saying is4
      ,,the ,,nature ,,of ,,muscular    
,,action    ,paying heed1 now1 to the   
muscle itself1 it must be freely        
admitted  that1 in the last analysis1   

the activities of the substance are as  
mysterious and as inexplicable as are   
those involved in the nervous           
mechanism4 ,it is easy to demonstrate   
that what we have just spoken  of as a  
muscle fibre consists in reality of a   
little tube of liquid  protoplasm1 and  
that the change in shape of this        
protoplasm constitutes  the contraction 
of which we are all along speaking4 ,but
 just what  molecular and atomic changes
 are involved in this change of form of 
the  protoplasm1 we cannot say4 ,we know
 that the power to contract is the  one 
universal attribute of living           
protoplasm4 ,this power is equally      
wonderful and equally inexplicable1     
whether manifested in the case  of the  
muscle cell or in the case of such a    
formless single-celled  creature as the 
amoeba4 ,when we know more of molecular 
and atomic  force1 we may perhaps be    
able to form a mental picture of what   
goes on  in the structure of protoplasm 
when it thus changes the shape of its   

mass4 ,until then1 we must be content to
 accept the fact as being the  vital one
 upon which all the movements of animate
 creatures depend4    ,but if1 here as  
elsewhere1 the ultimate activities of   
molecules and  atoms lie beyond our ken1
 we may nevertheless gain an insight    
into  the nature of the substances      
involved4 ,we know1 for example1 that   
the  chief constituents of all          
protoplasm are carbon1 hydrogen1 oxygen1
 and  nitrogen2 and that with these main
 elements there are traces of various   
other elements such as iron1 sulphur1   
phosphorus1 and sundry salts4  ,we know 
that when the muscle contracts some of  
these constituents  are disarranged     
through what is spoken of as chemical   
decomposition1  and that there results a
 change in the substance of the         
protoplasm1  accompanied by the         
excretion of a certain portion of its   
constituents1  and by the liberation of 
heat4 ,carbonic acid gas1 for example1  
is  generated and is swept away from the

 muscular tissues in the ever  active   
bloodstreams1 to be carried to the lungs
 and there expelled--it  being a noxious
 poison1 fatal to life if retained in   
large quantities4  ,equally noxious are 
other substances such as uric acid and  
its  compounds1 which are also results  
of the breaking down of tissue that     
attends muscular action4 ,in a word1    
there is an incessant formation of      
waste products1 due to muscular         
activity1 the removal of which requires 
the constant service of the purifying   
streams of blood and of the  various    
excretory organs4    ,but this constant 
outflow of waste products from the      
muscle  necessitates1 of course1 in     
accordance with the laws of the         
conservation of matter and of energy1 an
 equally constant supply  of new matter 
to take the place of the old4 ,this     
supply of what is  virtually fuel to be 
consumed1 enabling the muscle to perform
 its  work1 is brought to the muscle    
through the streams of blood which flow 

from the heart in the arterial channels1
 and in part also through the  lymphatic
 system4 ,the blood itself gains its    
supply from the digestive  system and   
from the lungs4 ,the digestive system   
supplies water1 that  all-essential     
diluent1 and a great variety of         
compounds elaborated into  the proper   
pabulum2 while the vital function of the
 lungs is to supply  oxygen1 which must 
be incessantly present in order that the
 combustion  which attends muscular     
activity may take place4 ,what virtually
 happens  is that fuel is sent from the 
digestive system to be burned in the    
muscular system1 with the aid of oxygen 
brought from the lungs4    ,in this     
view1 the muscular apparatus is a       
species of heat engine4 ,in  point of   
fact1 it is a curiously delicate one as 
regards the range of  conditions within 
which it is able to act4 ,the           
temperature of any given  organism is   
almost invariable2 the human body1 for  
example1 maintains  an average          

temperature of #ih-b_/e degrees1        
,fahrenheit4 ,the range of  variation   
from this temperature in conditions of  
health is rarely  more than a fraction  
of a degree2 and even under stress of   
the most  severe fever the temperature  
never rises more than about eight       
degrees  without a fatal result4 ,that  
an organism which is producing heat in  
such varying quantities through its     
varying muscular activities should      
maintain such an equilibrium of         
temperature1 would seem one of the most 
marvelous of facts1 were it not so      
familiar4    ,the physical means by     
which the heat thus generated is rapidly
 given  off1 on occasion1 to meet the   
varying conditions of muscular activity1
  is largely dependent upon the control 
of the blood supply1 in which           
involuntary muscles1 similar to those of
 the heart1 are concerned4  ,in times of
 great muscular activity1 when the      
production of heat is  relatively       
enormous1 the arterioles that supply the

 surface of the  body are rapidly       
dilated so that a preponderance of blood
 circulates  at the surface of the body1
 where it may readily radiate its heat  
into  space2 the vast system of         
perspiratory ducts1 with which the skin 
is  everywhere supplied1 aiding         
enormously in facilitating this result1 
through the secretion of a film of      
perspiration1 which in evaporating      
takes up large quantities of heat4      
,the flushed1 perspiring face of a      
person who has violently exercised      
gives a familiar proof of these         
physiological changes2 and the contrary 
condition1 in which the peripheral      
circulation is restricted1 and in  which
 the pores are closed1 is equally       
familiar4 ,moreover1 the same  cutaneous
 mechanism is efficient in affording the
 organism protection  from the changes  
of external temperature2 though the     
human machine1  thanks to the pampering 
influence of civilization1 requires     
additional  protection in the form of   

clothing4      ,,applications ,,of      
,,muscular ,,energy    ,having thus     
outlined the conditions under which the 
muscular machine  performs its work1 we 
have now to consider briefly the        
external  mechanisms with the aid of    
which muscular energy is utilized4  ,of 
course1 the simplest application of this
 power1 and the one  universally        
employed in the animal world is that in 
which a direct  push or pull is given to
 the substance1 the position of which it
  is desired to change4 ,we have already
 pointed out that there is no  essential
 difference between pushing and pulling4
 ,the fact receives  another            
illustration in considering the muscular
 mechanism4 ,we speak  of pushing when  
we propel something away from a body1 of
 pulling when  we draw something toward 
it1 yet1 as we have just seen1 each can 
be  accomplished merely through the     
contraction of a set of muscles1 acting 
on differently disposed levers4 ,all the
 bodily activities are reducible  to    

such muscular contractions1 and the     
diversified movements in which  the     
organism constantly indulges are merely 
due to the large number and  elaborate  
arrangement of the bony levers upon     
which these muscles are  operated4      
,we may well suppose that the primitive 
man continued for a long  period of time
 to perform all such labors as he       
undertook without  the aid of any       
artificial mechanism2 that is to say1   
without having  learned to gain any     
power beyond that which the natural     
levers  of his body provided4 ,a brief  
observation of the actions of a  man    
performing any piece of manual labor    
will1 however1 quickly  demonstrate how 
ingeniously the bodily levers are       
employed1 and how  by shifting positions
 the worker unconsciously makes the most
 of a  given expenditure of energy4 ,by 
bending the arms and bringing them      
close to the body1 he is able to shorten
 his levers so that he can  lift a much 
greater weight than he could possibly   

raise with the arms  extended4 ,on the  
other hand1 with the extended arm he can
 strike a  much more powerful blow than 
with the shorter lever of the flexed    
arm4 ,but however ingenious the         
manipulation of the natural levers1 a   
full utilization of muscular energy is  
possible only when they are             
supplemented with artificial aids1 which
 constitute primitive pieces of         
machinery4    ,these aids are chiefly of
 three types1 namely1 inclined planes1  
friction reducers1 and levers4 ,the use 
of the inclined plane was very  early   
discovered and put into practise in     
chipped implements1 which  took the form
 of the wedge1 in such modifications as 
axes1 knives1 and  spears of metal4 ,all
 of these implements1 it will be        
observed1 consist  essentially of       
inclined planes1 adapted for piercing   
relatively soft  tissues of wood or     
flesh1 and hence serving purposes of the
 greatest  practical utility4    ,the   
knife-blade is an extremely thin wedge1 

to be utilized by force of  pushing1    
without any great aid from acquired     
momentum4 ,the hatchet1 on  the other   
hand--and its modification the axe--has 
its blunter blade  fastened to a handle2
 that the principle of the wedge may be 
utilized  at the long end of a lever and
 with the momentum of a swinging blow4  
,ages before anyone could have explained
 the principle involved in such         
obscuring terms as that1 the implement  
itself was in use for the same  purpose 
to which it is still applied4 ,indeed1  
there is probably no  other implement   
that has played a larger part in the    
history of human  industry4 ,even in the
 ,rough ,stone ,age it was in full      
favor1 and the  earliest metallurgists  
produced it in bronze and then in iron4 
,the  blade of to-day is made of the    
best tempered steel1 and the handle  or 
helve of hickory is given a slight curve
 that is an improvement on  the straight
 handle formerly employed2 but on the   
whole it may be said  that the axe is a 

surviving primitive implement that has  
held its own  and demonstrated its      
utility in every generation since the   
dawn1 not of  history only1 but of      
barbarism1 perhaps even of savagery4    
,the saw1 consisting essentially of a   
thin elongated blade1 one ragged  or    
toothed edge1 is a scarcely less        
primitive and an equally useful and     
familiar application of the principle of
 the inclined plane--though it  requires
 a moment's reflection to see the manner
 of application4 ,each  tooth1 however  
minute1 is an inclined plane1 calculated
 to slide over  the tissue of wood or   
stone or iron even1 yet to tear at the  
tissue  with its point1 and1 with the   
power of numbers1 ultimately wear it    
away4      ,,the ,,wheel ,,and ,,axle   
,the primitive friction reducer1 which  
continues in use to the present  day    
unmodified in principle1 is the wheel   
revolving on an axle4  ,doubtless man   
had reached a very high state of        
barbarism before he  invented such a    

wheel4 ,the ,american ,indian1 for      
example1 knew no  better method than to 
carry his heavy burdens on his          
shoulders1 or  drag them along the      
ground1 with at most a pair of parallel 
poles or  runners to modify the         
friction2 every move representing a very
 wasteful  expenditure of energy4 ,but  
the pre-historic man of the old world   
had  made the wonderful discovery that a
 wheel revolving on an axle vastly      
reduces the friction between a weight   
and the earth1 and thus enables  a man  
or a woman to convey a load that would  
be far beyond his or her  unaided       
powers4 ,it is well to use both genders 
in this illustration1  since among      
primitive peoples it is usually the     
woman who is the bearer  of burdens4    
,and indeed to this day one may see the 
women of ,italy and  ,germany bearing   
large burdens on their backs and heads1 
and dragging  carts about the streets1  
quite after the primitive method4       
,the more one considers the mechanism1  

the more one must marvel at the         
ingenuity of the pre-historic man who   
invented the wheel and axle4 ,its       
utility is sufficiently obvious once the
 thing has been done4 ,in point  of     
fact1 it so enormously reduces the      
friction that a man may convey  ten     
times the burden with its aid that he   
can without it4 ,but how was  the       
primitive man1 with his small knowledge 
of mechanics1 to predict  such a result8
 ,in point of fact1 of course1 he made  
no such prediction4  ,doubtless his     
attention was first called to the       
utility of rolling  bodies by a chance  
observation of dragging a burden along a
 pebbly  beach1 or over rolling stones4 
,the observation of logs or round stones
  rolling down a hill might also have   
stimulated the imagination of some      
inventive genius4    ,illustration3 ,a  
,,belgian ,,milk-,,wagon4    ,in many of
 the countries of ,europe the dog plays 
an important part as  a beast of burden4
 ,stringent laws are enforced in these  

countries to  prevent possible abuse or 
neglect of the animals4    ,probably    
logs placed beneath heavy weights1 such 
as are still employed  sometimes in     
moving houses1 were utilized now and    
again for many  generations before the  
idea of a narrow section of a log       
adjusted on  an axis was evolved4 ,but  
be that as it may1 this idea was put    
into  practise before the historic      
period begins1 and we find the earliest 
civilized races of which we have        
record--those1 namely1 of ,old ,egypt   
and of ,old ,babylonia--in full         
possession of the principle of the wheel
  as applied to vehicles4 ,modern       
mechanics have1 of course1 improved the 
mechanism as regards details1 but the   
wheels depicted in ,old ,egyptian  and  
,babylonian inscriptions are curiously  
similar to the most modern  types4      
,indeed1 the wheel is a striking        
illustration of a mechanism  which      
continued century after century to serve
 the purposes of the  practical worker1 

with seemingly no prospect of           
displacement4      ,,modified ,,levers  
,for the rest1 the mechanisms which     
primitive man learned early to  use in  
adding to his working efficiency1 and   
which are still used by  the hand       
laborer1 are virtually all modifications
 of our familiar  type-implement1 the   
lever4 ,a moment's reflection will show 
that the  diversified purposes of the   
crowbar1 hoe1 shovel1 hammer1 drill1    
chisel1 are all accomplished with the   
aid of the same principles4  ,the       
crowbar1 for example1 enables man to    
regain the power which he  lost when his
 members were adapted to locomotion4    
,his hands1 left  to themselves1 as we  
have already pointed out1 give but      
inadequate  expression to the power of  
his muscles4 ,but by grasping the long  
end of  such a lever as the crowbar1 he 
is enabled to utilize his entire weight 
in addition to his muscular strength1   
and1 with the aid of this lever1  to    
lift many times his weight4    ,the hoe1

 on the other hand1 becomes virtually a 
lengthened arm1  enabling a very slight 
muscular motion to be transformed into  
the  long sweep of the implement1 so    
that with small expenditure of energy   
the desired work is accomplished4       
,similarly1 the sledge and the axe      
lengthen out the lever of the arms1 so  
that great momentum is readily          
acquired1 and with the aid of inertia a 
relatively enormous force can  be       
applied4 ,it will be observed that a    
laborer in raising a heavy  sledge      
brings the head of the implement near   
his body1 thus shortening  the leverage 
and gaining power at the expense of     
speed2 but extends his  arms to their   
full length as the sledge falls1 having 
now the aid of  gravitation1 to gain the
 full advantage of the long arm of the  
lever in  acquiring momentum4    ,even  
such elaborately modified implements as 
the treadmill and the  rowboat are      
operated on the principle of the lever4 
,these also are  mechanisms that have   

come down to us from a high antiquity4  
,their  utility1 however1 has been      
greatly decreased in modern times1 by   
the substitution of more elaborate and  
economical mechanisms for  accomplishing
 their respective purposes4 ,the        
treadmill1 indeed--which  might be      
likened to an overshot waterwheel in    
which the human foot  supplied the place
 of the falling water in giving         
power--has become  obsolete1 though a   
modification of it1 to be driven by     
animal power1 is  still sometimes used1 
as we shall see in a moment4    ,all    
these are illustrations of mechanisms   
with the aid of which human  labor is   
made effective4 ,they show the devices  
by which primitive man  used his        
ingenuity in making his muscular system 
a more effective  machine for the       
performance of work4 ,but perhaps the   
most ingenious  feat of all which our   
primitive ancestor accomplished was in  
learning  to utilize the muscular energy
 of other animals4 ,of course the       

example  was always before him in the   
observed activity of the animals on     
every  side4 ,nevertheless1 it was      
doubtless long before the idea suggested
  itself1 and probably longer still     
before it was put into practise1 of     
utilizing this almost inexhaustible     
natural supply of working energy4       
,,domesticated ,,animals    ,the first  
animal domesticated is believed to have 
been the dog1 and  this animal is still 
used1 as everyone knows1 as a beast of  
burden in  the far ,north1 and in some  
,european cities1 particularly in those 
of  ,germany4 ,subsequently the ox was  
domesticated1 but it is probable that   
for a vast period of time it was used   
for food purposes1 rather than as  a    
beast of burden4 ,and lastly the horse1 
the worker par excellence1  was made    
captive by some ,asiatic tribes having  
the genius of invention1  and in due    
course this fleetest of carriers and    
most efficient of  draught animals was  
introduced into all civilized nations4  

,doubtless for a long time the energy of
 the horse was utilized in an           
uneconomical way1 through binding the   
burden on its back1 or causing it  to   
drag the burden along the ground4 ,but  
this is inferential1 since1  as we have 
seen1 the wheel was invented in         
pre-historic times1 and at  the dawn of 
history we find the ,babylonians driving
 harnessed horses  attached to wheeled  
vehicles4 ,from that day to this the    
method of  using horse-power has not    
greatly changed4 ,the vast majority of  
the  many millions of horses that are   
employed every day in helping on the    
world's work1 use their strength without
 gain or loss through leverage1  and    
with only the aid of rolling friction to
 increase their capacity as  beasts of  
burden4    ,to a certain extent         
horse-power is still used with the aid  
of the  modified treadmill just referred
 to--consisting essentially of an       
inclined plane of flexible mechanism    
made into an endless platform1  which   

the horse causes to revolve as he goes  
through the movements of  walking upon  
it4 ,in agricultural districts this form
 of power is still  sometimes used to   
run threshing machines1 cider mills1    
wood-saws1  and the like4 ,another      
application of horse-power to the same  
ends  is accomplished through harnessing
 a horse to a long lever like the  spoke
 of a wheel1 fastened to an axis1 which 
is made to revolve as the  horse walks  
about it4 ,several horses are sometimes 
hitched to such  a mechanism1 which     
becomes then a wheel of several spokes4 
,but this  mechanism1 which was common  
enough in agricultural districts two or 
three decades ago1 has been practically 
superseded in recent years by  the      
perambulatory steam engine4             
,illustration3 ,,two ,,apparatuses ,,for
 ,,the ,,utilization ,,of ,,animal      
,,power4    ,the upper figure shows the 
type of portable horse-power machine    
used  for threshing grain in #ahea4 ,the
 lower figure is an inclined-plane      

horse-gear4 ,the horse stands on the    
sloping platform tied to the bar in     
front1 so that it is compelled to walk  
as the platform recedes4    ,it is      
obvious that the amount of work which a 
horse can accomplish  must vary greatly 
with the size and quality of the horse1 
and with the  particular method by which
 its energy is applied4 ,for the        
purposes  of comparison1 however1 an    
arbitrary amount of work has been fixed 
upon as constituting what is called a   
horse-power4 ,this amount is the        
equivalent of raising thirty-three      
thousand pounds of weight to the  height
 of one foot in one minute4 ,it would be
 hard to say just why this  particular  
standard was fixed upon1 since it       
certainly represents more  than the     
average capacity of a horse4 ,it is1    
however1 a standard which  long usage   
7it was first suggested by ,watt1 of    
steam-engine fame7 has  rendered        
convenient1 and one which the machinist 
refers to constantly  in speaking of the

 efficiency of the various types of     
artificial  machines4 ,all questions of 
the exact legitimacy of this particular 
standard aside1 it was highly           
appropriate that the labor of the horse1
  which has made up so large a share of 
the labor of the past1 and which  is    
still so extensively utilized1 should   
continue to be taken as the  measuring  
standard of the world's work4           
,,iv    ,,the ,,work ,,of ,,air ,,and   
,,water      ,the store of energy       
contained in the atmosphere and in the  
waters of  the globe is inexhaustible4  
,its amount is beyond all calculation2  
or if  it were vaguely calculated the   
figures would be quite incomprehensible 
from their very magnitude4 ,it is not1  
however1 an altogether simple  matter to
 make this energy available for the     
purposes of useful work4  ,we find that 
throughout antiquity comparatively      
little use was made of  either wind or  
water in their application to machinery4
    ,doubtless the earliest use of air  

as a motive power was through the       
application of sails to boats4 ,we know 
that the ,phoenicians used a  simple    
form of sail1 and no doubt their example
 was followed by all the  maritime      
peoples of subsequent periods4 ,but the 
use of the sail even by  the            
,phoenicians was as a comparatively     
unimportant accessory to the  galaxies  
of oars1 which formed the chief motive  
power4 ,the elaboration  of sails of    
various types1 adequate in extent to    
propel large ships1  and capable of     
being adjusted so as to take advantage  
of winds blowing  from almost any       
quarter1 was a development of the       
,middle ,ages4    ,the possibilities of 
work with the aid of running water were 
also but  little understood by the      
ancients4 ,in the days of slave labor it
 was  scarcely worth while to tax man's 
ingenuity to invent machines1 since  so 
efficient a one was provided by nature4 
,yet the properties of both  air and    
water were studied by various mechanical

 philosophers1 at the  head of whom were
 ,archimedes1 whose work has already    
been referred to1  and the famous       
,alexandrian1 ,ctesibius1 whose         
investigations became  familiar through 
the publications of his pupil1 ,hero4   
,perhaps the most remarkable device     
invented by ,ctesibius was a            
fire-engine1 consisting of an           
arrangement of valves constituting a    
pump1 and operating on the principle    
which is still in vogue4 ,it is  known1 
however1 that the ,egyptians of a much  
earlier period used  buckets having     
valves in their bottoms1 and these      
perhaps furnished the  foundation for   
the idea of ,ctesibius4 ,it is          
unnecessary to give details  of this    
fire-engine4 ,it may be noted1 however1 
that the principle of  the lever is the 
one employed in its operation to gain   
power4 ,a valve  consists essentially of
 any simple hinged substance1 arranged  
so that  it may rise or fall1           
alternately opening and closing an      

aperture4  ,a mere flap of leather1     
nailed on one edge1 serves as a         
tolerably  effective valve4 ,at least   
one of the valves used by ,ctesibius was
 a  hinged piece of smooth metal4 ,a    
piston fitted in a cylinder supplies    
suction when the lever is raised1 and   
pressure when it is compressed1         
alternately opening the valve and       
closing the valve through which the     
water enters the tube4 ,meantime a      
second valve alternating with the  first
 permits the water to enter the chamber 
containing air1 which  through its      
elasticity and pressure equalizes the   
force of the stream  that is ejected    
from the chamber through the hose4      
,,suction ,,and ,,pressure    ,in the   
construction of this and various other  
apparatus1 ,ctesibius and  ,hero were   
led to make careful studies of the      
phenomena of suction4 ,but  in this they
 were not alone1 since numerous of their
 predecessors had  studied the subject1 
and such an apparatus as the surgeon's  

cupping  glass was familiarly known     
several centuries before the ,christian 
era4  ,the cupping glass1 as perhaps    
should be explained to the reader of the
  present day--since the apparatus went 
out of vogue in ordinary medical        
practise two or three generations       
ago--consists of a glass cup in which   
the air is exhausted1 so as to suck     
blood from any part of the surface  of a
 body to which it is applied4 ,hero     
describes a method of exhausting  air by
 which such suction may be facilitated4 
,but neither he nor any  other          
philosopher of his period at all        
understood the real nature of  this     
suction1 notwithstanding their perfect  
familiarity with numerous  of its       
phenomena4 ,it was known1 for example1  
that when a tube closed  at one end is  
filled with water and inverted with the 
open end beneath  the surface of the    
water1 the water remains in the tube1   
although one  might naturally expect    
that it would obey the impulses of      

gravitation  and run out1 leaving the   
tube empty4 ,a familiar explanation of  
this and  allied phenomena throughout   
antiquity was found in the saying that  
,nature abhors a vacuum4 ,this          
explanation1 which of course amounts  to
 no explanation at all1 is fairly       
illustrative of the method of           
metaphysical word-juggling that served  
so largely among the earlier            
philosophers in explanation of the      
mysteries of physical science4    ,the  
real explanation of the phenomena of    
suction was not arrived  at until the   
revival of learning in the seventeenth  
century4 ,then  ,torricelli1 the pupil  
of ,galileo1 demonstrated that the word 
suction1  as commonly applied1 had no   
proper application2 and that the        
phenomena  hitherto ascribed to it were 
really due to the pressure of the       
atmosphere4 ,a vacuum is merely an      
enclosed space deprived of air1 and  the
 abhorrence that ,nature shows to such a
 space is due to the fact  that air has 

weight and presses in every direction1  
and hence tends  to invade every space  
to which it can gain access4 ,it was    
presently  discovered that if the       
inverted tube in which the water stands 
was  made high enough1 the water will no
 longer fill it1 but will sink to a     
certain level4 ,the height at which it  
will stand is about thirty feet2  above 
that height a vacuum will be formed1    
which1 for some reason1  ,nature seems  
not to abhor4 ,the reason is that the   
weight of any given  column of water    
about thirty feet in height is just     
balanced by the  weight of a            
corresponding column of atmosphere4 ,the
 experiments that  gave the proof of    
this were made by the famous            
,englishman1 ,boyle4 ,he  showed that if
 the heavy liquid1 mercury1 is used in  
place of water1  then the suspended     
column will be only about thirty inches 
in height4  ,the weight or pressure of  
the atmosphere at sea level1 as measured
 by  these experiments1 is about fifteen

 pounds to the square inch4    ,boyle's 
further experiments with the air and    
with other gases developed  the fact    
that the pressure exerted by any given  
quantity of gas is  proportional to the 
external pressure to which it is        
subjected1 which1  after all1 is only a 
special application of the law that     
action and  reaction are equal4 ,the    
further fact was developed that under   
pressure  a gas decreases at a fixed    
rate in bulk4 ,a general law1 expressing
  these facts in the phrase that density
 and elasticity vary inversely  with the
 pressure in a precise ratio1 was       
developed by ,boyle and the  ,frenchman1
 ,mariotte1 independently1 and bears the
 name of both of its  discoverers4 ,no  
immediate application of the law to the 
practical  purposes of the worker was   
made1 however1 and it is only in recent 
years that compressed air has been      
extensively employed as a motive  power4
 ,even now it has not proved a great    
commercial success1 because  other more 

economical methods of power production  
are available4 ,in  particular cases1   
however1 it has a certain utility1 as a 
relatively  large available source of   
energy may be condensed into a very     
small  receptacle4    ,a very striking  
experiment illustrating the pressure of 
the air was  made by a famous           
contemporary of ,boyle and ,mariotte1 by
 the name of  ,otto von ,guericke4 ,he  
connected an air pump with a large brass
 sphere1  composed of two hemispheres1  
the edges of which fitted smoothly1 but 
were not connected by any mechanism4    
,under ordinary conditions the          
hemispheres would fall apart readily1   
but von ,guericke proved1 by  a famous  
public demonstration1 that when the air 
was exhausted in  the sphere1 teams of  
horses pulling in opposite directions on
 the  hemispheres could not separate    
them4 ,this is famous as the experiment 
of the ,magdeburg spheres1 and it is    
often repeated on a smaller scale  in   
the modern physical laboratory1 to the  

astonishment of the tyro in  physical   
experiments4    ,the first question that
 usually comes to the mind of anyone who
 has  personally witnessed such an      
experiment1 is the question as to how   
the human body can withstand the        
tremendous force to which it is         
subjected by an atmosphere exerting a   
pressure of fifteen pounds on  every    
square inch of its surface4 ,the        
explanation is found in the  uniform    
distribution of the pressure1 the       
influence of which is thus              
counteracted1 and by the fact that the  
tissues themselves contain  everywhere a
 certain amount of air at the same      
pressure4 ,the familiar  experiment of  
holding the hand over an exhausted glass
 cylinder--which  experiment is indeed  
but a modification of the use of the    
cupping  glass above referred           
to--illustrates very forcibly the       
insupportable  difficulties which the   
human body would encounter were not its 
entire  surface uniformly subjected to  

the atmospheric pressure4      ,,air    
,,in ,,motion    ,at about the time when
 the scientific experiments with the    
pressure of  gases were being made1     
practical studies of the effects of     
masses of  air in motion were undertaken
 by the ,dutch philosopher1 ,servinus4  
,the  use of the windmill in ,holland as
 a means of generating power doubtless  
suggested to ,servinus the possibility  
of attaching a sail to a land  vehicle4 
,he made the experiment1 and in the year
 #afjj constructed a  sailing car which1
 propelled by the wind1 traversed the   
land to a  considerable distance1 on one
 occasion conveying a company of which  
,prince ,maurice of ,orange was a       
member4 ,but his experiments have seldom
  been repeated1 and indeed their lack  
of practical feasibility scarcely  needs
 demonstration4    ,the utility of the  
wind1 however1 in generating the power  
in a  stationary mechanism is familiar  
to everyone4 ,windmills were            
constructed at a comparatively early    

period1 and notwithstanding all  the    
recent progress in the development of   
steam and electrical power1  this       
relatively primitive so-called prime    
mover still holds its own in            
agricultural districts1 particularly in 
its application to pumps4 ,a  windmill  
consists of a series of inclined planes1
 each of which forms  one of the radii  
of a circle1 or spokes of a wheel1 to   
the axle of  which a gearing is adjusted
 by which the power generated is        
utilized4  ,the wheel is made to face   
the wind by the wind itself blowing     
against a  sort of rudder which projects
 from the axis4 ,the wind blowing       
against  the inclined surfaces or vanes 
of the wheel causes each vane to move in
  accordance with the law of component  
forces1 thus revolving the wheel  as a  
whole4    ,illustration3 ,,windmills    
,,of ,,ancient ,,and ,,modern ,,types4  
,the smaller figures show ,dutch        
windmills of the present day1 many of   
which are identical in structure with   

the windmills of the middle ages4  ,it  
will be seen that the sails can be      
furled when desired to put the  mill out
 of operation4 ,in the mill of modern   
type 7large figure7 the  same effect is 
produced by slanting the slats of the   
wheel4    ,it has been affirmed that the
 ,romans had windmills1 but the silence 
of  ,vitruvius1 ,seneca1 and            
,chrysostom1 who have spoken of the     
advantages of  the wind1 makes this     
opinion questionable4 ,it has been      
supposed by  other writers that         
windmills were used in ,france in the   
sixth century1  while still others have 
maintained that this mechanism was      
unknown in  ,europe until the time of   
the ,crusades4 ,all that is tolerably   
certain  is that in the twelfth century 
windmills were in use in ,france and    
,england4 ,it is recorded that when they
 began to be somewhat common  ,pope     
,celestine ,,iii4 determined that the   
tithes of them belonged to the  clergy4 
,,inherent ,,defects ,,of ,,the         

,,windmill    ,the medival ,european    
windmill was supplied with great sails  
of cloth1  and its picturesque          
appearance has been made familiar to    
everyone  through the famous tale of    
,don ,quixote4 ,the modern windmill1    
acting  on precisely the same principle1
 is a comparatively small affair1       
comprising many vanes of metal1 and     
constituting a far more practical       
machine4 ,the great defect of all       
windmills1 however1 is found in the     
fact that of necessity they furnish such
 variable power1 since the  force of the
 wind is incessantly changing4 ,worst of
 all1 there may be  protracted periods  
of atmospheric calm1 during which1 of   
course1 the  windmill ceases to have any
 utility whatever4 ,this ineradicable   
defect  relegates the windmill to a     
subordinate place among prime movers1   
yet  on the other hand1 its cheapness   
insures its employment for a long time  
to come1 and the industry of            
manufacturing windmills continues to be 

an  important one1 particularly in the  
,united ,states4      ,,running ,,water 
,the aggregate amount of work           
accomplished with the aid of the wind is
  but trifling1 compared with that which
 is accomplished with the aid of  water4
 ,the supply of water is practically    
inexhaustible1 and this fluid  being    
much more manageable than air1 can be   
made a far more dependable  aid to the  
worker4 ,every stream1 whatever its rate
 of flow1 represents  an enormous store 
of potential energy4 ,a cubic foot of   
water weighs  about sixty-two and a half
 pounds4 ,the working capacity of any   
mass  of water is represented by        
one-half its weight into the square of  
its  velocity2 or1 stated otherwise1 by 
its weight into the distance of its     
fall4 ,now1 since the interiors of the  
continents1 where rivers find  their    
sources1 are often elevated by some     
hundreds or even thousands  of feet1 it 
follows that the working energy         
expended--and for the most  part        

wasted--by the aggregate water current  
of the world is beyond all  calculation4
 ,meantime1 however1 a portion of the   
energy which in the  aggregate          
represents an enormous working power is 
utilized with the aid  of various types 
of water wheels4    ,watermills appear  
to have been introduced in the time of  
,mithridates1  ,julius ,csar1 and       
,cicero4 ,strabo informs us that there  
was a watermill  near the residence of  
,mithridates2 and we learn from         
,pomponius ,sabinus1  that the first    
mill seen at ,rome was erected on the   
,tiber1 a little  before the time of    
,augustus4 ,that they existed in the    
time of ,augustus  is obvious from the  
description given of them by ,vitruvius1
 and the  epigram of ,antipater1 who is 
supposed to have lived in the time of   
,cicero4 ,but though mills driven by    
water were introduced at this early     
period1 yet public mills did not appear 
till the time of ,honorius and          
,arcadius4 ,they were erected on three  

canals1 which conveyed water to  the    
city1 and the greater number of them lay
 under ,mount ,janiculum4  ,when the    
,goths besieged ,rome in #ecf1 and      
stopped the large aqueduct and          
consequently the mills1 ,belisarius     
appears to have constructed1 for the    
first time1 floating mills upon the     
,tiber4 ,mills driven by the tide       
existed at ,venice in the year #ajdf1 or
 at least in #ajgh4    ,the older types 
of water wheel are exceedingly simple in
 construction1  consisting merely of    
vertical wheels revolving on horizontal 
axes1  and so placed as to receive the  
weight or pressure of the water on      
paddles or buckets at their             
circumference4 ,the water might be      
allowed  to rush under the wheel1 thus  
constituting an under-shot wheel2 or    
more commonly it flows from above1      
constituting an over-shot wheel4  ,where
 the natural fall is not available1 dams
 are employed to supply an  artificial  
fall4    ,this primitive type of water  

wheel has been practically abandoned    
within the last generation1 its place   
having been taken by the much  more     
efficient type of wheel known as the    
turbine4 ,this consists of  a wheel1    
usually adjusted on a vertical axis1 and
 acting on what is  virtually the       
principle of a windmill4 ,to gain a     
mental picture of the  turbine in its   
simplest form1 one might imagine the    
propelling screw  of a steamship1 placed
 horizontally in a tube1 so that the    
water could  rush against its blades4   
,the tiny windmills which children often
 make  by twisting pieces of paper      
illustrate the same principle4 ,of      
course1  in its developed form the      
turbine is somewhat elaborated1 in the  
aim to  utilize as large a proportion of
 the energy of the falling water as is  
possible2 but the principle remains the 
same4    ,the turbine wheel was invented
 by a ,frenchman named ,fourneyron1     
about  three-quarters of a century ago  
7#ahbg71 but its great popularity1 in   

,america in particular1 is a matter of  
the last twenty or thirty years4        
,to-day it has virtually supplanted     
every other type of water wheel4  ,to   
use any other is indeed a wasteful      
extravagance1 as the perfected  turbine 
makes available more than eighty per    
cent4 of the kinetic  energy of any mass
 of falling water4 ,a turbine wheel two 
feet in  diameter is able to do the work
 of an enormous wheel of the old type4  
,turbine wheels are of several types1   
one operating in a closed tube to  which
 air has no access1 and another in an   
open space in the presence  of air4 ,the
 water may also be made to enter the    
turbine at the side  or from below1 thus
 serving to support the weight of the   
mechanism--a  consideration of great    
importance in the case of such gigantic 
turbines  as those that are employed at 
,niagara ,falls1 which we shall have    
occasion to examine in detail in a later
 chapter4    ,illustration3 ,,water     
,,wheels4    ,fig4 #a shows a model of  

the so-called breast wheel1 a familiar  
type of  water wheel that has been in   
use since the time of the ,romans4      
,figs4  #b and #c show similar wheels as
 used to-day in ,belgium4 ,fig4 #d shows
 a  model of ,fourneyron's turbine4     
,this wheel was made in #ahcg1 but the  
original turbine was introduced by      
,fourneyron in #ahbg4 ,the turbine      
wheel has now almost supplanted the     
other forms of water wheel except  in   
rural districts4    ,the power generated
 by a revolution of the turbine wheel   
may1 of  course1 be utilized directly by
 belts or gearings attached to its      
axle1 or it may be transferred to a     
distance1 with the aid of a  dynamo     
generating electricity4 ,the latter     
possibility1 which has only  recently   
been developed1 and which we shall have 
occasion to examine  in detail in       
connection with our studies of the power
 at ,niagara1 gives  a new field of     
usefulness to the turbine wheel1 and    
makes it probable  that this form of    

power will be vastly more used in the   
future than  it has been in the past4   
,indeed1 it would not be surprising were
 it  ultimately to become the prime     
source of working energy as utilized in 
every department of the world's work4   
,mr4 ,edward ,h4 ,sanborn1 in an article
 on ,motive ,power ,appliances in the   
,twelfth ,census ,report of the ,united 
,states1 comments upon the recent       
advances in the use of water wheels as  
follows3    ,one notable advance in     
turbine construction has been the       
production  of a type of wheel          
especially designed for operating under 
much higher  heads of water than were   
formerly considered feasible for wheels 
of  this type4 ,turbines are now built  
for heads ranging from #ajj to #a1bjj   
feet1 and quite a number of wheels are  
in operation under heads of from  #ajj  
to #bjj feet4 ,this is an encroachment  
upon the field occupied almost          
exclusively by wheels variously known as
 the 'impulse1' 'impact1'  'tangential1'

 or 'jet' type1 the principle of which  
is the impact of  a powerful jet of     
water from a small nozzle upon a series 
of buckets  mounted upon the periphery  
of a small wheel4    ,the impact water  
wheel1 ,mr4 ,sanborn continues1 has come
 largely  into use during the last ten  
years1 principally in the far ,west1    
where higher heads of water are         
available than can be found in other    
parts of the country4 ,with wheels of   
this type1 exceedingly simple  in       
construction and of comparatively small 
cost1 a large amount of  power is       
developed with great economy under the  
great heads that are  available4 ,with  
the tremendous water pressure developed 
by heads of  #a1jjj feet and upward1    
which in many cases are used for this   
purpose1  wheels of small diameter      
develop an extraordinary amount of      
power4  ,to the original type of impact 
wheel which first led the field have    
been added several styles embodying     
practically the same principle4         

,considerable study has been given to   
the designing of buckets with a  view to
 securing free discharge and the        
avoidance of any disturbing  eddies1 and
 important improvements have resulted   
from the thorough  investigation of the 
action of the water during1 and         
subsequent to1  its impact on the       
buckets4 ,the impact wheel has been     
adapted to a wide  range of service with
 great variation as to the conditions   
under which  it operates1 wheels having 
been made in ,california from #cj inches
 to  #cj feet in diameter1 and to work  
under heads ranging from #ce to #b1ajj  
feet1 and at speeds ranging from #fe to 
#a1ajj revolutions per minute4 ,a       
number of wheels of this type have been 
built with capacities of not  less than 
#a1jjj horse-power each4                
,,hydraulic ,,power    ,a few words     
should be said about the familiar method
 of transmitting  power with the aid of 
water1 as illustrated by the hydrostatic
 press4  ,this does not indeed utilize  

the energy of the water itself1 but it  
enables the worker to transmit energy   
supplied from without1 and to  gain an  
indefinite power to move weights through
 a short distance1  with the expenditure
 of very little working energy4 ,the    
principle on  which the hydrostatic     
press is based is the one which was     
familiar to  the ancient philosophers   
under the name of the hydrostatic       
paradox4  ,it was observed that if a    
tube is connected with a closed         
receptacle1  such as a strong cask1 and 
cask and tube are filled with water1 the
  cask will presently be burst by the   
pressure of the water1 provided the     
tube is raised to a height1 even though 
the actual weight of water in  the tube 
be comparatively slight4 ,a powerful    
cask1 for example1 may be  burst by the 
water poured into a slender pipe4 ,the  
result seems indeed  paradoxical1 and   
for a long time no explanation of it was
 forthcoming4  ,it remained for         
,servinus1 whose horseless wagon is     

elsewhere noticed1  to discover that the
 water at any given level presses       
equally in all  directions1 and that its
 pressure is proportionate to its depth1
 quite  regardless of its bulk4 ,then1  
supposing the tube in our experiment to 
have a cross-section of one square inch1
 a pressure equal to that in  the tube  
would be transmitted to each square inch
 of the surface of the  cask2 and the   
pressure might thus become enormous4    
,if1 instead of a tube lifted to a      
height1 the same tube is connected  with
 a force pump operated with a lever--an 
apparatus similar to the  fire-engine of
 ,ctesibius--it is obvious that         
precisely the same effect  may be       
produced2 whatever pressure is developed
 in the piston of the  force pump1      
similar pressure will be transferred to 
a corresponding  area in the surface of 
the cask or receptacle with which the   
force pump  connects4 ,in practise this 
principle is utilized1 where great      
pressure  is desired1 by making a       

receptacle with an enormous piston      
connecting  with the force pump just    
described4    ,an indefinite power may  
thus be developed1 the apparatus        
constituting  virtually a gigantic      
lever4 ,but the principle of the        
equivalence of  weight and distance     
still holds1 precisely as in an actual  
lever1  and while the pressure that may 
be exerted with slight expenditure  of  
energy is enormous1 the distance through
 which this pressure acts  is           
correspondingly small4 ,if1 for example1
 the piston of the force  pump has an   
area of one square inch1 while the      
piston of the press  has an area of     
several square feet1 the pressure       
exerted will be  measured in tons1 but  
the distance through which it is exerted
 will be  almost infinitesimal4 ,the    
range of utility of the hydrostatic     
press  is1 therefore1 limited1 but      
within its sphere1 it is an incomparable
  transmitter of energy4                
,illustration3 ,,hydraulic ,,press ,,and

 ,,hydraulic ,,capstan4    ,the upper   
figure shows ,bramah's original         
hydraulic pump and press1  now preserved
 in the ,south ,kensington ,museum1     
,london4 ,the machine was  constructed  
in #agif by ,joseph ,bramah to          
demonstrate the principle of  his       
hydraulic press4 ,the discrepancy in    
size between the small lever  worked by 
hand and the enormous lever carrying a  
heavy weight gives a  vivid impression  
of the gain in power through the use of 
the apparatus4  ,the lower figure shows 
the hydraulic capstan used on many      
modern ships1  in which the same        
principle is utilized4    ,moreover1 it 
is possible to reverse the action of the
 hydraulic  apparatus so as to gain     
motion at the expense of power4 ,a      
familiar type  of elevator is a case in 
point4 ,the essential feature of the    
hydraulic  elevator consists of a ram   
attached to the bottom of the elevator  
and  extending down into a cylinder1    
slightly longer than the height to      

which the elevator is to rise4 ,the ram 
is fitting into a cylinder with         
water-tight packing1 or a cut leather   
valve4 ,water under high pressure  is   
admitted to the cylinder through the    
valve at the bottom1 and the  pressure  
thus supplied pushes up the ram1        
carrying the elevator with  it1 of      
course4 ,another valve allows the water 
to escape1 so that ram  and elevator may
 descend1 too rapid descent being       
prevented by the  partial balancing of  
ram and elevator with weights acting    
over pulleys4  ,the ram1 to the end of  
which pressure is thus applied1 need be 
but a  few inches in diameter4 ,water   
pressure is secured by bringing water   
from an elevation4 ,such an elevator    
acts slowly1 but is a very safe  and in 
many ways satisfactory mechanism4 ,such 
elevators are still used  extensively in
 ,europe1 but have been almost          
altogether displaced in  ,america by the
 electric elevator4    ,the hydraulic   
elevator just described is virtually a  

water engine1 the  ram acting as piston4
 ,a veritable engine1 of small size1 to 
perform  any species of mechanical work1
 may be constructed on precisely the    
same principle1 the piston in this case 
acting in a cylinder similar to  that of
 the ordinary steam engine4 ,such an    
engine operates slowly but  with great  
power4 ,it has special utility where it 
is desirable to apply  power            
intermittently1 as in various parts of a
 dockyard1 or in handling  guns and     
ammunition on shipboard4 ,in the former 
case in particular1  it is often        
inconvenient to use steam power1 as     
steam sent from a  central boiler       
condenses in a way to interfere with its
 operation4 ,in  such a case any number 
of small water-pressure engines may be  
operated  from a single tank where water
 is at a high elevation1 or where the   
requisite pressure is secured           
artificially4 ,in the latter case1 the  
water is kept under pressure by a large 
piston or ram heavily weighted1  the    

entire receptacle being1 of course1 of  
water-tight construction  and adapted to
 withstand pressure4 ,the pump that     
supplies the tank is  ordinarily made to
 work automatically1 ceasing operation  
as soon as the  ram rises to the top of 
the receptacle1 and beginning again     
whenever1  through use of water1 the ram
 begins to descend4 ,such an apparatus  
is  called an accumulator4 ,such water  
engines have come into vogue only in    
comparatively recent times1 being       
suggested by the steam engine4 ,as      
already pointed out1 their utility is   
restricted1 yet the total number  of    
them in actual use to-day is large1 and 
their share in the world's  work is not 
altogether inconsiderable4          ,v  
,,captive ,,molecules3 ,,the ,,story    
,,of ,,the ,,steam ,,engine      ,we    
come now to that all-important          
transformer of power1 the steam  engine4
 ,everybody knows that steam is a state 
of water in which1  under the influence 
of heat1 the molecules have broken away 

from the  mutual attraction of cohesion1
 and are flying about at inconceivable  
speed1 rebounding from one another after
 collision1 in virtue of their          
elasticity1 exerting in the aggregate an
 enormous pressure in every  direction4 
,it is this consideration of the        
intimate character of steam  that       
justifies the title of the present      
chapter2 a title that has  further      
utility as drawing a contrast between   
the manner of working  with which we are
 now to be concerned1 and the various   
types of workers  that we have          
previously considered4    ,in speaking  
of the animal machine and of work       
accomplished by the air  and the water1 
we have been concerned primarily with   
masses of matter1  possessing and       
transmitting energy4 ,of course         
molecules--since they  make up the      
substance of all matter--could not be   
altogether ignored1  but in the main we 
have had to do with molar rather than   
with molecular  motion4 ,now1 however1  

we are concerned with a mechanism in    
which the  molecular activities are     
directly concerned in performing work4  
,even in the aggregate the molecules    
make up a mere intangible gas1  which   
requires to be closely confined in order
 that its energy may be  made available4
 ,once the molecules have performed     
their work1 they  are so changed in     
their activities that they sink back1 as
 it were1  exhausted1 into a relatively 
quiescent state1 which enables their    
latent cohesive forces to reduce them   
again to the state of a liquid4  ,in a  
word1 we are concerned with the         
manifestation of energy which  depends  
upon molecular activities in a way quite
 different from what  has been the case 
with any of the previously considered   
mechanisms4  ,the tangible manifestation
 of energy which we term heat is not    
merely  a condition of action and a     
by-product1 as it was in the case of    
the animal machine2 it is the essential 
factor upon which all the  efficiency of

 the mechanism depends4    ,it should   
perhaps be stated that this explanation 
of the action of  the steam engine is a 
comparatively modern scientific         
interpretation4  ,the earlier           
experimenters brought the steam engine  
to a high state of  efficiency1 without 
having any such conception as this of   
the nature  of steam itself4 ,for       
practical purposes it suffices to note  
that water  when heated takes the form  
of steam2 that this steam has the       
property  of powerful and indefinite    
expansion2 and thirdly1 that when       
allowed to  escape from a state of      
pressure1 sudden expansion of the steam 
cools it  sufficiently to cause the     
recondensation of part of its substance1
 thus  creating a vacuum4    ,stated in 
few words1 the entire action of the     
steam depends upon these  simple        
mechanical principles4 ,the principles  
are practically applied  by permitting  
the steam to enter the cylinder where it
 can act on  a piston1 to which it gives

 the thrust that is transmitted to an   
external mechanism by means of a rod    
attached to the piston4 ,when the       
piston has been driven to the end of the
 desired thrust1 the valve is  opened   
automatically1 permitting the steam to  
escape1 thus producing a  vacuum1 and   
insuring the return thrust of the       
piston1 which is further  facilitated1  
ordinarily1 by the admission of steam to
 the other side  of the piston4         
,practical operation of this mechanism  
is familiar to  everyone1 though the    
marvel of its power and efficiency seems
 none the  less because of its          
familiarity4    ,it is not too much to  
say that this relatively simple device1 
in its  first general application1      
marked one of the most important turning
  points in the history of civilization4
 ,to its influence1 more than to  any   
other single cause1 must be ascribed the
 revolutionary change that  came over   
the character of practical life in the  
nineteenth century4  ,from prehistoric  

times till well toward the close of the 
eighteenth  century1 there was scarcely 
any important change in carrying out the
  world's work4 ,and in the few         
generations that have since elapsed1 the
  entire aspect of the mechanical world 
has been changed1 the working           
efficiency of the individual has been   
largely increased2 mechanical  tasks    
have become easy which hitherto were    
scarcely within the range of  human     
capacity4    ,before we go on to the    
detailed study of the machine which has 
produced  these remarkable results1 it  
is desirable to make inquiry as to the  
historical development of so important  
an invention4    ,the practical steam   
engine in its modern form dates1 as just
 mentioned1  from the latter part of the
 eighteenth century1 and was perfected  
by  ,james ,watt1 who is commonly       
thought of as being its inventor4 ,in   
point  of fact1 however1 the history of 
most inventions is duplicated here1 as  
on examination it appears that various  

forerunners of ,watt had been on  the   
track of the steam engine1 and some of  
them1 indeed1 had produced a  workable  
machine of no small degree of           
efficiency4    ,the very earliest       
experiments were made away back in the  
,alexandrian  days in the second century
 before the ,christian era1 the         
experimenter  being the famous ,hero1   
whose work in an allied field was       
referred to  in the preceding chapter4  
,hero produced--or at least described   
and so  is credited with producing1     
though the actual inventor may have been
  ,ctesibius--a little toy mechanism1 in
 which a hollow ball was made to        
revolve on an axis through the agency of
 steam1 which escaped from  two bent    
tubes placed on opposite sides of the   
ball1 their orifices  pointing in       
opposite directions4 ,the apparatus had 
no practical  utility1 but it sufficed  
to establish the principle that heat1   
acting  through the agency of steam1    
could be made to do mechanical work4    

,had  not the age of ,hero been a time  
of mental stasis1 it is highly probable 
that the principle he had thus          
demonstrated would have been applied  to
 some more practical mechanism in       
succeeding generations4 ,as it  was1    
however1 nothing practical came of his  
experiment1 and the steam  turbine      
engine was remembered only as a         
scientific toy4    ,no other worker     
continued the experiments1 so far as is 
known1 until  the time of the great     
,italian1 ,leonardo da ,vinci1 who1 late
 in the  fifteenth century1 gave a new  
impulse to mechanical invention4        
,leonardo  experimented with steam1 and 
succeeded in producing what was         
virtually  an explosion engine1 by the  
agency of which a ball was propelled    
along  the earth4 ,but this experiment  
also failed to have practical result4   
,,beginnings ,,of ,,modern ,,discovery  
,such sporadic experiments as these have
 no sequential connection with  the     
story of the evolution of the steam     

engine4 ,the experiments which  led     
directly on to practical achievements   
were not begun until the  seventeenth   
century4 ,in the very first year of that
 century1 an ,italian  named ,giovanni  
,battista della ,porta published a      
treatise on pneumatics1  in which the   
idea of utilizing steam for the         
practical purpose of  raising water was 
expressly stated4 ,the idea of this     
inventor was put  into effect in #afbd  
by a ,french engineer and mathematician1
 ,solomon de  ,caus4 ,he invented two   
different machines1 the first of which  
required a  spherical boiler having an  
internal tube reaching nearly to the    
bottom2  a fire beneath the boiler      
produced steam which would force the    
water in  the boiler to a height        
proportional to the pressure obtained4  
,in the  other machine1 steam is led    
from the boiler into the upper part of a
  closed cistern containing water to be 
elevated4 ,to the lower portion of  the 
cistern a delivery pipe was attached so 

that water was discharged  under a      
considerable pressure4 ,this arrangement
 was precisely similar  to the apparatus
 employed by ,hero of ,alexandria in    
various of his  fountains1 as regards   
the principle of expanding gas to propel
 water4  ,an important difference1      
however1 consists in the fact that the  
scheme of della ,porta and of de ,caus  
embodied the idea of generating         
pressure with the aid of steam1 whereas 
,hero had depended merely on the        
expansive property of air compressed by 
the water itself4    ,while these       
mechanisms contained the germ of an idea
 of vast  importance1 the mechanisms    
themselves were of trivial utility4 ,it 
is  not even clear whether their        
projectors had an idea of the properties
  of the condensation of vapor1 upon    
which the working of the practical      
steam engine so largely depends4 ,this  
idea1 however1 was probably  grasped    
about half a century later by an        
,englishman1 ,edward ,somerset1  the    

celebrated ,marquis of ,worcester1 who  
in #affc described in his  ,century of  
,inventions an apparatus for raising    
water by the expansive  force of steam4 
,his own account of his invention is as 
follows3    ,an admirable and most      
forcible way to drive up water by fire2 
not by  drawing or sucking it upwards1  
for that must be as the philosopher     
calleth it1 intra sphram activitatis1   
which is but at such a  distance4 ,but  
this way hath no bounder1 if the vessel 
be strong enough3  for ,i have taken a  
piece of whole cannon1 whereof the end  
was burst1  and filled it three-quarters
 full of water1 stopping and screwing up
  the broken end1 as also the           
touch-hole2 and making a constant fire  
under it1 within twenty-four hours it   
burst and made a great crack2 so  that  
having a way to make my vessels so that 
they are strengthened by  the force     
within them1 and the one to fill after  
the other1 ,i have seen  the water run  
like a constant stream1 forty feet high3

 one vessel of  water1 rarefied by fire1
 driveth up forty of cold water2 and the
 man  that tends the work is but to turn
 two cocks1 that one vessel of water    
being consumed1 another begins to force 
and refill with cold water1  and so     
successively2 the fire being tended and 
kept constant1 which  the self-same     
person may likewise abundantly perform  
in the interim1  between the necessity  
of turning the said cocks4    ,it is    
unfortunate that the ,marquis did not   
give a more elaborate  description of   
this remarkable contrivance4 ,the fact  
that he treats it  so casually is       
sufficient evidence that he had no      
conception of the  possibilities of the 
mechanism2 but1 on the other hand1 his  
description  suffices to prove that he  
had gained a clear notion of1 and had   
experimentally demonstrated1 the        
tremendous power of expansion that      
resides in steam4 ,no example of his    
steam pump has been preserved1 and      
historians of the subject have been left

 in doubt as to some details  of its    
construction1 and in particular as to   
whether it utilized the  principle of a 
vacuum created through condensation of  
the steam4      ,,thomas ,,savery',s    
,,steam ,,pump    ,this principle was   
clearly grasped1 however1 by another    
,englishman1  ,thomas ,savery1 a        
,cornish mine captain1 who in #afih     
secured a patent for  a steam engine to 
be applied to the raising of water1 etc4
 ,a working  model of this machine was  
produced before the ,royal ,society in  
#afii4  ,the transactions of the        
,society contain the following3 ,june   
#adth1  #afii1 ,mr4 ,savery entertained 
the ,royal ,society with showing a small
  model of his engine for raising water 
by help of fire1 which he set to  work  
before them3 the experiment succeeded   
according to expectation1  and to their 
satisfaction4    ,the following very    
clear description of ,savery's engine is
 given in the  introduction to          
,beckmann's ,history of ,inventions3    

,this engine1 which was used for some   
time to a considerable extent for       
raising water from mines1 consisted of a
 strong iron vessel shaped like  an egg1
 with a tube or pipe at the bottom1     
which descended to the place  from which
 the water was to be drawn1 and another 
at the top1 which  ascended to the place
 to which it was to be elevated4 ,this  
oval vessel  was filled with steam      
supplied from a boiler1 by which the    
atmospheric  air was first blown out of 
it4 ,when the air was thus expelled and 
nothing but pure steam left in the      
vessel1 the communication with the      
boiler was cut off1 and cold water      
poured on the external surface4 ,the    
steam within was thus condensed and a   
vacuum produced1 and the water  drawn up
 from below in the usual way by suction4
 ,the oval vessel was  thus filled with 
water2 a cock placed at the bottom of   
the lower pipe  was then closed1 and    
steam was introduced from the boiler    
into the  oval vessel above the surface 

of the water4 ,this steam being of high 
pressure1 forced the water up the       
ascending tube1 from the top of  which  
it was discharged1 and the oval vessel  
being thus refilled with  steam1 the    
vacuum was again produced by            
condensation1 and the same  process was 
repeated4 ,by using two oval steam      
vessels1 which would act                
alternately--one drawing water from     
below1 while the other was forcing  it  
upwards1 an uninterrupted discharge of  
water was produced4 ,owing to  the      
danger of explosion1 from the high      
pressure of the steam which was  used1  
and from the enormous waste of heat by  
unnecessary condensation1  these engines
 soon fell into disuse4                 
,illustration3 ,,thomas ,,savery',s     
,,steam ,,engine4    ,the principle     
involved is that of the expansion of    
steam exerting a  propulsive force and  
its subsequent condensation to produce a
 vacuum4  ,these are the principles     
employed in the modern steam engine1 but

 the  only use to which they were put in
 ,savery's engine was the elevation of  
water by suction4    ,this description  
makes it obvious that ,savery had the   
clearest  conception of the production  
of a vacuum by the condensation of      
steam1  and of the utilization of the   
suction thus established 7which suction1
  as we know1 is really due to the      
pressure of outside air7 to accomplish  
useful work4 ,savery also arranged this 
apparatus in duplicate1 so that  one    
vessel was filling with water while the 
other was forcing water  to the delivery
 pipe4 ,this is credited with being the 
first useful  apparatus for raising     
water by the combustion of fuel4 ,there 
was a  great waste of steam1 through    
imparting heat to the water1 but the    
feasibility of the all-important        
principle of accomplishing mechanical   
labor with the aid of heat was at last  
demonstrated4    ,as yet1 however1 the  
experimenters were not on the track of  
the  method by which power could be     

advantageously transferred to outside   
machinery4 ,an effort in quite another  
direction to accomplish this  had been  
made as early as #afbi by ,giovanni     
,branca1 an ,italian  mathematician1 who
 had proposed to obtain rotary motion by
 allowing  a jet of steam to blow       
against the vanes of a fan wheel1       
capable of  turning on an axis4 ,in     
other words1 he endeavored to utilize   
the  principle of the windmill1 the     
steam taking the place of moving air4   
,the idea is of course perfectly        
feasible1 being indeed virtually that   
which is employed in the modern steam   
turbine2 but to put the idea  into      
practise requires special detailed      
arrangements of steam jet and  vanes1   
which it is not strange the early       
inventor failed to discover4  ,his      
experiments appear not to have been     
followed up by any immediate  successor1
 and nothing practical came of them1 nor
 was the principle  which he had        
attempted to utilize made available     

until long after a  form of steam engine
 utilizing another principle for the    
transmission  of power had been         
perfected4      ,,denis ,,papin         
,,invents ,,the ,,piston ,,engine       
,the principle in question was that of  
causing expanding steam to press        
against a piston working tightly in a   
cylinder1 a principle1 in short1  with  
which everyone is familiar nowadays     
through its utilization in  the ordinary
 steam engine4 ,the idea of making use  
of such a piston  appears to have       
originated with a ,frenchman1 ,denis    
,papin1 a scientific  worker1 who1 being
 banished from his own country1 was     
established as  professor of mathematics
 at the ,university of ,marburg4 ,he    
conceived the  important idea of        
transmitting power by means of a piston 
as early as  #afhh1 and about two years 
later added the idea of producing a     
vacuum in  a cylinder1 by cooling the   
cylinder1--the latter idea being1 as we 
have  just seen1 the one which ,savery  

put into effect4    ,illustration3      
,,diagrams ,,of ,,early ,,attempts ,,to 
,,utilize ,,the ,,power ,,of  ,,steam4  
,,giovanni ,,branca #afbi ,,guillaume   
,,amontons #afii ,two attempts  to give 
rotation to a mechanical apparatus      
through the action of  heated air or    
steam4 ,nothing practical came of either
 effort1 but the  mechanisms depicted   
are of historical interest4    ,it will 
be noted that ,papin's invention        
antedated that of ,savery2 to  the      
,frenchman1 therefore1 must be given the
 credit of hitting upon two  important  
principles which made feasible the      
modern steam engine4 ,papin  constructed
 a model consisting of a small cylinder 
in which a solid  piston worked4 ,in the
 cylinder beneath the piston was placed 
a small  quantity of water1 which1 when 
the cylinder was heated1 was turned     
into steam1 the elastic force of which  
raised the piston4 ,the cylinder  was   
then cooled by removing the fire1 when  
the steam condensed1 thus  creating a   

vacuum in the cylinder1 into which the  
piston was forced by  the pressure of   
the atmosphere4    ,such an apparatus   
seems crude enough1 yet it incorporates 
the essential  principles1 and required 
but the use of ingenuity in elaborating 
details of the mechanism1 to make a     
really efficient steam engine4  ,it     
would appear1 however1 that ,papin was  
chiefly interested in the  theoretical1 
rather than in the really practical side
 of the question1  and there is no      
evidence of his having produced a       
working machine of  practical power1    
until after such machines worked by     
steam had been  constructed elsewhere4  
,,thomas ,,newcomen',s ,,improved       
,,engine    ,as has happened so often in
 other fields1 ,englishmen were the     
first  to make practical use of the new 
ideas4 ,in #agje ,thomas ,newcomen1 a   
blacksmith or ironmonger1 and ,john     
,cawley1 a plumber and glazier1         
patented their atmospheric engine1 and  
five years later1 in the year  #agaj1   

namely1 ,newcomen had on the market an  
engine which is described  in the       
,report of the ,department of ,science  
and ,arts of the ,south  ,kensington    
,museum1 as the first real pumping      
engine ever made4    ,the same report   
describes the engine as a vertical steam
 cylinder  provided with a piston       
connected at one end of the beam1 having
 a  pivot or bearing in the middle of   
its length1 and at the other end of  the
 beam pump rods for working the pump4   
,the cylinder was surrounded  by a      
second cylinder or jacket1 open at the  
top1 and cold water could  be supplied  
to this outer cylinder at pleasure4 ,the
 single or working  cylinder could be   
supplied with steam when desired from a 
boiler below  it4 ,there was a drain    
pipe from the bottom of the working     
cylinder1  and one from the outer       
cylinder4 ,for the working of the engine
 steam  was admitted to the working     
cylinder1 so as to fill it and expel all
  the air1 the piston then being at the 

top1 owing to the weight of the  pump   
rods being sufficient to lift it2 then  
the steam was shut off and  the drain   
cocks closed and cold water admitted to 
the outer cylinder1  so that the steam  
in the working cylinder condensed1 and1 
leaving a  partial vacuum of pressure of
 the atmosphere1 forced the piston down 
and drew up the pump rods1 thus making a
 stroke of the pump4 ,then the  water   
was drawn off from the outer cylinder   
and steam admitted to the  working      
cylinder before allowing the piston to  
return to the top of its  stroke1 ready 
for the next down stroke4    ,it will be
 observed that this machine adopts the  
principle1 with only  a change of       
mechanical details1 of the ,papin engine
 just described4 ,a  later improvement  
made by ,newcomen did away with the     
outer cylinder  for condensing the      
steam1 employing instead an injection of
 cold water  into the working cylinder  
itself1 thus enabling the engine to work
 more  quickly4 ,it is said that the    

superiority of the internal condensing  
arrangement was accidentally discovered 
through the improved working  of an     
engine that chanced to have an          
exceptionally leaky piston or  cylinder4
 ,many engines were made on this plan   
and put into practical  use4    ,another
 important improvement was made by a    
connection from the beam  to the cocks  
or valves1 so that the engine worked    
automatically1  whereas in the first    
place it had been necessary to have a   
boy or man  operate the valves1--a most 
awkward arrangement1 in the light of    
modern  improvements4 ,as the story is  
told1 the duty of opening and closing   
the regulating and condensing valves was
 intrusted to boys called  cock boys4   
,it is said that one of these boys named
 ,humphrey ,potter  wishing to join his 
comrades at play without exposing       
himself to the  consequences of         
suspending the performance of the       
engine1 contrived1 by  attaching strings
 of proper length to the levers which   

governed the two  cocks1 to connect them
 with the beam1 so that it should open  
and close  the cocks as it moved up and 
down with the most perfect regularity4  
,this story has passed current for      
almost two centuries1 and it has been   
used to point many a useful moral4 ,it  
seems almost a pity to disturb  so      
interesting a tradition1 yet it must    
have occurred to more than one          
iconoclast that the tale is almost too  
good to be true4 ,and somewhat  recently
 it has been more than hinted that      
,desaguliers1 with whom the  story      
originated1 drew upon his imagination   
for it4 ,a print is in  existence1 made 
so long ago as #agai1 representing an   
engine erected  by ,newcomen at ,dudley 
,castle1 ,staffordshire1 in #agab1 in   
which an  automatic valve gear is       
clearly shown1 proving that the         
,newcomen engine  was worked            
automatically at this early period4     
,that the admirable  story of the       
inventive youth1 whose wits gave him    

leisure for play1  may not be altogether
 discredited1 however1 it should be     
added that  unquestionably some of the  
early engines had a hand-moved gear1 and
  that at least one such was still      
working in ,england after the middle of 
the nineteenth century4 ,it seems       
probable1 then1 that the very first     
engines were without the automatic valve
 gear1 and there is no inherent  reason 
why a quick-witted youth may not have   
been the first to discover  and remedy  
the defect4    ,according to the ,report
 of the ,department of ,science and     
,arts of  the ,south ,kensington        
,museum3 ,the adoption of ,newcomen's   
engine was  rapid1 for1 commencing in   
#agaa with the engine at ,wolverhampton1
 of  twenty-three inch diameter and six 
foot stroke1 they were in common use  in
 ,english collieries in #agbe2 and      
,smeaton found in #agfg that1 in the    
neighborhood of ,newcastle alone there  
were fifty-seven at work1 ranging  in   
size from twenty-eight inch to          

seventy-five inch cylinder diameter1    
and giving collectively about twelve    
hundred horse-power4 ,as ,newcomen      
obtained an evaporation of nearly eight 
pounds of water per pound of  coal1 the 
increase of boiler efficiency since his 
time has necessarily  been but slight1  
although in other requisites of the     
steam generator  great improvements are 
noticeable4    ,illustration3 ,a ,,model
 ,,of ,,the ,,newcomen ,,engine4        
,this engine has particular interest not
 only because it was a practical        
pumping engine1 but also because it was 
while repairing an engine of  this type 
that ,watt was led to the experiments   
that resulted in his  epoch-making      
discovery4      ,,the ,,coming ,,of     
,,james ,,watt    ,the ,newcomen engine 
had low working efficiency as compared  
with the  modern engine2 nevertheless1  
some of these engines are still used in 
a  few collieries where waste coal is   
available1 the pressure enabling the    
steam to be generated in boilers unsafe 

for other purposes4 ,the great          
importance of the ,newcomen engine1     
however1 is historical2 for it was      
while engaged in repairing a model of   
one of these engines that ,james  ,watt 
was led to invent his plan of condensing
 the steam1 not in the  working cylinder
 itself1 but in a separate vessel1--the 
principle upon  which such vast         
improvements in the steam engine were to
 depend4    ,it is impossible to        
overestimate the importance of the work 
which ,watt  accomplished in developing 
the steam engine4 ,fully to appreciate  
it1  we must understand that up to this 
time the steam engine had a very        
limited sphere of usefulness4 ,the      
,newcomen engine represented the  most  
developed form1 as we have seen2 and    
this1 like the others that  it had so   
largely superseded1 was employed solely 
for the pumping of  water4 ,in the main1
 its use was confined to mines1 which   
were often  rendered unworkable because 
of flooding4 ,we have already seen that 

a  considerable number of engines were  
in use1 yet their power in the          
aggregate added but a trifle to man's   
working efficiency1 and the work  that  
they did accomplish was done in a most  
uneconomical manner4 ,indeed  the amount
 of fuel required was so great as to    
prohibit their use in  many mines1 which
 would have been valuable could a       
cheaper means have  been found of       
freeing them from water4 ,watt's        
inventions1 as we shall  see1           
accomplished this end1 as well as       
various others that were not            
anticipated4    ,it was through         
consideration of the wasteful manner of 
action of the  steam engine that ,watt  
was led to give attention to the        
subject4  ,the great inventor was a     
young man at the ,university of         
,glasgow4 ,he  had previously served an 
apprenticeship of one year with a maker 
of  philosophical instruments in        
,london1 but ill health had prevented   
him  from finishing his apprenticeship1 

and he had therefore been prohibited    
from practising his would-be profession 
in ,glasgow4 ,finally1 however1  he had 
been permitted to work under the        
auspices of the ,university2  and in due
 course1 as a part of his official      
duties1 he was engaged  in repairing a  
model of the ,newcomen engine4 ,this    
incident is usually  mentioned as having
 determined the line of ,watt's future  
activity4    ,it should be recalled1    
however1 that ,watt had become a        
personal friend  of the celebrated      
,professor ,black1 the discoverer of    
latent heat1 and  the foremost authority
 in the world1 in this period1 on the   
study of  pneumatics4 ,just what share  
,black had in developing ,watt's idea1  
or  in directing his studies toward the 
expansive properties of steam1  it would
 perhaps be difficult to say4 ,it is    
known1 however1 that the  subject was   
often under discussion2 and the interest
 evinced in it by  ,black is shown by   
the fact that he subsequently wrote a   

history of  ,watt's inventions4    ,it  
is never possible1 perhaps1 for even the
 inventor himself to re-live  the       
history of the growth of an idea in his 
own mind4 ,much less is it  possible for
 him to say precisely what share of his 
progress has been  due to chance        
suggestions of others4 ,but it is       
interesting1 at least1  to recall this  
association of ,watt with the greatest  
experimenter of  his age in a closely   
allied field4 ,questions of suggestion  
aside1  it illustrates the technical    
quality of ,watt's mind1 making it      
obvious that he was no mere ingenious   
mechanic1 who stumbled upon his         
invention4 ,he was1 in point of fact1 a 
carefully trained scientific            
experimenter1 fully equipped with all   
the special knowledge of his time  in   
its application to the particular branch
 of pneumatics to which he  gave        
attention4    ,the first and most       
obvious defect in the ,newcomen engine  
was1 as ,watt  discovered1 that the     

alternating cooling and heating of the  
cylinder  resulted in an unavoidable    
waste of energy4 ,the apparatus worked1 
it  will be recalled1 by the            
introduction of steam into a vertical   
cylinder  beneath the piston1 the       
cylinder being open above the piston to 
admit  the air4 ,the piston rod         
connected with a beam suspended in the  
middle1  which operated the pump1 and   
which was weighted at one end in order  
to facilitate the raising of the piston4
 ,the steam1 introduced under  low      
pressure1 scarcely more than            
counteracted the pressure of the air1   
the raising of the piston being largely 
accomplished by the weight in  question4
    ,of course the introduction of the  
steam heated the cylinder4 ,in order  to
 condense the steam and produce a       
vacuum1 water was injected1 the         
cylinder being thereby cooled4 ,a vacuum
 being thus produced beneath  the       
cylinder1 the pressure of the air from  
above thrust the cylinder  down1 this   

being the actual working agent4 ,it was 
for this reason  that the ,newcomen     
engine was called1 with much propriety1 
a pneumatic  engine4 ,the action of the 
engine was very slow1 and it was        
necessary to  employ a very large piston
 in order to gain a considerable power4 
,the first idea that occurred to ,watt  
in connection with the probable         
improvement of this mechanism did not   
look to the alteration of any of  the   
general features of the structure1 as   
regards size or arrangement  of         
cylinder1 piston1 or beam1 or the       
essential principle upon which  the     
engine worked4 ,his entire attention was
 fixed on the discovery  of a method by 
which the loss of heat through          
periodical cooling of  the cylinder     
could be avoided4 ,we are told that he  
contemplated the  subject long1 and     
experimented much1 before he reached a  
satisfactory  solution4 ,naturally      
enough his attention was first directed 
toward the  cylinder itself4 ,he queried

 whether the cylinder might not be made 
of  wood1 which1 through its poor       
conduction of heat1 might better        
equalize  the temperature4 ,experiments 
in this direction1 however1 produced no 
satisfactory result4    ,illustration3  
,,watt',s ,,earliest ,,type ,,of        
,,pumping ,,engine4    ,the lower figure
 shows the ruins of ,watt's famous      
engine ,old ,bess4  ,the upper figure   
shows a reconstructed model of the ,old 
,bess engine4  ,it will be noted that   
the walking beam is precisely of the    
,newcomen  type4 ,in fact1 the entire   
engine is obviously only a modification 
of the ,newcomen engine4 ,it had1       
however1 certain highly important       
improvements1 as described in the text4 
,then at last an inspiration came to    
him4 ,why not connect the cylinder  with
 another receptacle1 in which the       
condensation of the steam could  be     
effected8 ,the idea was a brilliant one1
 but neither its originator  nor any    
other man of the period could possibly  

have realized its vast  and             
all-comprehending importance4 ,for in   
that idea was contained the  germ of all
 the future of steam as a motive power4 
,indeed1 it scarcely  suffices to speak 
of it as the germ merely2 the thing     
itself was  there1 requiring only the   
elaboration of details to bring it to   
perfection4    ,watt immediately set to 
work to put his brilliant conception of 
the  separate condenser to the test of  
experiment4 ,he connected the cylinder  
of a ,newcomen engine with a receptacle 
into which the steam could be           
discharged after doing its work on the  
piston4 ,the receptacle was  kept       
constantly cooled by a jet of water1    
this water and the water  of            
condensation1 together with any air or  
uncondensed steam that  might remain in 
the receptacle1 being constantly removed
 with the  aid of an air pump4 ,the     
apparatus at once demonstrated its      
practical  efficiency1--and the modern  
steam engine had come into existence4   

,it was in the year #agfe1 when ,watt   
was twenty-nine years old1 that he  made
 his first revolutionary experiment1 but
 his first patents were  not taken out  
until #agfi1 by which time his engine   
had attained a  relatively high degree  
of perfection4 ,in furthering his idea  
of keeping  the cylinder at an even     
temperature1 he had provided a covering 
for it1  which might consist of wood or 
other poorly conducting material1 or a  
so-called jacket of steam--that is to   
say1 a portion of steam admitted  into  
the closed chamber surrounding the      
cylinder4 ,moreover1 the  cylinder had  
been closed at the top1 and a portion of
 steam admitted  above the piston1 to   
take the place of the atmosphere in     
producing the  down stroke4 ,this steam 
above the piston1 it should be          
explained1 did  not connect with the    
condensing receptacle1 so the engine was
 still  single-acting2 that is to say it
 performed work only during one stroke  
of the piston4 ,a description of the    

mechanism at this stage of its          
development may best be given in the    
words of the inventor himself1 as       
contained in his specifications in the  
application for patent on his           
improvements in #agfi4    ,my method of 
lessening the consumption of steam1 and 
consequently  fuel1 in fire-engines1    
consists of the following principles3   
,first1 ,that vessel in which the powers
 of steam are to be employed to  work   
the engine1 which is called the cylinder
 in common fire-engines1  and which ,i  
call the steam vessel1 must1 during the 
whole time the  engine is at work1 be   
kept as hot as the steam that enters it2
 first  by enclosing it in a case of    
wood1 or any other materials that       
transmit heat slowly2 secondly1 by      
surrounding it with steam or other      
heated bodies2 and1 thirdly1 by         
suffering neither water nor any other   
substance colder than the steam to enter
 or touch it during that time4          
,secondly1 ,in engines that are to be   

worked wholly or partially  by          
condensation of steam1 the steam is to  
be condensed in vessels  distinct from  
the steam vessels or cylinders1 although
 occasionally  communicating with them2 
these vessels ,i call condensers2 and1  
whilst  the engines are working1 these  
condensers ought at least to be kept as 
cold as the air in the neighborhood of  
the engines1 by application of  water or
 other cold bodies4    ,thirdly1        
,whatever air or other elastic vapor is 
not condensed by the  cold of the       
condenser1 and may impede the working of
 the engine1 is to  be drawn out of the 
steam vessels or condensers by means of 
pumps1  wrought by the engines          
themselves1 or otherwise4    ,fourthly1 
,i intend in many cases to employ the   
expansive force of  steam to press on   
the pistons1 or whatever may be used    
instead of them1  in the same manner in 
which the pressure of the atmosphere is 
now  employed in common fire-engines4   
,in cases where cold water can not be   

had in plenty1 the engines may be       
wrought by this force of steam only1  by
 discharging the steam into the air     
after it has done its office4           
,sixthly1 ,i intend in some cases to    
apply a degree of cold not capable  of  
reducing the steam to water1 but of     
contracting it considerably1  so that   
the engines shall be worked by the      
alternate expansion and  contraction of 
the steam4    ,lastly1 ,instead of using
 water to render the pistons and other  
parts  of the engine air-and            
steam-tight1 ,i employ oils1 wax1       
resinous bodies1  fat of animals1       
quicksilver and other metals in their   
fluid state4      ,,rotary ,,motion     
,it must be understood that ,watt's     
engine was at first used exclusively  as
 an apparatus for pumping4 ,for some    
time there was no practical  attempt to 
apply the mechanism to any other        
purpose4 ,that it might  be so applied1 
however1 was soon manifest1 in          
consideration of the  relative speed    

with which the piston now acted4 ,it was
 not until #agha1  however1 that ,watt's
 second patent was taken out1 in which  
devices are  described calculated to    
convert the reciprocating motion of the 
piston  into motion of rotation1 in     
order that the engine might drive       
ordinary  machinery4    ,it seems to be 
conceded that ,watt was himself the     
originator of the  idea of making the   
application through the medium of a     
crank and  fly-wheel such as are now    
universally employed4 ,but the year     
before  ,watt took out his second       
patent1 another inventor named ,james   
,picard  had patented this device of    
crank and connecting rod1 having1 it is 
alleged1 obtained the idea from a       
workman in ,watt's employ4 ,whatever  be
 the truth as to this point1 ,picard's  
patent made it necessary for  ,watt to  
find some alternative device1 and after 
experimenting1 he hit  upon the         
so-called sun and planet gearing1 and   
henceforth this was used  on his rotary 

engines until the time for the          
expiration of ,picard's  patent1 after  
which the simpler and more satisfactory 
crank and  fly-wheel were adopted4      
,in the meantime1 ,watt had associated  
himself with a business partner  named  
,boulton1 under the firm name of        
,boulton and ,watt4 ,in #aggf a  special
 act of legislation extending the term  
of ,watt's original patent  for a period
 of twenty-five years had been secured4 
,all infringements  were vigorously     
prosecuted1 and the inventor1 it is     
gratifying to  reflect1 shared fully in 
the monetary proceeds that accrued from 
his  invention4    ,illustration3       
,,watt',s ,,rotative ,,engine4    ,the  
lower figure shows the earliest type of 
mechanism through which  ,watt applied  
his engine to other uses than that of   
pumping4 ,the  so-called sun-and-planet 
gearing1 through which rotary motion was
  attained1 is seen at the lower        
right-hand corner of the figure4 ,the   
upper figure shows a later and much     

improved type of the ,watt engine1  in  
which the sun-and-planet gearing has    
been supplanted by a simple  crank4     
,notwithstanding the early recognition  
of the possibility of securing  rotary  
motion with ,watt's perfected ,newcomen 
engine1 it was long  before the full    
possibilities of the application of this
 principle  were realized1 even by the  
most practical of machinists4 ,watt     
himself  apparently appreciated the     
possibilities no more fully than the    
others1 as the use of his famous engines
 ,beelzebub and ,old ,bess  in the      
establishment of ,boulton and ,watt     
amply testifies4 ,it appears  that      
,boulton had been an extensive          
manufacturer of ornamental metal        
articles4 ,to drive his machinery at    
,soho he employed two large water       
wheels1 twenty-four feet in diameter and
 six feet wide4 ,these sufficed  for his
 purpose under ordinary conditions1 but 
in dry weather from  six to ten horses  
were required to aid in driving the     

machinery4 ,when  ,watt's perfected     
engine was available1 however1 this was 
utilized to  pump water from the tail   
race back to the head race1 that it     
might be  used over and over4 ,old ,bess
 had a cylinder thirty-three inches in  
diameter with seven-foot stroke1        
operating a pump twenty-four inches  in 
diameter2 it therefore had remarkable   
efficiency as a pumping  apparatus4 ,but
 of course it utilized1 at best1 only a 
portion of the  working energy contained
 in the steam2 and the water wheels in  
turn  could utilize not more than fifty 
per cent4 of the store of energy  which 
the pump transferred to the water in    
raising it4 ,therefore1 such  use of the
 steam engine involved a most wasteful  
expenditure of energy4    ,it was long1 
however1 before the practical machinists
 could be made to  believe that the     
securing of direct rotary power from the
 piston could  be satisfactorily        
accomplished4 ,it was only after the    
introduction of  higher speed and       

heavier fly-wheels1 together with       
improved governors1  that the speed of  
rotation was so equalized as to meet    
satisfactorily  the requirements of the 
practical engineer1 and ultimately to   
displace  the wasteful method of        
securing rotary motion indirectly       
through the  aid of pump and water      
wheel4 ,it may be added1 that the       
centrifugal  governor1 with which modern
 engines are provided to regulate their 
speed1 was the invention of ,watt       
himself4      ,,final ,,improvements    
,,and ,,missed ,,opportunities    ,in   
the year #aghb ,watt took out patents   
which contained specifications  for the 
two additional improvements that        
constituted his final  contribution to  
the production of the steam engine4 ,the
 first of these  provided for the       
connection of the cylinder chamber on   
each side of the  piston with the       
condenser1 so that the engine became    
double acting4 ,the  second introduced  
the very important principle1--from the 

standpoint of  economy in the use of    
steam--of shutting off the supply of    
steam from  the cylinder while the      
piston has only partially traversed its 
thrust1  and allowing the remainder of  
the thrust to be accomplished through   
the expansion of the steam4 ,the        
application of the first of these       
principles obviously adds greatly to the
 efficiency of the engine1 and  in      
practise it was found that the          
application of the second principle     
produces a very great saving in steam1  
and thus adds materially to the         
economical working of the engine4       
,all of ,watt's engines continued to    
make use of the walking beam  attached  
to the piston for the transmission of   
power2 and engineers  were very slow    
indeed to recognize the fact that in    
many--in fact in  most--cases this      
contrivance may advantageously be done  
away with4 ,the  recognition of this    
fact constitutes one of the three really
 important  advances that have been made

 in the steam engine since the time of  
,watt4 ,the other two advances consist  
of the utilization of steam under  high 
pressure1 and of the introduction of the
 principle of the compound  engine4     
,neither of these ideas was unknown to  
,watt1 since the utilization  of steam  
under high pressure was advocated by his
 contemporary1  ,trevithick1 while the  
compound engine was invented by another 
contemporary named ,hornblower4 ,perhaps
 the very fact that these rival         
inventors put forward the ideas in      
question may have influenced ,watt  to  
antagonize them2 in particular since his
 firm came into legal  conflict with    
each of the other inventors4 ,at any    
rate1 ,watt continued  to the end of his
 life to be an ardent advocate of low   
pressure for  the steam engine1 and his 
firm even attempted to have laws passed 
making it illegal--on the ground of     
danger to human life--to utilize        
high-pressure steam1 such as employed by
 ,trevithick4    ,possibly the          

conservatism of increasing age may also 
have had its  share in rendering ,watt  
antagonistic to the new ideas2 for he   
was  similarly antagonistic to the idea 
of applying steam to the purposes  of   
locomotion4 ,trevithick1 among others1  
had1 as we shall see in due  course1    
made such application with astonishing  
success1 producing  a steam automobile  
which traversed the highway             
successfully4 ,in  his earlier years    
,watt had conceived the same idea1 and  
had openly  expressed his opinion that  
the steam engine might be used for this 
purpose4 ,but late in life he was so    
antipathetic to the idea that he  is    
said to have put a clause in the lease  
of his house1 providing that  no steam  
carriage should under any pretext be    
allowed to approach it4    ,these       
incidents have importance as showing--as
 we shall see illustrated  again and    
again in other fields--the disastrous   
influence in retarding  progress that   
may be exercised by even the greatest of

 scientific  discoverers1 when authority
 well earned in earlier years is        
exercised  in an unfortunate direction  
later in life4 ,but such incidents as   
these are inconsequential in determining
 the position among the  world's workers
 of the man who was almost solely       
responsible for the  transformation of  
the steam engine from an expensive and  
relatively  ineffective pumping         
apparatus1 to the great central power   
that has ever  since moved the major    
part of the world's machinery4          
,,the ,,supreme ,,importance ,,of ,,watt
    ,it is speaking well within bounds  
to say that no other invention  within  
historical times has had so important an
 influence upon the  production of      
property--which1 as we have seen1 is the
 gauge of the  world's work--as this    
invention of the steam engine4 ,we have 
followed  the history of that invention 
in some detail1 because of its supreme  
importance4 ,to the reader who was not  
previously familiar with that  history1 

it may seem surprising that after a     
lapse of a little over  a century one   
name and one alone should be popularly  
remembered in  connection with the      
invention2 whereas in point of fact     
various workers  had a share in the     
achievement1 and the man whose name is  
remembered  was among the last to enter 
the field4 ,we have seen that the steam 
engine existed as a practical working   
machine several decades before  ,watt   
made his first invention2 and that what 
,watt really accomplished  was merely   
the perfecting of an apparatus which    
already had attained a  considerable    
measure of efficiency4    ,there would  
seem1 then1 to be a certain lack of     
justice in ascribing  supreme importance
 to ,watt in connection with the steam  
engine4 ,yet  this measure of injustice 
we shall find1 as we examine the history
 of  various inventions1 to be meted    
always by posterity in determining the  
status of the men whom it is pleased to 
honor4 ,one practical rule1 and  one    

only1 has always determined to whom the 
chief share of glory shall  be ascribed 
in connection with any useful invention4
    ,the question is never asked as to  
who was the originator of the idea1  or 
who made the first tentative efforts    
towards its utilization1--or1  if asked 
by the historical searcher1 it is       
ignored by the generality of  mankind4  
,so far as the public verdict1 which in 
the last resort determines  fame1 is    
concerned1 the one question is1 ,who    
perfected the apparatus  so that it came
 to have general practical utility8 ,it 
may be1 and  indeed it usually is the   
case1 that the man who first            
accomplished the  final elaboration of  
the idea1 made but a comparatively      
slight advance  upon his predecessors2  
the early workers produced a machine    
that was  almost a success2 only some   
little flaw remained in their plans4    
,then  came the perfecter1 who hit upon 
a device that would correct this last   
defect1--and at last the mechanism1     

which hitherto had been only a          
curiosity1 became a practical working   
machine4    ,in the case of the steam   
engine1 it might be said that even a    
smaller  feat than this remained to be  
accomplished when ,watt came upon the   
scene2 since the ,newcomen engine was   
actually a practical working  apparatus4
 ,but the all-essential thing to        
remember is that this  ,newcomen engine 
was used for a single purpose4 ,it      
supplied power for  pumping water1 and  
for nothing else4 ,neither did it have  
possibilities  much beyond this1 until  
the all-essential modification was      
suggested by  ,watt1 of exhausting its  
steam into exterior space4    ,this     
modification is in one sense a mere     
detail1 yet it illustrates  once more   
the force of ,michelangelo's famous     
declaration that trifles  make perfect2 
for when once it was tested1 the whole  
practical  character of the steam engine
 was changed4 ,from a wasteful consumer 
of  fuel1 capable of running a pump at  

great expense1 it became at once a      
relatively economical user of energy1   
capable of performing almost any  manner
 of work4    ,needless to say1 its      
possibilities in this direction were not
  immediately realized1 in theory or in 
practise2 yet the conquest that  it made
 of almost the entire field of labor    
resulted in the most  rapid             
transformation of industrial conditions 
that the world has ever  experienced4   
,after all1 then1 there is but little   
injustice in that  public verdict which 
remembers ,james ,watt as the inventor1 
rather than  as the mere perfecter1 of  
the steam engine4      ,,the            
,,personality ,,of ,,james ,,watt       
,the man who occupies this all-important
 position in the industrial  world      
demands a few more words as to his      
personality4 ,his work we have          
sufficiently considered1 but before we  
pass on to the work of his  successors1 
it will be worth our while to learn     
something more of the  estimate placed  

upon the man himself4 ,let us quote1    
then1 from some  records written by men 
who were of the same generation4        
,independently of his great attainments 
in mechanics1 ,mr4 ,watt was  an        
extraordinary and in many respects a    
wonderful man4 ,perhaps no  individual  
in his age possessed so much1 or        
remembered what he had read  so         
accurately and well4 ,he had infinite   
quickness of apprehension1 a  prodigious
 memory1 and a certain rectifying and   
methodizing power of  understanding     
which extracted something precious out  
of all that was  presented to it4 ,his  
stores of miscellaneous knowledge were  
immense1  and yet less astonishing than 
the command he had at all times over    
them4 ,it seemed as if every subject    
that was casually started in            
conversation had been that which he had 
been last occupied in studying  and     
exhausting2 such was the copiousness1   
the precision1 and the  admirable       
clearness of the information which he   

poured out upon it  without effort or   
hesitation4 ,nor was this promptitude   
and compass of  knowledge confined1 in  
any degree1 to the studies connected    
with his  ordinary pursuits4    ,that he
 should have been minutely and          
extensively skilled in  chemistry1 and  
the arts1 and in most of the branches of
 physical  science1 might1 perhaps1 have
 been conjectured2 but it could not have
  been inferred from his usual          
occupations1 and probably is not        
generally  known1 that he was curiously 
learned in many branches of antiquity1  
metaphysics1 medicine1 and etymology1   
and perfectly at home in all  the       
details of architecture1 music1 and law4
 ,he was well acquainted1  too1 with    
most of the modern languages1 and       
familiar with their most  recent        
literature4 ,nor was it at all          
extraordinary to hear the great         
mechanician and engineer detailing and  
expounding1 for hours together1  the    
metaphysical theories of the ,german    

logicians1 or criticizing the  measures 
or the matter of the ,german poetry4    
,it is needless to say1 that with those 
vast resources1 his  conversation was at
 all times rich and instructive in no   
ordinary  degree4 ,but it was1 if       
possible1 still more pleasing than wise1
 and  had all the charms of familiarity1
 with all the substantial treasures  of 
knowledge4 ,no man could be more social 
in his spirit1 less assuming  or        
fastidious in his manners1 or more kind 
and indulgent towards  all who          
approached him4 ,his talk1 too1 though  
overflowing with  information1 had no   
resemblance to lecturing1 or solemn     
discoursing2  but1 on the contrary1 was 
full of colloquial spirit and           
pleasantry4  ,he had a certain quiet and
 grave humor1 which ran through most of 
his  conversation1 and a vein of        
temperate jocularity1 which gave        
infinite  zest and effect to the        
condensed and inexhaustible information 
which  formed its main staple and       

characteristic4 ,there was a little air 
of  affected testiness1 and a tone of   
pretended rebuke and contradiction1     
which he used towards his younger       
friends1 that was always felt by  them  
as an endearing mark of his kindness and
 familiarity1 and prized  accordingly1  
far beyond all the solemn compliments   
that proceeded from  the lips of        
authority4 ,his voice was deep and      
powerful2 though he  commonly spoke in a
 low and somewhat monotonous tone1 which
 harmonized  admirably with the weight  
and brevity of his observations1 and set
 off  to the greatest advantage the     
pleasant anecdotes which he delivered   
with the same grave tone1 and the same  
calm smile playing soberly on  his lips4
    ,illustration3 ,,james ,,watt4      
,there was nothing of effort1 indeed1 or
 of impatience1 any more than  of pride 
or levity1 in his demeanor2 and there   
was a finer expression  of reposing     
strength1 and mild self-possession in   
his manner1 than we  ever recollect to  

have met with in any other person4 ,he  
had in his  character the utmost        
abhorrence for all sorts of forwardness1
 parade1  and pretension2 and indeed    
never failed to put all such impostors  
out  of countenance1 by the manly       
plainness and honest intrepidity of his 
language and deportment4    ,he was     
twice married1 but has left no issue but
 one son1 associated  with him in his   
business and studies1 and two           
grandchildren by a  daughter who        
predeceased him4 ,he was fellow of the  
,royal ,societies both  of ,london and  
,edinburgh1 and one of the few          
,englishmen who were elected  members of
 the ,national ,institute of ,france4   
,all men of learning and  of science    
were his cordial friends2 and such was  
the influence of his  mild character1   
and perfect fairness and liberality1    
even upon the  pretender to these       
accomplishments1 that he lived to disarm
 even envy  itself1 and died1 we verily 
believe1 without a single enemy4        

,,vi    ,,the ,,master ,,worker      ,we
 have already pointed out at some length
 that1 in the hands of ,watt1  the steam
 engine came at once to be a relatively 
perfect apparatus1 and  that only three 
really important modifications have been
 applied to it  since the day of its    
great perfecter4 ,these modifications1  
as already  named1 are the doing away   
with the walking beam1 the utilization  
of  high pressure steam1 and the        
development of the compound engine4     
,each  of these developments requires a 
few words of explanation4    ,the       
retention of the heavy walking beam for 
so long a time after the  steam engine  
of ,watt had been applied to the various
 purposes of  machinery1 illustrates the
 power of a pre-conceived idea4 ,with   
the  ,newcomen engine this beam was an  
essential1 since it was necessary  to   
have a weight to assist in raising the  
piston4 ,but with the  introduction of  
steam rather than air as the actual     
power to push the  piston1 and in       

particular with the elaboration of the  
double-chamber  cylinder1 with steam    
acting equally on either side of the    
piston1 the  necessity for retaining    
this cumbersome contrivance no longer   
existed4  ,yet we find all the engines  
made by ,watt himself1 and nearly all   
those  of his contemporaries1 continuing
 to utilize this means of transmitting  
the power of the piston4 ,even the road 
locomotive1 as illustrated by  that     
first wonderful one of ,trevithick's and
 such colliery locomotives  as ,puffing 
,billy and ,locomotion1 utilized the    
same plan4 ,it was not  until almost a  
generation later that it became clear to
 the mechanics  that in many cases1     
indeed in most cases1 this awkward means
 of  transmitting power was really a    
needlessly wasteful one1 and that with  
the aid of fly-wheel and crank-shaft the
 thrust of the piston might be  directly
 applied to the wheel it was destined to
 turn1 quite as well as  through the    
intermediary channel of the additional  

lever4    ,the utility of the beam has1 
indeed1 still commended it for certain  
purposes1 notably for the propulsion of 
side-wheel steamers1 such as  the       
familiar ,american ferryboat4 ,but aside
 from such exceptional uses1  the beam  
has practically passed out of existence4
    ,there was no new principle involved
 in effecting this change4 ,it was      
merely another illustration of the      
familiar fact that it is difficult  to  
do things simply4 ,as a rule1 inventors 
fumble for a long time with  roundabout 
and complex ways of doing things1 before
 a direct and simple  method occurs to  
them4 ,in other words1 the highest      
development often  passes from the      
complex to the simple1 illustrating1 as 
it were1 an  oscillation in the great   
law of evolution4 ,so in this case1 even
 so  great an inventor as ,watt failed  
to see the utility of doing away with   
the cumbersome structure which his own  
invention had made no longer  a         
necessity1 but rather a hindrance to the

 application of the steam  engine4      
,however1 a new generation1 no longer   
under the thraldom of  the ideas of the 
great inventor1 was enabled to make the 
change1  gradually1 but in the end      
effectively4      ,,high-,,pressure     
,,steam    ,as regards the use of steam 
under high pressure1 somewhat the same  
remarks apply1 so far as concerns the   
conservatism of mankind1 and  the       
influence which a great mind exerts upon
 its generation4 ,just why  ,watt should
 have conceived an antagonism to the    
idea of high-pressure  steam is not     
altogether clear4 ,it has been          
suggested1 indeed1 that  this might have
 been due to the fact that a predecessor
 of ,watt had  invented a high-pressure 
engine which did not use the principle  
of  condensation1 but exhausted the     
steam into open space4 ,as early as     
#agbe1 indeed1 ,leupold in his ,theatrum
 ,machinarum1 had described  such a     
non-condensing engine1 which1 had it    
been made practically  useful1 would    

have required a high pressure of steam4 
,partly through  the influence of this  
work1 perhaps1 there came to be an      
association  between the words high     
pressure and non-condensing1 so that    
these terms  are considered to be       
virtually synonymous2 and since ,watt's 
great  contribution consisted of an     
application of the idea of condensation1
  he was perhaps rendered antagonistic  
to the idea of high pressure1  through  
this psychological suggestion4 ,in any  
event1 the antagonism  unquestionably   
existed in his mind2 though it has often
 enough been  pointed out that this     
seems the more curious since            
high-pressure steam  would so much      
better have facilitated the application 
of that other  famous idea of ,watt1 the
 use of the expansive property of steam4
    ,curiously enough1 however1 the     
influence of ,watt led to experiments   
in high-pressure steam through an       
indirect channel4 ,the contemporary     
inventor1 ,trevithick1 in connection    

with his partner1 ,bull1 had made       
direct-acting pumping engines with an   
inverted cylinder1 fixed in line  with  
the pump rod1 and actually dispensing   
with the beam4 ,but as these  engines   
used a jet of cold water in the exhaust 
pipe to condense the  steam1 ,boulton   
and ,watt brought suit successfully for 
infringement of  their patent1 and thus 
prevented ,trevithick from experimenting
 further  in that direction4 ,he was    
obliged1 therefore1 to turn his         
attention to  a different method1 and   
probably1 in part at least1 in this way 
was  led to introduce the               
non-condensing1 relatively high-pressure
 engine4  ,this was used about the year 
#ahjj4 ,at the same time somewhat       
similar  experiments were made by       
,oliver ,evans in ,america4    ,both    
,trevithick and ,evans applied their    
engines to the propulsion of  road      
vehicles2 and ,trevithick is credited   
with being the first man  who ran a     
steam locomotive on a track1--a feat    

which he accomplished  as early as the  
year #ahjd4 ,we are not here concerned  
with the details  of this               
accomplishment1 which will demand our   
attention in a later  chapter1 when we  
come to discuss the entire subject of   
locomotive  transportation4 ,but it is  
interesting to recall that the          
possibilities  of the steam engine were 
thus early realized1 even though another
  generation elapsed before they were   
finally demonstrated to the             
satisfaction of the public4 ,it is      
particularly interesting to note that   
in his first locomotive engine1         
,trevithick allowed the steam exhaust   
to escape into the funnel of the engine 
to increase the draught1--an  expedient 
which was so largely responsible for    
,stephenson's success  with his         
locomotive twenty years later1 and which
 retains its utility  in the case of the
 most highly developed modern           
locomotive4    ,trevithick was1 however1
 entirely subordinated by the great     

influence of ,watt1 and the use of high 
pressure was in consequence             
discountenanced by the leading          
mechanical engineers of ,england for    
some  decades4 ,meantime1 in ,america1  
the initiative of ,evans led to a much  
earlier general use of high-pressure    
steam4 ,in due course1 however1 the     
advantages of steam under high pressure 
became evident to engineers  everywhere1
 and its conquest was finally complete4 
,the essential feature of super-heated  
steam is that it contains1 as  the name 
implies1 an excess of heat beyond the   
quantity necessary to  produce mere     
vaporization1 and that the amount of    
water represented  in this vapor is not 
the maximum possible under given        
conditions4 ,in  other words1 the vapor 
is not saturated4 ,it has been already  
explained  that the amount of vapor that
 can be taken up in a given space under 
a  given pressure varies with the       
temperature of the space4 ,under normal 
conditions1 when a closed space exists  

above a liquid1 evaporation  occurs from
 the surface of the liquid until the    
space is saturated1  and no further     
evaporation can occur so long as the    
temperature and  pressure are unchanged4
 ,if now the same space is heated to a  
higher  degree1 more vapor will be taken
 up until again the point of saturation 
is attained4 ,but1 obviously1 if the    
space were disconnected with the        
liquid1 and then heated1 it would       
acquire a capacity to take up more      
vapor1 and so long as this capacity was 
latent1 the vapor present would  exist  
in a super-heated condition4            
,illustration3 ,,old ,,ideas ,,and ,,new
 ,,applied ,,to ,,boiler ,,construction4
    ,the lower figure shows ,robert     
,trevithick's famous boiler1 used in    
operating his locomotive about the year 
#ahjd4 ,the original is preserved  in   
the ,south ,kensington ,museum1 ,london4
 ,the upper figure shows a modern       
tubular boiler1 by way of contrast4     
,it will be understood from what has    

been said before1 that with all         
accessions of heat1 the expansive power 
of the vapor is increased1--its         
molecules becoming increasingly active2 
hence one of the very obvious           
advantages of super-heated steam for the
 purpose of pushing a piston4  ,there   
are other advantages1 however1 which are
 not at first sight  so apparent1 having
 to do with the properties of           
condensation4 ,to  understand these1 we 
must pay heed for a few moments to the  
changes  that take place in steam itself
 in the course of its passage through   
the cylinder1 where it performs its work
 upon the piston4    ,many of these     
changes were not fully understood by the
 earlier  experimenters1 including      
,watt4 ,indeed the theory of the steam  
engine1  or rather the general theory of
 the heat engine1 was not worked out    
until the year #ahbd1 when the          
,frenchman ,carnot took the subject in  
hand1 and performed a series of         
classical experiments1 which led to a   

nearly complete theoretical exposition  
of the subject4 ,it remained1  however1 
for the students of thermo-dynamics1    
about the middle of the  nineteenth     
century1 with ,clausius and ,rankine at 
their head1 to perfect  the theory of   
the steam engine1 and the general       
subject of the mutual  relations of heat
 and mechanical work4    ,we are not    
here concerned with any elaboration of  
details1 but merely  with a few of the  
essential principles which enter        
practically into  the operation of the  
steam engine4 ,it appears1 then1 that   
when steam  enters the cylinder and     
begins to thrust back the piston of the 
steam  engine1 a portion of the steam is
 immediately condensed on the walls  of 
the cylinder1 owing to the fact that    
previous condensation of steam  has     
cooled these walls to a certain extent4 
,we have already pointed  out that ,watt
 endeavored in his earlier experiments  
to overcome this  difficulty1 by        
equalizing the temperature of the       

cylinder walls to the  greatest         
practicable extent4    ,notwithstanding 
his efforts1 however1 and those of      
numberless later  experimenters1 it     
still remains true that under ordinary  
conditions1  particularly if steam      
enters the cylinder at the saturation   
point1  a very considerable condensation
 occurs4 ,indeed this may amount to     
from thirty to fifty per cent4 of the   
entire bulk of water contained  in the  
quantity of steam that enters the       
cylinder4 ,this condensation  obviously 
militates against the expansive or      
working power of the  steam4 ,but now as
 the steam expands1 pushing forward the 
cylinder1 it  becomes correspondingly   
rarefied1 and immediately a portion of  
the  condensed steam becomes again      
vaporized1 and in so doing it takes up  
a certain amount of heat and renders it 
latent4 ,this disadvantageous  cycle of 
molecular transformations is very much  
modified in the case of  super-heated   
steam1 for the obvious reason that such 

steam may be very  much below the       
saturation point1 and hence requires a  
very much greater  lowering of          
temperature in order to produce         
condensation of any portion  of its     
mass4 ,without elaborating details1 it  
suffices to note that in  all highly    
efficient modern engines1 steam is      
employed at a relatively  high pressure1
 and that sometimes this pressure       
becomes enormous4      ,,compound       
,,engines    ,as to the compound engine1
 that also1 as has been pointed out1 was
  invented by a contemporary of ,watt1  
,jonathan ,hornblower by name1 whose    
patent bears date of #agha4 ,in         
,hornblower's engine1 steam was first   
admitted to a small cylinder1 and then1 
after performing its work on  the       
piston1 was allowed to escape1 not into 
a condensing receptacle1  but into a    
larger cylinder where it performed      
further work upon another  piston4 ,this
 was obviously an instance of the use of
 steam expansively1  and it has been    

pointed out that1 in consequence1       
,hornblower was  the first to make use  
of this idea in practise1 although it is
 said  that ,watt's experiments had even
 at that time covered this field4  ,the 
application of the idea to the movement 
of the second cylinder1  however1       
appears to have been original with      
,hornblower4 ,certainly it  owed nothing
 to ,watt1 who refused to accept the    
idea1 and continued  throughout his life
 to frown upon the compound engine4     
,nevertheless1 the device had great     
utility1 as subsequent experiments  were
 very fully to demonstrate4 ,the        
compound engine was revived by  ,woolf  
in #ahjd1 and his name rather than      
,hornblower's is commonly  associated   
with it4 ,the latter experimenter       
demonstrated that the  compound engine  
has two important merits as against the 
simple engine4  ,one of these is that   
the sum of the two forces exerted by the
 joint  action results in a more even   
and continuous pressure throughout the  

cycle than could be accomplished by the 
action of a single cylinder4    ,to     
understand this it must be recalled that
 when using the expansive  property of  
steam1 the piston thrust could not      
possibly be uniform1  since the greatest
 pressure exerted by the steam would be 
exerted at  the moment before it was    
shut off from the boiler1 and its       
pressure  must then decrease            
progressively1 as it exerts more and    
more work upon  the piston and becomes  
more expanded1 thus obviously retaining 
less  elastic energy4 ,the operation of 
the fly-wheel largely compensates  this 
difference of pressure in practise1 but 
it would be obviously  advantageous     
could the pressure be equalized2 and1 as
 just stated1 the  compound engine tends
 to produce this result4    ,the second1
 and perhaps the more important merit of
 the compound  engine is1 that it is    
found in practise to keep the cylinders 
at a  more uniform temperature4 ,a      
moment's reflection makes it clear why  

this should be the case1 since in a     
single-cylinder engine the exhaust      
connects with the cool condenser1       
whereas in the compound engine the      
exhaust from the first cylinder connects
 with the second cylinder at  only      
slightly lower temperature4    ,in many 
modern engines a third cylinder and     
sometimes even a fourth  is added1      
constituting what are called            
respectively triple-expansion  and      
quadruple-expansion engines4 ,the       
triple-expansion system is very         
generally employed1 especially where it 
is peculiarly desirable to  economize   
fuel1 as1 for example1 in the case of   
ships4    ,illustration3 ,,compound     
,,engines4    ,the lower figure         
illustrates the use of a modern compound
 engine1  directly operating the        
propeller shaft of a steamship4 ,the    
middle  figure shows a similarly direct 
application of power to the axes of     
paddle wheels4 ,the upper figure shows  
the application of power through  a     

walking beam similar in principle to    
that of the original ,newcomen  and     
,watt engines4      ,,rotary ,,engines  
,all these improvements1 it will be     
observed1 have to do with details  that 
do not greatly modify the steam engine  
from the original type4 ,the  cylinder  
with its closely fitting piston1 as     
introduced in the ,newcomen  engine1 is 
retained and constitutes the essential  
mechanism through  which the energy of  
steam is transferred into mechanical    
energy4 ,but  from a comparatively      
remote period the idea has prevailed    
that it might  be possible to utilize a 
different principle2 that1 in short1 if 
the  steam instead of being made to     
press against a piston were allowed  to 
rush against fan-like blades1 adjusted  
to an axle1 it might cause  blades and  
axle to revolve1 precisely as a windmill
 is made to revolve  by the pressure of 
the wind1 or the turbine wheel by the   
pressure of  water4    ,in a word1 it   
has been believed that a turbine engine 

might be  constructed1 which would      
utilize the energy of the steam as      
advantageously as it is utilized in the 
piston engine1 and at the same  time    
would communicate its power as a direct 
rotation1 instead of as a  straight     
thrust that must be translated into a   
rotary motion by means  of a crank or   
other mechanism4    ,in point of fact1  
,james ,watt himself invented such an   
engine1 and  patented it in #aghb1      
though there is no evidence that he ever
  constructed even a working model4 ,his
 patent specifications show a  piston in
 the form of a closely-fitting radial   
arm1 projecting from an  axial shaft in 
a cylinder4 ,an abutment1 arranged as a 
flap is hinged  near a recess in the    
side of the cylinder1 and swings while  
remaining  in contact with the piston4  
,steam is admitted to the chamber on one
  side of the flap1 and so causes an    
unbalanced pressure upon the radial     
arm4    ,this arrangement has been      
re-invented several times4 ,essentially 

the  same principle is utilized by      
,joshua ,routledge1 whose name is well  
known in connection with the engineer's 
slide-rule4 ,a model of this  engine is 
preserved in the ,south ,kensington     
,museum1 and the apparatus  is described
 in the catalogue of the ,museum as     
follows3    ,the piston revolves on a   
shaft passing through the centre of the 
cylinder casing4 ,the flap or valve     
hinged to the casing1 with its free  end
 resting upon the piston1 acts like the 
bottom of an ordinary engine  cylinder4 
,the steam inlet port is on one side of 
the hinge1 and the  exhaust port on the 
other4 ,the admission of steam is       
controlled by a  side valve1 actuated by
 an eccentric on the fly-wheel shaft1 so
 that  the engine could work            
expansively1 and the steam pressure     
resisting the  lifting of the flap would
 also be greatly reduced1 so diminishing
 the  knock at this point1 which1       
however1 would always be a serious cause
  of trouble4 ,the exhaust steam passes 

down to a jet condenser1 provided  with 
a supply of water from a containing     
tank1 from which the injection  is      
admitted through a regulating valve4    
,the air pump1 which draws the  air and 
water from the condenser and discharges 
them through a pipe  passing out at the 
end of the tank1 is a rotary machine    
constructed  like the engine and driven 
by spur gearing from the fly-wheel      
shaft4  ,some efforts have been made to 
prevent leakage by forming grooves in   
the sides of the revolving piston and   
filling them with soft packing4         
,sundry other rotary engines1 some of   
them actual working models1 are  to be  
seen at the ,south ,kensington ,museum4 
,there is1 for example1 one  invented by
 the ,rev4 ,patrick ,bell1 a gentleman  
otherwise known to fame  as one of the  
earliest inventors of a practical       
reaping machine4 ,in  this apparatus1 ,a
 metal disc is secured to a horizontal  
axis carried  in bearings1 and the lower
 half of the disc is enclosed by a      

chamber  of circular section having its 
axis a semi-circle4 ,one end of this    
chamber is closed and provided with a   
pipe through which steam enters1  the   
exhaust taking place through the open   
end4 ,the disc is provided  with three  
holes1 each fitted with a circular plate
 turning on an  axis radial to the disc1
 and these plates when set at right     
angles  to the disc become pistons in   
the lower enclosing chamber4 ,toothed   
gearing is arranged to rotate these     
pistons into the plane of the disc  on  
leaving the cylinder and back again     
immediately after entering1  locking    
levers retaining them in position during
 the intervals4 ,the  steam pressure    
upon these pistons forces the disc      
round1 but the engine  is non-expansive1
 and although some provision for packing
 has been  made1 the leakage must have  
been considerable and the wear and tear 
excessive4    ,it is stated that almost 
the same arrangement was proposed by    
,lord  ,armstrong in #ahch as a water   

motor1 and that a model subsequently    
constructed gave over five horse-power  
at thirty revolutions per  minute1 with 
an efficiency of ninety-five per cent4  
,another working model of a rotary      
engine shown at the ,museum is one      
loaned by ,messrs4 ,fielding and ,platt 
in #ahhh4 ,the action of this  engine   
depends upon the oscillating motion     
which the cross of a  universal joint   
has relative to the containing jaws when
 the system is  rotated4    ,two shafts 
are set at an angle of #afe deg4 to each
 other and connected  by a ,hooke's     
joint2 one serves as a pivot1 the power 
being taken from  the other4 ,four      
curved pistons are arranged on the      
cross-piece1 two  pointing towards one  
shaft and two towards the other1 and on 
each  shaft or jaw are formed two curved
 steam cylinders in which the curved    
pistons work4 ,the steam enters and     
leaves the base of each cylinder        
through ports in the shaft1 which forms 
a cylindrical valve working in  the     

bearing as a seating4    ,on the        
revolution of the shafts the pistons    
reciprocate in their  cylinders in much 
the same way as in an ordinary engine1  
and the  valve arrangement is such that 
while each piston is receding from its  
cylinder the steam pressure is driving  
it1 and during the in-stroke  of each1  
its cylinder is in communication with   
the exhaust4 ,there are  thus four      
single-acting cylinders making each a   
double stroke for one  revolution of the
 driving-shaft4 ,the engine has no dead 
centres1 and  has been at #a1jjj        
revolutions per minute4                 
,illustration3 ,,rotary ,,engines4      
,the three types of rotary engines here 
shown are similar in principle1  and    
none of them is of great practical      
value1 though the upper figure  shows an
 engine that has met with a certain     
measure of commercial  success4    ,it  
is not necessary to describe other of   
the rotary engines that have  been made 
along more or less similar lines by     

numerous inventors1  models of which are
 for the most part1 as in the case of   
those just  described1 to be seen more  
commonly in museums than in practical   
workshops4 ,reference may be made1      
however1 to a rotary engine  which was  
invented by a ,mr4 ,hoffman1 of         
,buffalo1 ,new ,york1 about the         
beginning of the twentieth century1 an  
example of which was put into  actual   
operation in running the machinery of a 
shop in ,buffalo1 in #aije4    ,this    
engine consists of a solid elliptical   
shaft of steel1 fastened to  an axle at 
one side of its centre1 which axis is   
also the shaft of the  cylinder1 which  
revolves about the central ellipse in   
such a way that  at one part of the     
revolution the cylinder surface fits    
tightly against  the ellipse1 while the 
opposite side of the cylinder supplies a
 free  chamber between the ellipse and  
the cylinder walls4 ,running the length 
of the cylinder are two curved pieces of
 steel1 like longitudinal  sections of a

 tube4 ,these flanges are adjusted at   
opposite sides of  the cylinder and so  
arranged that their sides at all times  
press  against the ellipse1 alternately 
retreating into the substance of the    
cylinder1 and coming out into the free  
chamber4 ,steam is admitted to  the free
 chamber through one end of the shaft of
 ellipse and cylinder  and exhausted    
through the other end4 ,the pressure of 
the steam against  first one end and    
then the other of the flanges supplies  
the motive  power4 ,this pressure acts  
always in one direction1 and the entire 
apparatus revolves1 the cylinder1       
however1 revolving more rapidly than    
the central ellipse4    ,for this engine
 the extravagant claim is made that     
there is no limit  to its speed of      
revolution1 within the limit of         
resistance of steel  to centrifugal     
force4 ,it has been estimated that a    
locomotive might  be made to run two    
hundred or three hundred miles an hour  
without  difficulty1 with the ,hoffman  

engine4 ,such estimates1 however1 are   
theoretical1 and it remains to be seen  
what the engine can do in  practise when
 applied to a variety of tasks1 and what
 are its  limitations4 ,certainly the   
apparatus is at once ingenious and      
simple in  principle1 and there is no   
obvious theoretical reason why it should
 not  have an important future4         
,,turbine ,,engines    ,whatever the    
future may hold1 however1 it remains    
true that the first  practical solution 
of the problem of securing direct rotary
 motion from  the action of steam1 on a 
really commercial scale1 was solved with
 an  apparatus very different from any  
of those just described1 the inventor   
being an ,englishman1 ,mr4 ,c4 ,a4      
,parsons1 and the apparatus the steam   
turbine1 the first model of which he    
constructed in #ahhd1 and which  began  
to attract general attention in the     
course of the ensuing decade4  ,public  
interest was fully aroused in #ahig1    
when ,mr4 ,parson's boat1 the           

,turbinia1 equipped with engines of this
 type1 showed a trial speed  of #cb-c_/d
 knots per hour1 a speed never hitherto 
attained by any other  species of water 
craft4 ,more recently1 a torpedo boat1  
the ,viper1  equipped with engines      
developing about ten thousand           
horse-power1  attained a speed of       
#ce-a_/b knots4 ,the success of these   
small boats led  to the equipment of    
large vessels with the turbine1 and on  
,april first1  #aije1 the first         
transatlantic liner propelled by this   
form of engine  steamed into the harbor 
of ,halifax1 ,nova ,scotia4    ,this    
first ocean liner equipped with the     
turbine engine is called the            
,victorian4 ,she is a ship five hundred 
and forty feet long and sixty  feet     
wide1 carrying fifteen hundred          
passengers4 ,the ,victorian had  shown a
 speed of #ai-a_/b knots an hour on her 
trial trip1 and it had  been hoped that 
she would break the transatlantic       
record4 ,on her first  trip1 however1   

she encountered adverse winds and seas1 
and did not  attain great speed4 ,her   
performance was1 however1 considered    
entirely  satisfactory and creditable4  
,in the ensuing half-decade several     
large ships were equipped with  engines 
of the same type1 the most famous of    
these being the ,cunard  liners1        
,carmania1 ,lusitania1 and ,mauretania4 
,the two last-named  ships are sister   
craft1 and they are the largest boats of
 any kind  hitherto constructed4 ,the   
,lusitania was first launched and she   
entered immediately upon a              
record-breaking career1 only to be      
surpassed  within a few months by the   
,mauretania1 which soon acquired all    
records for speed and endurance4        
,fuller details as to the performance of
 these vessels will be found in  another
 place4 ,here we are of course concerned
 with the ,parsons turbine  engine      
itself rather than with its             
applications4    ,this turbine engine   
constitutes the first really important  

departure  from the old-type steam      
engine1 thus realizing the dream of the 
seventeenth-century ,italian1 ,branca1  
to which reference was made  above4 ,mr4
 ,parsons' elaboration of the idea      
developed a good deal of  complexity as 
regards the number of parts involved1   
yet his engine  is of the utmost        
simplicity in principle4 ,it consists of
 a large  number of series of small     
blades1 each series arranged about a    
drum  which revolves4 ,between the rings
 of revolving blades are adjusted       
corresponding rings of fixed blades1    
which project from the casing  to the   
cylinder1 and by means of which the     
steam is regulated in  direction1 so    
that it strikes at the proper angle     
against the revolving  blades of the    
turbine4    ,in practise1 three series  
of cylindrical drums are used1 each     
containing a large number of rings of   
blades of uniform size2 but each        
successive drum having longer blades1 to
 accommodate the greater volume  of the 

expanding steam4 ,the steam is fed      
against the first series of  blades in  
gusts1 which may be varied in frequency 
and length to meet  the requirements of 
speed4 ,after impinging on the first    
circle of  blades1 the steam passes to  
the next under slightly reduced         
pressure1  and the pressure is thus     
successively stepped down from one set  
of  blades to another until it is       
ultimately reduced from say two hundred 
pounds to the square inch1 to one pound 
to the square inch before it  passes to 
the condenser and ceases to act4        
,there is thus a fuller utilization of  
the kinetic energy of the gas1  through 
carrying it from high to low pressure1  
than is possible with  the old type of  
cylinder-and-piston engine4 ,on the     
other hand1 there is  a constant loss   
due to the fact that the blades of the  
turbine can not  fit with absolute      
tightness against the cylinder walls4   
,the net result  is that the compound   
turbine1 as at present developed1       

appears to have  about the same         
efficiency as the best engine of the old
 type4    ,one capital advantage of the 
turbine is that it keeps the cylinder   
walls at a more uniform temperature than
 is possible even with a  compound      
engine of the old type4 ,another        
advantage is that the power  of the     
turbine is applied directly to cause    
rotation of the shaft1  whereas no      
satisfactory means has ever been        
discovered hitherto of  making the      
action of the steam engine rotary1      
except with the somewhat                
disadvantageous crank-shaft4 ,this fact 
of adjustment of the turbine  blades to 
the revolving shaft seems to make this  
form of engine  particularly adapted to 
use in steamships4 ,it is also highly   
adapted  to revolving the shaft of a    
dynamo1 and has been largely applied to 
this use4 ,needless to say1 however1 it 
may be applied to any other  form of    
machinery4 ,it would be difficult at the
 present stage of  its development to   

predict the extent to which the turbine 
will  ultimately supersede the old type 
of engine4 ,its progress has already    
been extraordinary1 however1 as an      
engineer pointed out in the ,london     
,times of ,august #ad1 #aijg1 in the    
following words3    ,when the steam     
turbine was introduced by ,mr4 ,parsons 
some #be years  ago1 in the form of a   
little model1 which is now in the ,south
  ,kensington ,museum1 and the rotor of 
which may easily be held stationary  by 
the hand against the full blast of the  
steam1 who would have been  rash enough 
to predict1 except perhaps the          
far-seeing inventor himself1  that a    
vessel #gfj feet long1 loaded to #cg1jjj
 tons displacement1  drawing #cb ft4 #i 
in4 of water1 and providing             
accommodation for #b1ejj  people1 could 
be propelled at a speed of #bd4e knots  
per hour1 which it  is hoped she may    
maintain over the #c1jjj miles of the   
,atlantic voyage8    ,from this small   
model1 which will in time become as     

historic as the  ,rocket of ,stephenson1
 and which is only some few inches in   
diameter1  the turbine has been         
developed gradually in size4 ,the       
cylindrical  casings which take the     
place of the complicated machinery of   
the  piston engine in the engine room of
 the ,lusitania contain drums1  which in
 the high-pressure turbines are #h feet 
in diameter and in the  low-pressure #aa
 ft4 #h in41 and from which thousands of
 curved blades  project1 the longest of 
which are #bb inches1 and against which 
the  steam impinges in its course from  
the boiler to the condenser4    ,not    
only has the steam turbine justified the
 confidence of those who  have labored  
so successfully in its development1 but 
no other great  invention has proceeded 
from the laboratory stage to such an    
important  position in the engineering  
world in such a short space of time4    
,this  would not have happened if some  
inherent drawback1 such as lack of      
economy in steam consumption1 existed1  

and as the turbine has been  proved to  
be1 for land purposes1 very economical1 
there seems to be  no reason to doubt   
that marine turbines1 working as they do
 at full  load almost continually1 will 
show likewise that the coal bill is not 
increased1 but perhaps diminished by    
their use4    ,the records of the       
vibrations of the hull which were taken 
during the  trials by ,schlick's        
instruments showed that the vertical    
vibration  was #fj per minute on the    
run1 which was due to the propellers1   
and  which may be further modified4 ,the
 horizontal vibration was almost        
unnoticeable1 while the behavior of the 
ship in the heavy seas she  encountered 
in her long-distance runs was good1 the 
roll from side to  side having a period 
of #ah seconds4 ,the great length of    
this ship and  the gyrostatic action of 
the heavy rotating masses of the        
machinery  ought to render her almost   
insensible to the heaviest ,atlantic    
rollers2  certainly as far as pitching  

is concerned4    ,illustration3 ,,the   
,,original ,,parson',s ,,turbine        
,,engine ,,and ,,the                    
,,record-,,breaking ,,ship ,,for ,,which
 ,,it ,,is ,,responsible4    ,this small
 turbine engine1 with which ,mr4        
,parson's early experiments  were made  
in #ahhd1 is preserved in the ,south    
,kensington ,museum1 ,london4  ,at the  
time when it was made it seemed scarcely
 more than a toy1 and  engineers in     
general doubted that the principle it   
employed could ever  be made            
commercially available4 ,yet within the 
lifetime of its inventor  engines built 
on this model have come to be the most  
powerful of force  transmuters4 ,the    
,mauretania1 the largest1 and thanks to 
her turbine  engines the speediest1 of  
ships1 is here presented on the same    
page  with the little original turbine  
model1 as illustrating vividly the      
practical development of a seemingly    
visionary idea4    ,a more general      
comment upon the turbine engine1 with   

particular  reference to its use in     
,america1 is made by ,mr4 ,edward ,h4   
,sanborn in an  article on ,motive      
,power ,appliances1 in the ,twelfth     
,census ,report of  the ,united ,states1
 ,vol4 ,x4 part ,,iv4    ,apart from its
 demonstrated economy1 says ,mr4        
,sanborn1 other  important advantages   
are claimed for the steam turbine1 some 
of which  are worthy of brief mention4  
,there is an obvious advantage in       
economy of space as compared with  the  
reciprocating engine4 ,the largest steam
 turbine constructed in the  ,united    
,states is one of #c1jjj horse-power1   
which is installed in the  power house  
of the ,hartford ,electric ,light       
,company1 ,hartford1 ,conn4 ,the  total 
weight of this motor is #bh1jjj pounds1 
its length over all is #ai  feet #h     
inches1 and its greatest diameter six   
feet4 ,with the generator  to which it  
is directly connected1 it occupies a    
floor space of #cc feet  #c inches long 
by #h feet #i inches wide4    ,friction 

is reduced to a minimum in the steam    
turbine1 owing to the  absence of       
sliding parts and the small number of   
bearings4 ,the absence  of internal     
lubrication is also an important        
consideration1 especially  when it is   
desired to use condensers4    ,as there 
are no reciprocating parts in a steam   
turbine1 and as a  perfect balance of   
its rotating parts is absolutely        
essential to its  successful operation1 
vibration is reduced to such a small    
element that  the simplest foundations  
will suffice1 and it is safe to locate  
steam  turbines on upper floors of a    
factory if this be desirable or         
necessary4    ,the perfect balance of   
the moving parts and the extreme        
simplicity  of construction tend to     
minimize the wear and increase the life 
of a  turbine1 and at the same time to  
reduce the chance of interruption  in   
its operation through derangement of1 or
 damage to1 any of its  essential parts4
    ,although hardly beyond the stage of

 its first advent in the  motive-power  
field1 the steam turbine has met with   
much favor1 and  there is promise of its
 wide use for the purposes to which it  
is  particularly adapted4 ,at present1  
however1 its uses are restricted to     
service that is continuous and regular1 
its particular adaptability  being for  
the driving of electrical generators1   
pumps1 ventilating  fans1 and similar   
work1 especially where starting under   
load is not  essential4    ,steam       
turbines are now being built in the     
,united ,states in all sizes  up to     
#c1jjj horse-power4 ,their use abroad   
covers a longer period and  has become  
more general4 ,the largest turbines thus
 far attempted  are those of the        
,metropolitan ,district ,electric       
,traction ,company1  of ,london1        
embracing four units of #aj1jjj         
horse-power each4 ,several  turbines of 
large size have been operated           
successfully in ,germany4    ,it should 
be added that the compound turbine wheel

 of ,parsons is not  the only turbine   
wheel that has proved commercially      
valuable4 ,there  is a turbine          
consisting of a single ring of revolving
 blades1 the  invention of ,dr4 ,gustav 
,de ,laval1 which has proved itself     
capable of  competing with the old type 
of engine4 ,to make this form of single 
turbine operate satisfactorily1 it is   
necessary to have steam under  high     
pressure1 and to generate a very high   
speed of revolution4 ,in  practice1 the 
,de ,laval machines sometimes attain a  
speed of thirty  thousand revolutions   
per minute4 ,this is a much higher rate 
of speed  than can advantageously be    
utilized directly in ordinary machinery1
 and  consequently the shaft of this    
machine is geared to another shaft in   
such a way as to cause the second shaft 
to revolve much more slowly4            
,,vii    ,,gas ,,and ,,oil ,,engines    
,just at the time when the type of      
piston-and-cylinder engine has thus     
been challenged1 it has chanced that a  

new motive power has been  applied to   
the old type of engine1 through the     
medium of heated gas4  ,the idea of such
 utilization of a gas other than water  
vapor is by no  means new1 but there    
have been practical difficulties in the 
way of the  construction of a commercial
 engine to make use of the expansive    
power  of ordinary gases4    ,the       
principle involved is based on the      
familiar fact that a gas expands  on    
being heated and contracts when cool4   
,theoretically1 then1 all that  is      
necessary is to heat a portion of air   
confined in a cylinder1 to  secure the  
advantage of its expansion1 precisely as
 the expansion of  steam is utilized1 by
 thrusting forward a piston4 ,such an   
apparatus  constitutes a so-called      
caloric or hot-air engine4 ,as long ago 
as the year #ahjg ,sir ,g4 ,cayley in   
,england produced a motor of this  type1
 in which the heated air passed directly
 from the furnace to the  cylinder1     
where it did work while expanding until 

its pressure was not  greater than that 
of the atmosphere1 when it was          
discharged4 ,the chief  mechanical      
difficulty encountered resulted from the
 necessity for the  employment of very  
high temperatures2 and for a long time  
the engine  had no great commercial     
utility4 ,the idea was revived1 however1
 about  three-quarters of a century     
later and an engine operated on         
,cayley's  principle was commercially   
introduced in ,england by ,mr4 ,buckett4
 ,this  engine has a cold-air cylinder  
above the crank-shaft and a large       
hot-air cylinder below1 while the       
furnace is on one side enclosed in an   
air-tight chamber4 ,the fuel is supplied
 as required through a valve and        
distributing cone arranged above the    
furnace and provided with an air  lock  
in which the fuel is stored4 ,at about  
the time when this hot-air  engine was  
introduced1 however1 gas and oil engines
 of another and more  important type    
were developed1 as we shall see in a    

moment4    ,meantime1 an interesting    
effort to utilize the expansive property
 of  heated air was made by ,dr4        
,stirling in #ahbf2 his engine being one
  in which heat was distributed by means
 of a displacer which moved  the mass of
 air to and fro between the hot and cold
 portions of the  apparatus4 ,he also   
compressed the air before heating it1   
thus making a  distinct advance in the  
economy and compactness of the engine4  
,from an  engineering standpoint his    
design has further interest in that it  
was  a practical attempt to construct an
 engine working on the principle  of the
 theoretically perfect heat engine1 in  
which the cycle of  operations is       
closed1 the same mass of air being used 
throughout4 ,in  the theoretically      
perfect heat engine1 it may be added1   
the cycle of  operations may be         
reversed1 there being no loss of energy 
involved2 but  in practice1 of course1  
an engine cannot be constructed to meet 
this  ideal condition1 as there is      

necessarily some loss through           
dissipation  of heat4 ,dr4 ,stirling's  
practical engine had its uses1 but could
 not  compete with the steam engine in  
the general field of mechanical         
operations to which that apparatus is   
applied4    ,another important practical
 experimenter in the construction of    
hot-air engines was ,john ,ericsson1 who
 in #ahbd constructed an engine         
somewhat resembling the early one of    
,cayley1 and in #aheb built caloric     
engines on such a scale as to be adapted
 to the propulsion of ships4            
,notwithstanding the genius of          
,ericsson1 however1 engines of this     
type did not prove commercially         
successful on a large scale1 and  in    
subsequent decades the hot-air motors   
constructed for practical  purposes     
seldom exceeded one horse-power4 ,such  
small engines as  these are             
comparatively efficient and absolutely  
safe1 and they are  thoroughly adapted  
for such domestic purposes as light     

pumping4    ,the great difficulty with  
all these engines operated with heated  
air  has been1 as already suggested1    
that their efficiency of action is      
limited by the difficulties incident to 
applying high temperatures  to large    
masses of the gas4 ,there is1 however1  
no objection to the  super-heating of   
small quantities of gas1 and it was     
early suggested  that this might be     
accomplished by exploding a gaseous     
mixture  within a cylinder4 ,it was     
observed by the experimenters of the    
seventeenth century that an ordinary gun
 constitutes virtually an               
internal-combustion engine2 and such    
experimenters as the ,dutchman          
,huyghens1 and the ,frenchmen           
,hautefeuille and ,papin1 attempted to  
make  practical use of the power set    
free by the explosion of gunpowder1     
their experiments being conducted about 
the years #afgh to #afhi4  ,their       
results1 however1 were not such as to   
give them other than an  historical     

interest4 ,about a century later1 in    
#agid1 the ,englishman  ,robert ,street 
suggested the use of inflammable gases  
as explosives1 and  ever since that time
 there have been occasional             
experimenters along  that line4 ,in     
#ahbc ,samuel ,brown introduced a vacuum
 gas engine for  raising water by       
atmospheric pressure4 ,the first fairly 
practical gas  engine1 however1 was that
 introduced by ,j4 ,j4 ,e4 ,lenoir1 who 
in #ahej  proposed an engine working    
with a cycle resembling that of a steam 
engine4 ,his engine patented in #ahfj   
proved to be a fairly successful        
apparatus4 ,this engine of ,lenoir      
prepared the way for gas engines that   
have since become so enormously         
important4 ,its method of action is     
this3    ,to start the engine1 the      
fly-wheel is pulled round1 thus moving  
the  piston1 which draws into the       
cylinder a mixture of gas and air       
through  about half its stroke2 the     
mixture is then exploded by an electric 

spark1 and propels the piston to the end
 of its stroke1 the pressure  meanwhile 
falling1 by cooling and expansion1 to   
that of the atmosphere  when exhaust    
takes place4 ,in the return stroke the  
process is repeated1  the action of the 
engine resembling that of the           
double-acting steam  engine1 and having 
a one-stroke cycle4 ,the cylinder and   
covers are  cooled by circulating water4
 ,the firing electricity was supplied by
 two  ,bunsen batteries and an induction
 coil1 the circuit being completed at   
the right intervals by contact pieces on
 an insulating disc on the  crank-shaft2
 the ignition spark leaped across the   
space between two  wires carried about  
one-sixth of an inch apart in a         
porcelain holder4    ,in #ahfe ,mons4   
,p4 ,hugon patented an engine similar to
 that of ,lenoir1  except that ignition 
was accomplished by an external flame   
instead of  by electricity4 ,the        
ignition flame was carried to and fro in
 a cavity  inside a slide valve1 moved  

by a cam so as to get a rapid cut-off1  
and  permanent lights were maintained at
 the ends of the valve to re-light  the 
flame-ports after each explosion4 ,the  
gas was supplied to the  cylinder by    
rubber bellows1 worked by an eccentric  
on the crank-shaft4  ,this engine could 
be operated satisfactorily1 except as to
 cost1 but  the heavy gas consumption   
made it uneconomical4    ,an important  
improvement in this regard was          
introduced by the ,germans1  ,herrn4 ,e4
 ,langen and ,n4 ,a4 ,otto1 who under   
patents bearing date of  #ahff          
introduced a so-called free piston      
arrangement--that is to say  an         
arrangement by which the piston depends 
for its action partly upon  the momentum
 of a fly-wheel4 ,this principle had    
been proposed for a  gas engine as early
 as #aheg1 but the first machine to     
demonstrate its  feasibility was that of
 ,langen and ,otto4 ,their engine       
greatly decreased  the gas consumption  
and hence came to be regarded as the    

first  commercially successful gas      
engine4 ,it was1 however1 noisy and     
limited  to small sizes4 ,the cycle of  
operations of an engine of this type is 
described as follows3    ,illustration3 
,,gas ,,and ,,oil ,,engines4    ,lower  
right-hand figure1 a very early type of 
commercially successful  gas engine4 ,it
 has a free piston1 an arrangement that 
was first  proposed for a gas engine in 
#aheg1 but only brought into practical  
form  by ,langen  ,otto under their     
patent of #ahff4 ,upper figure1 the gas 
engine patented by ,lenoir in #ahfj1 one
 of the very first practically          
successful engines4 ,lower left-hand    
figure1 a sectional view of a  modern   
gas engine of the type used as the motor
 of the automobile4    7a7 ,the piston  
is lifted about one-tenth of its travel 
by the momentum  of the fly-wheel1 thus 
drawing in a charge of gas and air4     
7b7 ,the charge is ignited by flame     
carried in by a slide valve4    7c7     
,under the impulse of the explosion1 the

 piston shoots upward  nearly to the top
 of the cylinder1 the pressure in which 
falls by  expansion to about #d lbs4    
absolute1 while absorbing the energy of 
the  piston4    7d7 ,the piston descends
 by its own weight and the atmospheric  
pressure1 and in doing so causes a      
roller-clutch on a spur-wheel  gearing  
with a rack on the piston-rod to engage1
 so that the fly-wheel  shaft shall be  
driven by the piston2 during this       
down-stroke the  pressure increases from
 #d lbs4 absolute to that of the        
atmosphere1 and  averages #g lbs4 per   
square inch effective throughout the    
stroke4    7e7 ,when the piston is near 
the bottom of the cylinder1 the pressure
  rises above atmospheric1 and the      
stroke is completed by the weight of    
the piston and rack1 and the products of
 combustion are expelled4    7f7 ,the   
fly-wheel now continues running freely  
till its speed1 as  determined by a     
centrifugal governor1 falls below a     
certain limit when  a trip gear causes  

the piston to be lifted the short       
distance required  to recommence the    
cycle4    ,ignition is performed by an  
external gas jet1 near a pocket in the  
slide valve by which the charge is      
admitted2 this pocket carries flame  to 
the charge1 thus igniting it without    
allowing any escape4 ,the valve  also   
connects the interior of the cylinder   
with the exhaust pipe1  and a valve in  
the latter controlled by the governor   
throttles the  discharge1 and so defers 
the next stroke until the speed has     
fallen  below normal4 ,to run the engine
 empty about four explosions per minute 
are necessary1 and at full power #cj to 
#ce are made1 so that about #bh         
explosions per minute are available for 
useful work under the control  of the   
governor4    ,the definitive improvement
 in this gas engine was introduced in   
#ahgf  by ,dr4 ,n4 ,a4 ,otto1 when he   
compressed the explosive mixture in the 
working cylinder before igniting it4    
,this expedient--so all-important  in   

its results--had been suggested by      
,william ,barnett in #ahch1 but at  that
 time gas engines were not sufficiently 
developed to make use of  the idea4     
,now1 however1 ,dr4 ,otto demonstrated  
that by compressing the  gas before     
exploding it a much more diluted mixture
 can be fired1 and  that this gives a   
quieter explosion1 and a more sustained 
pressure  during the working stroke1    
while as the engine runs at a high speed
 the  fly-wheel action is generally     
sufficient to correct the fluctuations  
arising from there being but one        
explosion for four strokes of the       
piston4    ,in this perfected engine1   
then1 the method of operation is as     
follows3    ,the piston is pulled       
forward with the application of some    
outside  force1 which in practice is    
supplied by the inertia of the          
fly-wheel1  or in starting the engine by
 the action of a crank with which every 
user of an automobile is familiar4 ,in  
being pulled forward1 the piston  draws 

gas into the cylinder2 as the piston    
returns1 this gas is  compressed2 the   
compressed gas1 constituting an         
explosive mixture1 is  then ignited by a
 piece of incandescent metal or by an   
electric spark2  the exploding gas      
expands1 pushing the piston forward1    
this being the  only thrust during which
 work is done2 the returning piston     
expels the  expanded gas1 completing the
 cycle4 ,thus there are three           
ineffective  piston thrusts to one      
effective thrust4 ,nevertheless1 the    
engine has  proved a useful one for many
 purposes4    ,this so-called ,otto     
cycle has been adopted in almost all gas
 and oil  engines1 the later            
improvements being in the direction of  
still higher  compression1 and in the   
substitution of lift for slide valves4  
,there  has been a steady increase in   
the size and power of such engines1 the 
large ones usually introducing two or   
more working cylinders so as to  secure 
uniform driving4 ,cheap forms of gas    

have been employed such as  those made  
by decomposing water by incandescent    
fuel1 and it has been  proved possible  
thus to operate gas-power plants on a   
commercial scale  in competition with   
the most economical steam installations4
    ,a practical modification of vast   
importance was introduced when it  was  
suggested that a volatile oil be        
employed to supply the gas for          
operation in an internal combustion     
engine4 ,there was no new principle     
involved in this idea1 and the ,otto    
cycle was still employed as  before2 but
 the use of the volatile oil--either a  
petroleum product  or alcohol--made     
possible the compact portable engine    
with which  everyone is nowadays        
familiar through its use in automobiles 
and  motor boats4 ,the oil commonly used
 is gasoline which is supplied to  the  
cylinder through a so-called carburettor
 in which the vapors of  gasoline are   
combined with ordinary air to make an   
explosive mixture4  ,the introduction of

 this now familiar type of motor is to a
 large  extent due to ,herr ,g4         
,daimler1 who in #ahhd brought out a    
light and  compact high-speed oil       
engine4 ,about ten years later ,messrs4 
,panhard  and ,levassor devised the form
 of motor which has since been generally
  adopted4 ,few other forms of          
mechanisms are better known to the      
general  public than the oil engine with
 its two1 four1 six1 or even eight      
cylinders1 as used in the modern        
automobile4 ,as everyone is aware1 it   
furnishes the favorite type of motor1   
combining extraordinary power  with     
relative lightness1 and making it       
feasible to carry fuel for a  long      
journey in a receptacle of small        
compass4    ,with the gas engines a     
complication arises precisely opposite  
to that  which is met with in the case  
of the cylinder of the steam engine--the
  tendency1 namely1 to overheating of   
the cylinder4 ,to obviate this it  is   
customary to have the cylinder          

surrounded by a water jacket1 though    
air cooling is used in certain types of 
machines4 ,about fifty per cent4  of the
 total heat otherwise available is lost 
through this unavoidable  expedient4    
,the rapid introduction of the gas      
engine in recent years suggests that    
this type of engine may have a most     
important future4 ,it has even  been    
predicted that within a few years most  
trans-,atlantic steamers  will be       
equipped with this type of engine1      
producing their own gas  in transit4 ,it
 is possible1 then1 that through this   
medium the old  piston-and-cylinder     
engine may retain its supremacy1 as     
against the  turbine4 ,for the moment1  
at any rate1 the gas engine is gaining  
popularity1 not merely in its           
application to the automobile1 but for  
numerous types of small stationary      
engines as well4    ,in this connection 
it will be interesting to quote the     
report of the  ,special ,agent of the   
,twelfth ,census of the ,united ,states1

 as showing  the status of gas engines  
and steam engines in the year #aijb4    
,the decade between #ahij and #aijj1 he 
says1 was a period of marked            
development in the use of gas engines1  
using that term to denote all  forms of 
internal combustible engines1 in which  
the propelling force  is the explosion  
of gaseous or vaporous fuel in direct   
contact with  a piston within a closed  
cylinder4 ,this group embraces those    
engines  using ordinary illuminating    
gas1 natural gas1 and gas made in       
special  producers installed as a part  
of the power plant1 and also vaporised  
gasoline or kerosene4 ,this form of     
power for the first time is an item  of 
consequence in the returns of the       
present census1 and the very large      
increase in the horse-power in #aijj as 
compared with #ahij indicates the       
growing popularity of this class of     
motive power4    ,in #ahij the number of
 gas engines in use in manufacturing    
plants  was not reported1 but their     

total power amounted to only #h1icj     
horse-power1 or one-tenth of one per    
cent of the total power utilized  in    
manufacturing operations4 ,in #aijj1    
however1 #ad1hhd gas engines were       
reported1 with a total of #adc1hej      
horse-power1 or #a4c per cent of the    
total power used for manufacturing      
purposes4 ,this increase from #h1icj    
horse-power to #adc1hej horse-power1 a  
gain of #acd1ibj horse-power1 is        
proportionately the largest increase in 
any form of primary power shown  by a   
comparison of the figures of the        
,eleventh and ,twelfth censuses1        
amounting to #a1eaj4i per cent4         
,within the past decade1 and more       
particularly during the past  five      
years1 there has been a marked increase 
in the use of this  power in industrial 
establishments for driving machinery1   
for  generating electricity1 and for    
other kindred uses4 ,at the same time1  
internal-combustion engines have        
increased in popularity for uses apart  

from manufacturing1 and the amount of   
this kind of power in use for all       
purposes in #aijj was1 doubtless1 very  
much larger than indicated by the       
figures relating to manufacturing plants
 alone4    ,the average horse-power per 
gas engine in #aijj was #i4g            
horse-power4  ,there are no available   
statistics upon which to base a         
comparison of  this average with the    
average for #ahij1 but it is doubtful if
 there  has been any very material      
change in ten years2 for while gas      
engines  are built in much larger sizes 
than ever before1 there has been also a 
great increase in the number of small   
engines for various purposes4    ,the   
large increase in the use of            
internal-combustion engines has  been   
due to the rapid improvements that have 
been made in them1 their  increased     
efficiency and economy1 their decreased 
cost1 and the wider  range of           
adaptability that has been made         
practicable4    ,steam still continues  

to be preeminently the power of greatest
  importance1 and the census returns    
indicate that the proportion of  steam  
to the total of all powers has increased
 very largely in the past  thirty years4
 ,in #ahgj steam furnished #a1bae1gaa   
horse-power1 or #ea4h  per cent of a    
total of #b1cdf1adb2 in #ahhj the amount
 of steam power  used was #b1ahe1deh    
horse-power out of a total of           
#c1daj1hcg1 or #fd4a per  cent2 in #ahij
 out of an aggregate of #e1ied1fee      
horse-power1 #d1eha1eie1  or #gf4i per  
cent was steam2 while in #aijj steam    
figured to the extent  of #h1gdb1daf    
horse-power1 or #gg4d per cent1 in a    
total of #aa1cjj1jha4  ,this increase in
 thirty years1 from #ea4h per cent to   
#gg4d per cent of  the total power1     
shows how much more rapidly the use of  
steam power has  increased than other   
primary sources of power4    ,the       
tendency toward larger units in the use 
of steam power is shown  inadequately by
 the increase in the average horse-power

 per engine from  #ci horse-power in    
#ahhj1 to #ea horse-power in #ahij1 and 
#ef horse-power  in #aijj4    ,the      
tendency toward great operations which  
has been such a conspicuous  feature of 
industrial progress during the past ten 
years1 has shown  itself strikingly in  
the use of units of larger capacity in  
nearly  every form of machinery1 and    
nowhere has this tendency been more     
marked  than in the motive power by     
which the machinery is driven4 ,at the  
same  time there has been an increase in
 the use of small units1 which tends  to
 destroy the true tendency in steam     
engineering in these statistics4  ,for  
example1 a steam plant consisting of one
 or more units of several  thousand     
horse-power may also embrace a number of
 small engines of  only a few           
horse-power each1 the use of which is   
necessitated by the  magnitude of the   
plant1 for the operation of mechanical  
stokers1 the  driving of draft fans1    
coal and ash conveyors1 and other work  

requiring  power in small units4 ,on    
this account the average horse-power of 
steam  engines in use at different      
census periods fails to afford a true   
basis for measuring progress toward     
larger units during the past ten  years4
    ,developments of the past few years 
in the distribution of power by the  use
 of electric motors have served to      
accelerate the tendency toward  larger  
steam units and the elimination of small
 engines in large plants  and to change 
completely the conditions just          
described4 ,for example3  ,in one of the
 largest power plants in the world1     
which is now being  installed1 all the  
stokers1 blowers1 conveyors1 and other  
auxiliary  machinery are to be driven by
 electric motors4 ,such rapidly changing
  conditions tend to invalidate any     
comparisons of statistical averages     
deduced from figures for periods even   
but a few years apart4    ,comparison of
 two important industries will          
illustrate the foregoing4  ,the average 

horse-power of the steam engine used in 
the cotton mills of  the ,united ,states
 in #ahij was #aih1 and in #aijj it was 
#cjj4    ,in the iron and steel industry
 the average horse-power per engine in  
#ahij was #aga1 and in #aijj it was     
#bce4 ,in the cotton mills the use of   
single large units of motive power1 with
 few auxiliary engines of small         
capacity1 gives the largest horse-power 
per engine of any industry2  while in   
the iron and steel industry the average 
of the motive power  proper1 although   
probably larger than in the manufacture 
of cotton  goods1 is reduced by the     
large number of small engines which are 
used  for auxiliary purposes in every   
iron and steel plant4    ,it will be    
understood that the object of exploding 
the mixed gases in  the oil engine is to
 produce sudden heating of the entire   
gas4 ,there  is no reason whatever for  
introducing the gasoline beyond this4   
,could  a better method of heating air  
be devised1 the oil might be entirely   

dispensed with1 and the safety of the   
apparatus enhanced1 as well as  the     
economy of operation4 ,efforts have been
 made for fifty years to  construct a   
hot-air engine that would compete with  
steam successfully4  ,in the early      
fifties1 as already noted1 ,ericsson    
showed the feasibility  of substituting 
hot air for steam1 but although he      
constructed large  engines1 their power 
was so slight that he was obliged to    
give up the  idea of competing with     
steam1 and to use his engines for       
pumping where  very small power was     
required4    ,the great difficulty was  
that it was not found practicable to    
heat  the air rapidly4 ,all subsequent  
experimenters have met with the same    
difficulty until somewhat recently4 ,it 
is now claimed1 however1 that  a means  
has been found of rapidly heating the   
air1 and it is even  predicted that the 
hot-air engine will in due course       
entirely supersede  the steam engine4   
,mr4 ,g4 ,emil ,hesse1 in an article in 

,the ,american  ,inventor1 for ,april   
#ae1 #aije1 describes a ,svea caloric   
engine as  having successfully solved   
the problem of rapidly heating air4 ,the
  methods consist in breaking up the air
 into thin layers and passing  it over  
hot plates1 where it rapidly absorbs    
heat4 ,it passes from the  heater to the
 power cylinder which resembles the     
cylinder of a steam  engine2 thence     
after expanding and doing its work it is
 exhausted into  the atmosphere4 ,large 
engines may use the same air over and   
over again  under pressure of one       
hundred pounds per square inch1         
alternately  heating and cooling it4 ,a 
six horse-power engine of this type is  
said to have a cylinder four and        
one-half inches in diameter and a       
stroke of four and seven-eighth inches1 
and makes four hundred and  fifty       
revolutions per minute4 ,the heater is  
twenty inches in diameter1  sixteen     
inches long1 and has a heating surface  
of sixty square feet4  ,the total weight

 of heater and engine complete is four  
hundred pounds  for a half horse-power  
,ericsson engine4    ,the ,svea heater1 
says ,mr4 ,hesse1 absorbs the heat as   
perfectly  as an ordinary steam boiler1 
and the heat-radiating surface of both  
heater and engine is not larger than    
that of a steam plant of the same       
power1 thereby placing the two motors on
 the same basis1 as far as the          
utilization of the heat in the fuel     
itself is concerned4    ,the advantage  
which every hot-air engine has over the 
steam engine is  the amount of heat     
saved in the vaporization of the water4 
,it is now  well known that one gas is  
as efficient as another for the         
conversion  of heat into power4 ,air and
 steam at #ajj ,c4 are consequently on  
the  same footing and ready to be       
superheated4 ,the amount of heat        
required  to bring the two gases to this
 temperature is1 however1 very          
different4    ,with an initial          
temperature of #aj ,c4 for both air and 

water1 we find  that one kilogram of    
steam requires #ij  #ecg  #fbg thermal  
units1  and one kilogram of air #j4bd   
#ij  #ba4f thermal units4 ,some heat is 
recovered if the feed water is heated   
and the steam condensed1 but  the       
difference is still so great as to      
altogether exclude steam as a           
competitor1 provided air can be as      
readily handled4    ,having now the     
means to rapidly heat the air1 the      
outlook for the  external-combustion    
engine is certainly very promising4     
,the saving of more than half the coal  
now used by the steam engine  will be of
 tremendous importance to the whole     
world4    ,to what extent this          
optimistic prediction will be verified  
is a problem  for the future to decide4 
,,viii    ,,the ,,smallest ,,workers    
,in our studies of the steam engine and 
gas engine we have been  concerned with 
workers of infinitesimal size4 ,yet1 if 
we are to believe  the reports of the   
modern investigator1 the molecules of   

steam or of  ignited gas are small only 
in a relative sense1 and there is a     
legion  of workers compared with which  
the molecules are really gigantic in    
size4 ,these workers are the atoms1 and 
the yet more minute particles  of which1
 according to the most recent theories1 
they are themselves  composed4    ,these
 smallest conceivable particles1 the    
constituents of the atoms1  are called  
electrons4 ,they are a discovery of the 
physicists of the  most recent          
generation4 ,according to the newest    
theories they account  for most--perhaps
 for all--of the inter-molecular and    
inter-atomic  forces2 they are indeed   
the ultimate repositories of those      
stores of  energy which are known to be 
contained in all matter4 ,the theories  
are not quite as fully developed as     
could be wished1 but it would  appear   
that these minutest particles1 the      
electrons1 are the essential            
constituents of the familiar yet        
wonderful carrier of energy which  we   

term electricity4 ,in considering the   
share of electricity in  the world's    
work1 therefore1 we shall do well at the
 outset to put  ourselves in touch with 
recent views as to the nature of this   
most  remarkable of workers4    ,on     
every side in this modern world we are  
confronted by this strange  agent1      
electricity4 ,the word stares us in the 
face on every printed  page4 ,the thing 
itself is manifest in all departments of
 our every-day  life4 ,you go to your   
business in an electric car2 ascend to  
your  office in an electric elevator2   
utilize electric call-bells2 receive    
and transmit messages about the world   
and beneath the sea by electric         
telegraph4 ,your doctor treats you with 
an electric battery4 ,your  dentist     
employs electric drills and electric    
furnaces4 ,you ride in  electric cabs2  
eat food cooked on electric stoves2 and 
read with the  aid of electric light4   
,in a word1 the manifestations of       
electricity are  so obvious on every    

side that there can be no challenge to  
the phrasing  which has christened this 
the ,age of ,electricity4    ,but what1 
then1 is this strange power that has    
produced all these  multifarious        
results8 ,it would be hard to propound a
 scientific query  that has been more   
variously answered4 ,ever since the     
first primitive  man observed the       
strange effect produced by rubbing a    
piece of amber1  thoughtful minds must  
have striven to explain that effect4    
,ever since  the eighteenth-century     
scientist began his more elaborate      
studies of  electricity1 theories in    
abundance have been propounded4 ,and yet
 we  are not quite sure that even the   
science of to-day can give a correct    
answer as to the nature of electricity4 
,at the very least1 however1 it  is able
 to give some interesting suggestions   
which seem to show that  we are in a    
fair way to solve this world-old        
mystery4 ,and1 curiously  enough1 the   
very newest explanations are not so very

 far away from  some eighteenth-century 
theories which for a long time were     
looked  at askance if not altogether    
discarded4 ,in particular1 the theory of
  ,benjamin ,franklin1 which considered 
electricity as an immaterial fluid      
bearing certain curious relations to    
tangible matter1 is found to serve      
singularly well as an aid to the        
interpretation of the very newest       
experiments4      ,,franklin',s         
,,one-,,fluid ,,theory    ,such being   
the case1 we must consider this theory  
of ,franklin's  somewhat in detail4     
,perhaps we cannot do better than state 
the theory  in the words of the         
celebrated physicist1 ,dr4 ,thomas      
,young1 as given  in his work on natural
 philosophy1 published in #ahjg4 ,by    
quoting from  this old work we shall    
make sure that we are not reading any   
modern  interpretations into the theory4
 ,it is supposed1 says ,young1 that a   
peculiar ethereal fluid pervades the    
pores1 if not the actual substance  of  

the earth and of all other material     
bodies1 passing through them  with more 
or less facility1 according to their    
different powers of  conducting it2 that
 particles of this fluid repel each     
other1 and are  attracted by particles  
of common matter2 that particles of     
common  matter also repel each other2   
and that these attractions and          
repulsions  are equal among themselves1 
and vary inversely as to squares of the 
distances of the particles4 ,the effects
 of this fluid are distinguished  from  
those of all other substances by an     
attractive or repulsive  quality1 which 
it appears to communicate to different  
bodies1 and  which differs in general   
from other attractions and repulsions by
  its immediate diminution or cessation 
when the bodies1 acting on  each other1 
come into contact1 or are touched by    
other bodies4444 ,in  general1 a body is
 said to be electrified when it         
contains1 either as  a whole or in any  
of its parts1 more or less of the       

electric fluid  than is natural to      
it4444 ,in this common neutral state of 
all bodies1  the electrical fluid1 which
 is everywhere present1 is so           
distributed  that the various forces    
hold each other exactly in equilibrium  
and  the separate results are destroyed1
 unless we choose to consider           
gravitation itself as arising from a    
comparatively slight inequality  between
 the electrical attractions and         
repulsions4    ,the salient and striking
 feature of this theory1 it will be     
observed1  is that the electrical fluid1
 under normal conditions1 is supposed to
  be incorporated everywhere with the   
substance of every material in  the     
world4 ,it will be observed that nothing
 whatever is postulated as  to the      
nature or properties of this fluid      
beyond the fact that its  particles     
repel each other and are attracted by   
the particles of common  matter2 it     
being also postulated that the particles
 of common matter  likewise repel each  

other under normal conditions4    ,at   
the time when ,franklin propounded his  
theory1 there was a rival  theory before
 the world1 which has continued more or 
less popular ever  since1 and which is  
known as the two-fluid theory of        
electricity4  ,according to this theory1
 there are two uncreated and            
indestructible  fluids which produce    
electrical effects4 ,one fluid may be   
called  positive1 the other negative4   
,the particles of the positive fluid are
  mutually repellent1 as also are the   
particles of the negative fluid1  but1  
on the other hand1 positive particles   
attract and are attracted by  negative  
particles4 ,we need not further         
elaborate the details of this  two-fluid
 theory1 because the best modern opinion
 considers it less  satisfactory than   
,franklin's one-fluid theory4 ,meantime1
 it will be  observed that the two      
theories have much in common2 in        
particular they  agree in the essential 
feature of postulating an invisible     

something  which is not matter1 and     
which has strange properties of         
attraction and  repulsion4    ,these    
properties of attraction and repulsion  
constituted in the  early day the only  
known manifestations of electricity2 and
 the same  properties continue to hold  
an important place in modern studies of 
the subject4 ,electricity is so named   
simply because amber--the ,latin        
electrum--was the substance which1 in   
the experience of the ancients1  showed 
most conspicuously the strange property 
of attracting small  bodies after being 
rubbed4 ,modern methods of developing   
electricity  are extremely diversified1 
and most of them are quite unsuggestive 
of the rubbing of amber2 yet nearly all 
the varied manifestations of            
electricity are reducible1 in the last  
analysis1 to attractions and  repulsions
 among the particles of matter4    ,as  
to the alleged immaterial fluids which1 
according to the theories  just         
mentioned1 make up the real substance of

 electricity1 it was  perfectly natural 
that they should be invented by the     
physicists of the  elder day4 ,all the  
conceptions of the human mind are       
developed through  contact with the     
material world2 and it is extremely     
difficult to get  away1 even in theory1 
from tangible realities4 ,when the      
rubbed amber  acquires the property of  
drawing the pith ball to it1 we         
naturally  assume that some change has  
taken place in the condition of the     
amber2  and since the visible particles 
of amber appear to be unchanged--since  
its color1 weight1 and friability are   
unmodified--it seems as if some         
immaterial quality must have been added 
to1 or taken from it4 ,and it  was      
natural for the eighteenth-century      
physicist to think of this  immaterial  
something as a fluid1 because he was    
accustomed to think of  light1 heat1 and
 magnetism as being also immaterial     
fluids4 ,he did not  know1 as we now do1
 that what we call heat is merely the   

manifestation  of varying modes of      
motion among the particles of matter1   
and that  what we call light is not a   
thing sui generis1 but is merely our    
recognition of waves of certain length  
in the all-pervading ether4  ,the wave  
theory of light had1 indeed1 been       
propounded here and  there by a         
philosopher1 but the theory which       
regarded light as a  corpuscular        
emanation had the support of no less an 
authority than  ,sir ,isaac ,newton1 and
 he was a bold theorist that dared      
challenge it4  ,when ,franklin          
propounded his theory of electricity1   
therefore1 his  assumption of the       
immaterial fluid was thoroughly in      
accord with the  physical doctrines of  
the time4      ,,modern ,,views    ,but 
about the beginning of the nineteenth   
century the doctrine  of imponderable   
fluids as applied to light and heat was 
actively  challenged by ,young and      
,fresnel and by ,count ,rumford and     
,humphry ,davy  and their followers1 and

 in due course the new doctrines of     
light and  heat were thoroughly         
established4 ,in the light of the new   
knowledge1  the theory of the electric  
fluid or fluids seemed1 therefore1 much 
less plausible4 ,whereas the earlier    
physicists had merely disputed as  to   
whether we must assume the existence of 
two electrical fluids or  of only one1  
it now began to be questioned whether we
 need assume the  existence of any      
electrical fluid whatever4 ,the         
physicists of about  the middle of the  
nineteenth century developed the        
wonderful doctrine  of conservation of  
energy1 according to which one form of  
force may be  transformed into another1 
but without the possibility of adding   
to1 or  subtracting from1 the original  
sum total of energy in the universe4    
,it became evident that electrical force
 must conform to this law4  ,finally1   
,clerk-,maxwell developed his wonderful 
electromagnetic theory1  according to   
which waves of light are of electrical  

origin4 ,the work of  ,maxwell was      
followed up by the ,german ,hertz1 whose
 experiments produced  those            
electromagnetic waves which1 differing  
in no respect except in  their length   
from the waves of light1 have become    
familiar to everyone  through their use 
in wireless telegraphy4 ,all these      
experiments showed  a close relation    
between electrical phenomena1 and the   
phenomena of  light and of radiant heat1
 and a long step seemed to be taken     
toward  the explanation of the nature of
 electricity4    ,the new studies       
associated electricity with the ether1  
rather than with  the material substance
 of the electrified body4 ,many         
experiments seemed  to show that        
electricity in motion traverses chiefly 
the surface of  the conductor1 and it   
came to be believed that the essential  
feature of  the current consists of a   
condition of strain or stress in the    
ether  surrounding a conductor1 rather  
than of any change in the conductor     

itself4 ,this idea1 which is still      
considered valid1 has the merit of      
doing away with the thought of action at
 a distance--the idea that was  so      
repugnant to the mind of ,faraday4      
,so far so good4 ,but what determines   
the ether strain8 ,there is  surely     
something that is not matter and is not 
ether4 ,what is this  something8 ,the   
efforts of many of the most             
distinguished experimenters  have in    
recent years been directed toward the   
solution of that  question2 and these   
efforts1 thanks to the new methods and  
new  discoveries1 have met with a       
considerable measure of success4 ,i must
  not attempt here to follow out the    
channels of discovery1 but must  content
 myself with stating briefly the        
results4 ,we shall have occasion  to    
consider some further details as to the 
methods in a later chapter4    ,briefly1
 then1 it is now generally accepted1 at 
least as a working  hypothesis1 that    
every atom of matter--be it oxygen1     

hydrogen1 gold1  iron1 or what          
not--carries a charge of electricity1   
which is probably  responsible for all  
the phenomena that the atom manifests4  
,this charge  of electricity may be     
positive or negative1 or it may be      
neutral1 by  which is meant that the    
positive and negative charges may just  
balance4  ,if the positive charge has   
definite carriers1 these are unknown    
except  in association with the atom    
itself2 but the negative charge1 on the 
other hand1 is carried by minute        
particles to which the name electron    
7or corpuscle7 has been given1 each of  
which is about one thousand  times      
smaller than a hydrogen atom1 and each  
of which carries uniformly  a unit      
charge of negative electricity4         
,electrons are combined1 in what may be 
called planetary systems1 in the        
substance of the atom2 indeed1 it is not
 certain that the atom consists  of     
anything else but such combinations of  
electrons1 held together  by the        

inscrutable force of positive           
electricity4 ,some1 at least1 of  the   
electrons within the atom are violently 
active--perhaps whirling  in planetary  
orbits1--and from time to time one or   
more electrons may  escape from the     
atomic system4 ,in thus escaping an     
electron takes away  its charge of      
negative electricity1 and the previously
 neutral atom  becomes positively       
electrified4 ,meanwhile the free        
electron may hurtle  about with its     
charge of negative electricity1 or may  
combine with some  neutral atom and thus
 give to that neutral atom a negative   
charge4  ,under certain conditions      
myriads of these electrons1 escaped thus
 from  their atomic systems1 may exist  
in the free state4 ,for example1 the    
so-called beta 77 rays of radium and its
 allies consist of such  electrons1     
which are being hurtled off into space  
with approximately  the speed of light4 
,the cathode rays1 of which we have     
heard so much in  recent years1 also    

consist of free electrons4    ,but1 for 
that matter1 all currents of electricity
 whatever1 according  to this newest    
theory1 consist simply of aggregations  
of free  electrons4 ,according to       
theory1 if the electrons are in uniform 
motion  they produce the phenomena of   
constant currents of electricity2 if    
they move non-uniformly they produce    
electromagnetic phenomena 7for  example1
 the waves used in wireless telegraphy72
 if they move with  periodic motion they
 produce the waves of light4 ,meanwhile 
stationary  aggregations of electrons   
produce the so-called electrostatic     
phenomena4 ,all the various ether waves 
are thus believed to be produced  by    
changes in the motions of the electrons4
 ,a very sudden stoppage1  such as is   
produced when the cathode ray meets an  
impassable barrier1  produces the       
,x-ray4    ,with these explanations in  
mind1 it will be obvious how closely    
this  newest interpretation of          
electricity corresponds in its general  

features with the old one-fluid theory  
of ,franklin4 ,the efforts of  the      
present-day physicist have resulted     
essentially in an analysis of           
,franklin's fluid1 which gives to this  
fluid an atomic structure4 ,the  new    
theory takes a step beyond the old in   
suggesting the idea that  the same      
particles which make up the electric    
fluid enter also into  the              
composition--perhaps are the sole       
physical constituents--of every         
material substance as well4 ,but while  
the new theory thus extends  the bounds 
of our vision1 we must not claim that it
 fully solves the  mystery4 ,we can     
visualize the ultimate constituent of   
electricity as  an electron one thousand
 times smaller than the hydrogen atom1  
which  has mass and inertia1 and which  
possesses powers of attraction and      
repulsion4 ,but as to the actual nature 
of this ultimate particle we are  still 
in the dark4 ,there are1 however1 some  
interesting theories as to  its         

character1 which should claim at least  
incidental attention4    ,we have all   
along spoken of the electron as an      
exceedingly minute  particle1 stating   
indeed1 that in actual size it is       
believed to be  about one thousand times
 smaller than the hydrogen atom1 which  
hitherto  had been considered the       
smallest thing known to science4 ,but we
 have  now to offer a seemingly         
paradoxical modification of this        
statement4  ,it is true that in mass or 
weight the electron is a thousand times 
smaller than the hydrogen atom1 yet at  
the same time it may be  conceived that 
the limits of space which the electron  
occupies are  indefinitely large4 ,in a 
word1 it is conceived 7by ,professor ,j4
 ,j4  ,thomson1 who is the chief        
path-breaker in this field7 that the    
electron  is in reality a sort of       
infinitesimal magnet1 having two poles  
joined  by lines or tubes of magnetic   
force 7the so-called ,faraday tube71    
which  lines or tubes are of indefinite 

number and extent2 precisely as1 on  a  
large scale1 our terrestrial globe is   
such a magnet supplied with  such an    
indefinite magnetic field4 ,that the    
mass of the electron is so              
infinitesimally small is explained on   
the assumption that this mass  is due to
 a certain amount of universal ether    
which is bound up with  the tubes where 
they are thickest2 close to the point in
 space from  which they radiate1 which  
point in space constitutes the focus of 
the  tangible electron4    ,it will     
require some close thinking on the part 
of the reader to gain  a clear mental   
picture of this conception of the       
electron2 but the  result is worth the  
effort4 ,when you can clearly conceive  
all matter as  composed of electrons1   
each one of which cobwebs space with its
 system  of magnetic tubes1 you will at 
least have a tangible picture in mind of
  a possible explanation of the forces  
of cohesion and gravitation--in  fact1  
of all the observed cases of seeming    

action at a distance4 ,if  at first     
blush the conception of space as filled 
with an interminable  meshwork of lines 
of force seems to involve us in a       
hopeless mental  tangle1 it should be   
recalled that the existence of an       
infinity of such  magnetic lines joining
 the poles of the earth may be          
demonstrated at  any time by the        
observation of a compass1 yet that these
 do not in any  way interfere with the  
play of other familiar forces4 ,there is
 nothing  unthinkable1 then1 in the     
supposition that there are myriads of   
minor  magnetic centres exerting lesser 
degrees of force throughout the same    
space4    ,all that can be suggested as 
to the actual nature of the ,faraday    
tubes is that they perhaps represent a  
condition of the ether4 ,this1          
obviously1 is heaping hypothesis upon   
hypothesis4 ,yet it should be           
understood that the hypothesis of the   
magnetic electron as the basis of       
matter1 has received an amount of       

experimental support that has raised  it
 at least to the level of a working     
theory4 ,should that theory be          
demonstrated to be true1 we shall       
apparently be forced to conclude not    
merely that electricity is present      
everywhere in nature1 but that1 in  the 
last analysis1 there is absolutely no   
tangible thing other than  electricity  
in all the universe4      ,,how         
,,electricity ,,is ,,developed          
,turning from this very startling       
theoretical conclusion to the           
practicalities1 let us inquire how      
electricity--which apparently  exists1  
as it were1 in embryo everywhere--can be
 made manifest4 ,in so  doing we shall  
discover that there are varying types of
 electricity1  yet that these have a    
singular uniformity as to their         
essential  properties4 ,as usually      
divided--and the classification answers 
particularly well from the standpoint of
 the worker--electricity is  spoken of  
as either statical or dynamical4 ,the   

words themselves are  suggestive of the 
essential difference between the two    
types4 ,statical  electricity produces  
very striking manifestations4 ,we have  
already  spoken of it as theoretically  
due to the conditions of the electrons  
at rest4 ,it must be understood1        
however1 that the statical electricity  
will1 if given opportunity1 seek to     
escape from any given location to       
another location1 under certain         
conditions1 somewhat as water which is  
stored up in a reservoir will1 when     
opportunity offers1 flow down to a      
lower level4 ,the pent-up static        
electricity has1 like the water in the  
reservoir1 a store of potential energy4 
,the physicist speaks of it as  having  
high tension4 ,in passing to a condition
 of lower tension1 the  statical        
electricity may give up a large portion 
of its energy4    ,if1 for example1 on a
 winter day in a cold climate1 you walk 
briskly  along a wool carpet1 the       
friction of your feet with the carpet   

generates a store of statical           
electricity1 which immediately passes   
over the entire surface of your body4   
,if now you touch another person  or a  
metal conductor1 such as a steam        
radiator or a gas pipe1 a  brilliant    
spark jumps from your finger1 and you   
experience what is  spoken of as an     
electrical shock4 ,if the day is very   
cold1 and the air  consequently very    
dry1 and if you will take pains to rub  
your feet  vigorously or slide along the
 carpet1 you may light a gas jet with   
the spark which will spring from your   
finger to the tip of the jet1  provided 
the latter is of metal or other         
conducting substance2 and even  if you  
attempt to avoid the friction between   
your feet and the carpet  as much as    
possible1 you may be constantly annoyed 
by receiving a shock  whenever you touch
 any conductor1 since1 in spite of your 
efforts1 the  necessary amount of       
friction sufficed to generate a store of
 statical  electricity4    ,an          

illustration of the development of this 
same form of electricity1  on a large   
scale1 is supplied by the familiar      
statical machine1 which  consists of a  
large circle of glass1 so adjusted that 
it may be  revolved rapidly against a   
suitable friction producer4 ,with such a
  machine a powerful statical current is
 produced1 capable of generating  a     
spark that may be many inches or even   
several feet in length1--a  veritable   
flash of lightning4 ,it is with such a  
supply of electricity  conducted through
 a vacuum tube that the cathode ray and 
the ,roentgen  ray are produced4        
,such effects as this suggest           
considerable capacity for doing work4   
,yet in reality1 notwithstanding the    
very sporadical character of the        
result1 the quantity of electricity     
involved in such a statical current  may
 be very slight indeed4 ,even a         
lightning flash is held to represent  a 
comparatively small amount of           
electricity4 ,faraday calculated that   

the amount of electricity that could be 
generated from a single drop  of water1 
through chemical manipulation1 would    
suffice to supply the  lightning for a  
fair-sized thunder-storm4 ,nevertheless 
the destructive  work that may be done  
by a flash of lightning may be          
considerable1 as  everyone is aware4    
,but1 on the other hand1 while the      
visible effect of  a stroke of lightning
 on a tree trunk1 for example1 makes it 
seem a  powerful agency1 yet the actual 
capacity to do work--the power to move  
considerable masses of matter--is       
extremely limited4 ,the effect on a     
tree trunk1 it will be recalled1 usually
 consists of nothing more than  the     
stripping off of a channel of bark4 ,in 
other words1 the working  energy        
contained in a seemingly powerful supply
 of statical electricity  commonly plays
 but an insignificant part4    ,the     
working agent1 and therefore the form of
 electricity which concerns  us in the  
present connection1 is the dynamical    

current4 ,this may be  generated in     
various ways1 but in practice these are 
chiefly reducible  to two4 ,one of these
 depends upon chemical action1 the other
 upon the  inter-relations of mechanical
 motion and magnetic lines of force4 ,a 
common illustration of the former is    
supplied by the familiar voltaic  or    
galvanic battery4 ,the electromagnetic  
form has been rendered  even more       
familiar in recent times by the dynamo4 
,this newest and  most powerful of      
workers will claim our attention in     
detail in the  succeeding chapter4 ,our 
present consideration will be directed  
to the  older method of generating the  
electric current as represented by the  
voltaic cell4      ,,the ,,work ,,of    
,,the ,,dynamical ,,current    ,let us  
draw our illustration from a familiar   
source4 ,even should your  household    
otherwise lack electrical appliances1   
you are sure to have  an electric       
call-bell4 ,the generator of the        
electric current1 which  is stored away 

in some out-of-the-way corner1 is       
probably a small  so-called dry-cell    
which you could readily carry around in 
your  pocket2 or it may consist of a    
receptacle holding a pint or two of     
liquid in which some metal plates are   
immersed4 ,such an apparatus  seems     
scarcely more than a toy when we        
contrast it with the gigantic  dynamos  
of the power-house2 yet1 within the     
limits of its capacities1  one is as    
surely a generator of electricity as the
 other4 ,if we are  to accept the latest
 theory1 the electrical current which   
flows from  this tiny cell is precisely 
the same in kind as that which flows    
from  the five-thousand-horse-power     
dynamo4 ,the difference is only one of  
quantity4    ,to understand the         
operation of this common household      
appliance we must  bear in mind two or  
three familiar experimental facts in    
reference  to the action of the voltaic 
cell4 ,briefly1 such a cell consists of 
two plates of metal--for example1 one of

 copper and the other of  zinc--with a  
connecting medium1 which is usually a   
liquid1 but which  may be a piece of    
moistened cloth or blotting-paper4 ,so  
long as the two  plates of metal are not
 otherwise connected there is no        
electricity in  evidence1 but when the  
two are joined by any metal conductor1  
as1 for  example1 a piece of wire--thus1
 in common parlance1 completing the     
circuit--a current of electricity flows 
about this circuit1 passing  from the   
first metal plate to the second1 through
 the liquid and back  from the second   
plate to the first through the piece of 
wire4 ,the wire  may be of any length4  
,in the case of your call-bell1 for     
example1 the  wire circuit extends to   
your door1 and is there broken1 shutting
 off  the current4    ,when you press   
the button you connect the broken ends  
of the wire1 thus  closing the circuit1 
as the saying is1 and the re-established
 current1  acting through a little      
electromagnet1 rings the bell4 ,in      

another case1  the wire may be hundreds 
of miles in length1 to serve the        
purposes of  the telegrapher1 who       
transmits his message by opening and    
closing the  circuit1 precisely as you  
operate your door-bell4 ,for            
long-distance  telegraphy1 of course1   
large cells are required1 and numbers of
 them  are linked together to give a    
cumulative effect1 making a strong      
current2 but there is no new principle  
involved4    ,the simplest study of this
 interesting mechanism makes it clear   
that  the cell is the apparatus         
primarily involved in generating the    
electric  current2 yet it is equally    
obvious that the connecting wire plays  
an  important part1 since1 as we have   
seen1 when the wire is broken there  is 
no current in evidence4 ,now1 according 
to the electron theory1 as  previously  
outlined1 the electric current consists 
of an actual flow  along the wire of    
carriers of electricity which are unable
 to make  their way except where a      

course is provided for them by what is  
called  a conductor4 ,dry air1 for      
example1 is1 under ordinary             
circumstances1  quite impervious to     
them4 ,this means1 then1 that the       
electrons flow  freely along the wire   
when it is continuous1 but that they are
  powerless to proceed when the wire is 
cut4 ,when you push the button of  your 
call-bell1 therefore1 you are virtually 
closing the switch which  enables the   
electrons to proceed on their           
interrupted journey4      ,,theories    
,,of ,,electrical ,,action    ,but all  
this1 of course1 leaves quite untouched 
the question of the  origin of the      
electrons themselves4 ,that these go    
hurtling from one  plate or pole of the 
battery to the other1 along the wire1 we
 can  understand at least as a working  
theory2 that1 furthermore1 the          
electrons have their origin either in   
the metal plates or in the liquid  that 
connects them1 seems equally obvious2   
but how shall we account for  their     

development8 ,it is here that the       
chemist with his atomic theory  of      
matter comes to our aid4 ,he assures us 
that all matter consists  in the last   
analysis of excessively minute          
particles1 and that these  particles are
 perpetually in motion4 ,they unite with
 one another to  form so-called         
molecules1 but they are perpetually     
breaking away from  such unions1 even   
though they re-establish them again4    
,such activities  of the atoms take     
place even in solids1 but they are      
greatly enhanced  when any substance    
passes from the solid into the liquid   
state4    ,when1 for example1 a lump of 
salt is dissolved in water1 the atoms of
  sodium and of chlorine which joined   
together make up the molecules of  salt 
are held in much looser bondage than    
they were while the salt  was in a dry  
or crystalline form4 ,could we magnify  
the infinitesimal  particles            
sufficiently to make them visible we    
should probably see  large numbers of   

the molecules being dissociated1 the    
liberated atoms  moving about freely for
 an instant and then reuniting with     
other atoms4  ,thus at any given instant
 our solution of salt would contain     
numerous  free atoms of sodium and of   
chlorine1 although we are justified in  
thinking of this substance as a whole as
 composed of sodium-chlorine  molecules4
 ,it is only by thus visualizing the    
activity of the atoms  in a solution    
that we are able to provide even a      
thinkable hypothesis  as to the         
development of electricity in the       
voltaic cell4    ,what puts us on the   
track of the explanation we are seeking 
is the  fact that the diverse atoms are 
known to have different electrical      
properties4 ,in our voltaic cell1 for   
example1 sodium atoms would  collect at 
one pole and chlorine atoms at the      
other4 ,humphry ,davy  discovered this  
fact in the early days of               
electro-chemistry1 just about  a century
 ago4 ,he spoke of the sodium atom as   

electro-positive1 and  of the chlorine  
atom as electro-negative1 and he        
attempted to explain  all chemical      
affinity as merely due to the mutual    
attraction between  positively and      
negatively electrified atoms4 ,the      
modern theorist goes  one step farther1 
and explains the negative properties of 
the chlorine  atom by assuming the      
presence of one negative electron or    
electricity  in excess of the           
neutralizing charge4 ,the assumption is1
 that the  sodium atom has lost this    
negative electron and thus has become   
positively electrified4 ,the chlorine   
atom1 harboring the fugitive  electron1 
becomes negatively electrified4 ,hence  
the two atoms are  attracted toward     
opposite poles of the cell4    ,this    
disunion of atoms1 be it understood1    
must be supposed to take  place in the  
case of any solution of common salt1    
whether it rests  in an ordinary cup or 
forms a part of the ocean4 ,here we     
have1 then1  material for the generation

 of the electrical current1 if some     
means  could be found to induce the     
chlorine atom to give up the surplus    
electron which from time to time it     
carries4 ,and this means is provided    
when two pieces of metal of different   
kinds1 united with a metal  conductor1  
are immersed in the liquid4 ,then it    
comes to pass that the  electrons       
associated with the chlorine atoms that 
chance to lie in  contact with one of   
these plates of metal1 find in this     
metal an avenue  of escape4 ,they rush  
off eagerly along the metal and the     
connecting  wire1 and in so doing       
establish a current which acts--if we   
may venture  a graphic analogy from an  
allied field of physics--as a sort of   
suction1 attracting other chlorine atoms
 from the body of the liquid  against   
the metal plate that they also may      
discharge their electrons4  ,in other   
words1 the electrical current passes    
through the liquid as  well as through  
the outside wire1 thus completing the   

circuit4    ,according to this theory1  
then1 the electrical energy in evidence 
in  the current from the voltaic cell1  
is drawn from a store of potential      
energy in the atoms of matter composing 
the liquid in the cell4 ,in  practice1  
as is well known1 the liquid used is one
 that affects one  of the metal poles   
more actively than the other1 insuring  
vigorous  chemical activity4 ,but the   
principle of atomic and electrical      
dissociation just outlined is the one   
involved1 according to theory1  in every
 voltaic cell1 whatever the particular  
combination of metals  and liquids of   
which it is composed4 ,it should be     
added1 however1  that while we are thus 
supplied with a thinkable explanation of
 the  origin of this manifestation of   
electrical energy1 no explanation is    
forthcoming1 here any more than in the  
case of the dynamo1 as to why  the      
electrons rush off in a particular      
direction and thus establish an         
electrical current4 ,perhaps we should  

recall that the very existence of  this 
current has at times been doubted4      
,quite recently1 indeed1 it has  been   
held that the seeming current consists  
merely of a condition of  strain or     
displacement of the ether4 ,but we are  
here chiefly concerned  with the        
electron theory1 according to which1 as 
we have all along  noted1 the seeming   
current is an actual current2 the ether 
strain1 if  such exists1 being due to   
the passage of the electrons4           
,,practical ,,uses ,,of ,,electricity   
,various effects of the current of      
electrons have been hinted at above4    
,considered in detail1 the possible ways
 in which these currents may be         
utilized are multifarious4 ,yet1 they   
may be all roughly classified into      
three divisions as follows3    ,first1  
cases in which the current of           
electricity is used to transmit  energy 
from one place to another1 and reproduce
 it in the form of molar  motion4 ,the  
dynamo1 in its endless applications1    

illustrates one phase  of such          
transportation of energy2 and the       
call-bell1 the telegraph1  and the      
telephone represent another phase4 ,in  
one case a relatively  large quantity of
 electricity is necessary1 in the other 
case a small  quantity2 but the         
principle involved--that of electric and
 magnetic  induction--is the same in    
each4    ,the second method is that in  
which the current1 generated by either  
a dynamo or a battery of voltaic cells1 
is made to encounter a  relatively      
resistant medium in the course of its   
flow along the  conducting circuit4     
,such resistance leads to the production
 of active  vibrations among the        
particles of the resisting medium1      
producing the  phenomena of heat and1 if
 the activity is sufficient1 the        
phenomena of  light also4 ,it will thus 
appear that in this class of cases1 as  
in the  other1 there is an actual       
re-transformation of electrical energy  
into  the energy of motion1 only in this

 case the motion is that of molecules   
and not of larger bodies4 ,the principle
 is utilized in the electrical  heater1 
with which our electric street-cars are 
commonly provided1  and which is making 
its way in the household for purposes of
 general  heating and of cooking4 ,it is
 utilized also in various factories1    
where the very high degree of heat      
attainable with the electrical  furnace 
is employed to produce chemical         
dissociation and facilitate  chemical   
combinations4 ,by this means1 for       
example1 a compound of  carbon and      
silicon1 which is said to be the hardest
 known substance1  except the diamond1  
is produced in commercial quantities4 ,a
 familiar  household illustration of the
 use of this principle is furnished by  
the  electric light4 ,the carbon        
filament in the electric bulb furnishes 
such  resistance to the electric current
 that its particles are set violently   
aquiver4 ,under ordinary conditions the 
oxygen of the air would  immediately    

unite with the carbon particles1        
volatilizing them1 and  thus instantly  
destroying the filament2 but the vacuum 
bulb excludes  the air1 and thus gives  
relative permanency to the fragile      
thread4    ,the third class of cases in 
which the electric current is           
commercially  utilized is that in which 
the transformations it effects are      
produced  in solutions comparable to    
those of the voltaic cell1 the          
principles  involved being those pointed
 out in the earlier part of the present 
chapter4 ,by this means a metal may be  
deposited in a pure state upon  the     
surface of another metal made to act as 
a pole to the battery2 as1  for example1
 when forks1 spoons1 and other utensils 
of cheap metals  are placed in a        
solution of a silver compound1 and thus 
electroplated  with silver4 ,to produce 
the powerful effects necessary in the   
various  commercial applications of this
 principle1 the poles of the voltaic    
cell--which cell may become in practice 

a large tank--are connected  with the   
current supplied by a dynamo4 ,various  
chemical plants at  ,niagara utilize    
portions of the currents from the great 
generators  there in this way4 ,another 
familiar illustration of the principle  
is  furnished by the copper             
electroplates from which most modern    
books are  printed4    ,it appears1     
then1 that all the multifarious uses of 
electricity in  modern life are         
reducible to a few simple principles of 
action1 just  as electricity itself is  
reduced1 according to the analysis of   
the  modern physicist1 to the activities
 of the elementary electron4 ,there  is 
nothing anomalous in this1 however1 for 
in the last analysis the  mechanical    
principles involved in doing all the    
world's work are few  and relatively    
simple1 however ingenious and relatively
 complex may be  the appliances through 
which these principles are made         
available4          ,,ix    ,,man',s    
,,newest ,,co-,,laborer3 ,,the ,,dynamo 

,as you stand waiting for your train at 
elevated or subway station you  must    
have noticed the third rail4 ,to outward
 appearance it is not  different from   
the other rails4 ,it seems a mere inert 
piece of steel4  ,yet you are well aware
 that a strange power abides there      
unseen--a  power that pulls the train1  
and that lurks in hiding to strike a    
death-blow to any chance unfortunate    
whose foot or hand comes in  contact    
with the rail4 ,as the heavy train      
dashes up1 dragged by this  unseen      
power1 probably you1 in common with the 
rest of the world1 have  been led to    
remark1 ,is it not marvelous8           
,marvelous it surely seems4 ,yet the    
cause of our astonishment is to be      
sought in the relative newness of the   
phenomena rather than in the  nature of 
the phenomena themselves4 ,at first     
glance it may seem that  the intangible 
character of the electrical power gives 
it a unique  claim on our wonderment4   
,but a moment's reflection dispels this 

illusion4 ,after all1 electricity is no 
more intangible than heat4  ,neither the
 one nor the other can be seen or heard1
 but each alike may  be felt4 ,yet we   
observe without astonishment a          
locomotive propelled  by the power of   
heat--simply because the locomotive has 
become an old  story4 ,again1           
electricity is far less intangible than 
gravitation4  ,not merely may           
electricity be felt1 but it may be      
generated through  transformation of    
other forms of energy2 it may be stored 
away and  measured2 may be conducted at 
will through tortuous channels1 or      
obstructed in its flight by the         
intervention of non-conductors4 ,but    
gravitation submits to no such          
restrictions4 ,it eludes all of our     
senses1 and it absolutely disregards all
 barriers4 ,to its catholic  taste all  
substances are alike4 ,it holds in      
bondage every particle of  matter in the
 universe1 and can enforce its influence
 over every kind  of atom with an       

impartiality that is as astounding as it
 is inexorable4  ,moreover1 this weird  
force1 gravitation1 has thus far evaded 
all man's  efforts to classify or label 
it4 ,no man has the slightest inkling as
  to what gravitation really is4 ,if1 as
 you glance at these lines1 you  should 
chance to release your hold and allow   
the volume to drop to the  floor1 you   
will have performed a miracle which no  
scientist in the  world can even vaguely
 explain4    ,as regards our electric   
train1 then1 the fact that it stands    
there  firmly1 held fast to the rails by
 gravitation1 is in reality as great    
and as inexplicable a marvel as the fact
 that the electric current  gives it    
propulsion4 ,not only so1 but the fact  
that the train goes  forward of its own 
inertia1 as we say1 for a time after the
 current  is shut off1 presents to us   
yet another inexplicable marvel4 ,it is 
a  fundamental property of matter1 we   
say1 when once in motion to continue  in
 motion until stopped by some           

counter-force2 but that phrasing1       
expressive though it be of a fact upon  
which so many physical phenomena        
depend1 is in no proper sense of the    
word an explanation4    ,once for all1  
then1 there is nothing unique1 nothing  
preternaturally  marvelous1 about the   
phenomena of electricity4 ,and indeed1  
it is  interesting to note how quickly  
we become accustomed to these           
phenomena1 and how little wonder they   
excite so soon as they cease  to be     
novel4 ,even imaginative people have    
long since ceased to give  thought to   
the trolley car2 and within a week of   
the opening of ,new  ,york's subway the 
average man came to regard it as much as
 a matter of  course as if he had been  
accustomed to it from boyhood4    ,and  
yet1 in another sense of the word1 the  
electric motor is a  wonderful          
contrivance4 ,as an example of what     
man's ingenuity can  accomplish toward  
transforming the powers of nature and   
adapting them  to his own use1 it is    

fully entitled to be called a marvel4   
,moreover1  in the last analysis1 we are
 as helpless to explain the nature of   
electricity as we are to explain the    
nature of gravitation4 ,it is only  the 
proximal phenomena of the electric      
current that can be explained4  ,these  
phenomena1 however1 are full of         
interest4 ,let us examine them  somewhat
 in detail1 allowing them to lead us    
back from electric train  to power-house
 and dynamo1 and from dynamo as far     
toward the mystery of  electric energy  
as present-day science can guide us4    
,,the ,,mechanism ,,of ,,the ,,dynamo   
,if we could look into the interior of a
 mechanism in connection with  the      
trucks beneath the car1 we should find  
an apparatus consisting  essentially of 
coils of wire adjusted compactly about  
an axis1 and  closely fitted between the
 poles of a powerful electromagnet4     
,these  coils of wire constitute what is
 called an armature4 ,when the current  
is switched on it passes through this   

armature1 as well as through the        
electromagnet1 and the mutual           
attractions and repulsions between the  
magnetic poles and the electric current 
in the coils of wire1 cause  the        
armature to revolve with such tremendous
 energy as to move the  train--the      
motion of its axis being transmitted to 
the axle of the  car-wheels by a simple 
gearing4    ,all this is simple enough  
if we regard only the how and not the   
why  of the phenomena4 ,ignoring the why
 for the moment1 let us seek the  origin
 of the current which1 by being         
conducted through the armature1  has    
produced the striking effect we have    
just witnessed4 ,this current  reaches  
the car through an overhead or          
underground wire4 ,all that is          
essential is that some conducting       
medium1 such as an iron rail1 or  a     
copper wire1 shall form an unbroken     
connection between the motor  apparatus 
and the central dynamo where the power  
is generated--the  return circuit being 

made either by another wire or by the   
ordinary  rails4    ,the central dynamo 
in question will be found1 if we visit  
the  power-house1 to be a ponderous     
affair1 suggestive to the untechnical   
mind of impenetrable mysteries4 ,yet in 
reality it is a device  essentially the 
same in construction as the motor which 
drives  the train4 ,that is to say1 its 
unit of construction consists of a      
wire-wound armature revolving on an axis
 and fitted between the  poles of an    
electromagnet4 ,here1 however1 the      
sequence of phenomena  is reversed1 for 
the armature1 instead of receiving a    
current of  electricity1 is made to     
revolve by a belt adjusted to its axis  
and  driven by a steam engine4 ,the wire
 coils of the armature thus made to     
revolve cut across the so-called lines  
of magnetic force which connect  the two
 poles of the magnet1 and in so doing   
generate a current of  induced          
electricity1 which flows away to reach  
in due course the third  rail or the    

trolley-wire1 and ultimately to propel  
the motor4    ,illustration3 ,lower     
figure copyrighted by ,n4 ,y4 ,edison   
,co4    ,,an ,,electric ,,train ,,and   
,,the ,,dynamo ,,that ,,propels ,,it4   
,the lower figure gives an interior view
 of a power house of the  ,manhattan    
,elevated ,railway ,company4 ,the upper 
figure shows one of the  electric       
engines operating on the ,new ,york     
,central ,lines just outside  of ,new   
,york4 ,the power is conveyed to the    
engine by a third rail  clearly shown in
 the picture4    ,it is hardly necessary
 to state that in actual practice this  
generating  dynamo is a complex         
structure4 ,the armature is a complex   
series of  coils of wire2 the           
electromagnets surrounding the armature 
are several  or many2 and there is an   
elaborate system of so-called           
commutators  through which the currents 
of electricity--which would otherwise   
oscillate as the revolving coil cuts the
 lines of magnetic force in  opposite   

directions--are made to flow in one     
direction4 ,but details  aside1 the     
foundation facts upon which everything  
depends are 7#a7 that  a coil of wire   
when forced to move so that it cuts     
across the lines of  force in any       
magnetic field develops a so-called     
induced current of  electricity2 and    
7#b7 that such an induced current       
possesses power of  magnetic attraction 
and repulsion4 ,these facts were        
discovered more  than sixty years ago1  
and carefully studied by ,michael       
,faraday1 ,joseph  ,henry1 and others4  
,faraday found that such an induced     
current could be  produced not merely   
with the aid of an iron magnet1 but even
 by causing  a wire to cut the lines of 
force that everywhere connect the north 
and  south poles of the earth1--the     
earth being indeed1 as ,william ,gilbert
  long ago demonstrated1 veritably a    
gigantic magnet4 ,moreover1 these       
relations are reciprocal2 so that if a  
wire through which a current  of        

electricity is passing is placed across 
a magnetic field1 the wire  is impelled 
to move in a plane at right angles to   
the direction of the  lines of force4   
,it is forcibly thrust aside4 ,this     
side-thrust acting on  coils of wire is 
what produces the revolution of the     
armature of the  electric motor4        
,,the ,,origin ,,of ,,the ,,dynamo      
,the very first studies that had to do  
with the mutual relations  of           
electricity and magnetism were made by  
,hans ,christian ,oersted1  the ,dane1  
as early as #ahae4 ,he discovered that a
 magnetic needle  is influenced by the  
passage near it of a current of         
electricity1  demonstrating1 therefore1 
that the electric current in some way   
invades  the medium surrounding any     
conductor along which it is passing4    
,oersted's experiments were repeated1   
and some new phenomena observed by  the 
,frenchman ,andr ,marie ,ampre and      
,dominique ,franois ,arago4 ,arago      
constructed an interesting device1 in   

which a metal disk was made to  revolve 
in the presence of a current of         
electricity2 but neither he nor  anyone 
else at the time was able to explain the
 phenomenon4    ,in #ahbd an advance was
 made through the construction of the   
first  electric magnet by ,sturgeon4    
,hitherto it had not been known that a  
magnet could be made artificially1      
except by contact with a previously     
existing magnet4 ,sturgeon showed that  
any core of iron may be rendered        
magnetic if wound with a conducting     
wire1 through which a current  of       
electricity is passed4 ,the experiments 
thus inaugurated were  followed up in   
,america by ,joseph ,henry of ,albany   
who made enormous  electromagnets1      
capable of sustaining great weights4    
,one of his  magnets1 operated by a     
single cell1 was able to lift six       
hundred and  fifty pounds of metal4     
,it was this apparatus which was        
subsequently to make possible the       
utilization of electricity as a working 

force1 but as yet no one  suspected its 
possibilities in this direction4    ,it 
remained for ,michael ,faraday1 in      
#ahca1 to make the final  experiment    
which laid the secure foundation for the
 new science of  electrodynamics4       
,faraday constructed a tiny apparatus1  
consisting of a  magnet between the     
poles of which a metal disk was placed  
in such a way  that it could revolve on 
an axis1 the disk being connected with a
 wire  conveying an electric current4   
,the details as to this most ingenious  
mechanism need not be given here4       
,suffice it that ,faraday demonstrated  
the interrelations of magnetism  and    
electricity and the possibility of      
causing a metal disk to revolve  through
 this mutual interaction4 ,in so doing  
he constructed the first                
dynamo-electric machine4 ,in his hands  
it was a mere laboratory toy1  but the  
principles involved were fully          
elaborated by the original              
experimenter1 and stated in precise     

language which modern investigators     
have not been able to improve upon4     
,several decades elapsed after          
,faraday's initial experiment before the
  phenomena of magneto-electricity were 
proved to have any considerable         
commercial significance4 ,a vast amount 
of ingenuity was required to  devise a  
mechanism which could advantageously    
utilize the principle  in question for  
commercial purposes4 ,indeed the early  
experimenters  did not at once get upon 
the right track1 as their efforts were  
influenced disadvantageously by an      
attempt to follow the principle of  the 
steam engine4 ,some interesting         
mechanisms were devised whereby the     
motion of an armature in being drawn    
toward an electromagnet could be        
translated into rotary motion through   
the use of crank-shafts and even  of    
beams1 precisely comparable to those    
employed in the steam engine4  ,such    
devices worked with a comparatively low 
degree of efficiency and  were totally  

abandoned so soon as the idea of getting
 rotary motion  directly from the magnet
 or armature was made feasible4 ,the    
names of  ,saxton1 ,clarke1 ,woolrich1  
,wheatstone1 and ,werner ,siemens are   
intimately  connected with the early    
efforts at utilization of               
magneto-electric  power4 ,the           
shuttle-wound armature of ,siemens1     
invented in #ahed1 marked  an important 
progressive step4      ,,perfecting     
,,the ,,dynamo    ,the first separately 
excited dynamos were constructed by ,dr4
 ,henry  ,wilde1 ,f4,r4,s41 between     
#ahfc and #ahfe1 and this invention     
paved the way  for rapid progress4 ,in  
#ahff-g ,varley1 ,siemens1 ,wheatstone1 
and ,ladd  constructed machines with    
several iron electromagnets1            
self-excited1  which were described as  
dynamo-electric machines1 a term        
afterward  contracted to dynamos4 ,in   
#ahfg ,dr4 ,wilde improved the armature 
by  introducing several coils arranged  
around a cylinder2 the current  from a  

few of the coils was rectified and used 
to excite the field  magnet1 while the  
main current as given off by the rest of
 the coils  was taken off by            
ring-contacts1 the machine being a      
self-exciting1  alternating-current     
dynamo4    ,illustration3 ,,wilde',s    
,,separately ,,excited ,,dynamo4    ,dr4
 ,wilde invented and patented 7#ahfc-e7 
the first separately excited  dynamo1   
with which he demonstrated that the     
feeble current from a small             
magneto-electric machine would1 by the  
expenditure of mechanical power1        
produce currents of great strength from 
a large dynamo4    ,the ,italian1       
,picnotti1 in #ahfd invented a ring     
armature which1  although provided with 
teeth was wound with coils in such a way
 as to  obtain a very uniform current2  
but the practical introduction of the   
continuous-current machines dates from  
#ahgj1 when ,gramme re-invented  the    
ring and gave it the form which is still
 in vogue4 ,von ,alteneck in  #ahgc     

converted the ,siemens shuttle armature 
along the same lines and so  introduced 
the drum arrangement which has since    
been very extensively  adopted4    ,thus
 through the efforts of a great number  
of workers the idea of  utilizing       
electromagnetic energy for the purposes 
of the practical  worker came to be a   
reality4 ,numberless machines have been 
made  differing only as to details that 
need not detain us here4 ,everyone  is  
familiar with sundry applications of the
 dynamo to the purposes of  to-day's    
applied science4 ,it must be understood1
 of course1 that the  amount of         
electricity generated in any dynamo is  
precisely measurable1  and that by no   
possibility could the energy thus       
developed exceed  the energy required to
 move the coils of wire4 ,were it       
otherwise the  great law of the         
conservation of energy would be         
overthrown4 ,in actual  practice1 of    
course1 there is loss of energy in the  
transaction4 ,the  current of           

electricity that flows from the very    
best dynamo represents  considerably    
less working power than is expended by  
the steam engine in  forcibly revolving 
the armature4 ,in the early days of     
experiments the  loss was so great as to
 be commercially prohibitive4 ,with the 
perfected  modern dynamo the loss is not
 greater than fifteen per cent2 but even
  this1 it will be noted1 makes         
electricity a relatively expensive power
  as compared with steam1--except1      
indeed1 where some natural power1 like  
the ,falls of ,niagara1 can be utilized 
to drive the armature4      ,a          
,,mysterious ,,mechanism    ,the        
efficiency of the modern dynamo is due  
largely to the fact that  when the poles
 of the magnet are made to face each    
other1 the lines  of magnetic force     
passing between these poles are         
concentrated into a  narrow compass4    
,with the ordinary bar magnet1 as       
everyone is aware1  these lines of force
 circle out in every direction from the 

poles in  an almost infinite number of  
loops1 all converging at the poles1 and 
becoming relatively separated at the    
equator in a manner which may be        
graphically illustrated by the lines of 
longitude drawn on an ordinary  globe4  
,it is obvious that with a magnet of    
such construction only a small          
proportion of the lines of magnetic     
force could be utilized in  generating  
electricity4 ,but1 as already mentioned1
 when the magnet  is so curved that its 
poles face each other1 the lines of     
force1  instead of widely diverging1    
pass from pole to pole almost in a      
direct  stream4 ,the strength of this   
magnetic stream may be increased almost 
indefinitely by winding the iron core of
 the magnet with the coil of  wire      
through which the electric current is   
passed1 thus constituting  the          
electromagnet which has replaced the old
 permanent magnet in all  modern        
commercial dynamos4    ,illustration3   
,,the ,,evolution ,,of ,,the ,,dynamo4  

,fig4 #a4--;,a small example of the     
original commercial form of the drum    
armature machine1 patented in #ahgc by  
,dr4 ,werner ,siemens and ,f4 ,von      
,hefner ,alteneck4 ,the armature is a   
development of the ,siemens shuttle     
form of #ahef1 and gives a nearly       
continuous current4 ,fig4 #b4--;,an     
early  experimental dynamo4 ,fig4       
#c4--;,ferranti's original dynamo1      
patented in  #ahhb-ahhc4 ,the field     
magnets are stationary and consist of   
two sets  of electro-magnets each with  
#af projecting pull pieces1 between     
which  the armature revolves4 ,fig4     
#d4--,the gigantic rotary converters of 
the  ,manhattan ,elevated ,railway4     
,an electromagnet may be sufficiently   
powerful to lift tons of iron4  ,the    
force it exerts1 therefore1 is very     
tangible in its results4 ,yet  it seems 
mysterious1 because so many substances  
are unaffected by it4  ,you may place   
your head1 for example1 between the     
poles of the most  powerful magnet      

without experiencing any sensation or   
being in any  obvious way affected4 ,you
 may wave your hand across the lines of 
force  as freely as you may wave it     
anywhere else in space4 ,apparently     
nothing  is there4 ,but were you to     
attempt to pass a dumb-bell or a bar of 
iron  across the same space1 the unseen 
magnetic force would wrench it from     
your grasp with a power so irresistible 
as to be awe-inspiring4    ,similarly1  
the armature1 when its coils of wire are
 adjusted between  the poles of the     
magnet1 is held in a vise-like grip by  
the invisible  but potent lines of      
magnetic force which tend to make it    
revolve4  ,it requires a tremendous     
expenditure of energy--supplied by the  
steam-engine or by water power--to      
enable the coiled wires of the          
generating armature to stem the current 
of magnetic force1 which is  virtually  
what is done when the armature revolves 
in such a way as to  produce electrical 
energy4 ,part of the mechanical energy  

thus expended  is transformed into heat 
and dissipated into space2 but the main 
portion is carried off1 as we have seen1
 through the coiled wires of  the       
armature in the form of what we term the
 current of electricity1 to  be         
re-transformed in due course into the   
mechanical energy that moves  the car4  
,it appears1 then1 that the phenomena of
 the electric dynamo depend upon  the   
curious relations that exist between    
magnetism and electricity4  ,granted the
 essential facts of magneto-electric    
induction1 all the  phenomena of the    
dynamo are explicable4 ,but how explain 
these facts  themselves8 ,why is an     
electric current generated in a coil of 
wire  moving in a magnetic field8 ,and  
why is a wire carrying a current of     
electricity1 when placed across a       
magnetic field1 impelled to move at     
right angles to the lines of magnetic   
force8 ,no thoughtful person can        
consider the subject without asking     
these questions4 ,but as yet no         

definitive answer is forthcoming4 ,some 
suggestive half-explanations1  based on 
an assumed condition of torsion or      
strain in the ether1 have  been         
attempted1 but they can hardly be called
 more than scientific  guesses4         
,meanwhile1 it may be understood that   
the mutual relations of the  magnetic   
and electrical forces just referred to  
are not at all  dependent upon the      
manner in which the electric current is 
generated4  ,the magneto-electric motor 
may be operated as well with a chemical 
battery as with such a mechanical       
generating dynamo as has just been      
described4 ,the storage-batteries which 
have been employed in some  street      
railways and those which propel the     
electric cabs about our  city streets   
furnish cases in point4 ,the only reason
 these are not  more generally employed 
is that the storage battery has not yet 
been  perfected so that it can produce a
 large supply of electricity in         
proportion to its weight1 and produce it

 economically4          ,x    ,,niagara 
,,in ,,harness      ,harnessing         
,niagara--the phrase has been a         
commonplace for a  generation2 but until
 very recently indeed it was nothing    
more than a  phrase4 ,almost since the  
time when the ,falls were first viewed  
by a  white man the idea of utilizing   
their powers has been dreamed of4 ,but  
until our own day--until the last       
decade--science had not shown a way  in 
which the great current could be        
economically shackled4 ,a few puny      
mill-wheels have indeed revolved for    
thirty years or so1 but these  were of  
no greater significance than the        
thousands of others driven by  mountain 
streams or by the currents of ordinary  
rivers4 ,but about a  decade ago the    
engineering skill of the world was      
placed in commission1  and to-day       
,niagara is fairly in harness4    ,if   
you have ever seen ,niagara--and who has
 not seen it8-you must have  been struck
 with the metamorphosis that comes over 

the stream about  half a mile above the 
falls4 ,above this point the river flows
 with a  smooth sluggish current4 ,only 
fifteen feet have the waters sunk in    
their placid flowing since they left    
,lake ,erie4 ,but now in the course  of 
half a mile they are pitched down more  
than two hundred feet4 ,if  you follow  
the stream toward this decline you shall
 see it undergo  a marvelous change4 ,of
 a sudden the placid waters seem to feel
 the  beckoning of a new impulse4       
,caught with the witchery of a new      
motion1  they go swirling ahead with    
unwonted lilt and plunge1 calling out   
with  ribald voices that come to the ear
 in an inchoate chorus of strident1     
high-pitched murmurings4 ,each wavelet  
seems eager to hurry on to the  full    
fruition of the cataract4 ,it lashes    
with angry foam each chance             
obstruction1 and gurgles its disapproval
 in ever-changing measures4  ,even to   
the most thoughtless observer the mighty
 current thus unchained  attests the    

sublimity of almost irresistible power4 
,could a mighty  mill-wheel be adjusted 
in that dizzy current1 what labors might
 it  not perform8 ,five million tons of 
water rush down this decline each  hour1
 we are told2 and the force that thus   
goes to waste is as if  three million   
unbridled horses exhausted their        
strength in ceaseless  plunging4 ,this  
estimate may be only a guess1 but it    
matters not whether  it be high or low2 
all estimates are futile1 all           
comparisons inadequate  to convey even a
 vague conception of the majesty of     
power with which  the mighty waters rush
 on to their final plunge into the      
abysm4    ,it is here1 you might well   
suppose1 where the appalling force of   
the  current is made so tangible1 that  
man would place the fetters of his      
harness1 making the madcap current      
subject to his will4 ,you will  perhaps 
more than half expect to see gigantic   
mechanisms of man's  construction built 
out over the rapids or across the face  

of the  cataract--so much has been said 
of stheticism versus commercialism in   
connection with the attempt to utilize  
,niagara's power4 ,but whatever  your   
fears in this regard1 they will not be  
realized4 ,inspect the  rapids and the  
falls as you may1 you will see no       
evidence that man  has tampered with    
their pristine freedom4 ,subtler means  
have been  employed to tame the wild    
steed4 ,the mad waves that go dashing   
down  the rapids are as free and        
untrammeled to-day as they were when the
  wild ,indian was the only witness of  
their tempestuous activity4 ,such       
portions of the current as reach the    
rapids have full license to pass  on    
untrammeled1 paying no toll to man4 ,the
 water which is made to pay  tribute is 
drawn from the stream up there above the
 rapids1 where it  lies placid and as   
yet unstirred by the beckoning incline4 
,to see  ,niagara in harness1 then1 you 
must leave the cataract and the rapids  
and pass a full mile up the stream where

 the great river looks as calm  as the  
,hudson or the ,mississippi1 and where1 
under ordinary conditions1  not even the
 sound of the falls comes to your ear4  
,prosaic enough it seems to observe here
 nothing more startling than a  broad   
cul de sac of stagnant water1 like the  
beginning of a broad  canal1 extending  
in for a few hundred yards only from the
 main stream2  its waters silent1       
currentless1 seemingly impotent4 ,this  
stagnant  pool1 then1 not the whirling  
current below1 is to furnish the water  
whose reserve force of energy of        
position is drawn upon to serve man's   
greedy purpose4 ,coming from the rapids 
and cataract to this stagnant  canal1   
you seem to step from the realm of      
poetic beauty to the sordid  realities  
of the work-a-day world4 ,of a truth it 
would seem that  harnessing ,niagara is 
but a far-fetched metaphor4             
,,within ,,the ,,power-,,house    ,and  
yet if you will turn aside from the     
canal and enter one of the  long1 low   

buildings that flank it on either side1 
you will soon be  made to feel that the 
metaphor was amply justified4 ,little as
 there  was exteriorly to suggest it1   
you are entering a fairyland of applied 
science1 and within these plain walls   
you shall witness evidences  of the     
ingenuity of man that should appeal     
scarcely less to your  imagination than 
the sight of the cataract itself in all 
its sublimity  of power4    ,for within 
these walls1 by a miracle of modern     
science1 the potential  energy which    
resides in the water of the canal is    
transformed into  an electrical current 
which is sent out over a network of     
wires to  distant cities to perform a   
thousand necromantic tasks1--propelling 
a  street car in one place1 effecting   
chemical decompositions in another2     
turning the wheels of a factory here and
 lighting the streets of a city  there2 
in short1 subserving the practical needs
 of man in devious and  wonderful ways4 
,even as you gazed disdainfully at the  

stagnant canal1 its waters1             
miraculously transformed1 were          
propelling the trolley cars along the   
brink of the cliff over there on the    
,canadian shore1 and at the same  time  
were turning the wheels in many a       
factory in the distant city of          
,buffalo4 ,after all1 then1 the quiet   
pool of water was not so prosaic as  it 
seemed4    ,as you stand in the building
 where this wonderful transformation of 
power is effected1 the noble simplicity 
of the vista heightens the  mystery4    
,the most significant thing that strikes
 the eye is a row  of great             
mushroom-like affairs1 for all the world
 like giant tops1  that stand           
spinning--and spinning4 ,these great    
tops are about a dozen  feet in         
diameter4 ,they are whirling1 so we are 
told1 at a rate of two  hundred and     
fifty revolutions per minute4 ,hour     
after hour they spin on1  never varying 
in speed1 never faltering2 day and night
 are alike to  them1 and one day is like

 another4 ,they are as ceaselessly      
active1 as  unwearying as ,niagara      
itself1 whose power they symbolize2 and1
 like the  great ,falls1 they murmur    
exultingly as they work4                
,illustration3 ,,view ,,in ,,one ,,of   
,,the ,,power ,,houses ,,at ,,niagara4  
,each of the top-like dynamos generates 
#ejjj horse-power4    ,the giant tops   
which thus seem to bid defiance to the  
laws of motion  are in reality electric 
dynamos1 no different in principle from 
the  electric generators with which some
 visit to a street-car power-house  has 
doubtless made you familiar4 ,the       
anomalous feature of these  dynamos--in 
addition to their size--is found in the 
fact that they  revolve on a vertical   
shaft which extends down into a hole in 
the earth  for more than a hundred feet1
 and at the other end of which is       
adjusted  a gigantic turbine            
water-wheel4 ,water from the canal is   
supplied this  great turbine wheel      
through a steel tube or penstock1 seven 

feet in  diameter4 ,as the turbine      
revolves under stress of this mighty    
column  of water1 the long shaft        
revolves with it1 thus turning the      
electric  generator at the other end of 
the shaft--the generator at which we    
are looking1 and which we have likened  
to a giant top--without the             
interposition of any form of gearing    
whatever4    ,to gain a vivid mental    
picture of the apparatus1 we must take  
an  elevator and descend to the lower   
regions where the turbine wheel is  in  
operation4 ,as we pass down and down1   
our eyes all the time fixed on  the     
vertical revolving shaft1 which is      
visible through a network of  bars and  
gratings1 it becomes increasingly       
obvious that to speak of  this shaft as 
standing in a hole in the ground is to  
do the situation  very scant justice4 ,a
 much truer picture will be conceived if
 we think  of the entire power-house as 
a monster building1 about two hundred   
feet  high1 all but the top story being 

underground4 ,what corresponds to  the  
ground floor of the ordinary building is
 located one hundred and  fifty feet    
below the earth's surface2 and it is the
 top story which we  entered from the   
street level1 thus precisely reversing  
the ordinary  conditions4               
,,penstocks ,,and ,,turbines    ,as we  
descend now and reach at last the lowest
 floor of the building1  we step out    
into a long narrow room1 the main       
surface of which is taken  up with a    
series of gigantic turnip-shaped        
mechanisms1 each one having  a revolving
 shaft at its axis2 while from its side 
projects outward and  then upward a     
seven-foot steel tube1 for all the world
 like the funnel  of a steamship4 ,this 
seeming funnel--technically termed a    
penstock--is  in reality the great tube 
through which the massive column of     
water  finds access to the turbine      
wheel1 which of course is incased within
  the turnip-shaped mechanism at its    
base4    ,as you stand there beside this

 great steel mechanism a sense of       
wonderment and of utter helplessness    
takes possession of you4 ,as you  glance
 down the hall at this series of great  
water conduits1 and  strain your eyes   
upward in the endeavor to follow the    
great funnel to  its very end1 an       
oppressive sense of the irresistible    
weight of the  great column of water it 
supports comes to you1 and you can      
scarcely  avoid a feeling of            
apprehension4 ,suppose one of the great 
tubes were to  burst8--we should all be 
drowned like rats in a hole4 ,there is  
small  danger1 to be sure1 of such a    
contingency2 but it is well worth while 
to have stood thus away down here at the
 heart of the great power-house  to have
 gained an awed sense of what man can   
accomplish toward rivaling  the wonders 
of nature4 ,to have stood an hour ago on
 the ice bridge at  the foot of the most
 tremendous cataract in the world1 where
 ,nature  exhausts her powers amidst the
 mad rush and roar of seething waters2  

and now to stand beneath this other     
column of water which effects a no  less
 wonderful transformation of energy1    
serenely1 silently1--is to  have run    
such a gamut of emotions as few other   
hours in all your life  can have in     
store for you4      ,a ,,miraculous     
,,transformation ,,of ,,energy    ,there
 are eleven of these great turbine      
mechanisms1 each with a  supplying      
funnel of water and a revolving shaft   
extending upward to its  companion      
dynamo1 in the room in which we stand4  
,energy representing  fifty-five        
thousand horse-power is incessantly     
transformed and made  available for     
man's use in the subterranean building  
in which we stand4  ,and there is not a 
pound of coal1 not a lick of flame1 not 
an atom  of steam involved in the       
transformation4 ,there are no           
dust-grimed  laborers2 there is no glare
 of furnace1 no glow of heat1 no        
stifling  odor of burning fuel2--there  
is only the restful hum of the machinery

  that responds to the ceaseless flow of
 the silent and invisible waters4  ,day 
and night the mighty river here pulls   
away at its turbine harness2  and man1  
having once adjusted that harness1 may  
take his ease and enjoy  the fruits of  
his ingenuity4    ,as we return now to  
the top of the building1 we shall view  
the spinning  dynamos with renewed      
interest1 and a few facts regarding     
their output  of energy may well claim  
our attention4 ,in their principle of   
action1  as we have seen1 all dynamos   
are alike1--depending upon the mutual   
relations between the wire-wound        
armature and a magnetic field4 ,in the  
present case the magnets are made to    
revolve and the armatures are           
stationary1 but this is a mere detail4  
,there is one feature of these  dynamos1
 however1 which is of greater           
importance1--the fact namely that  they 
operate without commutators1 and        
therefore produce alternating  currents4
 ,this fact has an important bearing    

upon the distribution of  the current4  
,each of the dynamos before us generates
 the equivalent  of five thousand       
horse-power of energy4 ,there are eleven
 such dynamos  here before us2 there are
 ten more in the power-house on the     
other  side of the canal1 giving a total
 of one hundred and five thousand       
horse-power for this single plant2 and  
there are five such plants now  in      
existence or in course of construction  
to utilize the waters of  ,niagara1     
three being on the ,canadian shore4     
,when in full operation the  aggregate  
output of these plants will be six or   
seven hundred thousand  horse-power4    
,,subterranean ,,tail-,,races    ,as we 
step from the door of the power-house   
and stand again beside the  canal whose 
waters produce the wonderful effects we 
have witnessed  in imagination1 one     
question remains to be answered3 ,what  
becomes of  the water after it has      
passed through the turbine wheels down  
there  in the depths8 ,the answer is    

simple3 ,all the water from the various 
turbines flows away into a great        
subterranean canal which passes down    
beneath the city of ,niagara ,falls1 and
 discharges finally at the level  of the
 rapids a few hundred yards below the   
,falls4 ,the construction of  this      
subterranean canal would in itself have 
been considered a great  engineering    
feat a few decades ago2 but of late     
years mountain tunnels1  such           
subterranean railways as the ,london    
tube system and tunnels  beneath rivers 
have robbed such structures of their    
mystery4 ,it may be  added that another 
such subterranean canal1 to serve as a  
tail-race for  one of the new ,canadian 
plants1 extends beneath the cataract    
itself1  discharging not far from the   
centre of the ,horseshoe ,falls4        
,another of  the power companies        
utilizes the water of the old surface   
canal which  extends to the brink of the
 gorge some distance below the ,falls4  
,yet  another company on the ,canadian  

side conveys water from far above the   
rapids in a gigantic closed tube to the 
brink of the gorge just below  the      
,canadian ,falls1 above the point where 
their power-house is located4    ,but   
the principle involved is everywhere the
 same4 ,the idea is merely  to utilize  
the weight of falling water4 ,the water 
of ,niagara ,river  is of course no     
different from any other body of water  
of equal size4  ,it is merely that its  
unique position gives the engineer an   
easy  opportunity to utilize the        
potential energy that resides in any    
body  of water--or1 for that matter1 in 
any other physical substance--lying  at 
a high level4 ,in due course1 doubtless1
 other bodies of water1  such as        
mountain lakes and mountain streams will
 be similarly put  into electrical      
harness4 ,the electrical feature is of  
course the one  that most appeals to the
 imagination4 ,but it may be well to    
recall  that the ultimate source of all 
the power in question is gravitation4   

,people fond of philosophical gymnastics
 may reflect with interest that1        
according to the newest theory1         
gravitation itself is1 in the last      
analysis1 an electrical phenomenon--a   
reflection which1 it will be  noted1    
leads the mind through a very curious   
cycle4      ,,the ,,effect ,,on ,,the   
,,falls    ,much solicitude has been    
expressed as to the possible effect1    
upon the  ,falls themselves1 of this    
withdrawal of water4 ,for the present1  
it is  admitted1 there is no visible    
effect2 and to the casual observer it   
may seem that almost any quantity of    
water the power-houses are likely  to   
need might be withdrawn without         
seriously marring the wonderful         
cataract4 ,but the statistics supplied  
by the power companies1 taken in        
connection with estimates as to the bulk
 of water that passes over the  ,falls1 
do not support this optimistic view4    
,taking what seems to be a  reasonable  
estimate for a basis of computation it  

would appear that  when the power-houses
 now rapidly approaching completion are 
in full  operation1 the total withdrawal
 of water from the stream will represent
  a very appreciable fraction of its    
entire bulk--one-twenty-fifth at  the   
very least1 perhaps as much as          
one-tenth4 ,such a diminution as  this  
will by no means ruin the ,falls1 yet it
 would seem as if it must  sensibly     
affect them1 particularly at some places
 near ,goat ,island1  where the water   
flows at present in a very shallow      
stream4 ,be that as  it may1 however1   
the power-houses are there1 and it is   
probable that  their number will be     
added to as years go on4 ,whether       
commercialism or  stheticism will win in
 the end1 it remains for the legislators
 of the  future to decide4              
,meanwhile1 it is gratifying to reflect 
that for the present the ,falls  retain 
their pristine beauty1 even though part 
of the water that is  their normal due  
is turned aside and made to do service  

for man in  another way4 ,there is only 
one reason why the ,falls have escaped  
desecration so long as they have2 that  
reason being the very practical  one    
that until quite recently man has not   
known how to utilize their  powers to   
advantage4 ,the effort was indeed made1 
a full generation  ago1 through the     
construction of the canal leading from  
the upper  river to the bluffs          
overlooking the gorge below the         
cataract4 ,here  a few mill-wheels were 
set whirling1 and a tiny fraction of the
  potential energy of the water was     
utilized4 ,there was no mechanical      
difficulty involved in the utilization  
of this power4 ,mill-wheels are  a      
familiar old-time device1 and even the  
turbine wheel is modern only  in a      
relative sense of the word4 ,and it must
 be understood that the  turbine        
water-wheel utilizes the greatest       
proportion of the power of  falling     
water of any contrivance as yet known to
 mechanics4 ,it was  possible1 then1 to 

utilize the water of ,niagara with full 
effectiveness  fifty years ago1 so far  
as the direct action of the water-wheel 
upon  machinery near at hand was        
concerned4 ,the sole difficulty lay in  
the  fact that only a small amount of   
machinery can be placed in any one      
location4 ,the real problem was not how 
to produce the power1 but how to        
transmit it to a distance4      ,,the   
,,transmission ,,of ,,power    ,for     
fifty years mechanical engineers have   
looked enviously upon  unshackled       
,niagara1 and have striven to solve the 
problem of  transmitting its power4 ,it 
were easy enough to harness the great   
,fall1  but futile to do so1 so long as 
the power generated must be used in the 
immediate vicinity4 ,so1 many schemes   
for transmitting power were tried  one  
after another1 and as often laid aside4 
,there was one objection  to even the   
best of them--the cost4 ,at one time it 
was thought that  compressed air might  
solve the problem4 ,but repeated        

experiments did  not justify the hope4  
,then it was believed that the storage  
battery  might be made available4 ,the  
storage battery1 it might be explained1 
does not really store electricity in the
 sense in which the ,leyden  jar1 for   
example1 stores it4 ,rather is it to be 
likened to an ordinary  voltaic cell1   
the chemical ingredients of which have  
been rendered  active by the passage of 
the electric current4 ,the active       
ingredients  of the storage battery are 
usually lead compounds1 which through   
action  of the electric currents have   
been decomposed and placed in a state of
  chemical instability4 ,the dissociated
 molecule of the lead compound1  when   
permitted to reunite with the atoms with
 which it was formerly  associated1 will
 give up electrical energy4    ,such a  
storage battery might readily be charged
 with electricity  generated at ,niagara
 ,falls4 ,it might then be conveyed to  
any part of  the world1 and1 its poles  
being connected1 the charge of          

electricity  would be made available4   
,such storage batteries are in common   
use  in connection with electric        
automobiles1 as we have seen4 ,but the  
great difficulty is that they are       
enormously heavy in proportion to  the  
amount of electricity that they can     
generate2 therefore1 their              
transportation is difficult and         
expensive4 ,in practice it is cheaper   
to produce electricity through the      
operation of a steam engine in a        
distant city than to transmit the       
electricity with the aid of a storage   
battery from ,niagara4 ,so the storage  
battery served as little as  compressed 
air to solve the engineer's problem4    
,when the electric dynamo became a      
commercial success for such purposes  as
 the operation of trolley lines it      
seemed as if the ,niagara problem  was  
on the verge of solution4 ,and so1 in   
point of fact1 it really was1  though   
more time was required for it than at   
first seemed needed4 ,the  power        

generated by the dynamo could1 indeed1  
be transmitted along a  wire1 but not   
without great loss4 ,sir ,william       
,siemens1 in #ahgg1 had  pointed out in 
connection with this very subject of the
 wasted power  of ,niagara1 that a      
thousand horse-power might be           
transmitted a distance  of1 say1 thirty 
miles over a copper rod three inches in 
diameter4 ,but a  copper rod three      
inches in diameter is enormously        
expensive1 and when  ,siemens further   
stated that sixty per cent of the power 
involved would  be lost in transmission1
 it was obvious that the method was far 
too  wasteful to be commercially        
practicable4    ,for a time the         
experimenters with the transmission of  
electricity  along a wire were on the   
wrong track4 ,they were experimenting   
with a  continuous current which1 as we 
have seen1 is produced from an ordinary 
dynamo with the aid of a commutator4    
,but hosts of experiments finally  made 
it clear that this form of current1 no  

matter how powerful it  might be1 is    
unable to traverse considerable distance
 without great  loss1 being frittered   
away in the form of heat4    ,but the   
very term continuous current implies the
 existence of a  current that is not    
continuous4 ,in point of fact1 we have  
already  seen that a dynamo1 if not     
supplied with a commutator1 will produce
  what is called an alternating current1
 and such a current has long  been known
 to possess properties peculiar to      
itself4 ,it is1 in  effect1 an          
interrupted current1 and it is sometimes
 spoken of as if  it really consisted of
 an alternation of currents which move  
first in  one direction and then in     
another4 ,such a conception is not      
really  justifiable4 ,the more plausible
 explanation is that the alternating    
current is one in which the electrons   
are not evenly distributed and  move    
with irregular motion4 ,perhaps we may  
think of the individual  electrons of   
such a current as oscillating in their  

flight1 and1 as  it were1 boring their  
way into the resisting medium4 ,in any  
event1  experience shows that such a    
current1 under proper conditions1 may be
  able to traverse a conducting wire for
 a long distance with relatively  small 
loss4    ,it must be understood1        
however1 that the mere fact that a      
current  alternates is not in itself    
sufficient to make feasible its         
transmission to a remote distance4 ,to  
meet all the requirements a  current    
must be of very high voltage4 ,this     
means1 in so far as we  can represent   
the conditions of one form of energy in 
the terms of  another1 that it shall be 
under high pressure4 ,fortunately a     
relatively  simple apparatus enables the
 electrician to transform a current from
  low to high voltage without           
difficulty4 ,and so at last the problem 
of transmitting power to a distance of  
many miles has been solved4  ,electrical
 currents representing thousands of     
horse-power are to-day  transmitted from

 ,niagara ,falls to the city of ,buffalo
 over ordinary  wires1 with a loss that 
is relatively insignificant4 ,a plant is
 in  process of construction that will  
similarly transmit the power to         
,toronto2 and it is predicted that in   
the near future the powers of  ,niagara 
will be drawn upon by the factories of  
cities even as far  distant as ,new     
,york and ,chicago4 ,practical          
difficulties still stand in  the way of 
such very distant transmission1 to be   
sure1 but these are  matters of detail1 
and are almost certain to be overcome in
 the near  future4    ,all this being   
explained1 it will be understood that   
the sole reason  why the new            
power-houses at ,niagara generate       
electricity is that  electricity is the 
one readily transportable carrier of    
energy4 ,we have  already explained that
 there is loss of energy when the steam 
engine  operates the dynamo4 ,at        
,niagara1 of course1 no steam is        
involved2 it  is the energy of falling  

water that is transformed into the      
energy of  the electrical current4      
,moreover1 the revolving dynamo is      
attached to  the same shaft with the    
turbine water-wheel1 so that there is no
 loss  through the interposition of     
gearing4 ,yet even so1 the electric     
current  that flows from the dynamo     
represents somewhat less of energy than 
the water current that flows into the   
turbine4 ,this loss1 however1 is        
compensated a thousandfold by the fact  
that the energy of the electric  current
 may now be distributed in obedience to 
man's will4      ,,step ,,up ,,and      
,,step ,,down ,,transformers    ,the    
dynamos in operation at ,niagara do not 
differ in principle from  those in the  
street-car power-house1 except in the   
fact that they  are not supplied with   
commutators4 ,we have seen that these   
dynamos  are of enormous size4 ,those   
already in operation generate five      
thousand horse-power2 others in process 
of construction will develop  ten       

thousand4 ,the generator which produces 
this enormous current is  about eleven  
feet in diameter1 and it makes two      
hundred and fifty  revolutions per      
minute4 ,the armatures are so wound that
 the result is  an alternating current  
of electricity of twenty-two hundred    
volts4  ,this current represents1 it has
 been said1 raw material which is to  be
 variously transformed as it is supplied
 to different uses4 ,to  factories near 
at hand1 indeed1 the current of         
twenty-two hundred  volts is supplied   
unchanged2 but for more distant         
consumption it is  raised to ten        
thousand volts2 and that portion which  
is sent away to  the factories of       
,buffalo and other equally distant      
places is raised to  twenty-two thousand
 volts4    ,illustration3 ,,electrical  
,,transformers4    ,the upper figure    
shows ,ferranti's experimental          
transformer built in  #ahhh4 ,it has a  
closed iron circuit1 built up of thin   
strips filling the  interior of the coil

 and having their ends bent over and    
overlapping  outside4 ,the lower figure 
shows a simple transformer known as     
,sturgeon's induction coil4 ,the middle 
figure gives a view of the series  of   
converters in the power house of the    
,manhattan ,elevated ,railway4    ,the  
transformation from a relatively low    
voltage to the high one  is effected by 
means of what is called a step-up       
transformer4 ,this  is an apparatus     
which brings into play a principle of   
electric  induction not very different  
from that which was responsible for the 
generation of the current of electricity
 in the dynamo4 ,the principle  is that 
evidenced in the familiar laboratory    
apparatus known as the  ,ruhmkorff coil4
 ,the transformer consists essentially  
of a primary  coil of relatively large  
wire1 surrounded by1 but insulated from1
 a  secondary coil of relatively fine   
wire4 ,when the interrupted current  is 
sent through the primary coil of such an
 apparatus1 an induced  counter-current 

is generated in the secondary coil4 ,of 
course there is  no gain in the actual  
quantity of electricity1 but the voltage
 of the  current generated in the finer 
wire is greatly increased4 ,for example1
  as we have seen1 the current that came
 from the dynamo at twenty-two  hundred 
volts is raised to ten thousand or      
twenty-two thousand volts4  ,these      
proportions may be varied indefinitely  
by varying the relative  sizes and      
lengths of the primary and secondary    
coils4    ,how shall we picture to      
ourselves the actual change in the      
current  represented by this difference 
in voltage8 ,we might prove1 readily    
enough1 that the difference is a real   
one1 since a wire carrying a  current of
 low voltage may be handled with        
impunity1 while a similar  wire carrying
 a current of high voltage may not      
safely be touched4 ,but  when we attempt
 to visualize the difference in the two 
currents we are  all at sea4 ,we may    
suppose1 of course1 that electrons      

spread out over a  long stretch of the  
secondary coil must be more widely      
scattered4 ,one  can conceive that the  
electrons1 thus relatively unimpeded1   
may acquire  a momentum1 and hence a    
penetrative power1 which they retain    
after they  are crowded together in a   
straight conductor4 ,but this suggestion
 at  best merely hazards a guess4       
,arrived at the other end of its        
journey1 the current which travels      
under this high voltage is retransformed
 into a low-voltage current  by means of
 an apparatus which simply reverses the 
conditions  of the step-up transformer1 
and which1 therefore1 is called a       
step-down transformer4 ,the electricity 
which came to ,buffalo as a             
twenty-two-thousand-volt current is thus
 reduced by any desired  amount before  
it is applied to the practical purposes 
for which it is  designed4 ,it may1 for 
example1 be stepped-down to two thousand
 volts  to supply the main wires of an  
electric-lighting plant2 and then again 

stepped-down to two hundred volts to    
supply the electric lamps of an         
individual house4    ,who that reads by 
the light of one of these electric      
lamps1 let us say  in ,buffalo1 and     
realizes that he is reading by the      
transformed energy  of ,niagara ,river1 
dare affirm that in our day there is    
nothing new  under the sun8             
,,xi    ,,the ,,banishment ,,of ,,night 
,one great fundamental advantage that   
man has won over the other  animals is  
that although by nature a diurnal animal
 he has made night  almost equally      
subject to his dominion through the use 
of artificial  light4 ,he thus          
establishes an average day of sixteen or
 eighteen  hours in place of the        
twelve-hour day within which his        
activities  would otherwise be          
restricted4 ,of course this conquest of 
the night  began at an early stage of   
the human development1 since a certain  
familiarity with the uses of fire was   
attained long before man came out  of   

the ages of savagery4 ,but when the     
transition had been made from  the      
primitive torch to the simplest type of 
lamp1 there was for many  centuries a   
cessation of progress in this direction1
 and it remained  for comparatively     
recent generations to provide more      
efficient methods  of lighting4 ,indeed1
 the culminating achievements are       
matters which  make the most recent     
history4 ,it is the purpose of the      
ensuing pages  to narrate the story of  
the successive practical achievements   
through  which man has been enabled     
virtually to turn night into day4       
,,primitive ,,torch ,,and ,,open ,,lamp 
,to moderns1 in an age when even the    
time-honored gas jets and kerosene      
lamps are regarded as obsolescent1 that 
ancient form of illuminant1  the candle1
 seems about the most primitive form of 
light-producing  apparatus4 ,in point of
 fact1 however1 the candle holds no such
 place  in the chronological order of   
lighting-device discovery1 being a      

relatively late innovation4 ,indeed1    
lamps of various kinds1 even those      
burning petroleum1 were used thousands  
of years before the relatively  clean   
and effective candle was invented4      
,the camp fires of primitive man must   
have suggested the use of a  fire-brand 
for lighting purposes almost as soon as 
the discovery of  fire itself2 but the  
development of any means of lighting his
 caves or  rude huts1 even in the form  
of torches1 was probably a slow process4
  ,for our earliest ancestors were not  
the nocturnal creatures their           
descendants became early in the history 
of civilization4 ,to them the  period of
 darkness was the time for sleeping1 and
 their waking hours  were those between 
dawn and dusk4 ,it was only when man had
 reached a  relatively high plane above 
the other members of the animal kingdom1
  therefore1 that he would wish to      
prolong the daylight1 and then the use  
of the torch made of some resinous wood 
would naturally suggest itself4    ,just

 when the ancient lamp was invented in  
the form of a vessel  filled with oil   
into which some kind of wick was dipped1
 cannot be  ascertained1 but its        
invention certainly antedated the       
,christian ,era  by several centuries4  
,and it is equally certain that once    
this smoky1  foul-smelling lamp had been
 discovered1 it remained in use1        
practically  without change or          
improvement1 until the end of the       
twelfth century1  the date of the       
invention of the candle4 ,such lamps    
were used by the  ,greeks and ,romans1  
great quantities of them being still    
preserved4 ,they  were simply shallow1  
saucer-like vessels for holding the oil1
 into  which the wick was laid1 so      
arranged that the upper end rested      
against  the edge of the vessel4 ,here  
the oil burned and smoked1 capillarity  
supplying oil to the burning end of the 
wick1 which was pulled up from  time to 
time as it became shortened by burning1 
either with pincers  made for the       

purpose1 or perhaps more frequently by  
the ever useful  hairpin of the matron4 
,as the thick wick did not allow the air
 to penetrate to burn the carbon  of the
 oil completely1 a nauseous smoke was   
given off constantly which  was stifling
 when a draught of air prevented its    
escape through the  hole in the         
roof--the only chimney used by the      
,greeks4 ,and since this  was the only  
kind of lamp known at the time1 the     
palace of the ,roman  ,emperor and hut  
of the ,roman peasant were necessarily  
alike in their  methods of lighting if  
in little else4 ,the ,emperor's lamps   
might be  modeled of gold and set with  
precious stones1 while those of the     
peasant were of rudely modeled clay2 but
 each must have evoked1 along  with its 
dim light1 an unwholesome modicum of    
smoke and malodor4    ,it was this form 
of lamp1 practically unaltered except   
occasionally in  design1 that remained  
in common use during the ,middle ,ages2 
and when1  at the close of the twelfth  

century1 the tallow candle was invented1
  that now despised device must have    
been almost as revolutionary in its     
effect as the incandescent burner and   
the electric bulb were destined  to be  
in a more recent generation4 ,it burned 
with dazzling brilliancy  in comparison 
with the oil lamp2 it gave off no smoke 
and little smell2  it needed no care1   
and it occupied little space4 ,then for 
the first  time in the history of the   
world reasonably good house illumination
  became possible4 ,several additional  
centuries elapsed1 however1 before  the 
idea was developed of placing a candle  
in a covered glass-sided  receptacle1 to
 form a lantern or a street lamp4       
,for generations the candle held supreme
 place1 though its cost made it         
something of a luxury2 doubly so if wax 
was substituted for tallow in  its      
composition4 ,but toward the close of   
the eighteenth century1 when  the action
 of combustion had begun to be better   
understood1 attempts  were made to      

improve the wicks and burners of oil    
lamps4 ,in #aghc1 an  inventor named    
,leger1 of ,paris1 produced a burner    
using a broad1 flat1  ribbonlike wick in
 which practically every part of the oil
 supply was  brought into contact with  
the air1 producing1 therefore1 a steady 
flame  relatively free from smoke4 ,the 
flame1 while broad1 was extremely thin1 
and its light was consequently radiated 
very unevenly4 ,portions of a  room     
lying in the direction of the long axis 
of the flame were but  poorly lighted4  
,to overcome this difficulty1 a curved  
form of burner  was adopted2 and this   
led eventually to the invention of the  
circular  ,argand burner1 the prototype 
of the best modern lamp-burners4        
,,tallow ,,candle ,,and ,,perfected     
,,oil ,,lamp    ,stated in scientific   
terms1 the problem of the ideal         
lamp-wick resolves  itself into a       
question of how to supply oxygen to     
every portion of  the flame in          
sufficient quantities to bring all the  

carbon particles  to a temperature at   
which they are luminous4 ,it occurred to
 ,argand  that this could be done by    
giving the wick a circular form like a  
cylindrical tube1 giving the air free   
access to the centre of the tube  as    
well as to its outer surface4 ,in his   
lamp the reservoir of oil was  placed at
 a little distance from1 and slightly   
above1 the tube holding  the burner1    
connected with it by a small tube much  
as the tank of  the modern student lamp 
connects with the burner4 ,in this      
manner a  fairly good lamp was          
produced1--a decided improvement over   
any made  heretofore1--and when1 in     
#agfe1 ,quinquet added a glass chimney  
to this  lamp a new epoch of artificial 
lighting was inaugurated4 ,this date is 
of as much importance in artificial     
lighting as is #aghi in politics1  says 
one writer4 ,between the ancient lamps  
and the lamps of ,quinquet  there is as 
much difference as between the          
chimney-place of our parlors  and the   

fireplaces of our original ,aryan       
ancestors1 formed by a hole  dug in the 
ground in the centre of their cabins4   
,a little later ,carcel still further   
improved the ,quinquet lamp by  adapting
 a clock movement that forced the oil to
 rise to the wick1  so that it was no   
longer necessary to have the burner and 
the  reservoir separated by a tube4     
,this was still further improved upon   
by substituting a spring for the        
clockwork1 the result being a lamp  of  
great simplicity1 yet one which gave    
such results that it replaced  the      
candle as a unit for measuring the      
illuminating power of different  sources
 of light4    ,these various burners    
should not be confused with the modern  
burners of  the ordinary kerosene lamps4
 ,mineral oils had not as yet come into 
use  for illuminating purposes1 except  
as torches or in simple lamps like      
those of the ,romans1 as refining       
processes had not been perfected1 and   
the smoke and odors from crude petroleum

 were absolutely intolerable in  closed 
rooms4    ,many other substances were   
tried in place of the heavy oils1 such  
as  the volatile hydrocarbons and       
alcohols1 but with no great success4    
,early in the nineteenth century a lamp 
burning turpentine1 under  the name of  
camphine1 was invented that gave a good 
light and was  smokeless2 but like most 
others of its type1 it was dangerous    
owing  to its liability to explode4 ,and
 it was not until methods of refining   
petroleum had been improved that        
mineral-oil lamps--the predecessors  of 
the modern type of lamps--came into use4
    ,the invention of this type of lamp 
was a relatively easy task--a  simple   
transition and adaptation as processes  
of refining the oil were  perfected4    
,the principle of combustion was1 of    
course1 the same as in  the ,argand type
 of lamps burning animal and vegetable  
oils2 but mineral  oils are of such     
consistency that capillarity causes an  
abundant supply  of oil to rise in the  

wick1 so that clockwork and spring      
devices1 such  as were used in the      
,carcel lamps1 could be dispensed with4 
,,gas ,,lighting    ,while the rivalry  
between the candle and the new forms of 
lamps was at  its height1 and just as   
the lamp was gaining complete supremacy1
 a new  method of artificial            
illumination was discovered that was    
destined to  eclipse all others for half
 a century1 and then finally to succumb 
to a  still better form4 ,as early as   
the beginning of the eighteenth century 
the ,rev4 ,joseph ,clayton1 in ,england1
 had made experiments in the            
distillation of coal1 producing a gas   
that was inflammable4 ,a little  later  
,dr4 ,stephen ,hales published his work 
on ,vegetable ,staticks1 in  which he   
described the process of distilling coal
 in which a definite  amount of gas     
could be obtained from a given quantity 
of coal4    ,no practical use was made  
of this discovery1 however1 until over  
half a century later4 ,but just at the  

close of the century a ,scot1  ,william 
,murdoch1 became interested in the      
possibilities of gases  as illuminants1 
and finally demonstrated that coal gas  
could be  put to practical use4 ,in     
#agih1 being employed in the workshops  
of  ,boulton and ,watt in ,birmingham1  
he fitted up an apparatus in which he   
manufactured gas1 lighting the workshops
 by means of jets connected by  tubes   
with this primitive plant4 ,shortly     
after this1 a ,frenchman1 ,m4  ,lebon1  
lighted his house in ,paris with gas    
distilled from wood1 and  the ,parisians
 soon became interested in the new      
illuminant4 ,england  seems to have been
 the first country to use it extensively
 in public  buildings1 however1 the     
,london ,lyceum ,theatre being lighted  
with gas  in #ahjc4 ,by #ahaj the great 
,gas-,light and ,coke ,company was      
formed1 and  within the next five years 
gas street-lamps had become familiar    
objects  in the streets of ,london1 and 
house illumination by this means a      

common  thing among the wealthier       
classes4    ,in the early days of       
gas-lighting the results were frequently
  disappointing1 because no suitable and
 efficient type of burner had  been     
devised2 but in #ahbj ,neilson of       
,glasgow discovered the principle  of   
the now familiar flat burner1 of which  
more examples still remain  in use the  
world over than of all other kinds      
combined4 ,indeed1 this  simple1 but as 
we now regard it1 inefficient burner1   
would probably  have remained the       
best-known type for many years longer   
than it did  had not the possibilities  
of lighting by electricity aroused      
persons  interested in the great        
gas-plants to the fact that the new     
illuminant  was jeopardizing their      
enormous investments2 making it clear   
that they  must bestir themselves and   
improve their flat burners if they would
  arrest disaster4 ,to be sure1 several 
modifications of the round ,argand      
burner had been introduced from time to 

time1 some of them being a  distinct    
improvement over the flat burner1 but   
these did not by any  means seriously   
compete with electric light4 ,and it was
 not until the  incandescent mantle was 
perfected that gas as a brilliant       
illuminant  was able to make a stand    
against its new competitor4      ,,the  
,,incandescent ,,gas ,,mantle    ,it has
 been known almost since the beginnings 
of civilization that all  solids can be 
made to emit light when heated to       
certain temperatures4  ,some substances 
were known to be peculiarly adapted to  
this purpose1  such as lumps of lime1   
and for many years the calcium light or 
lime-light as it is popularly called1   
had been in use for special  purposes1  
and was the most intense light known4   
,this light is made by  heating a block 
of lime to the highest practicable      
temperature by means  of a blast of     
oxygen and coal gas2 but such lights    
were too complicated  and expensive for 
general purposes4 ,it had been          

determined even as  early as the        
beginning of the nineteenth century1    
however1 that the  high temperature     
necessary for producing this light was  
due in part at  least to the fact that  
such a large amount of material had to  
be raised  to incandescence4 ,it was    
evident1 therefore1 that if a small     
amount  of some such substance as lime  
and magnesia could be spread out so as  
to present a large surface in a small   
space1 such as is represented  by       
basket-work1 sufficient heat for making 
it incandescent might be  obtained from 
an ordinary gas-and-air blowpipe4       
,here then was the germ of the mantle   
idea2 and such an apparatus1  known as  
the ,clamond mantle1 which was made of  
threads of calcined  magnesia1 was shown
 at the ,crystal ,palace ,exhibition1 in
 ,london1 in  #ahhb4 ,curiously enough1 
this mantle and burner worked in an     
inverted  position1 the mantle being    
suspended bottom upwards below the      
burner  through which the blast of gas  

was forced4 ,the light given by this    
mantle was most brilliant--little short 
of the older calcium light1  in         
fact--but the device itself was too     
complicated to be of service  for       
ordinary lighting purposes4 ,the        
principle was correct1 but the          
construction of the mantle was          
defective4    ,meanwhile a ,german      
scientist1 ,dr4 ,auer von ,welsbach1 who
 had become  famous in the scientific   
world for his researches on rare metals1
 was  experimenting with certain oxides 
of different metals1 and developing  a  
method of handling them that finally    
resulted in the perfected  incandescent 
burner in use at present4 ,his process1 
which in theory at  least was not       
entirely original with him1 was to dip  
an open fabric  of cotton into a        
solution of the nitrates of the metals  
to be used1  drying it1 and converting  
the nitrates into oxides by burning2 the
  cotton fabric disappearing but leaving
 the skeleton of the oxide1 which       

retained its original shape4    ,at the 
same time corresponding improvements    
were made in the type of  burner1 which 
is quite as essential to success as the 
mantle itself4  ,it had been found that 
it was absolutely essential for such a  
burner  to give a practically           
non-luminous flame1 as otherwise the    
deposit of  carbon particles will ruin  
the mantle4 ,two ways of obtaining this 
are  possible2 one by mixing a certain  
quantity of air with the gas before     
combustion1 the other to burn the gas in
 so thin a flame that the air  permeates
 it freely4 ,several burners of both    
types were used at first1  but gradually
 the burners in which the air is mixed  
with the gas became  the more popular1  
and most of the incandescent burners now
 on the  market are of this type4    ,in
 the construction of mantles at the     
present time1 while the principle  of   
their use remains the same as that of   
the lime-light1 lime itself  is not     
used1 the oxides of certain other metals

 having proved better  adapted for the  
purpose4 ,thus the ,welsbach patent of  
#ahhf covered the  use of thoria1 either
 alone or mixed with other substances   
such as  zirconia1 alumina1 magnesia1   
etc42 thoria being considered as having 
a very high power of light emission4    
,later it was discovered that  pure     
thoria emits very little light by       
itself1 although it possesses  a        
refractory nature that gives a stability
 to the mantle unequalled  by any other 
material as yet discovered4 ,when       
combined with a small  trace of the     
oxides of certain rare metals1 however1 
such as uranium1  terbium1 or cerium1   
thoria mantles have a very high power of
 light  emission1 most modern mantles   
being composed of about ninety-nine per 
cent4 thoria with one per cent4 cerium4 
,in the ordinary method of manufacturing
 such mantles1 a cotton-net  cylinder   
about eight inches long1 more or less   
according to the size  of mantle        
required1 is made1 one end being        

contracted by an asbestos  thread4 ,a   
loop of the same material1 or in some   
cases a platinum wire1  is fastened     
across the opening1 to be used for      
suspending the mantle  when in use4 ,the
 cotton-thread cylinder is soaked in a  
solution of  the nitrates of the metals 
thorium and cerium1 and is then wrung   
out  to remove the excess1 stretched on 
a conical mold1 and dried4 ,the  flame  
of an atmospheric burner being applied  
to the upper part at the  constricted   
position1 the burning extends downward1 
converting the  nitrates into oxides1   
and removing the organic matter4        
,considerable  skill is required in this
 part of the process1 as the regular    
shape of  the mantle is largely         
dependent upon the regularity of the    
burning4  ,as a finishing process a     
flame is applied to the inside of the   
mantle  after it has cooled1 to remove  
all traces of carbon that may remain4   
,the mantle is now ready for use1 but is
 so fragile that it can scarcely  be    

touched without breaking1 and such      
handling as would be necessary  for     
shipment would be out of the question4  
,it is therefore strengthened           
temporarily by being dipped into a      
mixture of collodion and castor oil1    
which1 when dry1 forms a firm but       
elastic jacket surrounding all parts4   
,it is this collodion jacket that is    
burned away when the new mantle is      
placed on the burner before the gas is  
turned on4    ,quite recently the method
 of manufacturing mantles used by       
,clamond has  been revived4 ,in this    
method the cotton thread is dispensed   
with1 the  thread used being made from a
 paste containing the mantle material   
itself4 ,the paste is placed in a proper
 receptacle the bottom of  which is     
perforated with minute openings1 and    
subjected to pressure1  squeezing out   
the material in long filaments4 ,when   
dry these are wound  on bobbins1 and1   
after being treated by certain chemical 
processes1 are  ready for weaving into  

mantles4 ,it is claimed for mantles made
 on this  principle that they last much 
longer and retain their light-emitting  
power more uniformly than mantles made  
by the older process4      ,,the        
,,introduction ,,of ,,acetylene ,,gas   
,when the incandescent mantle had been  
perfected so as to be an  economical as 
well an as efficient light-giver1 the   
position of coal  gas as an illuminant  
seemed again secured against the        
encroachments  of its rivals1 the arc   
and incandescent electric lights4 ,but  
just at  this time another rival        
appeared in the field that not only     
menaced  the mantle lamp but the arc and
 incandescent light as well4 ,curiously 
enough1 this new rival1 acetylene gas1  
had been brought into existence         
commercially by the electric arc itself4
 ,for although it had been  known as a  
possible illuminant for many years1 the 
calcium carbide for  producing it could 
not be manufactured economically until  
the advent of  the electric furnace1    

itself the outcome of ,davy's arc light4
    ,even as early as #ahcf an ,english 
chemist had made the discovery that  one
 of the by-products of the manufacture  
of metallic potassium would  decompose  
water and evolve a gas containing       
acetylene2 and this was  later observed 
independently from time to time by      
several chemists in  different          
countries4 ,no importance was attached  
to these discoveries1  however1 and     
nothing was done with acetylene as an   
illuminant until the  last decade of the
 nineteenth century4 ,by this time      
electric furnaces  had come into general
 use1 and it was while working with one 
of these  furnaces in #ahib that ,mr4   
,thomas ,f4 ,wilson1 in preparing       
metallic  calcium from a mixture of lime
 and coal1 produced a peculiar mass of  
dark-colored material1 calcium carbide1 
which1 when thrown into water1  evolved 
a gas with an extremely disagreeable    
odor4 ,when lighted1 this  gas burned   
with astonishing brilliancy1 and1 as its

 cost of production  was extremely      
small1 the idea of utilizing it for     
illuminating was at  once conceived and 
put into practice4    ,the secret of the
 cheap manufacture of the carbide lies  
in the  fact that the extremely high    
temperature required--about #dejj       
,fahrenheit--can be obtained            
economically in the electric furnace1   
but not otherwise4 ,thus electricity    
created its own greatest rival  as an   
illuminant4 ,it followed naturally that 
the ideal place for  manufacturing the  
carbide would be at the source of the   
cheapest supply  of electricity1 and as 
the harnessed ,niagara ,falls           
represented the  cheapest source of     
electric supply1 this place soon became 
the centre  of the carbide industry4    
,here the process of manufacture is     
carried out  on an enormous scale4 ,in  
practice1 lime and ground coke are      
thoroughly  mixed in the proportion of  
about fifty-six parts of lime to        
thirty-six  parts of coke4 ,when this   

mixture has been subjected to the heat  
of the  electric furnace for a short    
time an ingot of pure calcium carbide is
  formed1 surrounded by a crust of less 
pure material4 ,the ingot and  crust    
together represent sixty-four parts of  
the original ninety-two  parts of lime  
and coke1 the remaining twenty-eight    
parts being  liberated as               
carbon-monoxide gas4    ,calcium carbide
 as produced by this process is a       
dark-brown crystalline  substance which 
may be heated to redness without danger 
or change4 ,it  will not burn except    
when heated in oxygen1 and will keep    
indefinitely  if sealed from the air4   
,chemically it consists of one atom of  
lime  combined with two atoms of carbon 
7,ca,c#b72 and to produce acetylene     
gas1 which is a combination of carbon   
and hydrogen 7,c#b;,h#b7 it is  only    
necessary to bring it into contact with 
water1 acetylene gas and  slaked lime   
being formed4 ,one pound of pure carbide
 will produce five  and one half cubic  

feet of gas of greater illuminating     
power than  any other known gas4 ,the   
flame is absolutely white and of        
blinding  brilliancy1 giving a spectrum 
closely approximating that of sunlight4 
,the light is so strongly actinic that  
it is excellent for photography4        
,here was a gas that could be made in   
any desired quantities simply by  adding
 water to a substance costing only about
 three cents a pound2  its cost of      
production1 therefore1 representing only
 about one sixth  of the                
dollar-per-thousand-feet rate usually   
charged for illuminating  gas in our    
cities4 ,it could be used in lamps and  
lanterns made with  special burners and 
with the simple mechanism of a small    
water tank  which allowed water to drip 
into a receptacle holding the carbide2  
or--reversing the process--an apparatus 
that dropped pieces of carbide  into the
 water tanks4 ,it was1 in short1 the    
cheapest illuminant known1  generated by
 an apparatus that was simplicity       

itself4    ,there were1 however1 two    
defects in this gas3 its odor was       
intolerable--the smell of decayed       
garlic1 it has been aptly  called--and  
when mixed with air it was highly       
explosive4 ,the first of  these defects 
could be overcome easily2 when the      
burner consumed all  the gas there was  
no odor4 ,the second1 the explosive     
quality1 presented  greater             
difficulties4 ,these were emphasized and
 magnified by the number  of defective  
lamps that soon flooded the market1 many
 of these being so  badly constructed   
that explosions were inevitable4 ,as a  
result a strong  prejudice quickly arose
 against the gas1 some countries passing
 laws  prohibiting its use4    ,but     
further inquiry into the cause of the   
frequent disasters revealed  the fact   
that when the burner of a lamp was      
constructed so that the air  for        
combustion was supplied after the gas   
issued from the jet1 there  was no      
danger of explosion4 ,and as lamps      

carefully constructed on this  principle
 replaced the early ones of faulty      
construction1 confidence  in acetylene  
was restored4 ,methods were devised for 
supplying the gas  for                  
house-illumination like ordinary gas1   
and the occupants of country  houses    
were afforded a means of lighting their 
houses on a scale of  brilliancy        
hitherto unapproached1 yet with economy 
and relative safety4    ,it was found   
also that the brilliancy of the         
acetylene flame was of  such intensity  
that it could be used1 like the electric
 arc light1 as a  search-light4 ,it thus
 furnished a simple means of supplying  
small boats  and vehicles with such     
lights1 which they could not otherwise  
have  had4 ,it also supplied army       
signal-corps with an apparatus for      
flashing  messages--an apparatus that   
was ideal on account of its simplicity  
and  small size4    ,at the             
,pan-,american ,exhibition at ,buffalo  
the various illuminating  exhibits were 

among the most conspicuous and          
attractive features4 ,but  even amid the
 dazzling electrical displays the       
,acetylene ,building was  a noteworthy  
object4 ,it was the most brilliantly and
 beautifully  lighted building in the   
grounds1 declared one observer4 ,it     
sparkled  like a diamond1 and was the   
admiration of all visitors4 ,in it were 
generators of all types--most of them   
supplying the gas for their own         
exhibits--several being the latest      
exponents of the art1 so simple that    
they can be safely managed by unskilled 
labor2 in fact1 'the brains are  in the 
machines1' and when the attendant has   
charged them with carbide  and filled   
them with water--given them food and    
drink--they will work  steadily until   
they need another meal4 ,indeed1 these  
exhibits at the  ,pan-,american         
,exhibition demonstrated conclusively   
that acetylene gas  occupies a field by 
itself as a practical illuminant4    ,at
 the same exposition a standard was     

established for good stationary         
acetylene generators for house-lighting1
 and the fact that a large  number of   
generators fulfilled the requirements of
 the set of rules  laid down showed how 
thoroughly the problem of handling this 
gas has  been solved4 ,some of these    
rules used as tests are instructive to  
anyone interested in the subject1 and a 
few of them are given here4  ,they      
specified1 for example1 that--    ,the  
carbide should be dropped into the      
water1 the reverse process of  letting  
the water drip on the carbide1 as was   
done in most of the early  generators1  
being condemned4 ,there must be no      
possibility of mixing  air with the     
acetylene gas4 ,construction must be    
such that an addition  to the charge of 
carbide can be made at any time without 
affecting the  lights4 ,generators must 
be entirely automatic in their          
action--that is  to say3 after a        
generator has been charged1 it must need
 no further  attention until the carbide

 has been entirely exhausted4 ,the      
various  operations of discharging the  
refuse1 filling with fresh water1       
charging with carbide1 and starting the 
generator must be so simple  that the   
generator can be tended by an unskilled 
workman without danger  of accident4    
,when the lights are out1 the generation
 of gas should  cease4 ,the carbide     
should be fed automatically into the    
water in  proportion to the gas         
consumed4    ,perhaps the most          
significant thing1 showing the stage of 
progress that  has been made in         
overcoming the danger of explosions from
 acetylene  gas1 is that the use of     
generators meeting some such            
requirements as  the above is not       
prohibited by fire underwriters4 ,this  
in itself is  very convincing evidence  
of their safety4      ,,the ,,triumph   
,,of ,,electricity    ,throughout the   
ages primitive man had had constantly   
before him two  sources of light other  
than that of the sun1 moon1 and stars4  

,one  of these1 the fire of ordinary    
combustion1 he could understand and     
utilize2 the other1 more powerful and   
more terrible1 which flashed  across the
 heavens at times1 he could not even    
vaguely understand1 and1  naturally1 did
 not attempt to utilize4 ,but early in  
the seventeenth  century some scientific
 discoveries were made which1 although  
their  destination was not even imagined
 at the time1 pointed the way that      
eventually led to man's imitating in the
 most striking manner ,nature's         
electrical illumination4    ,about this 
time ,otto von ,guericke1 the           
burgomaster-philosopher of  ,magdeburg1 
in the course of his numerous           
experiments1 had discovered  some of the
 properties of electricity1 by rubbing a
 sulphur ball1 and  among other things  
had noticed that when the ball was      
rubbed in a  darkened room1 a faint glow
 of light was produced4 ,he was aware1  
also1  that in some way this was        
connected with the generation of        

electricity1  but in what manner he had 
no conception4 ,in the opening years of 
the  following century ,francis         
,hauksbee obtained somewhat similar     
results  with glass globes and tubes1   
and made several important discoveries  
as to the properties of electricity that
 stimulated an interest in  the subject 
among the philosophers of the time4     
,gray in ,england1 and  ,dufay in       
,france1 who became enthusiastic workers
 in the field1 soon  established        
important facts regarding conduction and
 insulation1 and  by the middle of the  
eighteenth century the production of an 
electric  spark had become a commonplace
 demonstration4    ,but until this time 
it had not been demonstrated that this  
electric  spark was actual fire1        
although there was no disputing the fact
 that  it produced light4 ,in #agdd1    
however1 this point was settled         
definitely  by the ,german1 ,christian  
,friedrich ,ludolff1 who projected a    
spark  from a rubbed glass rod upon the 

surface of a bowl of ether1 causing  the
 liquid to burst into flame4 ,a few     
years later ,benjamin ,franklin         
demonstrated with his kite and key that 
lightning is a manifestation of         
electricity4    ,but neither the        
galvanic cell nor the dynamo had been   
invented at  that time1 and there was no
 possibility of producing anything like 
a  sustained artificial light with the  
static electrical machines then  in use4
 ,it was not until the classic discovery
 of ,galvani and the  resulting         
invention of the voltaic1 or galvanic1  
cell shortly after1  that the electric  
light1 in the sense of a sustained      
light1 became  possible4 ,and even then1
 as we shall see in a moment1 such a    
light was  too expensive to be of any   
use commercially4      ,,davy ,,and     
,,the ,,first ,,electric ,,light    ,as 
soon as ,volta's great invention was    
made known a new wave of  enthusiasm in 
the field of electricity swept over the 
world1 for the  constant and relatively 

tractable current of the galvanic       
battery  suggested possibilities not    
conceivable with the older friction     
machines4 ,batteries containing large   
numbers of cells were devised2 one      
having two thousand such elements being 
constructed for ,sir ,humphry  ,davy at 
the ,royal ,institution1 of ,london4 ,by
 bringing two points of  carbon1        
representing the two poles of the       
battery1 close together1 ,davy  caused a
 jet of flame to play between them--not 
a momentary spark1 but  a continuous    
light--a true voltaic arc1 like that    
seen in the modern  street-light to-day4
    ,when pieces of charcoal about an   
inch long and one-sixth of an inch in   
diameter were brought near each other   
7within the thirtieth or fortieth  of an
 inch71 wrote ,davy in describing this  
experiment1 a bright  spark was         
produced1 and more than half the volume 
of charcoal became  ignited to          
whiteness2 and1 by withdrawing the      
points from each other1 a  constant     

discharge took place through the heated 
air1 in a space equal  to at least four 
inches1 producing a most brilliant      
ascending arch of  light1 broad and     
conical in form in the middle4 ,when any
 substance was  introduced into this    
arch1 it instantly became ignited2      
platina melted  in it as readily as wax 
in a common candle2 quartz1 the         
sapphire1  magnesia1 lime1 all entered  
into fusion2 fragments of diamond and   
points of charcoal and plumbago seemed  
to evaporate in it1 even when  the      
connection was made in the receiver of  
an air-pump2 but there was  no evidence 
of their having previously undergone    
fusion4 ,when the  communication between
 the points positively and negatively   
electrified  was made in the air        
rarefied in the receiver of the         
air-pump1 the  distance at which the    
discharge took place increased as the   
exhaustion  was made2 and when the      
atmosphere in the vessel supported only 
one-fourth of an inch of mercury in the 

barometrical gauge1 the sparks  passed  
through a space of nearly half an inch2 
and1 by withdrawing the  points from    
each other1 the discharge was made      
through six or seven  inches1 producing 
a most brilliant coruscation of purple  
light2 the  charcoal became intensely   
ignited1 and some platina wire attached 
to  it fused with brilliant             
scintillations and fell in large        
globules upon  the plate of the pump4   
,all the phenomena of chemical          
decomposition were  produced with       
intense rapidity by this combination4   
,it will be seen from this that as far  
as the actual lighting-part of  ,davy's 
apparatus was concerned1 it was         
completely successful4 ,but the  source 
of the current--the most essential part 
of the apparatus--was  such that even   
the wealthy could hardly afford to      
indulge in it as a  luxury4 ,the initial
 cost of two thousand cells was only a  
small item of  expense compared with the
 cost of maintaining them in working    

order1  and paying skilled operators to 
care for them4 ,so that for the moment  
no practical results came from this     
demonstration1 conclusive though  it    
was1 and the introduction of a          
commercial electric light was of        
necessity deferred until a cheaper      
method of generating electricity  should
 be discovered4    ,this discovery was  
not made for another generation1 but    
then1 as  seems entirely fitting1 it was
 made by ,davy's successor and former   
assistant at the ,royal ,institution1   
,sir ,michael ,faraday4 ,his discovery  
of electromagnetic induction in #ahca   
for the first time made possible  the   
electric dynamo1 although still another 
generation passed before  this invention
 took practical form4 ,in the meantime1 
however1 the  magneto-electric machine  
of ,nollet was used for generating an   
electric  current for illuminating      
purposes as early as #ahfc2 and when    
finally  the dynamo-electric machine was
 produced by ,gramme in #ahgj1 engineers

  and inventors had at their disposal   
everything necessary for producing  a   
practical electric illuminant4    ,it   
must not be supposed1 however1 that     
inventors stood by patiently  with      
folded hands waiting for the coming of a
 machine that would  furnish them with  
an adequate current without attempting  
to produce  electric lamps4 ,on the     
contrary1 they were constantly wrestling
 with  the problem1 in some instances   
being fairly successful1 even before the
  invention of the magneto-electric     
machine4 ,great advances had been made  
in batteries and cell construction over 
the primitive cells of the time  of     
,davy1 and for exhibition purposes1 and 
even for lighting factories  and large  
buildings1 fairly good electric lights  
had been used before  #ahfc4    ,the    
first practical application of electric 
lighting seems to have  been made in    
,france in #ahdi4 ,during the production
 of the opera ,the  ,prophet the sun was
 to appear1 and for this purpose an     

electric arc  light was used4 ,the      
success of this effort--an artificial   
sun being  produced that seemed almost  
as dazzling to the astonished audience  
as  ,old ,sol himself--stimulated       
further efforts in the same direction4  
,the  previous year ,w4 ,e4 ,staite in  
,england made experiments along similar 
lines in the large hall of the hotel of 
,sunderland4 ,he generated a  light     
resembling the sun1 or the light of day1
 and making candles  appear as obscure  
as they do by daylight1 according to the
 ,times of  the following morning4 ,the 
electric light was therefore proved to  
be a  practical illuminator1 although it
 was not until the introduction of  the 
,gramme dynamo-electric machine that its
 great economic utility was             
demonstrated4      ,,the ,,jablochkoff  
,,candle    ,in ,sir ,humphry ,davy's   
experiments with his arc light he was   
led to  believe that the light between  
the two points of carbon would be       
produced even in an absolute vacuum1 if 

it were possible to create one4         
,several scientists at the time disputed
 this contention1 and ,m4 ,masson1      
,professor of ,physics in the cole      
,centrale des ,arts et ,manufactures  in
 ,paris was particularly active in      
combatting the idea1 maintaining  that  
the arc had the same cause as the       
electric spark--the transport  by       
electricity of the incandescent         
particles of the electrodes through  the
 atmosphere4 ,it was certain1 at any    
rate1 that no light was produced  when  
the opposing carbons were brought into  
contact with each other1  or were1 on   
the other hand1 separated too widely2   
and since there  was a constant wearing 
away and shortening of the points1 and  
thus  a constantly increasing space     
between them1 the great difficulty in   
making a practical lamp lay in          
regulating this distance automatically4 
,it was finally accomplished1 however1  
by the invention of a ,russian  officer1
 ,m4 ,jablochkoff1 in #ahgf4 ,the       

,jablochkoff candle1 as his  lamp was   
called1 marked an epoch in the history  
of electric lighting4  ,one great merit 
of this invention was its simplicity1   
and while it  has long since gone out of
 use1 having been superseded by still   
simpler and better devices1 it must     
always be recalled as an important      
stepping-stone in the progress of       
artificial illumination4    ,the name   
candle for ,jablochkoff's lamp was      
suggested by the fact  that the two     
carbons were placed side by side1       
instead of point to  point1 the light at
 the top thus suggesting a candle4      
,between these  two carbons1 and        
extending their whole length except at  
the very tips1  was an insulating       
material that the arc could not pierce1 
but which  burned away at a rate        
commensurate with the shortening of the 
carbons4  ,in this manner the points    
were kept constantly at the proper      
distance  without regulating-machinery  
of any kind4 ,this ingenious apparatus  

had the additional advantage that it    
could be placed on any kind of a        
bracket or chandelier that was properly 
wired1 thus dispensing with the         
cumbersome frames and machines of the   
point-to-point carbon arc lights  then  
being introduced4    ,one difficulty at 
first encountered in using the          
,jablochkoff candle was  the starting of
 the voltaic arc4 ,in doing this it was 
necessary that  contact be made between 
two carbon points1 whether they lie     
parallel or  point to point1 and the    
necessary slight separation for         
producing the  light effected later4 ,to
 accomplish this ,jablochkoff joined the
 tips of  the carbons of his candle with
 a thin strip of carbon1 which quickly  
burned away when the current was turned 
on1 leaving the necessary space  between
 the points for the arc4    ,there was  
one difficulty with the candle that     
seemed insurmountable  for a time--the  
wasting of the two carbons was unequal1 
as in any arc  light1 the points thus   

gradually drawing apart until the       
passage of the  current was no longer   
possible4 ,to overcome this the rapidly 
wasting  positive carbon was made double
 the thickness of its mate2 but while   
this answered fairly well the thinner   
negative carbon gradually became  heated
 by the increased resistance1 and burned
 up too rapidly4 ,the  difficulty was   
finally overcome by the simple expedient
 of alternating  the flow of the        
current1 so that each carbon was        
alternately a  positive and a negative  
pole4 ,as the magneto-electric machines 
then in  use produced alternating       
currents it was only necessary to use   
such  machines for generating the       
current to produce an equal destruction 
of  both carbons4    ,the simplicity and
 excellence of the light of these       
candles brought  them at once into      
general popularity1 not only in the     
large cities of  ,europe1 but in many   
out-of-the-way places4 ,greece1         
,portugal1 and other  obscure ,european 

countries adopted them1 and even        
,brazil1 ,la ,plata1  and ,mexico       
installed many plants4 ,but stranger    
still1 they were soon  used for         
illuminating the palaces of the ,shah of
 ,persia and the ,king  of ,cambodia1   
and a little later were introduced into 
the residence of  the savage ,king of   
,burma4 ,in short1 their use became     
universal almost  immediately4          
,,the ,,improved ,,arc ,,light    ,about
 the time that ,jablochkoff's candles   
were making such a sensation  in        
,europe1 ,charles ,f4 ,brush1 of        
,cleveland1 ,ohio1 invented an arc light
  in which the carbons were set point to
 point1 the distance being  maintained  
and the necessary feed produced         
automatically in much the  same manner  
as in the lamps used at present4 ,other 
inventions soon  followed1 some of the  
lamps being regulated by clockwork1 some
 by  electricity and magnetism4    ,the 
advantage of this type of arc lamp over 
the candle type--an  advantage that led 

to its general adoption--was largely    
that of  efficiency1 a far greater      
amount of light being obtainable from   
the  same expenditure of power by the   
point-to-point type of lamp4    ,in this
 lamp it is necessary that the points of
 carbon shall come in  contact when the 
current is off1 but be drawn apart a    
moment after the  current is turned on1 
and remain at this fixed distance4 ,to  
accomplish  this1 the lower carbon is   
usually made stationary1 the feeding    
being  regulated by the position of the 
upper carbon4 ,in the usual type of     
modern lamp the passage of the current  
causes the points to separate  the      
required distance through the action of 
an electromagnet the coils  of which are
 traversed by the current4 ,a clutch    
holds the carbon in  place1 the position
 of this being also determined by an    
electromagnet4  ,the action is regulated
 by the difference in the resistance to 
the  passage of the current caused by   
the increase in the separation of the   

points4    ,in the older type of arc    
lamp it was necessary to trim the lights
 by  replacing the carbons every day2   
but recently lamps have been perfected  
in which the carbons last from one      
hundred to one hundred and twenty       
hours4 ,in these the arc is enclosed in 
a glass globe which is made as  nearly  
air-tight as possible with the necessary
 feed devices4 ,this  closed chamber is 
fitted with a valve opening outward1    
which allows  the air to be forced out  
by the heat of the lamp1 but does not   
admit a  return current4 ,in this manner
 a rarefied chamber is produced in which
  the carbons are oxidized very slowly2 
yet there is no diminution in the       
brilliancy of the light4    ,early in   
the history of electric lighting it     
became apparent that the  proper        
construction of the carbon electrodes   
was a highly important  item in the     
manufacture of a lighting apparatus4    
,the value of carbons  depends largely  
upon their purity and freedom from ash  

in burning1 and  it required a countless
 number of experiments to develop the   
highly  efficient carbons now in general
 use4 ,davy made use of pieces of wood  
charcoal in his experiments1 but these  
were too fragile to be of  practical    
value1 even if their other qualities had
 been ideal4 ,later  experimenters tried
 various compounds1 and in #ahgf ,carr  
in ,france  produced excellent carbons  
made of coke1 lampblack1 and syrup4     
,from  these were developed the present 
carbons1 usually made by mixing some    
finely divided form of carbon1 such as  
soot or lampblack made from  burning    
paraffin or tar1 with gum or syrup to   
form a paste4 ,rods of  proper size and 
shape are made by forcing this paste    
through dies by  hydraulic pressure1    
subsequently baking them at a high      
temperature4  ,sometimes they are given 
a coating of copper1 a thin layer of the
 metal  being deposited upon them by    
electrolysis4      ,,edison ,,and ,,the 
,,incandescent ,,lamp    ,the familiar  

incandescent electric-light bulb seems  
such a simple  apparatus to-day1 being  
nothing apparently but a small wire     
enclosed in  an ordinary glass bulb1    
that it is almost impossible to realize 
what  an enormous amount of money1      
energy1 and that particular quality of  
mentality which we call genius has been 
required to produce it4 ,first  and     
foremost among the names of the men of  
genius who finally evolved  this lamp is
 that of ,thomas ,a4 ,edison2 and only  
second to this foremost  name are those 
of ,swan1 ,lane-,fox1 and ,hiram ,maxim4
 ,but ,edison's name  must stand        
preeminent2 and there are probably very 
few1 even among  ,europeans1 who would  
attempt or wish to deny him the enviable
 place as  the actual perfecter of the  
incandescent-light bulb4                
,illustration3 ,,thomas ,a4 ,,edison    
,,and ,,the ,,dynamo ,,that ,,generated 
,,the ,,first  ,,commercial ,,electric  
,,light4    ,it is said that ,edison    
first conceived the idea of an          

incandescent  electric light while on a 
trip to the ,rocky ,mountains in company
  with ,draper1 in #ahgh4 ,be this as it
 may1 he certainly set to work          
immediately after completing this       
journey1 and never relaxed or ceased    
his efforts until a practical           
incandescent lamp had been produced4    
,his  idea was to perfect a lamp that   
would do everything that gas could do1  
and more2 a lamp that would give a      
clear1 steady light1 without odor1  or  
excessive heat such as was given by the 
arc lights--in short1 a  household lamp4
    ,early in his experiments he        
abandoned the voltaic arc1 deciding that
  a successful lamp must be one in which
 incandescence is produced by a  strong 
current in a conductor1 the heat caused 
by the resistance to  the current       
producing the glow and light4 ,but when 
search was made for  a suitable         
substance possessing the necessary      
properties to be the  incandescent      
material1 the inventor was confronted by

 a vast array of  difficulties4 ,it was 
of course essential that the substance  
must remain  incandescent without       
burning1 and at the same time offer a   
resistance  to the passage of the       
current precisely such as would bring   
about  the heating that produced        
incandescence4 ,it should be infusible  
even  under this high degree of heat1 or
 otherwise it would soon disappear2  and
 it must not be readily oxidizable1 or  
it would be destroyed as  by ordinary   
combustion4 ,it should also be of       
material reducible to  a filament as    
fine as hair1 but capable of preserving 
a rigid form4  ,these1 among others1    
were the qualities to be considered in  
selecting  this apparently simple       
filament for the incandescent lamp4 ,it 
was not a  task for the tyro1 therefore1
 that ,edison undertook when he began   
his  experiments for producing an ideal 
lamp4    ,the substance in nature that  
seemed to possess most of the necessary 
qualities just enumerated was the metal 

platinum1 and ,edison began  at once    
experimenting with this4 ,he made a     
small spiral of very fine  platinum     
wire1 which he enclosed in a glass globe
 about the size of an  ordinary         
baseball4 ,the two ends of the wires    
connected with outside  conducting      
wires1 which were sealed into the base  
of the bulb4 ,the air  in the bulb had  
to be exhausted and a vacuum maintained 
to diminish the  loss of heat and of    
electricity and to prevent the oxidation
 of the  platinum4 ,but when the current
 was passed through the spiral wire in  
this vacuum a peculiar change took place
 in the platinum itself4 ,the  gases    
retained in the pores of the metal at   
once escaped1 and the wire  took on such
 peculiar physical properties that it   
was supposed for a  time by some        
physicists that a new metal had been    
produced4 ,the metal  acquired a very   
high degree of elasticity and became    
susceptible of a  high polish like      
silver1 at the same time becoming almost

 as hard as  steel4 ,it also acquired a 
greater calorific capacity so that it   
could  be made much more luminous       
without fusing4 ,to diminish the loss of
  heat the wire was coated with some    
metallic oxide1 and the slope of  the   
spiral also aided in this as each turn  
of the spiral radiated heat  upon its   
neighbor1 thus utilizing a certain      
amount that would otherwise  have been  
lost4 ,but despite all this1 ,edison    
found1 after tedious  experimenting1    
that platinum did not fulfil the        
requirements of a  practical filament   
for his lamp2 it either melted or       
disintegrated in a  short time and      
became useless2 and the other           
experimenters had met with  the same    
obstacles to its use1 and were forced to
 the same conclusion4    ,some other    
substance must be found4 ,the use of    
carbon for arc lights  and ,edison's own
 experiments with carbon in his work on 
the telephone  naturally suggested this 
substance as a possibility4 ,it is said 

that  this idea was brought forcibly to 
the inventor's attention by noticing    
the delicate spiral of vegetable carbon 
left in his hand after using  a twisted 
bit of paper1 one day1 for lighting a   
cigar4 ,this spiral of  carbon was1 of  
course1 too fragile to be of use in its 
ordinary form4  ,but it occurred to     
,edison that if a means of consolidating
 it could  be found1 there was reason to
 hope that it would answer the purpose4 
,experiments were begun at once1        
therefore1 not only with processes of   
consolidation but also with various     
kinds of paper1 and neither effort  nor 
expense was spared to test every known  
variety of paper4 ,moreover1  many new  
varieties of paper were manufactured at 
great expense from  substances having   
peculiar fibres4 ,one of these1 made    
from a delicate  cotton grown on some   
little islands off ,south ,carolina1    
gave a carbon  free from ash1 and seemed
 to promise good results2 but later it  
was  found that the current of          

electricity did not circulate through   
this  substance with sufficient         
regularity to get protracted and uniform
  effects4 ,nevertheless1 since many    
things pointed to this fibre carbon  as 
the ideal substance1 ,edison set about  
determining the cause of the            
irregularity in the circulation of the  
current in the filament1 and a  number  
of other experimenters soon became      
interested in the problem4    ,it was   
soon determined that the arrangement of 
the fibres themselves  were directly    
responsible for the difficulty4 ,in     
ordinary paper the  fibres are pressed  
together without any special            
arrangement1 like wool  fibres in       
felting4 ,in passing through such a     
substance1 therefore1 the  current      
cannot travel along a continuous fibre1 
but must jump from  fibre to fibre1 like
 a man crossing a brook on              
stepping-stones4 ,each  piece of fibre  
constitutes a lamp or miniature voltaic 
arc1 so that the  current is no longer a

 continuous one2 and the little interior
 sparks  thus generated quickly destroy 
the filament4 ,this discovery made it   
apparent that such an artificial1       
feltlike substance as paper could not   
be made to answer the purpose1 and      
,edison set about searching for some    
natural substance having fibres         
sufficiently long to give the necessary 
homogeneity for the passage of the      
current4    ,for this purpose specimens 
of all the woods and fibre-substances of
  all countries were examined4 ,special 
agents were sent to ,india1 ,china1     
,japan1 ,south ,america1 in quest of    
peculiar fibrous substances4 ,the       
various woods thus secured were         
despatched to the ,edison plant at      
,menlo  ,park and there carefully       
examined and tested4 ,without dwelling  
on the  endless details of this tedious 
task1 it may be said at once that only  
three substances out of all the mass    
withstood the tests reasonably  well4   
,of these1 a species of ,japanese bamboo

 was found to answer the  purpose best4 
,thus the practical incandescent lamp1  
which had cost so  much time1 ingenuity1
 and money1 came into existence1        
fulfilling the  expectation of the most 
sanguine dream of its inventor4    ,in  
using these bamboo carbon filaments the 
original spiral form of  filament was   
abandoned1 the now familiar elongated   
horseshoe being  adopted1 as the carbon 
could not be bent into the tortuous     
shapes  possible with platinum4 ,later  
various modifications in the shape of   
the  filament were made1 usually as     
adaptations to changes in the shape of  
the bulbs4    ,at the same time that    
,edison was succeeding with his bamboo  
carbon  filaments1 ,j4 ,w4 ,swan had    
been almost as successful with a        
filament  formed by treating cotton     
thread with sulphuric acid1 thus        
producing a  parchmentized thread1 which
 was afterwards carbonized4 ,a          
modification  of this process eventually
 supplanted the ,edison bamboo filament2

 and  the filament now in common        
use--the successor of the parchmentized 
thread--is made of a form of soluble    
cellulose prepared by dissolving        
purified cotton wool in a solution of   
zinc chloride1 and then pressing  the   
material out into long threads by       
pressing it through a die4    ,the long 
thread so obtained is a semi-transparent
 substance1 resembling  catgut1 which   
when carbonized at a high temperature   
forms a very  elastic form of carbon    
filament4 ,to prepare the filament the  
cellulose  threads are cut into the     
proper lengths1 bent into horseshoe     
shape1  double loops1 or any desired    
form1 and then folded round carbon      
formers  and immersed in plumbago       
crucibles4 ,on heating these crucibles  
to a  high temperature the organic      
matter of the filaments is destroyed1   
the carbon filaments remaining4 ,these  
filaments are then ready for  attachment
 to the platinum leading-in wires1 which
 is accomplished  either by means of a  

carbon cement or by a carbon-depositing 
process4  ,they are then placed in the  
glass bulbs and the wires hermetically  
sealed1 after which the bulbs are       
exhausted1 tested1 fitted with the      
familiar brass collars1 and are ready   
for use4    ,the combined discoveries of
 all experimenters had made it evident  
that certain conditions were necessary  
to success1 regardless of  the structure
 of the carbon filament4 ,it was        
essential that the  vessel containing   
the filament should be entirely of      
glass2 that the  current should be      
conveyed in and out this by means of    
platinum wires  hermetically sealed     
through the glass2 and that the glass   
globe must  be as thoroughly exhausted  
as possible4 ,this last requirement     
proved  a difficult one for a time1 but 
by improved methods it finally became   
possible to produce almost a perfect    
vacuum in the bulbs1 with a             
corresponding increase in the efficiency
 of the lamps4      ,,the ,,tungsten    

,,lamp    ,for twenty years the         
carbon-filament lamp stood without a    
rival4  ,but meanwhile the science of   
chemistry was making rapid strides and  
putting at the disposal of practical    
inventors many substances hitherto      
unknown1 or not available in commercial 
quantities4 ,among these were  three    
metals1 osmium1 tantalum1 and tungsten1 
and these metals soon  menaced the      
apparently secure position of the highly
 satisfactory1  although expensive1     
,edison lamp4    ,it will be recalled   
that the early experimenters had used   
two metals1  platinum and iridium1 for  
lamp filaments2 and that these two1     
although  unsatisfactory1 were the only 
ones that had given even a promise  of  
success4 ,but in #ahih ,dr4 ,auer von   
,welsbach took out patents1 and  in     
#aijc produced a lamp using an osmium   
filament4 ,its advent marked  the       
beginning of the return to              
metal-filament lamps1 although the  lamp
 itself did not prove to be very        

satisfactory and was quickly  displaced 
by a lamp invented by ,messrs4 ,siemens 
and ,halske1 having  a tantalum         
filament4 ,on account of its ease to    
manufacture1 its  brilliant light1 and  
relatively low consumption of power1    
this lamp  gained great popularity at   
once1 and for a single year was         
practically  without a rival4 ,then1 in 
#aijd1 patents were taken out by ,just  
and  ,hanaman1 ,kuzel1 and ,welsbach1   
for lamps using filaments of tungsten1  
and the superiority of these lamps over 
the tantalum lamps gave  them an        
immediate popularity never attained by  
either of the other  metal-filament     
lamps4    ,needless to say there is good
 ground for this popularity1 which may  
be  explained by the simple statement   
that the tungsten lamp gives more  light
 with much less consumption of power per
 candle power than any of  its          
predecessors4 ,unlike the carbon        
filament1 which projects in the         
familiar elongated horse-shoe loop1 or  

double loop1 into the exhausted  bulb1  
the tungsten filament is wound on a     
frame1 so that several  filaments       
7usually eight or more7 are used for    
producing the light  in each bulb4 ,the 
chief defect of this lamp is the        
fragility of the  filament1 which breaks
 easily when subjected to mechanical    
vibration4  ,on the other hand1 tungsten
 lamps can be used in places at a long  
distance from the central generating    
plant1 where the electric current  is   
too weak for carbon-filament lamps4     
,,the ,,mercury-,,vapor ,,light ,,of    
,,peter ,,cooper ,,hewitt    ,on an     
evening in ,january1 #aijb1 a great     
crowd was attracted to the  entrance of 
the ,engineers' ,club in ,new ,york     
city4 ,over the doorway  a narrow glass 
tube gleamed with a strange blue-green  
light of such  intensity that print was 
easily readable across the street1 and  
yet  so softly radiant that one could   
look directly at it without the         
sensation of blinding discomfort which  

accompanies nearly all brilliant        
artificial lights4 ,the hall within1    
where ,mr4 ,hewitt was making the  first
 public announcement of his great       
discovery1 was also illuminated  by the 
wonderful new tubes4 ,the light was     
different from anything ever  seen      
before1 grateful to the eyes1 much like 
daylight1 only giving the  face a       
curious1 pale-green1 unearthly          
appearance4 ,the cause of this          
phenomenon was soon evident2 the tubes  
were seen to give forth all the  rays   
except red1--orange1 yellow1 green1     
blue1 violet1--so that under  its       
illumination the room and the street    
without1 the faces of the  spectators1  
the clothing of the women1 lost all     
their shades of red2  indeed1 changing  
the face of the world to a pale         
green-blue4    ,the extraordinary       
appearance of this lamp and its profound
  significance as a scientific discovery
 at once awakened a wide  public        
interest1 especially among electricians 

who best understood  its importance4    
,here was an entirely new sort of       
electric light4  ,the familiar          
incandescent lamp1 though the best of   
all methods of  illumination1 is also   
the most expensive4 ,mr4 ,hewitt's lamp1
 though  not yet adapted to all the     
purposes served by the ,edison lamp1 on 
account of its peculiar color1 produces 
eight times as much light with  the same
 amount of power4 ,it is also           
practically indestructible1 there  being
 no filament to burn out2 and it        
requires no special wiring4 ,by  means  
of this invention electricity1 instead  
of being the most costly  means of      
illumination becomes the                
cheapest--cheaper even than kerosene4   
,no further explanation than this is    
necessary to show the enormous          
importance of this invention4    ,as    
just stated1 the defect of the ,edison  
incandescent lamp is its  cost1 due to  
its utilizing only a small fraction of  
the power used  in producing the        

incandescence1 and1 of much less        
importance1 the  relatively short life  
of the filament itself4 ,only about     
three per  cent4 of the actual power is 
utilized by the light1 the remaining    
ninety-seven per cent4 being absolutely 
wasted2 and it was this  enormous waste 
of energy that first attracted the      
attention of ,mr4  ,hewitt1 and led him 
to direct his energies to finding a     
substitute that  would be more          
economical4 ,a large part of the waste  
in the ,edison bulb  is known to be due 
to the conversion of the energy into    
useless heat1  instead of light1 as     
shown by the heated glass4 ,mr4 ,hewitt 
attempted to  produce a light that would
 use up the power in light alone--to    
produce  a cool light1 in short4        
,instead of directing his efforts to the
 solids1 ,mr4 ,hewitt turned his        
attention to gaseous bodies1 believing  
that an incandescent gas would  prove   
the more nearly ideal substance for a   
cool light4 ,the field of  the passage  

of electricity through gases was by no  
means a virgin  one1 but was            
nevertheless relatively unexplored3 and 
,mr4 ,hewitt was1  therefore1 for the   
most part obliged to depend upon his own
 researches  and experiments4 ,in these 
experiments hundreds of gases were      
examined1  some of them giving          
encouraging results1 but most of them   
presenting  insurmountable difficulties4
 ,finally mercury vapor was tried1 with 
the  result that the light just referred
 to was produced4    ,the possibilities 
of mercury-vapor gas had long been      
vaguely  suspected--suspected1 in fact1 
since the early days of electrical      
investigation1 two centuries before4    
,the ,english philosopher1 ,francis     
,hauksbee1 as early as #agje had shown  
that light could be produced by  passing
 air through mercury in an exhausted    
receiver4 ,he had discovered  that when 
a blast of air was driven up against the
 sides of the glass  receiver1 it       
appeared all round like a body of fire1 

consisting of an  abundance of glowing  
globules1 and continuing until the      
receiver was  about half full of air4   
,hauksbee called this his mercurial     
fountain1  and although he was unable to
 account for the production of this     
peculiar light1 which he remarked       
resembled lightning1 he attributed  it  
to the action of electricity4           
,between ,hauksbee's mercurial fountain 
and ,hewitt's mercury-vapor  light1     
however1 there is a wide gap1 and1 as it
 happened1 this gap  is practically     
unbridged by intermediate experiments1  
for ,mr4 ,hewitt  had never chanced to  
hear anything of ,hauksbee's early      
experiments1  or of any of the tentative
 ones of later scientists4 ,but this1 on
 the  whole1 may have been rather       
advantageous than otherwise1 as1 being  
ignorant1 he was perhaps in a more      
receptive state of mind than if         
hampered by false or prejudicial        
conceptions4 ,be this as it may1 he     
began experimenting with mercury        

confined in a glass tube from which  the
 air had been exhausted1 the mercury    
being vaporized either by  heating1 or  
by a current of electricity4 ,no results
 of any importance  came of his numerous
 experiments for a time1 but at last he 
made the  all-important discovery that  
once the high resistance of the cold    
mercury was overcome1 a comparatively   
weak current would then be  conducted1  
producing a brilliant light from the    
glow of the mercury  vapor4 ,here1 then1
 was the secret of the use of mercury   
vapor for  lighting--a powerful current 
of electricity for a fraction of a      
second  passed through the vapor to     
overcome the initial resistance1 and    
then  the passage of an ordinary current
 to produce the light4    ,in practice  
this apparent difficulty in overcoming  
the initial  resistance with a strong   
current is easily overcome by the use of
 a  boosting coil1 which supplies the   
strong current for an instant1 and  is  
then shut off automatically1 the        

ordinary current continuing for         
producing the light4 ,the mechanism is  
hardly more complex than that of  the   
ordinary incandescent light1 but the    
current of ordinary strength  produces  
an illumination about eight times as    
intense as the ordinary  incandescent   
bulb of equal candle-power4    ,the form
 of lamp used is that of a long1        
horizontal tube suspended  overhead in  
the room1 a brilliant light being       
diffused1 which1 lacking  the red rays  
of ordinary lights1 gives a bluish-green
 tone to objects1  and a particularly   
ghastly and unpleasant appearance to    
faces and  hands1 as referred to a      
moment ago4 ,in many ways this feature  
of the  light is really a peculiarity   
rather than a defect1 and for practical 
purposes in work requiring continued    
eye-strain the absence of the  red rays 
is frequently advantageous4 ,in such    
close work as that of  pen-drawing1 for 
example1 some artists find it           
advantageous to use  globes filled with 

water tinted a faint green color1 placed
 between  the lamps and their paper1 the
 effect produced being somewhat the same
  as that of the mercury-vapor light4   
,for such work the absence of the  red  
rays of the ,hewitt light would not be  
considered a defect2 and in  workshops  
and offices where ,mr4 ,hewitt's lamps  
are used the workmen  have become       
enthusiastic over them4    ,on the other
 hand1 the fact that the color-values of
 objects are so  completely changed     
makes this light objectionable for      
ordinary use2  so much so1 in fact1 that
 the inventor was led to take up the    
problem  of introducing red rays in some
 manner so as to produce a pure white   
light4 ,he has partly accomplished this 
by means of pink cloth colored  with    
rhodium thrown around the glass2 but    
this causes a distinct loss  of         
brilliancy4    ,the most natural method 
of introducing the red rays1 it would   
seem1  would be to use globes of red    
glass2 but a moment's reflection will   

show that this would not solve the      
difficulty4 ,red glass does not  change 
light waves1 but simply suppresses all  
but the red rays2 and  since there are  
no red rays in the mercury-vapor light  
the result of  the red globe would be to
 suppress all the light4 ,obviously1    
therefore1  this apparently simple      
method does not solve the difficulty2   
but those  familiar with ,mr4 ,hewitt's 
work will not be surprised any day to   
hear  that he has finally overcome all  
obstacles1 and produced a perfectly     
white light4 ,in the meantime the       
relatively expensive arc light and  the 
incandescent bulb with its filament of  
carbon or metal hold  unchallenged      
supremacy in the commercial field4      
,,xii    ,,the ,,mineral ,,depths       
,ages before the dawn of civilization1  
primitive man had learned to  extract   
certain ores and metals from the earth  
by subterranean mining4  ,such nations  
as the ,egyptians1 for example1         
understood mining in most  of its       

phases1 and worked their mines in       
practically the same manner as  all     
succeeding nations before the time of   
the introduction of the steam  engine4  
,the early ,britons were good miners and
 the products of their  mines were      
carried to the ,orient by the           
,phoenicians many centuries  before the 
,christian era4 ,the ,romans were1 of   
course1 great miners1 and  remains of   
the ,roman mines are still in existence1
 particularly good  examples being found
 in ,spain4    ,even the aborigines of  
,north ,america possessed some knowledge
 of  mining1 as attested by the ancient 
copper mines in the ,lake ,superior     
region1 although by the time of the     
discovery of ,america1 and probably     
many centuries before1 the interloping  
races of ,indians who had driven  out or
 exterminated the ,lake ,superior copper
 mines had forgotten the  art of mining1
 if indeed they had ever learned it4    
,but the fact that  their predecessors  
had worked the copper mines is shown by 

the number  of stone mining implements  
found in the ancient excavations about  
,lake  ,superior1 these implements being
 found literally by cart loads in some  
places4    ,the great progress in mining
 methods1 however1 as in the case of    
most  other mechanical arts1 began with 
the introduction of steam as a means  of
 utilizing energy2 and another          
revolution is in rapid progress owing   
to the perfection of electrical         
apparatus for furnishing power1 heat1   
and light4 ,methods of mining a hundred 
years ago were undoubtedly  somewhat in 
advance of the methods used by the      
ancients2 but the  gap was not a wide   
one1 and the progress made by decades   
after the  introduction of steam has    
been infinitely greater than the        
progress  made by centuries previous to 
that time4    ,this progress1 of course1
 applies to all kinds of mines and all  
phases  of mining2 but steam and        
electricity are not alone responsible   
for  the great nineteenth-century       

progress4 ,geology1 an unknown science  
a century ago1 has played a most active 
and important part2 and  chemistry1     
whose birth as a science dates from the 
opening years of the  nineteenth        
century1 is responsible for many of the 
great advances4    ,obviously a very    
important feature of any mine must be   
its location1  and the determination of 
this must always constitute the         
principal  hazard in practical mining4  
,prospecting1 or exploring for suitable 
mining sites1 has been an important     
occupation for many years1 and  has in  
fact become a scientific one recently4  
,formerly mines were  frequently        
stumbled upon by accident1 but such     
accidental discoveries  are becoming    
less and less frequent4 ,the prospector 
now draws largely  upon the knowledge of
 the scientist to aid him in his search4
 ,geology1  for example1 assists him in 
determining the region in which his     
mines  may be found1 if it cannot       
actually point out the location for     

sinking  his shaft2 and at least a rough
 knowledge of botany and chemistry  is  
an invaluable aid to him4 ,it is obvious
 that it would be useless  to prospect  
for coal in a region where no strata of 
rocks formed  during the ,carboniferous 
or coal-forming age are to be found     
within a  workable distance below the   
surface of the earth4 ,the prospector   
must1  therefore1 direct his efforts    
within geological confines if he would  
hope to be successful1 and in this he is
 now greatly aided by the  geological   
surveys which have been made of almost  
every region in the  ,united ,states and
 ,europe4    ,an example of what science
 has done in this direction was shown a 
few  years ago in a western ,american   
town during one of the oil booms  that  
excited so many communities at that     
time4 ,in the neighborhood  of this town
 evidences of oil had been found from   
time to time--some  of them under       
peculiar and suspicious circumstances1  
to be sure--and  the members of the     

community were in an intense state of   
excitement  over the possibility of oil 
being found on their lands4 ,prices of  
land  jumped to fabulous figures1 and   
the few land-owners that could be       
induced to part with their farms became 
opulent by the transactions4 ,an  oil   
expert appeared upon the scene about    
this time--just happening  to drop      
in--who declared1 after an examination1 
that the entire region  abounded in oil4
 ,he backed up his assertion by offering
 to stake his  experience against the   
capital of a company which was formed at
 his  suggestion4 ,before any wells were
 actually started1 however1 a prudent   
member of the company consulted the     
,state geologist on the subject1        
receiving the assurance that no oil     
would be found in the neighborhood4     
,strangely enough the word of the man of
 science triumphed over that of  the oil
 expert1 and although some tentative    
borings were made on a  minor scale1 no 
great amount of money was sunk4 ,it     

developed afterwards  that the evidences
 of oil found from time to time had been
 the secret  work of the expert4    ,in 
general1 prospecting for oil differs    
pretty radically from  prospecting for  
most other minerals4 ,a very common way 
of locating an  ore-mine is by the      
nature of the out-crop1--that is1 the   
broken edges  of strata of rocks        
protruding from hillsides1 or tilted at 
an angle on  level areas4 ,if the       
ore-bearing vein is harder than the     
surrounding  strata it will be found as 
a jutting edge1 protruding beyond the   
surface of the other layers of rocks    
which1 being softer1 are more  easily   
worn away4 ,on the other hand1 if this  
stratum is soft or  decomposable it will
 show as a depression1 or sag as it is  
called4 ,of  course such protrusions and
 depressions may only be seen and       
examined  where the rocks themselves are
 exposed2 vegetation1 drift1 and snow   
preventing such observations4 ,but the  
vegetation may in itself serve  as a    

guide to the experienced prospector in  
determining the location  of a mine1    
peculiar mineral conditions being       
conducive to the growth  of certain     
forms of vegetation1 or to the          
arrangement of such growth4             
,alterations in the color of the rocks  
on a hillside are also important        
guides1 as such discolorations          
frequently indicate that oxidizable     
minerals are located above4    ,in hilly
 or mountainous regions1 where the      
underlying rocks are covered  with      
earth1 portions of these surfaces are   
sometimes uncovered by the  method known
 as booming4 ,in using this method the  
prospector selects  a convenient        
depression near the top of a hill and   
builds a temporary  dam across the point
 corresponding to the lowest outlet4    
,when snow and  rain have turned the    
basin so formed into a lake1 the dam is 
burst  and the water rushing down the   
hillside cuts away the overlying dirt1  
exposing the rocks beneath4 ,this method

 is effective and inexpensive4    ,the  
beds of streams1 particularly those in  
hilly and mountainous  regions1 are     
fertile fields for prospecting1         
particularly for precious  metals4      
,stones and pebbles found in the bed are
 likely to reveal the  ore-foundations  
along the course of the stream1 and the 
shape of  these pebbles helps in        
determining the approximate location of 
such  foundations4 ,an ore-bearing      
pebble1 well worn and rounded1 has      
probably  traveled some little distance 
from its original source1 being rounded 
and worn in its passage down the stream4
 ,on the other hand1 if it is  still    
angular it has come a much shorter      
distance1 and the prospector  will be   
guided accordingly in his search for the
 ore-vein4    ,but prospecting is not   
limited to these simple surface methods4
 ,in  enterprises undertaken on a large 
scale1 borings are frequently made  in  
regions where there are perhaps no      
specific surface indications4  ,in such 

regions a shaft may be sunk or a tunnel 
may be dug1 and the  condition of the   
underlying strata thus definitely       
determined4 ,this  last is1 of course1 a
 most expensive method1 the simpler and 
more usual  way being that of making    
borings to certain depths4 ,the         
difficulty with  such borings is that   
rich veins may be passed by the borer   
without  detection2 or1 on the other    
hand1 a small vein happening to lie in  
the  same plane as the drill may give a 
wrong impression as to the extent of    
the vein4    ,one of the most           
satisfactory ways of making borings is  
by means of the  diamond drill4 ,this   
drill is made in the form of a long     
metal tube1  the lower edge of which is 
made into a cutting implement by black  
diamonds fixed in the edge of the metal4
 ,by rotating this tube a ring  is cut  
through the layers of rock1 the solid   
cylinder or core of rock  remaining in  
the hollow centre of the drill4 ,this   
can be removed from  time to time1 the  

nature and thickness of the geological  
formation  through which the drill is   
passing being thus definitely           
determined4      ,,conditions ,,to ,,be 
,,considered ,,in ,,mining    ,three    
great problems always confront the mine 
operator--light1 power1  and            
ventilation4 ,of these ventilation is   
the most important from the  workman's  
standpoint1 although the problem of     
light is scarcely  less so4 ,obviously a
 cavity of the earth where hundreds of  
men are  constantly consuming the       
atmosphere and vitiating it1 and where  
thousands of lights are burning1 would  
become like the black hole of  ,calcutta
 in a few minutes if some means were not
 adopted to relieve  this condition4    
,but besides this vitiation of the      
atmosphere caused by  the respiration of
 the men and the burning of lamps there 
are likely  to be accumulations of      
poisonous gases in mines1 that are even 
more  dangerous4 ,of the two classes of 
dangerous gases--those that asphyxiate  

and those that explode or burn--it may  
be said in a general way that  the      
suffocating or poisonous gases1 such as 
carbonic acid1 which is  known as black 
damp1 or choke damp1 are more likely to 
occur in ore  mines1 while the explosive
 gases are found more frequently in coal
  mines4    ,choke damp1 which is a gas 
considerably heavier than the           
atmosphere1  is usually found near the  
bottom of mines1 running along declines 
and  falling into holes in much the same
 manner as a liquid4 ,it kills by       
suffocation1 and1 as it will not support
 combustion1 it may be detected  by     
lowering a lighted candle into a        
suspected cavity1 the light being       
extinguished at once if the gas is      
present4 ,to rid the cavity of it1      
forced ventilation is used where        
possible1 the gas being scattered by    
draughts of fresh air4 ,if this is      
impracticable1 and the cavity small1    
the choke damp may be dipped out with   
buckets4    ,but the problem of the     

mining engineer is not so much to rid   
cavities  of gas as to prevent its      
accumulation4 ,in modern mining1 with   
proper  ventilation and drainage1 there 
is comparatively little danger of       
extensive accumulation of this gas4     
,illustration3 ,a ,,flint-,,and-,,steel 
,,outfit1 ,,and ,a ,,miner',s ,,steel   
,,mill4    ,the upper picture shows a   
flint-and-steel outfit1 the implements  
for  lighting a fire before the days of 
matches4 ,the lower picture shows a     
miner's steel mill1 which was used for  
giving light in mines before the  day of
 the safety-lamp4 ,it consists of a     
steel disk which is rotated  rapidly    
against a piece of flint1 producing a   
stream of sparks4 ,it was  thought that 
such sparks would not ignite            
fire-damp--a belief which is  now known 
to be erroneous4    ,the danger from    
this choke damp1 therefore1 is one that 
concerns the  individual workman rather 
than large bodies of men or the         
structure of  the mine itself4 ,with    

fire damp1 however1 the case is         
different1 as an  explosion of this gas 
may destroy the mine itself and all the 
workmen  in it4 ,it is1 therefore1 the  
most dreaded factor in mining1 and is   
the  one to which more attention has    
been directed than to almost any other  
problem4    ,this fire damp is a mixture
 of carbonic oxide and marsh gas which1 
being lighter than air1 tends to rise to
 the upper part of the mines4  ,for this
 reason explosions are more likely to   
occur near the openings  of the mine1   
frequently entombing the workmen in a   
remote part of the  mine even when not  
actually killing them by the explosion4 
,as this gas  is poisonous as well as   
explosive the miners who survive the    
explosion  may succumb eventually to    
suffocation4    ,previous to the year   
#ahaf no means had been devised for     
averting the  explosions of fire damp   
except the uncertain one of watching the
 flame  of the candle with which the    
miner was working4 ,on coming in contact

  with air mildly contaminated with fire
 damp the candle flame takes  on a blue 
tint and assumes a peculiarly elongated 
shape which may be  instantly detected  
by a watchful workman4 ,but miners were1
 and still  are1 a proverbially careless
 class of men even where a matter of    
life  and death is concerned1 and too   
frequently gave no heed to the warning  
flame4 ,but in #ahaf ,sir ,humphrey     
,davy invented his safety lamp1 a       
device that has been the means of saving
 thousands of lives1 and which  has not 
as yet been entirely supplanted by any  
modern invention4    ,in making his     
numerous experiments1 ,davy had observed
 that iron-wire  gauze is such a good   
conductor of heat that a flame enclosed 
in  such gauze could not pass readily   
through meshes to ignite a gas on  the  
outside4 ,he found by experiment that a 
considerable quantity of  explosive gas 
might be brought into contact with the  
gauze surrounding  a flame1 and no      
explosion occur4 ,at the same time this 

gas would give  warning of its presence 
by changing the color of the flame4     
,when a  lamp was made with a           
surrounding gauze having seven hundred  
and eighty  meshes to the square inch1  
it was found to give sufficient light   
and  at the same time to be practically 
non-explosive in the presence of        
ordinary quantities of gas4    ,one     
would suppose that such a life-saving   
invention would have been  eagerly      
adopted by the men whose lives it       
protected2 but1 as a matter  of fact1   
owing to certain inconveniences of      
,davy's lamps1 many miners  refused to  
use them until forced to do so by the   
mine-owners4 ,one  of these             
disadvantages was that this safety lamp 
gave a poor light  overhead4 ,this is   
particularly annoying to the miner1 who 
wishes always  to watch the condition of
 the ceiling under which he is working4 
,when  not under constant observation1  
therefore1 a miner would frequently     
remove the gauze of the lamp and work by

 the open flame1 regardless  of         
consequences4 ,or again1 he would       
sometimes forgetfully use the  flame for
 lighting his pipe4 ,to overcome the    
possibility of such  forgetfulness or   
wilful disobedience1 it was found       
necessary to equip  safety lamps with   
locking devices1 so that the miner had  
no means of  access to the open flame of
 his lamp once it had been lighted4     
,since the time of the first ,davy      
safety lamp there have been numerous    
improvements in mechanical details1     
although the general principle  remains 
unchanged4 ,one of these improvements is
 a device whereby the  lamp1 when       
accidentally extinguished1 may be       
relighted without opening  it1 and      
without the use of matches4 ,this is    
done by means of little  strips of paper
 containing patches of a fulminating    
substance which  is ignited by friction1
 working on the same principle as the   
paper  percussion caps used on toy      
pistols4    ,but even the improved      

safety lamp seems likely to disappear   
from mines  within the next few years1  
now that electricity has come into such 
general use4 ,as yet1 however1 no       
satisfactory portable electric lamp  or 
lantern has been perfected1 such lamps  
being as a rule too heavy1  expensive1  
and unreliable4 ,even if these defects  
were remedied1 the  advantage would     
still lie with the ,davy lamp1 since the
 electric lamp1  being enclosed1 cannot 
be used for the detection of fire damp4 
,but  this advantage of the safety lamp 
is becoming less important1 since       
well-regulated mines are now more       
thoroughly ventilated1 and the danger   
from fire damp correspondingly lessened4
    ,in some ,continental mines the     
experiment has been tried of constantly 
consuming the fire damp1 before it has  
had time to accumulate in  explosive    
quantities1 by means of numerous open   
lights kept constantly  burning4 ,this  
method is effective1 but since the      
numerous lights  consume the precious   

oxygen of the air as well as the damp1  
the method  has never become popular4   
,obviously1 then1 the question of mine  
ventilation is closely associated with  
that of lighting4    ,probably the      
simplest method of properly ventilating 
a mine is that of  having two openings  
at the surface1 one on a much higher    
level than  the other if the mine is on 
a hillside1 the lower one corresponding 
to  the lowest portion of the mine where
 possible4 ,by such an arrangement      
natural currents will be established1   
and may be controlled and  distributed  
through the mine by doors or permanent  
partitions1 or aided  by fans4 ,but of  
course only a comparatively small number
 of mines are  so situated that this    
system can be used4    ,it is possible1 
of course1 to ventilate a mine from a   
single shaft or  opening by use of      
double sets of pipes1 one for admitting 
air and the  other for expelling it2 but
 this system is obviously not an ideal  
one1  and is prohibited by law in most  

mining districts4 ,such laws usually    
stipulate that there must be at least   
two openings situated at some  distance 
from each other4    ,the older method of
 creating air currents was by means of  
furnaces1  but this method1 while very  
effective1 is expensive and dangerous4  
,in  using this system a furnace is     
built near the outlet of the air shaft1 
the combustion of the fuel creating the 
necessary draught4 ,but in the  nature  
of things this furnace is a constant    
menace to the mine1 besides  being an   
extremely wasteful expenditure of       
energy4 ,the modern method  of          
ventilating is by means of rotary fans1 
the electric fan having  practically    
solved the problem4 ,the air currents   
established by such  fans are controlled
 either by the doors in the passages1 or
 by means of  auxiliary fans4 ,in       
addition1 jets of compressed air are    
sometimes used1  and have become very   
popular4    ,another important problem  
that constantly confronts the mining    

engineer  is that of drainage4 ,mines   
are1 of course1 great reservoirs for the
  accumulation of water1 which must be  
drained or pumped out continually2  and 
as the shafts are sunk deeper and deeper
 it becomes increasingly  difficult to  
raise the water to the surface4 ,special
 means and  machinery are employed for  
this purpose which will be considered   
more  in detail in a moment4            
,,electric ,,machinery ,,in ,,mining    
,electricity is1 of course1 the great   
revolutionary factor in modern  mining4 
,there is scarcely a department of      
mining in which electric  power has not 
wrought revolutionary changes in recent 
years2 and the  subject has become so   
important and so thoroughly specialized 
as to  create a literature and a        
technology of its own4 ,from the        
electric  drill1 working hundreds of    
feet below the surface of the earth1 to 
the  delicate testing-instruments in the
 laboratory of the assaying offices1    
the effect of this electrical revolution

 is being felt progressively  more and  
more every year4    ,moreover1          
electricity1 on account of its          
transmutability1 has made  accessible   
many important mining sites hitherto    
unworkable4 ,rich mines  are now in     
operation on an economical basis which1 
thirty years ago1  were worthless on    
account of their isolation4 ,when such  
mines were  situated in mountainous     
regions where there was no coal supply  
at hand  for creating steam power1 and  
where the only available water power was
  perhaps several miles away1 operations
 on a paying basis were out of  the     
question before the era of electric     
power4    ,at present1 however1 the     
question of distance of the seat of     
power  has been practically eliminated  
by the possibilities of electric        
conduction4 ,a stream1 situated miles   
away1 when harnessed to a turbine  and  
electric motors may afford a source of  
power more economical than  could be    
furnished a few years ago by a power    

plant supplied with  fuel at the very   
door of the mine4 ,we need not enter    
into the details  of this transmission  
of power1 however1 since the subject has
 been  discussed in a general way in    
another place4 ,our subject here is     
rather to deal with the application of  
electricity to certain mining           
implements of special importance4       
,one of the most useful acquisitions to 
the equipment of the modern  miner is a 
portable mechanical drill1 which makes  
it possible for  him to dispense with   
the time-honored pick1 hammer1 and      
hand-drill4  ,but it is only recently   
that inventors have been able to produce
  this implement4 ,the great difficulty 
has lain in the fact that a             
reciprocating motion1 which is essential
 for certain kinds of drilling1  is not 
readily secured with electric power4    
,the use of steam or  compressed air for
 operating such reciprocating drills    
presents no  mechanical difficulties1   
and the fact that power of this kind can

 be  transmitted long distances by the  
use of flexible tubes made such  drills 
popular for several years4 ,but the cost
 of operating such drills  is so much   
greater than that of the new electric   
drills that they are  rapidly being     
replaced in mining work4    ,the first  
attempts to produce an electric drill   
with a reciprocating  motion were so    
unsuccessful that inventors turned their
 attention to  perfecting some rotary   
device4 ,this proved more successful1   
and rotary  drills1 operating long      
augers and acting like ordinary         
wood-boring  machines1 are now used     
extensively for certain kinds of        
drilling4 ,the  more recent forms       
perform the same amount of work as the  
air drill1  with a consumption of about 
one-tenth the power4 ,moreover1 none of 
the energy is lost at high altitudes as 
in the case of air drills1  and they are
 not affected by low temperatures which 
sometimes render  the air drill         
inoperable4 ,on the other hand1 the air 

drill is a hardy  implement1 capable of 
withstanding very rough usage1 whereas  
the  electric drill is probably the more
 economical1 as well as the more        
convenient drill of the two4    ,in     
certain kinds of mining1 such as in the 
potash mines of ,europe and  the coal   
mines of ,america1 these electric drills
 operating their long  augers have been 
found particularly useful4 ,the ordinary
 type of drill  is so arranged that it  
can be operated at any angle1 vertically
 or  horizontally4 ,the lighter forms   
are mounted on upright stands1 with     
screws at the ends for fastening to the 
floor and roof1 although the  heavier   
types are sometimes mounted on trucks4  
,the motor1 which is  not much larger or
 heavier than an ordinary fan motor1 is 
fastened to  the upright and is from    
four to six horse-power4 ,this connects 
with a  flexible wire which transmits   
the power from the generating station1  
frequently several miles away4 ,the     
auger1 which is about the largest  part 

of the machine and entirely out of      
proportion to the little motor  that    
drives it1 is simply a long bar of      
steel1 twisted spirally at the          
cutting-end like an ordinary wood auger4
    ,from the workman's standpoint these
 rotary drills are infinitely  superior 
to reciprocating or percussion drills1  
where the constant  jarring of the      
machine1 besides being extremely        
tiresome1 sometimes  produces the       
serious disease known as neuritis4      
,various means have  been attempted to  
prevent this1 such as by overcoming the 
jar in a  measure by flexible levers    
which do not transmit the vibrations to 
the  hands and arms2 but such attempts  
are only partially successful1 and  a   
certain amount of jarring cannot be     
avoided4 ,in the rotary electric  drills
 there is none of this1 the workmen     
simply controlling the drill  and the   
motor with levers1 and receiving at most
 only a slight jar from  the vibrations 
of the auger4      ,,traction ,,in      

,,mining    ,in recent years electric   
traction engines for use in mines have  
been  rapidly replacing horse-and       
mule-power1 and have become important   
economic factors in mining operations4  
,the pioneer of this type of  locomotive
 seems to have been one built by ,mr4   
,w4 ,m4 ,schlessinger  for one of the   
collieries of the ,pennsylvania         
,railroad about #ahhb1  and which has   
remained in active use ever since4 ,the 
total weight of  this locomotive was    
five tons and it was equipped with      
thirty-two  horse-power electric motors4
 ,the current was supplied through a    
trolley  pole which took the current    
from a ,t-shaped rail placed above and  
at  one side of the track4 ,the train   
hauled by this locomotive consisted of  
fifteen cars1 carrying from two to three
 tons of coal each4    ,following this  
first mining-locomotive a great number  
were quickly  produced4 ,in             
,pennsylvania alone something like four 
hundred are now  in use1 and in         

,illinois two million tons of coal were 
hauled in this  manner in twelve mines  
in #aija4 ,it was estimated at the      
beginning of  the present century that  
some #c1jjj electric locomotives        
specially  built for mining were in use 
in the ,united ,states alone4    ,the   
earlier types of mining-locomotives were
 much higher and bulkier  than those of 
more recent construction1 the motors    
being mounted above  the trucks and     
geared downward4 ,very soon1 however1   
the turtle-back  or terrapin-back type  
was developed1 with the motors brought  
close  to the ground1 so that even quite
 a heavy locomotive might not be  much  
higher than the diameter of its         
driving-wheels4 ,when these             
queer-looking machines were boxed in so 
that even the wheels were  covered1 they
 lost all resemblance to locomotives or 
vehicles of any  kind1 appearing like   
low1 rectangular metal boxes placed upon
 the car  tracks1 that glided along the 
rails in some mysterious manner4 ,the   

presence of the trolley pole helped to  
dispel this illusion1 but in  some      
instances this is wanting1 the power    
being taken from a third rail4    ,with 
these locomotives1 some of them not more
 than two and a half  feet high1 it was 
possible to haul trains even in very low
 and narrow  passages--much lower1 in   
fact1 than could be entered by the      
little  mules used in former years4     
,this in itself was revolutionary in its
  effects1 as many thin veins were thus 
made workable4    ,this type of low     
locomotive is the one that has come into
 general use  throughout the world4     
,such locomotives range in size from two
 to twenty  tons1 with wheel gauges from
 a foot and a half wide to the standard 
railway gauge of four feet1 eight and a 
half inches4 ,locomotives  weighing more
 than twenty tons are not in general use
 on account of the  small size of the   
mine entrances4    ,in the ordinary     
types the motorman sits in front1       
controlling the  locomotive with levers 

and mechanical brakes placed within easy
 reach1  but sunk as low as possible4   
,as a rule1 the motors are geared to the
  truck axles1 either inside or outside 
the locomotive frame4 ,an overhead      
copper wire supplies the current by     
contact with a grooved trolley  wheel   
mounted on the end of the regulation    
trolley pole4 ,an electric  headlight is
 used1 and the ordinary speed attained  
by the compact  motors is from six to   
ten miles an hour4    ,the amount of    
work that can be performed by one of    
these little1  flat1 box-like           
locomotives is entirely out of          
proportion to its size4  ,a #aj-ton     
locomotive in a ,pennsylvania mine      
hauled about #aej1jjj  tons of coal in a
 year at a cost of less than one-tenth  
of a cent per  ton for repairs4 ,the    
usual train was made up of thirty-five  
cars1  each loaded with about #c1gjj    
pounds of coal1 which was hauled up a   
three-per-cent grade4 ,the cost of such 
haulage was only about #b4gf  cents per 

ton1 as against #g4ae cents when hauled 
by mule-power4 ,these  figures may be   
considered representative1 as other     
mines show similar  results4            
,illustration3 ,,the ,,locomotive       
,,puffing ,,billy ,,and ,a ,,modern     
,,colliery  ,,trolley4    ,this         
locomotive was constructed in #ahac at  
,wylam ,colliery1 ,england1  by ,william
 ,hedley4 ,it was entirely successful1  
and was in operation  for almost half a 
century1 up to the time of its removal  
in #ahfb to  the ,south ,kensington     
,museum4 ,the vertical cylinders and    
arrangement of  walking beams for       
transmitting power are particularly     
interesting4 ,the  power was transmitted
 through cogged wheels to the rear axle1
 as is  done with modern automobiles4   
,a particular advantage has been gained 
by the use of electric  locomotives over
 older methods in the process of        
gathering the cars4  ,in many coal      
mines1 even when the main hauling is    
done by electricity1  the gathering or  

collecting of cars from the working     
faces of the rooms  was formerly done   
either by mule-power or by hand4 ,in    
some low-veined  mines1 hand power alone
 was used1 on account of the low roof4  
,in such places1 low1 compressed-air    
locomotives were sometimes used2  but   
these were very expensive4 ,these have  
now been very generally  replaced by    
turtle-back electric locomotives1       
operated at a distance  from the main   
trolley wire by means of long1 flexible 
cables1 so geared  that they can be paid
 out or coiled as desired4    ,on the   
main line these locomotives take the    
current from the trolley  wire by means 
of the trolley pole1 but when the place 
for gathering is  reached1 the          
connection is made by means of the      
flexible cable1 and the  trolley pole   
fastened down so as not to be in the    
way4 ,this allows the  locomotive to    
push the little cars into the rooms far 
removed from the  main line1 with       
passages too low and narrow to allow the

 use of the  trolley pole4 ,by the time 
the last cars have been delivered the   
first  cars of the train have been      
filled1 and the process of gathering may
 be  begun at once1 and the loaded train
 made up for the return trip4 ,with     
such a locomotive two men can distribute
 and gather up from one hundred  to one 
hundred and twenty cars in an ordinary  
eight-hour working-day1  hauling from   
three hundred to three hundred and fifty
 tons of coal4    ,in certain regions1 a
 system of third-rail current-supply is 
used1 this  rail being also a tooth rail
 with which a cog on the locomotive     
works  frictionally4 ,for climbing steep
 grades this system of cogged rails has 
many advantages over other systems4     
,another type of electric locomotive    
used in some mines is a  self-propelling
 or automobile one equipped with storage
 batteries4 ,such  locomotives do away  
with the inconvenience and dangers of   
contact rails  or trolley wires1 but are
 heavy and expensive4 ,a compromise     

locomotive1  particularly useful for    
gathering1 is one equipped with both    
trolley  pole and storage batteries4    
,this locomotive is so made that the    
storage  batteries are charged while it 
is running with the trolley connection1 
so that no time is lost in the charging 
process4 ,such locomotives  have been   
found very satisfactory for many        
purposes1 and but for the  imperfections
 common to all storage batteries would  
be ideal in many  ways4 ,they can be    
worked over any improvised track1       
regardless of  distance1 which is an    
advantage over the flexible-cable system
 where  distances are limited by the    
length of cable2 and the first cost of  
the battery is no more than the outlay  
on trolley wires and supports4  ,it is  
also claimed that the cost of           
maintenance is relatively low1 but  it  
is doubtful if it equals the trolley or 
third-rail systems in this  respect4    
,closely allied to the systems of       
traction by electric locomotives1 is    

the modern electric telpherage system4  
,until quite recently the haulage  of   
ores and other raw materials used in    
mining1 when done aerially1  has been by
 means of travelling rope or cable4     
,when distances to be  travelled in this
 manner are short1 such as across       
streams or valleys1  where no supports  
are used1 the term cableway is generally
 applied2  but where the distance is so 
long that supports are necessary1 the   
term  tramway cable is used4 ,it is to  
these longer systems that electric      
telpherage is particularly applicable4  
,the advantage of such an electric      
system over the older method is  the    
same as the advantages of the trolley   
road over the cable1 all  ropes and     
cables being stationary1 the electric   
motor1 or telpher1  travelling along on 
one cable and taking its current by     
means of a  trolley pole from a wire    
above4 ,for heavier work metal rails    
supported  between posts are employed in
 place of a flexible cable1 and over    

such  systems loads of several tons can 
be hauled4    ,such an electric telpher 
system is used in one of the ,cuban     
limestone  quarries1 the telpher and    
cars travelling a long distance upon    
cables1  except at some of the curves1  
where solid rails are substituted1      
hauling a load of a thousand pounds at a
 speed of from twelve to  fifteen miles 
an hour4 ,the current comes from a      
distant source1 and the  telpher is so  
arranged that it travels automatically  
when the current  is turned on1 stopping
 when the current is cut off4 ,this is  
quite a  common arrangement for smaller 
telphers1 but in the larger ones a man  
travels with the telpher and load1      
controlling the train just as in the    
case of the ordinary trolley system4    
,the various processes of hoisting in   
mines by electricity is closely  akin to
 that of traction1 since1 after all1 an 
elevator is virtually a  railway with a 
#ajj-per-cent grade4 ,as such work is   
done spasmodically1  long periods of    

rest intervening between actual periods 
of work1 a  great deal of energy is     
wasted by steam hoisting engines1 where 
a  certain pressure of steam in the     
boiler must be maintained at all  times4
 ,for this reason electrical energy for 
hoisting has come rapidly  into         
popularity in recent years4 ,the        
throttling of steam to control  speed1  
said ,mr4 ,f4 ,o4 ,blackwell in         
addressing the ,american ,institute  of 
,mining ,engineers1 the necessity for   
reversing the engine1 the  variation in 
steam pressure1 the absence of          
condensing apparatus1 the  cooling and  
large clearance of cylinders1 and the   
condensation and  leakage of steam pipes
 when doing no work1 are all against the
 steam  hoisting engine4 ,one of the    
largest hoisting engines in the world   
was  recently tested and found to take  
sixty pounds of steam per indicated     
horse-power per hour4 ,the electric     
motor1 on the other hand1 is ideal  for 
intermittent work4 ,it wastes absolutely

 no energy when at rest1  there being no
 leakage or condensation4 ,its          
efficiency is high1 from  one-quarter   
load to twice full load4    ,there seems
 to be practically no difference as far 
as the element of  danger is concerned  
between steam and electric hoists4 ,the 
difference  is largely one of economy4  
,the importance of this is shown by the 
recent comparisons in a gold mine which 
has replaced its steam  apparatus by    
electricity4 ,in this mine the hoist    
moves through the  shaft at a rate of   
over twelve hundred feet per minute1    
elevating five  hundred tons of ore     
daily on double-decked cages4 ,it is    
estimated that  this system shows an    
efficiency of #ge per cent1 taking into 
account  losses of all kinds1 with a    
resulting reduction of cost of from     
seven  to twenty dollars per horse-power
 per month4    ,results comparing very  
favorably with these have been obtained 
also  in some of the mines in ,germany  
and ,bohemia1 where electricity has     

been introduced extensively in mining4  
,in one of these mines the daily        
hoisting capacity is twenty-seven       
hundred tons from a depth of over       
sixteen hundred feet1 at a speed of over
 fifty-two feet per second4 ,in  the    
,comstock mine1 at ,virginia ,city1     
,nev41 electric hoists are used  which  
obtain their power from a plant situated
 on the ,truchee ,river  thirty-two     
miles away4      ,,electric ,,mining    
,,pumps    ,in pumping1 which is always 
one of the important items in mining1   
the  use of electric power has been     
found quite as advantageous as in the   
other fields of its application4 ,no    
special features are embodied in  most  
of the types of mining pumps over the   
rotary and reciprocating  types used for
 ordinary purposes1 except perhaps a    
type of pump known  as the sinking pump4
 ,this is a movable pump that can be    
easily lowered  from one place to       
another1 and has proved to be a great   
time-saver over  steam or air pumps used

 for similar purposes4    ,for some time
 the question of the durability of      
electric pumps was in  dispute1 but     
developments in quite recent years seem 
to prove that1 in  some instances at    
least1 such pumps are practically       
indestructible4    ,the question of what
 would happen to an electric motor in a 
mine  if pumps and motors get flooded   
has often come up4 ,from tests made     
recently at the ,university of ,lige1   
,belgium1 it appears that a  suitably   
designed polyphase alternating-current  
motor of a type largely  used on the    
continent of ,europe was completely     
submerged in water4  ,it was run for a  
quarter of an hour2 it was then stopped 
and allowed  to remain submerged1 under 
official seal1 for twenty-four hours1 at
  the end of which time it was again run
 for a few minutes4 ,it was next        
removed from the water1 again put under 
seal1 and left to dry for  twenty-four  
hours4 ,the insulation was then tested1 
and the motor was  found to be in       

perfect order4 ,it would be hard to     
imagine a test more  severe than this4  
,as bearing upon this question it is    
interesting to note that among  the     
pumps in use around ,johannesburg1      
,south ,africa1 at the beginning  of the
 ,anglo-,boer ,war1 there were twelve of
 a well-known ,american  make1 each of  
which was operated by a #ej-;horse-power
 induction motor  of ,american          
construction with three #ae-kilowatt    
transformers4 ,when the  mines were shut
 down1 upon the breaking out of the war1
 the water  rose so rapidly that it was 
impossible to remove the pumps1 motors1 
transformers1 etc41 and consequently    
they remained under #ejj to #a1jjj  feet
 of water4 ,two and a half years later1 
when peace was declared in  ,south      
,africa1 the water in the shaft was     
pumped out and the electrical  apparatus
 was removed to the surface4 ,three of  
the motors were stripped  and completely
 rewound1 but to the general surprise of
 the experts the  condition of the      

insulation indicated that the rewinding 
might not be  absolutely necessary4     
,accordingly the other nine motors were 
thoroughly  dried in an oven and then   
soaked in oil4 ,after this treatment    
they were  rigidly tested1 proved to be 
all right1 and were at once restored to 
regular service in the mine4 ,the       
transformers were treated in the same   
manner as the motors1 with equally      
gratifying results4    ,an interesting  
illustration of the flexibility and     
adaptability of  electric motors for    
pumping purposes is furnished by the    
,gneisenau  mine1 near ,dortmund1       
,germany1 where a very large electric   
mining plant  was installed in #aijc4   
,in this instance the pump is located   
more than  #a1bjj feet below the        
surface1 and the difficulties of        
installing the  apparatus were so great1
 on account of the small cross section  
of the  shaft1 that it was necessary to 
build up the motor in the pumping       
chamber1 the material being transported 

through the wet shaft and the  winding  
of the coils being performed in situ4   
,an interesting use of the electric pump
 associated with the telephone  in      
connection with mining is noted by ,mr4 
,w4 ,b4 ,clarke4 ,in one coal  mine1    
where an electric pump is located in a  
worked-out portion of the  mine1 the    
circuits are so arranged that the pump  
is started from the  power house1 some  
distance away4 ,near the pump is placed 
a telephone  transmitter connected to a 
receiver in the power house4 ,to start  
the  motors1 or to ascertain whether the
 pumps are working properly1 the        
engineer merely listens at the telephone
 receiver1 without leaving his  post4   
,,electricity ,,in ,,coal ,,mining      
,in coal mining the effect of the use of
 electrical machinery has been          
revolutionary in recent years1          
particularly in the development of      
electric coal cutters4 ,the old method  
of picking out coal by hand1  where the 
miner labored with the heavy pick1      

working in all manner of  cramped and   
dangerous positions1 was supplanted a   
few years ago by  the puncher machine1  
worked by steam or compressed air4 ,with
 these  machines the coal was picked out
 just as in the case of the hand        
method1 except that the energy was      
derived from some power other than      
muscular4 ,so that while these machines 
worked more rapidly than the  hand      
picks1 they utilized the same general   
principle in applying their  energy4    
,within recent years1 however1 various  
coal-cutting machines have been         
devised1 with which the coal was        
actually cut1 or sawed out1 these       
machines being peculiarly well adapted  
to using the electric current4  ,the    
most practical and popular form of      
machine is one in which the  sawing is  
done by an endless chain1 the links of  
which are provided  with a cutting      
blade4 ,these have been very generally  
replacing the  compressed-air or pick   
type of machine1 and their popularity   

accounts  largely for the enormous      
increase in the use of coal-mining      
machinery  during the past decade4 ,thus
 in #ahih there were #b1fbb coal-mining 
machines in use in the ,united ,states4 
,four years later this number had  more 
than doubled1 the increase being due    
largely to the adoption of  chain       
machines4    ,like electric locomotives1
 and for similar reasons1 the           
coal-cutting  machines are low1 broad1  
flat machines1 from eighteen to         
twenty-eight  inches high4 ,they rest   
upon a flat shoeboard that can be moved 
easily along the face of the coal4 ,an  
ordinary machine weighs in the          
neighborhood of a ton1 and requires two 
men to operate4 ,the apparatus  is      
described briefly as follows3    ,on an 
outside frame1 consisting of two steel  
channel bars and two  angle irons       
riveted to steel cross ties1 rests a    
sliding frame  consisting of a heavy    
channel or centre rail1 to which is     
bolted the  cutter head4 ,the cutter    

head is made entirely of two milled     
steel  plates1 which bolt together1     
forming the front guide for the cutter  
chain4 ,this chain1 which is made of    
solid cast steel links connected  by    
drop forge straps1 is carried around    
idlers or sprockets placed at  each end 
of the cutter head and along the chain  
guides at the side to  the rear of the  
machine1 where it engages with and      
receives its power  from a third        
sprocket1 under the motor4 ,the electric
 motor1 which is  of ironclad multipolar
 type1 rests upon a steel carriage1     
which forms  the bearing for the main   
shaft4444 ,a reversing switch is        
provided1 so  that the truck can travel 
in either direction1 and when the       
machine has  reached its stopping point1
 either forward or backward1 it is      
checked  by an automatic cut-off4 ,the  
return travel is made in about          
one-fourth  of the time required to make
 the cut4    ,in veins of coal of a     
thickness from twenty-eight to thirty   

inches1  such a machine will cut about  
one hundred tons of coal in a day4 ,the 
cost of production with such machines   
has been estimated at about  sixty-three
 cents a ton1 as against ninety cents as
 the cost of pick  mining in rooms1--a  
saving of about twenty-seven cents a    
ton4 ,since it  is estimated that for a 
cost of #aj1jjj an electrical equipment 
can  be installed capable of working    
four such machines besides affording    
power for lighting1 pumping1 ventilation
 of the mine1 etc41 thus saving         
something like #ajj a day for the       
operator1 the great popularity of  these
 machines is readily understood4        
,after such a machine has been placed in
 position1 a cut some four feet  wide1  
four or five inches high1 and six feet  
deep can be made in five  minutes1 with 
the expenditure of very little energy on
 the part of the  workmen4 ,one of the  
largest cuttings ever recorded by one of
 these  machines is #a1gjj square feet  
in nine and one-half hours1 although    

this  may have been exceeded and not    
recorded4    ,among the several         
advantages claimed for the chain machine
 over the  older pick machines is the   
small amount of slack coal produced1 and
  the absence of the racking vibrations 
that exhaust the workmen1 and1  like the
 air drills1 sometimes cause serious    
diseases4 ,on the other  hand the       
advocates of the pick machines point out
 that they can be  used in mines too    
narrow for the introduction of chain    
machines4 ,they  show also that there is
 a constant element of danger from      
motor-driven  machines in mines where   
the quantity of gas present makes it    
necessary  to use safety lamps1 on      
account of the sparking of the machines 
which  may produce explosions4 ,both    
these claims are valid1 but apply only  
to special cases1 or to certain mines1  
and do not affect the general           
popularity of the chain machines4       
,there are several different types of   
chain cutting machines1 such as         

long-wall machines1 and shearing        
machines1 but these need not be         
considered in detail here4 ,the general 
principle upon which they work  is the  
same as the ordinary chain machine1 the 
difference being in the  method of      
applying it for use in special          
situations4      ,,electric ,,lighting  
,,of ,,mines    ,for many obvious       
reasons the ideal light for mining      
purposes is one  in which the danger    
from the open flame is avoided1         
particularly in  well-ventilated mines1 
or mines under careful supervision1     
where the  danger from inflammable gases
 is slight4 ,the incandescent electric  
light1 therefore1 has become practically
 indispensable in modern  mining        
operations4 ,for certain purposes and in
 certain locations where  an intense    
light is desirable and where there is no
 danger from  combustible gases1 arc    
lights are used to a limited extent4    
,but there  is constant danger from the 
open flame in using such lights1 and    

also  from the connecting wires leading 
to them4 ,furthermore1 such intense     
light is not usually necessary in the   
narrow passages of the mine4    ,to be  
sure1 there is a certain element of     
danger even with incandescent  lights on
 account of the possibility of breakage 
of the globes1 and of  short-circuiting 
where improper wiring has been done4 ,to
 overcome as  much as possible the      
dangers from these sources1 special     
precautions  are taken in wiring mines1 
and special bulbs are used4 ,in general 
the  incandescent lamps as used in      
mining are made of stout round bulbs  of
 thick glass which are not likely to    
crack from the effects of  water        
dripping upon them while heated4 ,as a  
further protection it is  customary to  
enclose the bulbs in wire cages4 ,it is 
also customary to  use low-current lamps
 with a rather high voltage1 although   
this must be  limited1 as excessive     
voltage may in itself become a source of
 danger4          ,,xiii    ,,the ,,age 

,,of ,,steel      ,the iron industry has
 of late years become more and more     
merged into  the steel industry1 as     
steel has been gradually replacing the  
parent  metal in nearly every field of  
its former usefulness4 ,steel is so much
  superior to iron for almost every     
purpose and the process of making  it   
has been so simplified by ,bessemer's   
discovery that it may justly  be said   
that civilization has emerged from the  
,iron ,age1 and entered  the ,age of    
,steel4 ,while iron is mined more       
extensively now than at  any time in the
 history of the world1 the ultimate     
object of most of  this mining is to    
produce material for manufacturing      
steel4 ,we still  speak of boiler iron1 
railroad iron1 iron ships1 etc41 but    
these names  are reminiscent1 for in the
 construction of modern boilers and     
modern  ships1 steel is used            
exclusively4 ,in the past decade it is  
probable  that no railroad rails even   
for the smallest and cheapest of tracks 

have been made of anything but steel4   
,the last half of the nineteenth century
 has been one of triumph of  steel      
manufacture and production in ,america1 
and at the present time  the ,united    
,states stands head and shoulders above 
any other nation in  this industry4 ,in 
the middle of the century both ,germany 
and ,england  were greater producers    
than ,america2 but by the close of the  
century  the annual output in the       
,united ,states was above fifteen       
million tons  as against ,england's ten 
and ,germany's seven2 and since #aijj   
this lead  has been greatly increased4  
,the steel industry has become so great1
 in  fact1 that it is a sort of         
barometer of trade and national         
progress4    ,the great advances in the 
quantity of steel produced have been    
made  possible by corresponding advances
 in methods of winning the iron ore     
from the earth4 ,mining machinery has   
been revolutionized at least twice      
during the last half century1 first by  

improved machines driven by  steam1 and 
again by electricity and compressed air4
 ,ore is still mined  to a limited      
extent by men with picks and shovels1   
but these implements  now play so       
insignificant a part in the process that
 they cannot be  considered as important
 factors4 ,steam shovels1 automatic     
loaders and  unloaders1 dynamite and    
blasting powder1 have taken the place of
 brawn  and muscle1 which is now mostly 
expended in directing and guiding       
mining machinery rather than in actually
 handling the ore4      ,,the ,,lake    
,,superior ,,mines    ,at the present   
time the greatest iron-ore fields lie in
 the ,lake  ,superior region1 and it is 
in this region that the greatest        
progress  in mining methods has been    
made in recent years4 ,there are1 of    
course1  extensive mines in other       
sections of the ,united ,states1 but at 
least  three-quarters of all the iron   
produced in ,america comes from the     
,lake ,superior mines1 and the systems  

of mining pursued there may be          
considered as representative of the most
 advanced modern methods4    ,where the 
iron ore of these mines is found near   
the surface of the  earth1 the great    
system of open-pit mining is practised2 
but as only  a relatively small portion 
of the ore is so situated1 modifications
  of older mining methods are still     
employed4 ,of these the three most      
important are known as overhead         
scooping1 caving1 and milling4    ,in   
the overhead method a shaft is sunk into
 the earth to a depth of  several       
hundred feet1 according to the depth of 
the ore1 this shaft  being lined with   
timbers for support4 ,from this shaft   
horizontal  tunnels are made in all     
directions in the ore deposits1 and     
through  these tunnels the ore is       
conveyed to the shaft and thence to the 
surface4 ,as the ore is removed and the 
earth thus honeycombed in  all          
directions1 supports of various kinds   
must be made to prevent  caving4 ,for   

this purpose columns of the ore itself  
may be left1 or  supports of masonry or 
wood or steel may be introduced4 ,under 
certain  circumstances1 however1 these  
supports are not employed1 the earth    
being allowed gradually to cave in at   
the surface as the ore is  removed1 this
 being the method of mining known as    
caving4    ,where the ore deposit occurs
 in a favorable hillside the milling    
system is frequently employed4 ,in      
working this system a large  horizontal 
tunnel1 twenty or more feet in diameter1
 is dug into the  hillside4             
,perpendicular shafts are then sunk from
 the top of the hill1  connected with   
openings leading directly into the top  
of the main  horizontal shaft4 ,by this 
arrangement the ore1 when loosened in   
these  perpendicular shafts1 falls      
directly into the bins placed for its   
reception about the openings1 or into   
the rows of cars in waiting to  receive 
it4 ,in this method dynamite and powder 
take the place of hand  labor1 the main 

mass of ore being dislodged and thrown  
into the shaft  by blasting1 instead of 
by hand labor4    ,but all these methods
 are overshadowed in magnitude by the   
great open  pit systems1 where the ore  
is taken from the surface and handled   
entirely by machinery1 the only part    
played by the miner's pick being  that  
of assisting in loosing certain         
fragments so that they may be  more     
easily seized by the machines4 ,indeed1 
this system of mining  partakes of the  
nature of quarrying rather than that of 
mining in the  ordinary sense1 the ore  
being scooped from the surface of the   
ground4  ,one naturally thinks of a mine
 as being subterranean2 but in the great
  open-pit mines in the ,lake ,superior 
region1 which are the largest mines  in 
the world1 all the mining is done at the
 surface of the earth4    ,it should not
 be understood1 however1 that in such   
mines nature has  left the red iron ore 
exposed at the surface in any great     
quantities4  ,on the contrary1 it is    

usually covered by a layer of earth     
ranging from  a yard to ten or more     
yards in depth1 and this1 of course1    
must be  removed before open-pit methods
 can be practised4 ,prospecting for such
  deposits is therefore just as         
necessary as in cases where the deposit 
is situated much deeper in the earth2   
and the business of prospecting  by test
 pit men is as important an industry as 
ever4    ,when an available open-pit    
mine of sufficient extent has been      
located  the gigantic task of stripping 
or removing the overlying layer of      
earth begins4 ,immense areas of land    
have been thus stripped in some of      
these undertakings1 no difficulties     
being considered insurmountable4  ,if a 
small river-bed lies in an unfavorable  
position1 the course of  the river is   
changed regardless of expense4 ,farms   
and farm houses  are purchased and      
literally carted away1 neither land nor 
houses  representing values worth       
considering when compared with the      

stratum  of ore beneath them4 ,the      
single contract for stripping one area  
in the  ,lake ,superior region was let  
for a sum amounting to half a million   
dollars4    ,as soon as a sufficiently  
large area has been stripped1 railroads 
are  constructed into the pit1 steam    
shovels are run into place1 and the     
actual work of mining begins4 ,five     
shovels full make a car-load1 and  under
 ordinary circumstances the five loads  
may be delivered in as many  minutes4   
,the number of men required to          
manipulate one of these steam shovels is
  from ten to twelve4 ,the ore itself is
 frequently so hard that the scoop  of  
the shovel could not penetrate it until 
loosened and broken up1 and  it is the  
business of the gang of workmen to do   
this and slide the ore  down within easy
 working distance of the shovel4 ,this  
is mostly done  by blasting with        
dynamite and powder1 little of the      
actual labor being  performed by hand4  
,in blasting1 a deep hole is first      

drilled into  the ore near the top of   
the embankment1 and into this hole a    
stick of  dynamite is dropped and       
exploded4 ,this enlarges the cavity     
sufficiently  so that a quantity of     
blasting powder may be poured in and set
 off1  tumbling the ore down within     
reach of the shovel4    ,this ore is    
frequently almost as hard as iron       
itself1 many of the  pieces thus        
dislodged being too large for convenient
 handling1 either  by the steam shovel  
or in the chutes at the wharves1 and    
must be still  further broken up4 ,this 
is sometimes done by the men with picks2
 but  in mining on a large scale1 where 
the deposit is all of a very hard       
nature1 crushing machines are used4     
,in this manner the steam shovel is kept
 constantly supplied with ore  for the  
waiting train of cars4 ,these trains are
 arranged on a track  running parallel  
with the track from which the steam     
shovel operates1  and at such a distance
 that the centre of the car will be     

directly  under the opening in the      
bottom of the shovel when it is swung   
around  on its crane4 ,the engineer in  
charge of the locomotive drawing the    
train stops it in a position so that the
 first shovelful of ore will  be dumped 
into the forward end of the first car4  
,as each successive  shovelful is       
deposited1 representing about one-fifth 
of a car-load1  the train is pulled or  
backed along the track about one-fifth  
of a  car-length4 ,in this manner it is 
only necessary for the steam shovel to  
be swung into the same position and     
dumped at the same point each time  to  
insure the proper loading of the cars4  
,from what has been said it will be seen
 that in this open-pit mining  the steam
 engine and steam locomotive still play 
a conspicuous part2  but in the other   
forms of iron mining1 electric or       
compressed-air  motors are used1 as much
 better adapted for underground work4   
,in  the ,lake ,superior region1 where  
everything is done by the most  modern  

methods1 the use of horses and mules for
 hauling purposes is  practically       
unknown4    ,the cars used for hauling  
the ore are of peculiar construction4   
,the  latest types are built of steel   
with a carrying capacity of fifty tons  
of ore1 and are so made that by simply  
knocking loose a few pins their  bottoms
 open and discharge the ore into the    
receiving bins on the  wharves1 or into 
the chutes leading to the waiting boats4
    ,a perennial problem in iron mining1
 whether surface or subterranean1  just 
as in all other kinds of mining1 is the 
removal of accumulations  of water1 some
 of these mines filling at the rate of  
from twenty-five  to thirty thousand    
gallons an hour4 ,but an equally        
important problem  is that of removing  
moisture from the ore itself4 ,obviously
 every  additional pound of moisture    
adds to the cost and difficulty in      
handling1 and inasmuch as this ore must 
be transported a distance of  something 
like a thousand miles1 necessitating    

three or four handlings  in the process1
 the aggregate amount of wasted energy  
caused by each  ton of water is         
enormous4 ,it has been found that at    
least ten per  cent of the moisture may 
be dried out of the ore before shipping1
 and  that the ore does not tend to     
absorb moisture again under ordinary    
circumstances once it has been dried4   
,this is of course of great  advantage  
where it is found necessary to store it 
in heaps some little  time before       
shipping4      ,,from ,,mine ,,to       
,,furnace    ,in most industries1       
particularly where the percentage of    
waste products  is large1 it is found   
advantageous and economical to establish
  factories as near the source of supply
 of raw material as possible4 ,but  the 
iron ore mined in the ,lake ,superior   
region is transported something  like a 
thousand miles before being delivered to
 the factories4 ,the  question naturally
 arises1 ,why is not the ore turned into
 pig iron or  steel ingots at once as   

near the mouths of the mines as         
possible1 and  sent in this condensed   
form to the factories1 thus saving more 
than  half the cost of transportation8  
,the answer is simple3 the coal mines   
and steel factories lie in the ,east1   
one established by nature1 the  other by
 man many years before iron ore was     
found in the ,lake region4  ,and it is  
found just as cheap and easy to         
transport the iron to the  coal regions 
as it would be to transport the coal to 
the ore regions4  ,furthermore1 the     
factories in the neighborhood of        
,pittsburg and along  the southern      
shores of ,lake ,erie and ,lake ,ontario
 are near the great  centres of         
civilization1 and are accessible the    
year round2 while the  ,lake ,superior  
region is frozen in for at least three  
months in the  year4    ,and so1 in     
place of a great traffic of coal        
westward to the ,lake  ,superior        
regions1 there is a great eastward      
traffic of ore1 by rail and  water1     

passing from the mines to furnaces and  
factories a thousand  miles away4       
,indeed1 this is probably the greatest  
and most remarkable  system of          
transportation in the world4 ,specially 
constructed trains1  wharves1 boats1 and
 machinery1 used for this single        
purpose1 and not  duplicated either in  
design or extent1 make this stupendous  
enterprise  a unique1 as well as a      
purely ,american one4    ,the           
transportation begins with the train    
loads of ore that run from  the mines to
 the lake shore and out upon the wharves
 built to receive  them4 ,these wharves 
are enormous structures1 sometimes half 
a mile in  length1 built up to about the
 height of the masts of ore boats4 ,on  
the  sides and in the centres of these  
towering structures are huge bins for   
holding the ore1 these bins             
communicating directly with the holds of
  the ore steamers tied up alongside4   
,four tracks are frequently laid on  the
 top of the wharves1 and are so arranged

 that trains four abreast  can dump the 
ore into the bins1 or waiting ships1 at 
the same time4  ,if the bins are empty  
and boats waiting to receive a cargo1   
the ore  is discharged by long chutes   
into the holds from the cars4 ,otherwise
  the bins are filled1 the trains       
returning to the mines as quickly as    
possible for fresh loads4    ,the boats 
for receiving this cargo are of special 
design1 many of  them differing very    
greatly in appearance from ordinary     
ocean liners  of corresponding size4    
,this is particularly true of the       
whale-backs  which have little in common
 in appearance with ordinary steamers   
except  in the matter of funnels2 and   
even these are misplaced sternwards to  
a distance quite out of drawing with the
 length of the hull4 ,their  shape is   
that of the ordinary type of submarine  
boat--that is1  cigar-shaped--this      
effect being obtained by a curved deck  
completely  covering the place          
ordinarily occupied by a flat deck4 ,a  

wheel-house1  like a battle-ship's      
conning-tower1 is placed well forward1  
supported  on steel beams some distance 
above the curved deck for observation   
purposes2 and engines1 boilers1 and coal
 bunkers occupy a small space  in the   
stern4 ,the boat1 therefore1 is mostly  
hold4    ,but the whale-backs form only 
a small portion of the ore-fleet4 ,the  
ordinary type of boat conforms more     
nearly to the shape of ocean boats1     
except that the bridge1 wheel-house1 and
 engines are located as in the          
whale-backs4 ,the bows of these boats   
are blunt1 the desideratum in  such     
craft being hull-capacity rather than   
speed4 ,for sea-worthiness  they are    
equal to any ocean boats1 as the        
battering waves of ,lake  ,superior are 
quite as powerful and even more         
treacherous than those  of the ,atlantic
 or ,pacific4 ,some of these boats are  
five hundred feet  long1 equal to all   
but the largest ocean vessels4 ,their   
coal-carrying  capacity is relatively   

small1 since coaling stations are       
numerous at  various points on the      
journey1 and every available inch of    
space is  utilized for the precious iron
 ore4    ,in order to facilitate        
loading1 the decks are literally        
honey-combed  with hatches1 some boats  
having fifteen or sixteen openings      
extending  the width of the deck4 ,by   
this arrangement the time of loading is 
reduced to a matter of a few hours1 as a
 dozen chutes1 each discharging  several
 tons of ore per minute1 soon fill the  
yawning compartments  with the necessary
 six1 eight1 or nine thousand tons1 that
 make up the  cargo4    ,quite recently 
lake-navigators have learned1 what      
rivermen have long  known1 that cheap   
transportation may be effected on a     
large scale by  barges and towing4      
,before the outbreak of the ,civil ,war 
forty years  ago1 the ,mississippi river
 swarmed with great cargo-carrying      
steamers1  employing armies of men and  
consuming enormous quantities of fuel4  

,but after the war the experiment was   
tried of hauling the cargoes on  barges 
towed by tug boats1 and this proved to  
be so much cheaper that  the fleet of   
great river boats soon disappeared4 ,in 
somewhat the same  way the barge has    
come into use of late years in the      
ore-traffic1 and  the great ore-steamers
 now tow behind them one or two barges  
equal in  carrying capacity to          
themselves4 ,in this way three ships'   
cargoes of  ore are transported a       
thousand miles by a score of men1 a     
dozen on the  steamer and three or four 
on each of the barges4 ,the barges      
themselves  are rigged as ships1 and if 
necessary can shift for themselves by   
means  of sails attached to their stubby
 masts4 ,but these are used only on     
special and unusual occasions1 as in    
case of accidental parting of the       
hawsers during a storm4    ,the problem 
of loading the ships at the ore wharves 
is a simple one as  compared with the   
equally important one of transferring   

the ore from  the hold to trains of cars
 in waiting at the eastern end of the   
water  route4 ,for four handlings of the
 ore are necessary before it is finally 
deposited in the furnaces in the east4  
,the first of these is from the  mine to
 cars2 the second from the cars to the  
boats2 the third from the  boats to     
cars2 and the fourth from the cars to   
the blast furnaces4    ,for many years  
about the only hand work done in any of 
these processes  was that of            
transferring from the boats to the      
ore-trains1 and even  here automatic    
unloaders are now rapidly supplanting   
the tedious hand  method4 ,by the older 
methods a travelling crane1 or swinging 
derrick1  dropped a bucket into the hold
 of the ore-vessel1 where workmen       
shovelled it full of the red ore4 ,it   
was then lifted out by machinery  and   
the contents dumped into cars in much   
the same manner as that of  the steam   
shovel in the mines4 ,recently1 however1
 a machine has been  perfected which    

scoops up the ore from the ship's hold  
and transfers  it to the cars without   
the aid of shovellers4 ,the only human  
aid given  this gigantic machine is to  
guide it by means of controlling        
levers--to  furnish brains for it1 in   
short--the muscle being furnished by    
steam  power4 ,the great arm of this    
automatic unloader1 resembling the sweep
  of the old-fashioned well in          
principle1 moves up and down1 burying   
the jaws of the shovel into the ore in  
the hold1 and pulling them out  again   
filled with ore1 with monotonous        
regularity1 quickly emptying the  vessel
 under the guidance of half a dozen men1
 and performing the labor  of hundreds4 
,thus the last field of activity for the
 laborer and his shovel1 in the         
iron-ore industry1 has been usurped by  
mechanical devices4 ,from the  time the 
ore is taken from the mine until it     
appears as molten metal  from the       
furnaces1 it is not touched except by   
mechanisms driven by  steam1 compressed 

air1 or electricity4 ,and yet1 so rapid 
is the growth  of the iron and steel    
industry that there is almost always a  
demand for  more workmen4    ,for this  
reason1 and perhaps because of the      
,american spirit among  workmen1        
innovations in the way of labor-saving  
machinery are not  resisted among the   
mine laborers4 ,the ,american workman   
seldom resists  or attacks machinery on 
the ground that it throws him out of a  
job1  as does his ,english cousin4 ,it  
would be unjust to attribute this       
attitude to superior acumen on the part 
of the ,american workman1 and it  is    
probably a difference in conditions and 
surroundings that accounts  for the     
diametrically opposite views held by    
laborers on the two sides  of the       
,atlantic4 ,but after all1 results must 
speak for themselves1 and  the advantage
 all lies in favor of the progressive   
attitude of the  western laborer1 if we 
may judge by the relative social status 
and  financial standing of ,european and

 ,american workmen4      ,,the          
,,conversion ,,of ,,iron ,,ore ,,into   
,,iron ,,and ,,steel    ,since steel is 
a compound substance composed           
essentially of two  elementary          
substances in varying proportions1 it   
appears that the  name steel1 like wood1
 refers to a class of which there are   
several  varieties4 ,this1 of course1 is
 the case1 but for the moment we may    
consider steel as a single substance    
composed chiefly of iron and  containing
 a certain percentage of carbon4 ,in    
this respect it  resembles cast iron1   
steel having a smaller amount of carbon4
 ,wrought  iron1 on the other hand1     
contains no carbon at all1 or at least  
only a  trace of it4 ,but whatever the  
ultimate destiny of iron ore--whether it
  is to become aristocratic manganese   
steel1 or plebeian cast iron--it  must  
first pass through certain processes    
before being converted4    ,to extract  
the pure iron from the iron ore it is   
necessary to heat  the ore in a furnace 

containing a certain quantity of coal1  
coke1 or  charcoal1 and limestone4 ,the 
furnaces used in this process are known 
as blast-furnaces1 and in these about   
one ton of iron is extracted for  every 
two tons of ,lake ,superior ore1 one and
 a quarter tons of coke1  and half a ton
 of limestone used4 ,these quantities   
are by no means  constant1 of course1   
but they may be taken as representing   
roughly the  relative amounts of        
material that must be fed into the      
furnaces4    ,like everything else in   
the world of iron and steel1 these      
blast-furnaces have undergone           
revolutionary improvements during the   
past quarter of a century4 ,from being  
most dangerous and destructive          
structures causing frightful loss of    
life and producing only about one  ton  
of iron a day for every man working     
about them1 as formerly1 they  have now 
become relatively harmless monsters1    
capable of turning out  six times that  
quantity of ore for each man employed4  

,the older blast-furnace was a huge1    
chimney-like structure1 perhaps a       
hundred feet high1 into which the ore1  
coal1 and limestone were poured4  ,most 
of the work about these furnaces was    
done by manual labor1 or  at least      
manual labor was an active assistant to 
the machinery used  in manipulating the 
furnaces4 ,the top of the furnace was   
closed in by  a great movable lid1 or   
bell1 and the material for charging it  
was  hauled up the sides by elevators   
and dumped in at the top4 ,about the    
top of the furnace was constructed a    
staging upon which the workmen  stood1  
an elevator shaft connecting the staging
 with the ground4 ,the  ore and other   
materials were brought to the foot of   
the shaft on cars  from which it was    
shovelled into peculiarly designed      
wheelbarrows1  trundled to the elevator1
 and hauled to the top4    ,in order to 
dump the wheelbarrow loads into the     
furnaces it was  necessary to raise the 
bell4 ,this was always dangerous1 and   

frequently  resulted in the suffocation 
or injury of the workmen on the staging4
  ,for when the bell was raised there   
was an escape of poisonous gases1  which
 might flare out in a sheet of flame1   
with the possibility of  burning or     
suffocating the workmen4 ,the fumes from
 these gases1 if  inhaled in small      
quantities1 might simply cause coughing1
 hiccoughing1  or dizziness2 but when   
inhaled in large quantities they struck 
down  a man like the fumes of           
chloroform1 suffocating him in a few    
seconds  if he was not removed at once  
into a purer atmosphere4 ,indeed1 the   
likelihood of this was so great that at 
many of these furnaces a  special       
workman was detailed to take the        
position on the staging1 well  out of   
range of the gas1 his sole duty being to
 rescue any of the men  who might be    
overcome1 and hurry them as quickly as  
possible down the  elevator shaft into  
the pure atmosphere below4 ,it was not  
an uncommon  thing in the neighborhood  

of these older furnaces to see stretched
  about on the ground at the base       
several workmen in various stages of    
suffocation4 ,fortunately1 by use of    
precautionary measures1 fatal  accidents
 were rather unusual1 the men being     
overcome only temporarily1  and usually 
recovering quickly and returning to     
work4    ,but the poisonous gas coming  
from the top of the furnace was not the 
only1 nor the worst1 danger constantly  
menacing the men on the staging4  ,their
 greatest dread was the possibility of  
explosions occurring in the  furnace1   
which might hurl the bell into the air  
and deluge the upper  structure with    
molten metal4 ,against this possibility 
there was no  safeguard in the older    
furnaces1 explosions occurring without  
warning  and frequently with terrible   
effects4 ,but fortunately these older   
types  of furnaces are being rapidly    
replaced by the newer forms in which the
  danger to life1 at least from gas and 
explosions1 is minimized4 ,and  even in 

the older furnaces1 improvements in the 
structure of the bell  and in methods of
 filling have greatly lessened the      
dangers4    ,in the modern type of      
blast-furnace the work at the top       
formerly  performed by men on the       
staging is accomplished entirely by     
machinery4  ,the general appearance of  
these furnaces is that of huge iron     
pipes or  kettles mounted on several    
iron legs4 ,the outer structure1 or     
shaft1  is constructed of plate iron1   
but this is lined with fire brick of    
considerable thickness1 and may have a  
water jacket interposed between  these  
bricks and the shaft4 ,about this large 
kettle are smaller  kettles of somewhat 
similar shape having pipes leading from 
their tops  to the larger structure4    
,these smaller kettles are the stoves   
used in  producing the hot air for the  
furnace4    ,the working capacity of    
some of these furnaces is in the        
neighborhood  of a thousand tons of iron
 a day1 although the average furnace    

produces  only about half that quantity4
 ,the powerful machinery used for       
charging  these monster caldrons hauls  
the ore and other charging materials to 
the top and dumps it in car-load lots4  
,in the older methods of manufacturing  
steel1 the contents of the              
blast-furnaces were first drawn off into
 molds and allowed to cool  into what is
 known as pig-iron4 ,it was then        
necessary to re-heat  this iron and     
treat it by the various methods for     
producing the kind  of steel desired4   
,by the newer methods1 however1 time and
 money are  saved by converting the     
liquid iron from the blast-furnace      
directly  into steel without going      
through the transitional stage of       
cooling it  into pigs4 ,pigs of iron are
 still made in enormous quantities1 to  
be  sure1 but mostly for shipment to    
distant places or for stores as stock   
material4 ,for statistical purposes1    
however1 the entire product of the      
blast-furnace1 whether liquid or solid1 

is known as pig iron4    ,the older     
method of removing the iron from the    
blast furnaces was by  tapping at the   
opening near the bottom1 the stream of  
liquid iron being  allowed to flow into 
a connected series of sand molds1 each  
mold being  about three feet long by    
three or four inches wide4 ,the bottom  
of  these molds was flat but as the     
metal cooled in them the upper surface  
became round in shape1 assuming a       
fanciful resemblance to a pig's back4   
,in this molding a great amount of time 
was wasted in the slow process  of      
cooling1 and a large expenditure of     
energy wasted in this handling  and     
re-handling of the metal4    ,in modern 
smelting works1 however1 pigs are no    
longer cast in sand  molds1 the molten  
metal from the furnace being discharged 
directly into  iron molds attached to an
 endless chain4 ,these molds are long1  
narrow1  and shallow1 having the general
 shape of sand molds4 ,each mold as it  
passes beneath the opening in the       

furnace remains just long enough to     
receive the requisite amount of metal to
 fill it1 and then moves on to  a point 
where it is either sprayed with water1  
or cooled by actually  passing through a
 tank of water1 emerging from this bath 
with the metal  sufficiently solidified 
so that it may be dropped into a waiting
 car at  the turning point of the       
endless chain4 ,in this manner the      
charge from  the blast-furnace may be   
drawn1 cooled1 and converted into pigs1 
loaded  into cars1 and hauled away      
without extra handlings or loss of time1
 the  whole process occupying           
practically no more time than the       
initial step  of tapping by the older   
method4    ,where the contents of the   
blast-furnace are to be converted into  
steel at once1 the molten metal is run  
off into movable tanks which  carry it  
directly to the steel furnaces4 ,these  
tanks1 holding perhaps  twenty tons of  
metal1 are made of thick iron lined with
 fire brick1  and arranged on low1 flat 

cars designed specially for the purpose4
  ,these tanks are run under the spout  
of the furnace1 filled with molten      
metal1 and drawn to the steel works1    
possibly five miles away4 ,as a  rule1  
the distance is much less1 but as far as
 the condition of the  metal is         
concerned distance seems to make little 
difference1 as even  at the extreme     
distance there is no apparent cooling of
 the seething  mass4 ,the intense heat  
given off by these trains necessitates  
specially  constructed cars1 tracks1    
bridges1 and crossings4    ,the         
destination of this train load of iron  
pots is the mixer--a great  #bjj-ton    
kettle in which the products from the   
various furnaces are  mixed and rendered
 uniform in quality4 ,on the arrival of 
the train at  the mixer1 ,titanic       
machinery seizes the twenty-ton pots and
 dumps their  contents bodily into the  
glowing pool in the great crucible4     
,like the  filling process1 this        
operation occupies only a few minutes4  

,from the mixer the metal is poured out 
into ladles and transferred  immediately
 to the converter--the important        
development of ,sir ,henry  ,bessemer's 
discovery that has made possible the    
modern steel industry4  ,this converter 
resembles in shape some of the old      
mortars used in the  ,american ,civil   
,war--barrel-shaped structures suspended
 vertically by  trunnions at the middle 
and having an opening at the top4 ,into 
this  opening at the top the metal from 
the mixer is poured and when the        
converter has been sufficiently charged 
a blast of cooled air is blown  in at   
the bottom through the molten metal4    
,this blast emerges at the  top as a    
long roaring flame1 of a red color at   
first but gradually  changing into      
white1 and then faint blue4 ,these      
changes in color are  indicative of the 
changes that are taking place in the    
metal1 and the  appearance of a certain 
shade of color indicates that the       
conversion  into steel is complete1 and 

that it is time for shutting off the    
blast  of air4 ,any mistake in this     
matter--even the variation of thirty    
seconds' time--means a loss of thousands
 of dollars in the quality of  steel    
produced4 ,the man whose duty it is to  
determine this important  point1        
therefore1 holds an exceptionally       
delicate and responsible  position1 and 
receives pay accordingly4    ,in        
deciding the exact moment when the blast
 shall be turned off1 this  workman is  
guided entirely by the sense of sight4  
,mounted on a platform  commanding the  
best possible view of the mouth of the  
converter and  wearing green glass      
goggles of special construction1 this   
man watches  the change of color in the 
flame until a certain shade is          
reached--a  shade that to the ordinary  
untrained observer does not differ in   
appearance from that of a moment        
before--when he gives the signal to     
shut off the blast4 ,when this signal is
 given the contents of the  converter is

 no longer common-place cast iron1 but  
steel1 ready to be  molded into rails1  
boilers1 or a thousand and one other    
useful things4    ,the contents of the  
converter may now be drawn off as liquid
 steel into  molds of any desired shape 
and size1 and when cooled will be ready 
for  shipment4 ,but in the great steel  
factories the metal is not ordinarily   
allowed to cool completely before being 
sent to the rolling mills1  being drawn 
off into molds placed along the surface 
of small1 flat  cars4 ,these molds are  
rectangular1 ordinarily four or five    
feet high by  less than two feet in     
diameter4 ,the metal is poured into     
openings in  the top of each mold1 and  
allowed to cool1 solidify1 and to       
contract  enough to permit the outer    
casings of the molds to be pulled off by
  machinery1 leaving the glowing ingots 
of steel ready for molding by  machinery
 in the mills4    ,the process just     
described is the one by which ,bessemer 
steel is  made4 ,there is another       

important process in use1 the open      
hearth  method1 which differs           
considerably from this2 but before      
considering  this process something more
 should be said of the man whose        
discoveries  made possible the modern   
steel industry4      ,,sir ,,henry      
,,bessemer    ,in the history of the    
progress of science and invention some  
one great  name is usually pre-eminently
 associated with epoch-marking advances1
  although there may be a cluster of    
important but minor associates4 ,this   
is true in the history of the modern    
steel industry1 and the central  name   
here is that of ,sir ,henry ,bessemer4  
,bessemer was born at ,charlton1        
,england1 on ,jan4 #ai1 #ahac4 ,always  
of an inventive turn of mind1 his       
attention was first directed to         
improving the methods then in use for   
the manufacture of steel1 while         
experimenting with the manufacture of   
guns4 ,after several years of           
experimenting in his little iron works  

near ,london1 he reached some  definite 
results which he announced to the       
,british ,association in #ahef4  ,in    
this paper he described a process of    
converting cast iron into  steel by     
removing the excess of carbon in the    
molten metal by a blast  of air driven  
through it4 ,this paper1 in short1      
described the general  principles still 
employed in the ,bessemer process of    
manufacturing  steel4 ,and although the 
first simple process described by       
,bessemer has  been modified and        
supplemented in recent years1 it was in 
this paper  that the process which      
placed steel upon the market as a       
comparatively  cheap1 and infinitely    
superior1 substitute for ordinary iron1 
was first  disclosed4    ,this famous   
paper before the ,british ,association  
aroused great interest  among the       
,english ironmasters1 and applications  
for licenses to use  the new process    
were made at once by several firms4 ,but
 the success  attained by these firms   

was anything but satisfactory1 although 
,bessemer himself was soon able to      
manufacture an entirely satisfactory    
product4 ,the disappointed ironmasters1 
therefore1 returned to the  earlier     
processes1 the inventor himself being   
about the only practical  ironmaster who
 persisted in using it4    ,recognizing 
the defects in his process1 ,bessemer   
set about overcoming  them1 and at the  
end of two years he had so succeeded in 
perfecting  his methods that his        
product1 equal in every respect to that 
of the  older process1 could be         
manufactured at a great saving of time  
and  money4 ,but the ironmasters were   
now skeptical1 and refused to be again  
inveigled into applying for licenses4   
,bessemer1 therefore1 with the  aid of  
friends1 erected extensive steel works  
of his own at ,sheffield1  and began    
manufacturing steel in open competition 
with the other steel  operators4 ,the   
price at which he was able to sell his  
product and  realize a profit was so    

much below the actual cost of           
manufacture by  the older process1 that 
there was soon consternation in the     
ranks of  his rivals4 ,for when it      
became known that the firm of ,henry    
,bessemer   ,co4 was selling steel at a 
price something like one hundred dollars
 a  ton less than the ordinary market   
price1 there was but one thing left  for
 the ironmasters to do--surrender1 and  
apply for licenses to be  allowed to use
 the new process4    ,by this means1 and
 through the profits of his own         
establishment1  ,bessemer eventually    
amassed a well-earned fortune4          
,moreover1 he was  honored in due course
 by a fellowship in the ,royal ,society1
 and  knighted by his government4       
,one other name is usually associated   
with that of ,bessemer in the  practical
 development of the inventor's original 
idea4 ,that is the  name of ,robert     
,mushet1 and the ,bessemer-,mushet      
process is still in  use4 ,mushet's     
improvement over ,bessemer's original   

process was that  of adding a certain   
quantity of spiegeleisen1 or iron       
containing  manganese1 which1 for some  
reason not well understood1 simplifies  
the  process of steel making4 ,mushet1  
therefore1 must be considered as the    
discoverer of a useful1 though not an   
absolutely essential1 accessory  to the 
,bessemer process4      ,,open-,,hearth 
,,method    ,in the open-hearth method  
the metal from the blast-furnaces is not
  sent to the converter1 but is poured  
into oven-like structures built  of fire
 brick1 and in these heated to a        
terrific temperature4 ,this  heat has   
the same effect upon the metal as the   
blast of air in the  ,bessemer          
converter1 and this open-hearth process 
has become very  popular for            
manufacturing certain kinds of steel4   
,while in the method  of application    
this process differs greatly from that  
of ,bessemer1 it  differs largely in the
 fact that the oxygen necessary to burn 
off the  carbonic oxide1 silicon1 etc41 

is made to play over the molten mass    
instead of passing through it4    ,it   
has been noted that the old type of     
blast-furnace gave off great  quantities
 of combustible gases which became waste
 products4 ,even gases  containing      
something like #bj or #be per cent4 of  
carbonic acid may be  highly            
inflammable1 and thus an enormous       
quantity of valuable fuel  was          
constantly wasted4 ,in some furnaces1 to
 be sure1 they were put to  practical   
use for heating the blast1 but as the   
quantities given off  were greatly in   
excess of the amount necessary for this 
purpose1 there  was a constant loss even
 with such furnaces4    ,quite recently 
it has been found that the gases can be 
used directly  in gas engines1          
developing three or four times as much  
energy in this  way as if they were used
 as fuel under ordinary steam boilers4  
,these  engines are now used for        
operating the rolling-mill machinery1   
and the  machinery of shops adjoining   

the furnaces1 which1 however1 must not  
be  situated at any very great distances
 from the furnaces4 ,this accounts      
partly for the grouping together of     
blast-furnaces1 rolling mills1  and     
machine shops1 the economical feature of
 this arrangement being  so great that  
segregated establishments find it next  
to impossible to  compete in the open   
market with such communities under the  
conditions  prevailing in the steel     
industry4      ,,alloy ,,steels    ,the 
introduction of ,krupp steel1 or nickel1
 for armor plates1 a few  years ago1    
called attention in a popular way to the
 fact that for  certain purposes pure   
steel--that is1 iron plus a certain     
quantity of  carbon--was not as useful  
as an alloy of steel with some other    
metal4  ,an alloy was a great           
improvement over ordinary steel or iron 
plates  used in warfare2 but in the more
 peaceful pursuits1 as well as in       
warfare1 certain alloyed steels1 such as
 chrome steel1 tungsten steel1  and     

manganese steel play a very important   
part4    ,chrome steel1 for example1 in 
the form of projectiles1 is the most    
dreaded enemy of nickel-steel armor     
plates1 because of the hardness  and    
elasticity of armor-piercing projectiles
 made of it4 ,such a  steel contains    
about two per cent4 of chromium with    
about one or  two per cent4 of carbon1  
which when suddenly cooled is extremely 
hard and tough4 ,this kind of steel and 
manganese steel are the best  guards    
against the burglar and safe-blower1 as 
they resist even very  highly tempered  
and hardened drills4 ,as this steel is  
relatively  cheap to manufacture1 it is 
frequently used in the construction of  
safes and burglar-proof gratings4 ,for  
this purpose1 however1 it is  sometimes 
combined in alternate layers with soft  
wrought iron1 the  steel resisting the  
point of the drill1 while the iron      
furnishes the  necessary elasticity to  
resist the blows of the sledge4 ,the    
bars used  in modern jails and prisons  

are often made in a similar manner of   
alternate sheaths of iron and chrome    
steel4 ,against the time-honored        
hack-saw1 the bugbear of prison         
officials for generations1 such  bars an
 inch and a quarter in diameter offer an
 almost insurmountable  obstacle2 and   
they are equally effective against a    
heavy sledge hammer4    ,at least one   
case is recorded in which the use of    
these composite  bars resulted in a     
disastrous fire in a prison4 ,a small   
blaze having  started in the basement of
 this prison1 attempts to reach it with 
a  stream of water were defeated by the 
bars of the steel gratings at the       
windows1 which would not admit the      
nozzle of the hose4 ,a corps of men     
armed with hack-saws1 crow-bars1 and    
sledges attacked this grating1  which1  
if made of ordinary steel1 could have   
been readily broken4 ,but  against these
 composite bars they produced no        
appreciable effect4  ,meanwhile the fire
 gained rapidly1 threatening the        

building and its  eight hundred inmates1
 and was only checked after holes had   
been made  through fire-proof floors and
 ceilings for admitting the nozzle4     
,manganese steel is peculiar in becoming
 ductile by sudden cooling1 and  brittle
 on cooling slowly--precisely the       
reverse of ordinary steel4 ,it  contains
 about #a4ej per cent4 of carbon1 and   
about #ab per cent4 of  manganese4 ,if a
 small quantity of manganese1 that is1  
#a or #b per cent41  is used the steel  
is very brittle1 and becomes more so as 
greater  quantities of the manganese are
 used1 up to about #e per cent4 ,from   
that  point1 however1 it becomes more   
ductile as the quantity of manganese  is
 increased1 until at about #ab per cent4
 it reaches an ideal state4  ,when used 
for safes and money vaults this steel   
has one great advantage  over chrome    
steel--it is not affected by heat4 ,by  
using a blow-pipe  and heating a limited
 area of steel1 the burglar is able to  
draw the  temper of ordinary steel to a 

sufficient depth so that he can drill  a
 hole to admit a charge of dynamite2 but
 manganese steel retains  its temper    
under the blow-pipe no matter how long  
it may be applied4  ,against attacks of 
the sledge1 however1 it is probably     
inferior to  chrome steel4    ,like     
manganese steel1 tungsten steel retains 
its temper even when  heated to high    
temperatures4 ,for this reason it is    
used frequently in  making tools for    
metal-lathe work where thick slices of  
iron are to be  cut1 as even at red heat
 such a tool continues to cut off metal 
chips  as readily as when kept at a     
lower temperature4 ,this steel contains 
from #f to #aj per cent4 of tungsten1 a 
metallic element with which we  have    
previously made acquaintance in our     
studies of the incandescent  lamp4      
,,xiv    ,,some ,,recent ,,triumphs ,,of
 ,,applied ,,science      ,not long ago 
a little company of men met in a lecture
 hall of ,columbia  ,university to      
discuss certain questions in applied    

science4 ,it was  a small gathering1 and
 its proceedings were so unspectacular  
as to  be esteemed worth only a few     
lines of newspaper space4 ,the very     
name--,society of                       
,electro-,chemistry--seemed to mark it  
as having to do  with things that are   
caviar to the general4 ,the name seems  
to smack of  fumes of the laboratory1   
far removed from the interests of the   
man in  the street4 ,yet ,professor     
,chandler said in his address of welcome
 to  the members of the society1 that   
though theirs was the very youngest  of 
scientific organizations1 he could      
confidently predict for it a  future    
position outranking that of all its     
sister societies2 and his  prediction   
was based on the belief that            
electro-chemistry is destined  to       
revolutionize vast and important        
departments of modern industry4 ,a      
majority of the heat-using methods of   
mechanics will owe their future         
development to the new science4    ,in a

 word1 then1 despite its repellent name1
 the society in question  has to do with
 affairs that are of the utmost         
importance to the man in  the street4   
,though its members may sometimes deal  
in occult formulas  and abstruse        
calculations1 yet the final goal of     
their studies has to  do not with       
abstractions but with                   
practicalities1--with the saving  of    
fuel1 the smelting of metals1 the       
manufacture of commodities4 ,but  theory
 in the main must precede practice--the 
child creeps before it  walks4 ,the     
later developments of industrial        
chemistry1 says ,sir  ,william ,ramsey1 
owe their success entirely to the growth
 of chemical  theory2 and it is obvious1
 he adds significantly1 that that nation
  which possesses the most competent    
chemists1 theoretical and practical1  is
 destined to succeed in the competition 
with other nations for  commercial      
supremacy and all its concomitant       
advantages4    ,fortunately this        

interdependence of science and industry 
is not a  mere matter of prophecy--for  
the future tense is never quite so      
satisfying as the present4 ,vastly      
important changes have already  been    
accomplished2 old industries have been  
revolutionized1 and new  industries     
created4 ,the commercial world of to-day
 owes vast debts to  the new science4   
,professor ,chandler outlined the       
character of one or  two of these in the
 address just referred to4 ,he cited in 
some detail1  for example1 the          
difference between old methods and new  
in such an  industry as the manufacture 
of caustic soda4 ,he painted a vivid    
word  picture of the distressing        
conditions under which soda was produced
  in the old-time factories4 ,salt and  
sulphuric acid were combined to  produce
 sulphate of soda1 which was mixed with 
lime and coal and heated  in a          
reverberatory furnace4 ,each phase of   
the process was laborious4  ,the workmen
 operating the furnaces sweltered all   

day long in an  almost unbearable       
atmosphere--stripped to the waist1      
dripping with  perspiration1 sometimes  
overcome with heat4 ,their task was one 
of the  most trying to which a man could
 be subjected4    ,but to-day1 in such  
establishments as the soda manufactories
 at ,niagara  ,falls1 all this is       
changed4 ,a salt solution circulates    
continuously in  retorts where it can be
 acted upon by electricity supplied from
 dynamos  operated by the waters of the 
,niagara ,river4 ,the workmen1          
comfortably  dressed and moving about in
 a normal temperature1 have really      
nothing  to do but refill the retorts   
now and then and remove the finished    
product4 ,it almost seems1 ,professor   
,chandler added with a smile1 as  if    
workmen ought to be glad to pay for the 
privilege of participating  in so       
pleasant an occupation4 ,at all events  
it is1 in all seriousness1  a pleasure  
for the visitor who knows nothing of old
 practices to  witness this triumph of a

 modern scientific method4    ,even more
 interesting1 said ,professor ,chandler1
 are the processes  employed in the     
modern method of producing the metal    
aluminum by the  electrolytic process4  
,the process is based on the discovery  
made  by ,mr4 ,charles ,m4 ,hall while  
he was a student working in a college   
laboratory1 that the mineral cryolite   
will absorb alumina to the extent  of   
twenty-five per cent4 of its bulk1 as a 
sponge absorbs water4 ,the  solution of 
this compound is then acted on by       
electricity1 and the  aluminum is       
deposited as pure metal4 ,a curiously   
interesting practical  detail of the    
process is based on the fact that       
pulverized coke remains  perfectly dry  
and rises to the surface when stirred   
into a crucible  containing the hot     
alumina solution3 moreover1 it rises to 
the surface  and remains there as a     
shield to protect the workmen against   
the heat  of the solution4 ,it serves   
yet another purpose1 as the powdered    

alumina  may be sifted upon it and left 
there to dry before being stirred into  
the crucible4 ,a most ingenious yet     
simple device tells the workman when    
any particular crucible is in need of   
replenishing4 ,a small1 ordinary1       
incandescent electric-light bulb is     
placed in circuit between the poles     
that convey the electric current through
 the alumina solution4 ,so long  as the 
crucible contains alumina1 the bulb does
 not glow1 because  twenty volts of     
electricity are required to make it     
incandescent1  whereas seven volts pass 
through the solution4 ,but so soon as   
the  alumina becomes exhausted1         
resistance to the current rises in the  
cryolite solution and1 as it were1 dams 
back the electric current  until it     
overflows into the wire at sufficient   
pressure to start the  signal lamp4     
,then it is necessary merely for a      
workman to stir into  the solution the  
dry alumina resting on the surface1     
along with the  coke that supports it4  

,this1 of course1 reestablishes the     
electrolytic  process2 the lamp goes out
 and the coke1 unaffected by its bath1  
rises  to the surface to support a fresh
 supply of alumina4    ,such a process  
as this1 contrasted with the usual      
methods of smelting  metals in fiercely 
heated furnaces1 seems altogether       
wonderful4 ,here  a pure metal is       
extracted from the clayey earth of which
 it formed  a part1 without being melted
 or subjected to any of the familiar    
processes of the picturesque1 but       
costly1 laborious1 and even  dangerous1 
blast-furnaces4 ,there is no glare and  
roar of fires2 there  are no showers of 
sparks2 there is no gush of fiery       
streams of molten  metal4 ,a silent and 
invisible electric current1 generated by
 the fall  of distant waters1 does the  
work more expeditiously1 more           
efficiently1  and more cheaply than it  
could be done by any other method as yet
  discovered4    ,fully to appreciate   
the importance of the method just       

outlined1 we  must reflect that aluminum
 is a metal combining in some measure   
the  properties of silver1 copper1 and  
iron4 ,it rivals copper as a conductor  
of electricity2 like silver it is white 
in color and little subject  to         
tarnishing2 like iron it has great      
hardness and tensile strength4  ,true1  
it does not fully compete with the more 
familiar metals in their  respective    
fields2 but it combines many valuable   
qualities in fair  degree2 and it has an
 added property of extreme lightness    
that is all  its own4 ,add to this the  
fact that aluminum is extremely abundant
  everywhere in nature--it is a         
constituent of nearly all soils and is  
computed to form about the twelfth part 
of the entire crust of the              
earth--whereas the other valuable metals
 are relatively rare1 and it  will      
appear that aluminum must be destined to
 play an important part in  the         
mechanics of the future4 ,there is every
 indication that the iron  beds will    

begin to give out at no immeasurably    
distant day2 but the  supply of aluminum
 is absolutely inexhaustible4 ,until now
 there has  been no means known of      
extracting it cheaply from the clay of  
which  it forms so important a          
constituent4 ,but at last               
electro-chemistry  has solved the       
problem2 and aluminum is sure to take an
 important  place among the industrial  
metals1 even should it fall short of    
the preeminent position as the metal of 
the future that was once  prematurely   
predicted for it4      ,,nitrogen ,,from
 ,,the ,,air    ,there is a curious     
suggestiveness about this finding of    
aluminum at our  very door1 so to speak1
 some scores of centuries after the     
relatively  rare and inaccessible metals
 had been known and utilized by man4    
,but  there is another yet more striking
 instance of an abundant element  which 
man needed1 but knew not how to obtain  
until the science of our  own day solved
 the problem of making it available4    

,this is the case of  the nitrogen of   
the air4 ,as every one knows1 this gas  
forms more than  three-fourths of the   
bulk of the atmosphere4 ,but1 unlike the
 other  chief constituent1 oxygen1 it is
 not directly available for the use of  
plants and animals4 ,yet nitrogen is an 
absolutely essential constituent  of the
 tissues of every living organism1      
vegetable and animal4 ,any  living thing
 from which it is withheld must die of  
starvation1 though  every other         
constituent of food be supplied without 
stint2 and the fact  that the starving  
organism is bathed perpetually in an    
inexhaustible  sea of atmosphere chiefly
 composed of nitrogen would not abate by
 one  jot the certainty of its doom4    
,to be made available as food for plants
 7and thus indirectly as food  for      
animals7 nitrogen must be combined with 
some other element1 to  form a soluble  
salt4 ,but unfortunately the atoms of   
nitrogen are  very little prone to enter
 into such combinations2 under all      

ordinary  conditions they prefer a      
celibate existence4 ,in every           
thunder-storm1  however1 a certain      
quantity of nitrogen is1 through the    
agency  of lightning1 made to combine   
with the hydrogen of dissociated        
water-vapor1 to form ammonia2 and this  
ammonia1 washed to the earth  dissolved 
in rain drops1 will in due course       
combine with constituents  of the soil  
and become available as plant food4     
,once made captive  in this manner1 the 
nitrogen atom may pass through many     
changes and  vicissitudes before it is  
again freed and returned to the         
atmosphere4  ,it may1 for example1 pass 
from the tissues of a plant to the      
tissues  of a herbivorous animal and    
thence to help make up the substance of 
a  carnivorous animal4 ,as animal       
excreta or as residue of decaying flesh 
it may return to the soil1 to form the  
chief constituent of a guano  bed1 or of
 a nitrate bed1--in which latter case it
 has combined with  lime or sodium to   

form a rocky stratum of the earth's     
crust that may  not be disturbed for    
untold ages4    ,a moment's reflection  
on the conditions that govern vegetable 
and  animal life in a state of nature   
will make it clear that a soil once     
supplied with soluble nitrates is likely
 to be replenished almost  perpetually  
through the decay of vegetation4 ,but it
 is equally clear  that when the same   
soil is tilled by man1 the balance of   
nature is  likely to be at once         
disturbed4 ,every pound of grain or of  
meat  shipped to a distant market       
removes a portion of nitrogen2 and      
unless  the deficit is artificially     
supplied1 the soil becomes presently    
impoverished4    ,but an artificial     
supply of nitrogen is not easily        
secured--though  something like         
twenty-five million tons of pure        
nitrogen are weighing  down impartially 
upon every square mile of the earth's   
surface4 ,in the  midst of this         
tantalizing sea of plenty1 the farmer   

has been obliged  to take his choice    
between seeing his land become yearly   
more and more  sterile and sending to   
far-off nitrate beds for material to    
take the  place of that removed by his  
successive crops4 ,the most important of
  the nitrate beds are situated in      
,chili1 and have been in operation      
since the year #ahcj4 ,the draft upon   
these beds has increased enormously  in 
recent years1 with the increasing needs 
of the world's population4  ,in the year
 #ahgj1 for example1 only #aej1jjj tons 
of nitrate were  shipped from the ,chili
 beds2 but in #ahij the annual output   
had grown  to #hjj1jjj tons2 and it now 
exceeds a million and a half4           
,conservative  estimates predict that at
 the present rate of increased output   
the  entire supply will be exhausted in 
less than twenty years4 ,and for some   
years back scientists and economists    
have been asking themselves1 ,what      
then8    ,but now electro-chemistry has 
found an answer--even while the         

alarmists  were predicting dire         
disaster4 ,means have been found to     
extract the  nitrogen from the          
atmosphere1 in a form available as plant
 food1 and at  a cost that enables the  
new synthetic product to compete in the 
market  with the ,chili nitrate4 ,so all
 danger of a nitrogen famine is now at  
an end1--and applied science has placed 
to its credit another triumph1  second  
to none1 perhaps1 among all its         
conquests4 ,the author of this  truly   
remarkable feat is a ,swedish scientist1
 ,christian ,birkeland  by name1        
,professor of ,physics in the           
,university of ,christiania4 ,his       
experiments were begun only about the   
year #aijc1 and the practical  machinery
 for commercializing the results--in    
which enterprise  ,professor ,birkeland 
has had the co-operation of a practical 
engineer1  ,mr4 ,s4 ,eyde--is still in a
 sense in the experimental              
stage1--albeit  a large factory was put 
in successful operation in #aije at     

,notodden1  ,norway4    ,professor      
,birkeland has thus accomplished what   
many investigators in  various parts of 
the world have been striving after for  
years4 ,the  significance of his        
accomplishment consists in the fact that
 he has  demonstrated the possibility of
 making nitrogen combine with oxygen in 
large quantities and at a relatively low
 expense4 ,the mere fact of the         
combination1 as a laboratory            
possibility1 had been demonstrated in an
  elder generation by ,cavendish1 and   
more recently by such workers as  ,sir  
,william ,crookes1 and ,lord ,rayleigh  
in ,england and ,professors ,w4         
,mutjmaan and ,h4 ,hofer in ,germany4   
,moreover1 the experiments of ,messrs4  
,bradley and ,lovejoy1 conducted on a   
commercial scale at ,niagara ,falls1    
had seemed to give promise of a complete
 solution of the problem2  had1 indeed1 
produced a nitrogen compound from the   
air in commercial  quantity1 but not1   
unfortunately1 at a cost that made      

competition  with the ,chili nitrate    
possible4 ,equally unsuccessful in      
solving this  important part of the     
problem had been the experiments1       
conducted on a  large scale1 of         
,professors ,kowalski and ,moscicki1 at 
,freiburg4    ,all these experimenters  
had adopted the same agent as the means 
of1 so  to say1 forcing the             
transformation--namely1 electricity4    
,the ,american  investigators employed a
 current of ten thousand volts2 the     
,german  workers carried the current to 
fifty thousand volts4 ,the flame of the 
electric arc thus produced ignited the  
nitrogen with which it came in  contact 
readily enough2 but the difficulty was  
that it came in contact  with so little4
 ,despite ingenious arrangements of     
multiple poles1 the  burning-surface of 
the multiple arc remained so small in   
proportion to  the expenditure of energy
 that the cost of the operation far     
exceeded  the commercial value of the   
product4 ,such1 at least1 must be the   

inference from the fact that the        
establishments in question did not      
attain commercial success4    ,the      
peculiarity of ,professor ,birkeland's  
method is based upon the  curious fact  
that when the electric arc is made to   
pass through a  magnetic field1 its line
 of flame spreads out into a large      
disk--like  a flaming sun4 ,the sheet of
 flame thus produced represents no      
greater  expenditure of energy than the 
lightning flash of light that the same  
current would produce outside the       
magnetic field2 but it obviously  adds  
enormously to the arc-light surface that
 comes in contact with  the air1 and    
hence in like proportion to the amount  
of nitrogen that  will be ignited4 ,in  
point of fact1 this burning of nitrogen 
takes  place so rapidly in laboratory   
experiments as to vitiate the air of    
the room very quickly4 ,in the          
commercial operation1 with powerful     
electro-magnets and a current of five   
thousand volts1 operating1 of  course1  

in closed chambers1 the ratio between   
energy expended and  result achieved is 
highly satisfactory from a business     
standpoint1  and will doubtless become  
still more so as the apparatus is       
further  perfected4    ,to the casual   
reader1 unaccustomed to chemical        
methods1 there may seem  a puzzle in the
 explanation just outlined4 ,he may be  
disposed to say1  ,you speak of the     
nitrogen as being ignited and burned2   
but if it is  burned and thus consumed1 
how can it be of service8 ,such a       
thought  is natural enough to one who   
thinks of burning as applied to ordinary
  fuel1 which seems to disappear when it
 is burned4 ,but1 of course1 even  the  
tyro in chemistry knows that the fuel   
has not really disappeared  except in a 
very crude visual sense2 it has merely  
changed its form4  ,in the main its     
solid substance has become gaseous1 but 
every atom of  it is still just as real1
 if not quite so tangible1 as before2   
and the  chemist could1 under proper    

conditions1 collect and weigh and       
measure  the transformed gases1 and even
 retransform them into solids4    ,in   
the case of the atmospheric nitrogen1 as
 in the case of ordinary  fuel1 a       
burning consists essentially in the     
union of nitrogen atoms  with atoms of  
oxygen4 ,the province of the electric   
current is to  produce the high         
temperature at which alone such union   
will take place4  ,the portion of       
nitrogen that has been thus burned is   
still gaseous1  but is no longer in the 
state of pure nitrogen2 its atoms are   
united  with oxygen atoms to form       
nitrous oxide gas4 ,this gas1 mixed with
 the  atmosphere in which it has been   
generated1 may now be passed through a  
reservoir of water1 and the new gas     
combines with a portion of water  to    
form nitric acid1 each molecule of which
 is a compound of one atom  of hydrogen1
 one atom of nitrogen1 and three atoms  
of oxygen2 and  nitric acid1 as everyone
 knows1 is a very active substance1 as  

marked  in its eagerness to unite with  
other substances as pure nitrogen is in 
its aloofness4    ,in the commercial    
nitrogen-plant at ,notodden1 the        
transformed nitrogen  compound is       
brought into contact with a solution of 
milk of lime1  with the resulting       
formation of nitrate of lime 7calcium   
nitrate71  a substance identical in     
composition--except that it is of       
greater  purity--with the product of the
 nitrate beds of ,chili4 ,stored in     
closed  cans as a milky fluid1 the      
transformed atmosphere is now ready for 
the  market4 ,a certain amount of it    
will be used in other manufactories for 
the production of various nitrogenous   
chemicals2 but the bulk of it  will be  
shipped to agricultural districts to be 
spread over the soil as  fertilizer1 and
 in due course to be absorbed into the  
tissues of plants  to form the food of  
animals and man4      ,,another ,,method
 ,,of ,,nitrogen ,,fixation    ,just at 
the time when the ,scandinavian         

experimenters were solving  the problem 
of securing nitrogen from the air1 other
 experimenters  in ,italy1 operating    
along totally different lines1 reached  
the same  important result4 ,the process
 employed by these investigators is     
known  as the ,frank and ,caro process1 
and it bids fair to rival the ,norwegian
  method as a commercial enterprise4    
,the process is described as  follows by
 an engineering correspondent of the    
,london ,times in the  ,engineering     
,supplement of that periodical for      
,january #bb1 #aijh3    ,this process is
 based upon the absorption of nitrogen  
by calcium  carbide1 when this gas1 in  
the pure form1 is passed over the       
carbide  heated to a temperature of     
#a1ajj degrees centigrade in retorts of 
special form and design4 ,the calcium   
carbide required as raw material  for   
the cyanamide manufacture is produced in
 the usual manner by  heating lime and  
coke to a temperature of #b1ejj degrees 
centigrade in  electric furnaces of the 

resistance type4    ,the ,european      
patent rights of the ,frank and ,caro   
process have  been purchased by the     
,societa ,generale per la ,cianamide of 
,rome1  and the various subsidiary      
companies promoting the manufacture in  
,italy1 ,france1 ,switzerland1 ,norway1 
and elsewhere1 are working under        
arrangement with the parent company as  
regards sharing of profits4    ,the     
first large installation of a plant for 
carrying out this process  was erected  
at ,piano d',orta1 in ,central ,italy1  
and was put into  operation in          
,december1 #aije4 ,the power for this   
factory is developed  by an independent 
company1 and is obtained by taking water
 from the  river ,pescara and leading it
 to a point above the generating station
  at ,tramonti4 ,a head of #ij feet1    
equivalent to #h1djj horse-power1 is    
here made available for the industries  
of the district4 ,the power of  the     
cyanamide factory is transmitted a      
distance of #f-a_/d miles at #f1jjj     

volts4 ,an aluminum and chemical works  
are also dependent upon the same  power 
station4    ,the ,piano d',orta works   
contains six furnaces for the           
manufacture of  cyanamide1 each furnace 
containing five retorts for absorption  
of the  nitrogen by the carbide4 ,a     
retort is capable of working off three  
charges of #ajj kilograms 7#bbj pounds7 
of carbide per day of #bd hours1  the   
weight of the charge increasing to #abe 
kilograms by the nitrogen  absorbed4    
,the present carbide consumption of the 
,piano d',orta factory  is1 therefore1  
at the rate of about #c1jjj tons per    
annum1 and the  output of calcium       
cyanamide is about #c1gej tons per      
annum4 ,the company  controlling the    
manufacture at ,piano d',orta is named  
the ,societa  ,italiana per la          
,fabbricazione di ,prodotti ,azotati4   
,extensions of  the factory at this     
place to a capacity of #aj1jjj tons per 
annum are  already in progress4 ,another
 company is also planning the erection  

of similar works at ,fiume and at       
,sebenico1 on the eastern borders  of   
the ,adriatic ,sea4 ,the additional     
electric power required will be         
obtained by carrying out the second     
portion of the power development  scheme
 on the river ,pescara4 ,a fall of #bce 
feet1 equivalent to #bb1jjj             
horse-power1 is available at the new    
power station1 which is being  erected  
at ,piano d',orta4    ,after stating    
that companies to operate the ,frank and
 ,caro process have  been organized in  
,france1 in ,switzerland1 in ,germany1  
in ,england1 and  in ,america1--the     
last-named plant being at ,muscle       
,shoals1 ,tennessee  ,river1 in         
,northern ,alabama--the writer          
continues3    ,these facts prove that   
the manufacture of the new nitrogenous  
manure  will soon be carried on in all  
the more important countries on  both   
sides of the ,atlantic4 ,if the         
financial results come up to the        
promoter's expectations the industry in 

five years' time will have  become one  
of considerable magnitude4    ,a        
modification of the original process of 
some importance has been  suggested by  
,polzeniusz4 ,this chemist has found    
that the addition of  fluorspar         
7,ca,f#b7 to the carbide reduces the    
temperature required  for the absorption
 process by #djj degrees centigrade1    
while it also  produces a less          
deliquescent finished material4    ,as  
regards cost of manufacture1 no very    
reliable figures are yet  available1 but
 the companies promoting the new        
manufacture are  regulating their sale  
prices by those of the two rival        
artificial  manures--ammonium sulphate  
and nitrate of soda4 ,calcium cyanamide 
is  now being sold in ,germany at #as4  
to #as4 #f;d4 7#be to #cg cents7 per    
unit  of combined nitrogen cheaper than 
ammonium sulphate1 and #cs4 to #cs4     
#f;d4  7#ge to #hg cents7 per unit      
cheaper than nitrate of soda4 ,whether  
the  manufacture will prove remunerative

 at this price of about #aj #ajs4       
7#ajb4ej7 per ton remains to be seen4   
,it is evident that1 as the raw         
material of the cyanamide manufacture   
7calcium carbide7 costs at least  #h    
7#dj7 per ton to produce under the most 
favorable conditions1 the  margin of    
profit will not be large1 and that very 
efficient management  will be required  
to earn fair dividends on the capital   
sunk in the new  industry4    ,it must  
be noted1 however1 that the processes   
are new and are  doubtless capable of   
improvement as experience is gained in  
working  them2 while1 on the other hand1
 the competition of the two rival       
artificial manures is likely to diminish
 as the years pass on4    ,the new      
industry is1 therefore1 likely to be a  
permanent addition to  the list of      
electro-metallurgical processes4 ,but   
for the present its  success can only be
 expected in centres of very cheap      
water-power1 as1  for instance1 in those
 localities where the electric          

horse-power year  can be generated and  
transmitted to the cyanamide works at an
 inclusive  cost of #b 7#aj7 or under4  
,,electrical ,,energy ,,and ,,high      
,,temperatures    ,it will be observed  
that the active instrumentality by which
 the  industrial feats thus far outlined
 have been accomplished1 is that  weird 
conveyer of energy known as electricity4
 ,in the case of the  aluminum          
manufacture1 electricity operated       
according to the strange  process of    
electrolysis1 in virtue of which certain
 atoms of matter  move to one pole of a 
battery while other atoms move to the   
opposite  pole1 thus effecting a        
separation--the result being1 in the    
case in  question1 the deposit of pure  
aluminum at the negative pole4 ,in the  
case of the nitrogen factories1 however1
 the manner of operation of  the        
electric current is quite different4    
,electricity1 as such1 is not  really   
concerned in the matter2 the efficiency 
of the current depends  solely upon the 

production of heat4 ,for example1 any   
other agency  that brought the          
atmosphere to a corresponding           
temperature would be  equally           
efficacious in igniting the nitrogen4   
,but in actual practice1  for this      
particular purpose1 no other known means
 of producing high  temperatures could  
at all compete with the electric arc4   
,there are numerous other operations    
involving the employment of high        
temperatures in which electricity is    
equally preeminent4 ,it is feasible     
with the electric arc to attain a       
temperature of about #c1fjj degrees     
centigrade--and even this might be      
exceeded were it not that carbon1  of   
which the electrodes are composed1      
volatilizes at that temperature4        
,meantime1 the highest attainable       
temperature with ordinary fuels in  the 
blast furnace is only about #a1hjj      
degrees2 and the oxy-hydrogen  flame is 
only about two hundred degrees higher4  
,a mixture of oxygen and  acetylene1    

however1 burns at a temperature almost  
equaling that of the  electric arc2 and 
this flame1 manipulated with the aid of 
a blowpipe1  offers a useful means of   
applying a high temperature locally1 for
 such  processes as the welding of      
metals4 ,the very highest temperatures  
yet  reached in laboratory or workshop1 
however1 are due to the use of          
explosive mixtures4 ,thus a mixture of  
the metal aluminum granulated1  and     
oxide of iron1 when ignited by a        
fulminating powder1 readjusts its  atoms
 to form oxide of aluminum and pure     
iron1 and does this with such  fervor   
that a temperature of about three       
thousand degrees is reached1  the       
resulting iron being not merely melted  
but brought almost to the  boiling      
point4 ,practical advantage is taken of 
this reaction for the  repair of broken 
implements of iron or steel1 the making 
of continuous  rails for trolleys1 and  
the like4    ,this reaction of aluminum 
and iron does not1 to be sure1 give a   

higher  temperature than the electric   
arc2 but this culminating feat has been 
achieved1 in laboratory experiments1    
through the explosion of cordite  in    
closed steel chambers2 the experimenters
 being the ,englishmen ,sir  ,andrew    
,noble and ,sir ,f4 ,abel4 ,it is       
difficult to estimate accurately  the   
degree of heat and pressure attained in 
these experiments2 but it  is believed  
that the temperature approximated #e1jjj
 degrees centigrade1  while the pressure
 represented the almost inconceivable   
push of ninety  tons to the square inch4
    ,it may be of interest to explain   
that cordite is a form of smokeless     
powder composed of gun cotton1          
nitroglycerine1 and mineral jelly4 ,no  
doubt the extreme heat produced by its  
explosion is associated with  the       
suddenness of the reaction2             
corresponding to the efficiency as a    
propellant that has led to the adoption 
of this powder for use in the  small    
arms of the ,british ,army4 ,no         

commercial use has yet been made  of    
cordite as a mere producer of heat2 but 
there is an interesting  suggestion of  
possible future uses in the fact that   
crystals of diamond  have been found in 
the residue of the explosion            
chamber--microscopic  in size1 to be    
sure1 but veritable diamonds in         
miniature4 ,sir  ,william ,crookes has  
suggested that1 could the reaction be   
prolonged  sufficiently1 there is little
 doubt that the artificial formation of 
diamonds would soon pass from the       
microscopic stage to a scale more       
likely to satisfy the requirements of   
science1 if not those of personal       
adornment4      ,,other ,,industrial    
,,problems ,,of ,,to-,,day ,,and        
,,to-,,morrow    ,in attempting to      
suggest the importance of science in its
 relation  to modern industries1 ,i have
 thought it better to cite three or     
four illustrative cases in some detail  
rather than to attempt a  comprehensive 
summary of the almost numberless lines  

of commercial  activity that have a     
similar origin and dependence4    ,to   
attempt a full list of these would be   
virtually to give a catalogue  of       
mechanical industries4 ,it may be well1 
however1 to point out a few  familiar   
instances1 in order to emphasize the    
economic importance of  the subject2 and
 to suggest a few of the lines along    
which present-day  investigators are    
seeking further conquests4    ,very     
briefly1 then1 consider how the         
application of scientific  knowledge has
 changed the aspect of the productive   
industries4 ,thanks  to science1 farming
 is no longer a haphazard trade4 ,the   
up-to-date  farmer knows the chemical   
constitution of the soil2 understands   
what  constituents are needed by        
particular crops and what fertilizing   
methods to employ to keep his land from 
deteriorating4 ,he knows how  to select 
good seed according to the teaching of  
heredity2 how to  combat fungoid and    
insect pests by chemical means2 how to  

meet the  encroachments of the army of  
weeds4 ,in the orchard1 he can tell by  
the  appearance of leaf and bark whether
 the soil needs more of nitrogen1  of   
potash1 or of humus2 he uses sprays as a
 surgeon uses antiseptics2  he          
introduces friendly insects to prey on  
insect pests2 he irrigates  or          
surface-tills or grows cover crops in   
accordance with a good  understanding of
 the laws of capillarity as applied to  
water in the  earth's crust4 ,in        
barnyard and dairy he applies a         
knowledge of the  chemistry of foods in 
his treatment of flock and herd2 he     
ventilates  his stables that the stock  
may have an adequate supply of oxygen2  
he  milks his cows with a mechanical    
apparatus1 extracts the cream with a    
centrifugal separator1 and churns by    
steam or by electric power4    ,in the  
affairs of manufacturer and transporter 
of commodities1 methods  are no less    
revolutionary4 ,steam power and electric
 dynamo everywhere  hold sway2 trolley  

and electric light and telephone have   
found their  way to the most distant    
hamlet2 electricians and experimental   
chemists  are searching for new methods 
in the factories2 artificial stone is   
competing with the product of the       
quarries2 artificial dyes have  sounded 
the doom of the madder and indigo       
industries4    ,and yet it requires no  
great gift of prophecy to see that what 
has been  accomplished is only an       
earnest of what is to come in the not   
distant  future4 ,in every direction    
eager experimenters are on the track of 
new  discoveries4 ,any day a chance     
observation may open new and important  
fields of exploration1 just as ,hall's  
observation about the power  of cryolite
 to absorb aluminum pointed the way to  
the new aluminum  industry2 and as      
,birkeland's chance observation of the  
electric arc in  a magnetic field       
unlocked the secret of the unresponsive 
nitrogen4 ,it  will probably not be     
long1 for example1 before a way will be 

found to  produce electric light without
 heat--in imitation of the wonderful    
lamp  of the glow-worm4    ,then in due 
course we must learn to use fuel without
 the appalling  waste that at present   
seems unavoidable4 ,a modern            
steam-engine makes  available only five 
to ten per cent4 of the energy that the 
burning  fuel gives out as heat--the    
rest is dissipated without serving man  
the  slightest useful purpose4          
,moreover1 the new studies in           
radio-activity  have taught us that     
every molecule of matter locks up among 
its  whirling atoms and corpuscles a    
store of energy compared with which  the
 energy of heat is but a bagatelle4 ,it 
is estimated that a little  pea-sized   
fragment of radium has energy enough in 
store--could we  but learn to use it--to
 drive the largest steamship across the 
ocean--taking the place of hundreds of  
tons of coal as now employed4  ,the     
mechanics of the future must learn how  
to unlock this treasury of  the         

molecule2 how to get at these atomic and
 corpuscular forces1 the  very existence
 of which was unknown to science until  
yesterday4 ,the  generation that has    
learned that secret will look back upon 
the fuel  problems of our day somewhat  
as we regard the flint and steel and the
  open fire of the barbarian4    ,if    
problems of energy offer such alluring  
possibilities as this1  problems of     
matter are even more inspiring4 ,the new
 synthetic chemistry  sets no bounds to 
its ambitions4 ,it has succeeded in     
manufacturing  madder1 indigo1 and a    
multitude of minor compounds4 ,it hopes 
some day  to manufacture rubber1 starch1
 sugar--even albumen itself1 the very   
basis of life4 ,rubber is a relatively  
simple compound of hydrogen and  carbon2
 starch and sugar are composed of       
hydrogen1 carbon1 and oxygen2  albumen  
has the same constituents1 plus         
nitrogen4 ,the raw materials  for       
building up these substances lie        
everywhere about us in abundance4  ,a   

lump of coal1 a glass of water1 and a   
whiff of atmosphere contain  all the    
nutritive elements1 could we properly   
mix them1 of a loaf of  bread or a      
beefsteak4 ,and science will never rest 
content until it has  learned how to    
make the combination4 ,it is a long road
 to travel1 even  from the relatively   
advanced standpoint of to-day2 but      
sooner or later  science will surely    
travel it4    ,and then--who can        
imagine1 who dare predict1 the social   
and economic  revolution that must      
follow8 ,our social and business life   
to-day  differs more widely from that of
 our grandfathers than theirs differed  
from the life of the ,egyptian and      
,babylonian of three thousand years     
ago2 but this gap is as ditch to caon   
compared with the gap that  separates us
 from the life of that generation of our
 descendants which  shall have learned  
the secret of making food-stuffs from   
inorganic  matter in the laboratory and 
factory4 ,it is a long road to travel1  

,i  repeat2 but modern science travels  
swiftly and with many short-cuts1  and  
it may reach this goal more quickly than
 any conservative dreamer  of to-day    
would dare to predict4    ,all speed to 
the ambitious voyager6                  
,,appendix    ,,reference ,,list ,,and  
,,notes      ,,chapter ,i    ,,man ,,and
 ,,nature    ,for a general discussion  
of primitive conditions of labor and    
prehistoric man's civilization1 it will 
be of interest in connection  with this 
chapter to consult volume ,i41 chapter  
,i41 which deals with  prehistoric      
science4 ,the appendix notes on that    
chapter 7vol4 ,i41  pp4 #cjb1 #cjc7     
refer to some books which may be        
consulted for fuller  information along 
the same lines4      ,,chapter ,,ii     
,,how ,,work ,,is ,,done    7p4 #ca74   
,for study of ,archimedes1 giving a     
detailed account of his  discoveries1   
see vol4 ,i41 p4 #aif seq4 ,it will be  
of interest also to  review1 in         
connection with this chapter1 the story 

of the growth of  knowledge of mechanics
 in the time of ,galileo1 ,descartes1   
and ,newton as  told in the chapters    
entitled ,galileo and the ,new ,physics1
 vol4 ,,ii4  7p4 #ic seq471 and ,the    
,success of ,galileo in ,physical       
,science1 vol4  ,,ii41 p4 #bjd seq4     
,,chapter ,,iii    ,,the ,,animal       
,,machine    ,for further insight into  
the activities of the animal machine1   
the  reader may refer to various        
chapters on the progress of physiology  
and  anatomy in earlier volumes4 ,the   
following references will guide to the  
accounts of the successive advances from
 the earliest time3    ,vol4 ,i41 pp4   
#aid1 #aie describe briefly the earlier 
anatomical studies  of the ,alexandrian 
physicians1 ,herophilus and             
,erasistratus2 and pp4  #bhb1 #bhc1     
outline the studies of the famous       
physician1 ,galen4    ,vol4 ,,ii41 ,from
 ,paracelsus to ,harvey1 in particular1 
p4 #afc seq42  and chapters ,,iv4 7p4   
#agc seq47 and ,v4 7p4 #bjb seq47       

dealing with  the progress of anatomy   
and physiology in the eighteenth and    
nineteenth  centuries respectively4 ,the
 chapter on ,experimental ,psychology   
7p4  #bde seq47 may also be consulted4  
,vol4 ,v41 chapter ,v41 dealing with the
 ,marine ,biological ,laboratory  at    
,naples 7p4 #aac seq47 and chapter      
,,vi41 ,ernst ,haeckel and the  ,new    
,zoology 7p4 #add seq47 present other   
aspects of physiological  problems4     
,,chapter ,,iv    ,,the ,,work ,,of     
,,air ,,and ,,water    ,on page #fc     
reference is made to the work of the old
 ,greeks1 ,archimedes  and ,ctesibius4  
,an account of ,archimedes' discovery of
 the laws of  buoyancy of solids and    
liquids will be found in vol4 ,i41 p4   
#bjh4    7p4 #fd74 ,the machines of     
,ctesibius and ,hero4 ,see vol4 ,i41 p4 
#bdb  seq41 for a full account of these 
mechanisms4    7p4 #fe74 ,toricelli1 the
 pupil of ,galileo1 and his discovery of
  atmospheric pressure4 ,for a fuller   
account of his discovery and what  came 

of it see vol4 ,,ii41 p4 #abj seq4      
7p4 #ff74 ,boyle's experiments on       
atmospheric pressure4 ,see vol4 ,,ii41  
p4  #bjd seq4    7p4 #ff74 ,mariotte and
 ,von ,guericke4 ,see vol4 ,,ii41 p4    
#baj seq4    7p4 #ga74 ,roman mills4 ,a 
scholarly discussion of the subject of  
,roman  mills1 based on a comprehensive 
study of the references in classical    
literature1 is given in ,beckmann's     
,history of ,inventions1 ,london1       
#ahdf4    7p4 #gc74 ,recent advances in 
water wheels4 ,as stated in the text1   
the  quotation is from an article on    
,motive ,power ,appliances1 by ,mr4     
,edward ,h4 ,sanborn1 in the ,twelfth   
,census ,report of the ,united ,states4 
,,chapter ,v    ,,captive ,,molecules2  
,,the ,,story ,,of ,,the                
,,steam-,,engine    7p4 #hb74 ,the      
experiments of ,hero of ,alexandria4    
,for a full account of  the experiments 
see vol4 ,i41 pp4 #bdi1 #bej4    7p4    
#hd74 ,the ,marquis of ,worcester's     
steam engine4 ,the original account     

appeared1 as stated1 in the ,marquis of 
,worcester's ,century of  ,inventions1  
published in #affc4    7p4 #ib74        
,newcomen's engine4 ,as stated in the   
text1 the account of  ,newcomen's engine
 is quoted from the report of the       
,department of  ,science and ,arts of   
the ,south ,kensington ,museum1 now     
officially known  as the ,victoria and  
,albert ,museum4    7pp4 #ajg-aji74     
,james ,watt4 ,the characterization of  
,watt here given is  taken from an      
article in an early edition of the      
,edinburgh ,encyclopdia  published about
 the year #ahae4      ,,chapter ,,vi    
,,the ,,master ,,worker    7p4 #aab74   
,high-pressure steam4 ,the work referred
 to is ,leupold's  ,theatrum            
,machinarum1 #agbe4    7p4 #abb74       
,rotary ,engines4 ,the quotation is from
 the report of the  ,victoria and       
,albert ,museum above cited4    7pp4    
#abg1 #abh74 ,turbine engines4 ,the     
quotation is from an anonymous  article 
in the ,london ,times1 ,august #ad1     

#aijg4    7pp4 #abi1 #acj74 ,turbine    
engines4 ,the quotation is from an      
article on  ,motive ,power ,appliances  
in the ,twelfth ,census ,report of the  
,united  ,states1 vol4 ,x41 part ,,iv41 
by ,mr4 ,edward ,h4 ,sanborn4           
,,chapter ,,vii    ,,gas ,,and ,,oil    
,,engines    7pp4 #ace1 #acf1 #acg74    
,gas engines4 ,quoted from the report of
 the  ,victoria and ,albert ,museum     
above cited4    7pp4 #ada-add74 ,gas    
engines and steam engines in the ,united
 ,states4  ,quoted from the report of   
the ,special ,agents of the ,twelfth    
,census of  the ,united ,states1 #aijb4 
7pp4 #adf1 #adg74 ,the ,svea heater4    
,from an article by ,mr4 ,g4 ,emil      
,hesse  in ,the ,american ,inventor for 
,april #ae1 #aije4      ,,chapter ,,viii
    ,,the ,,smallest ,,workers    ,in   
connection with this chapter the reader 
will do well to review  various earlier 
portions of the work outlining the      
general history of  the growth of       
knowledge of electricity and magnetism4 

,for example3    ,vol4 ,,ii41 p4 #aaa   
seq41 for an account of ,william        
,gilbert's study  of magnetism2 pp4     
#bac1 #bae describing first electrical  
machine2 and  chapter ,,xiv41 ,the      
,progress of ,electricity from ,gilbert 
and ,von  ,guericke to ,franklin1 p4    
#bei seq4    ,vol4 ,,iii41 chapter      
,,vii41 ,the ,modern ,development of    
,electricity and  ,magnetism1 p4 #bbi   
seq4    ,vol4 ,v41 p4 #ib seq41 the     
section on ,prof4 ,j4 ,j4 ,thompson and 
the  nature of electricity4    ,other   
chapters that may be advantageously     
reviewed in connection with  the present
 one are the following3    ,vol4 ,,iii41
 chapter ,,vi41 ,modern ,theories of    
,heat and ,light1 p4 #bjf  seq42 chapter
 ,,viii41 ,the ,conservation of ,energy1
 p4 #bec seq42 and  chapter ,,ix41 ,the 
,ether and ,ponderable ,matter1 p4 #bhc 
seq4      ,,chapter ,,ix    ,,man',s    
,,newest ,,co-,,laborer3 ,,the ,,dynamo 
,the references just given for chapter  
,,viii4 apply equally here4    ,the     

experiments of ,oersted and ,faraday are
 detailed in vol4 ,,iii41 p4  #bcf seq4 
,,chapter ,x    ,,niagara ,,in ,,harness
    ,same references as for chapters    
,,viii4 and ,,ix4      ,,chapter ,,xi   
,,the ,,banishment ,,of ,,night    7p4  
#bba74 ,davy and the electric light4    
,the quotation here given is  reproduced
 from vol4 ,,iii41 pp4 #bcd1 #bce4 ,the 
very great importance  and general      
interest of the subject seem to justify 
the repetition1  descriptive of this    
first electric light4 ,davy's original  
paper was  given at the ,royal          
,institution in #ahaj4    7p4 #bcg74    
,peter ,cooper ,hewitt--,inventor1 by   
,ray ,stannard ,baker1 in  ,mc,clure's  
,magazine1 ,june1 #aijc1 p4 #agb4    ,in
 connection with the problem of color of
 the light emitted by ,mr4  ,hewitt's   
mercury-vapor tube1 the chapter on      
,newton and the ,composition  of ,light 
7vol4 ,,ii41 p4 #bbe seq47 may be       
consulted4 ,also ,modern  ,theories of  
,heat and ,light1 vol4 ,,iii41 p4 #bjf  

seq4      ,,chapter ,,xii    ,,the      
,,mineral ,,depths    ,the chapter on   
,the ,origin and ,development of ,modern
 ,geology1 vol4  ,,iii41 p4 #aaf seq41  
may be read in connection with the      
allied subjects  here treated4    ,in   
preparing the section on the use of     
electricity in mining1 the  article by  
,thomas ,commerford ,martin1 entitled   
,electricity in ,mining1  in the ,united
 ,states ,census ,report of #aije1 has  
been freely drawn  upon4 ,the quotations
 on pp4 #bfb1 #bff1 #bfh1 and #bgj are  
from that source4      ,,chapter ,,xiii 
,,the ,,age ,,of ,,steel    ,see note   
under chapter ,,xii4      ,,chapter     
,,xiv    ,,some ,,recent ,,triumphs ,,of
 ,,applied ,,science    ,in connection  
with various portions of this chapter   
the reader will  find much that is of   
interest in the story of chemical       
development in  general as detailed in  
volume ,,iii41 pp4 #c-gb inclusive4     
,also various chapters on electricity as
 outlined under chapter ,,vii4  above4  

7p4 #caj74 ,nitrogen from the air4 ,the 
quotation is from the ,engineering      
,supplement of the ,london ,times1      
,january #bb1 #aijh4                    
,,transcriber',s ,,notes      ,italic   
text is denoted by underscores4    ,the 
oe ligature has been expanded to 'oe'4  
,subscripts in chemical formulas are    
denoted by normal numbers2      for     
example ,ca,c#b4      ,obvious          
typographical and punctuation errors    
have been corrected    after careful    
comparison with other occurrences within
 the text    and consultation of        
external sources4      ,except for those
 changes noted below1 inconsistent or   
archaic    spelling of a word or        
word-pair within the text has been      
retained4    ,for example3 horseshoe    
horse-shoe2 superheated super-heated2   
intrusted2 incased4      p iii4         
',friction1 p4 #ce' changed to          
',friction1 p4 #ci'4    p iii4          
'muscular action1 p4 #de' changed to    
'444 action1 p4 #di'4    p iv4          

'wind-mill' changed to 'windmill'4    p 
iv4     ',ctesibus' changed to          
',ctesibius'4    p #ic4     'was done   
is' changed to 'was done in'4    p #aad 
7,illustration caption74  ',trevethick' 
changed to ',trevithick'4    p #abb4    
'drlving' changed to 'driving'4    p    
#ahj 7,illustration caption74  'pull    
pieces' left unchanged 7probably        
meant to be 'pole pieces'74    p #aia4  
',horsehoe' changed to ',horseshoe'4    
p #bfd4    ',lige' changed to ',lige'4  
p #bii4    'repellant' changed to       
'repellent'4