,a ,,history ,,of ,,science  ,,by       
,,henry ,,smith ,,williams1 ,m4,d41     
,,ll4,d4  ,,assisted ,,by ,,edward ,h4  
,,williams1 ,m4,d4  ,,in ,,five         
,,volumes  ,,volume ,,ii4    ,,contents 
,,book ,,ii     ,,chapter ,i4 ,,science 
,,in ,,the ,,dark ,,age     ,,chapter   
,,ii4 ,,mediaeval ,,science ,,among     
,,the ,,arabians     ,,chapter ,,iii4   
,,mediaeval ,,science ,,in ,,the ,,west 
,,chapter ,,iv4 ,,the ,,new             
,,cosmology--,,copernicus ,,to ,,kepler 
,,and ,,galileo     ,,chapter ,v4       
,,galileo ,,and ,,the ,,new ,,physics   
,,chapter ,,vi4 ,,two                   
,,pseudo-,,sciences--,,alchemy ,,and    
,,astrology     ,,chapter ,,vii4 ,,from 
,,paracelsus ,,to ,,harvey     ,,chapter
 ,,viii4 ,,medicine ,,in ,,the          
,,sixteenth ,,and ,,seventeenth         
,,centuries     ,,chapter ,,ix4         
,,philosopher-,,scientists ,,and ,,new  
,,institutions ,,of    ,,learning       
,,chapter ,x4 ,,the ,,successors ,,of   
,,galileo ,,in ,,physical ,,science     

,,chapter ,,xi4 ,,newton ,,and ,,the    
,,composition ,,of ,,light     ,,chapter
 ,,xii4 ,,newton ,,and ,,the ,,law ,,of 
,,gravitation     ,,chapter ,,xiii4     
,,instruments ,,of ,,precision ,,in     
,,the ,,age ,,of ,,newton     ,,chapter 
,,xiv4 ,,progress ,,in ,,electricity    
,,from ,,gilbert ,,and ,,von            
,,guericke ,,to ,,franklin     ,,chapter
 ,,xv4 ,,natural ,,history ,,to ,,the   
,,time ,,of ,,linnaeus     ,,appendix   
,a ,,history ,,of ,,science     ,,book  
,,ii4 ,,the ,,beginnings ,,of ,,modern  
,,science  ,the studies of the present  
book cover the progress of science from 
the close of the ,roman period in the   
fifth century ,a4,d4 to about the middle
 of the eighteenth century4 ,in tracing 
the course of events through so long a  
period1 a difficulty becomes prominent  
which everywhere besets the historian in
 less degree--a difficulty due to the   
conflict between the strictly           
chronological and the topical method of 
treatment4 ,we must hold as closely as  

possible to the actual sequence of      
events1 since1 as already pointed out1  
one discovery leads on to another4 ,but1
 on the other hand1 progressive steps   
are taken contemporaneously in the      
various fields of science1 and if we    
were to attempt to introduce these in   
strict chronological order we should    
lose all sense of topical continuity4   
,our method has been to adopt a         
compromise1 following the course of a   
single science in each great epoch to a 
convenient stopping-point1 and then     
turning back to bring forward the story 
of another science4 ,thus1 for example1 
we tell the story of ,copernicus and    
,galileo1 bringing the record of        
cosmical and mechanical progress down to
 about the middle of the seventeenth    
century1 before turning back to take up 
the physiological progress of the       
fifteenth and sixteenth centuries4 ,once
 the latter stream is entered1 however1 
we follow it without interruption to the
 time of ,harvey and his contemporaries 

in the middle of the seventeenth        
century1 where we leave it to return to 
the field of mechanics as exploited by  
the successors of ,galileo1 who were    
also the predecessors and contemporaries
 of ,newton4  ,in general1 it will aid  
the reader to recall that1 so far as    
possible1 we hold always to the same    
sequences of topical treatment of       
contemporary events2 as a rule we treat 
first the cosmical1 then the physical1  
then the biological sciences4 ,the same 
order of treatment will be held to in   
succeeding volumes4  ,several of the    
very greatest of scientific             
generalizations are developed in the    
period covered by the present book3 for 
example1 the ,copernican theory of the  
solar system1 the true doctrine of      
planetary motions1 the laws of motion1  
the theory of the circulation of the    
blood1 and the ,newtonian theory of     
gravitation4 ,the labors of the         
investigators of the early decades of   
the eighteenth century1 terminating with

 ,franklin's discovery of the nature of 
lightning and with the ,linnaean        
classification of plants and animals1   
bring us to the close of our second     
great epoch2 or1 to put it otherwise1 to
 the threshold of the modern period4    
,i4 ,,science ,,in ,,the ,,dark ,,age   
,an obvious distinction between the     
classical and mediaeval epochs may be   
found in the fact that the former       
produced1 whereas the latter failed to  
produce1 a few great thinkers in each   
generation who were imbued with that    
scepticism which is the foundation of   
the investigating spirit2 who thought   
for themselves and supplied more or less
 rational explanations of observed      
phenomena4 ,could we eliminate the work 
of some score or so of classical        
observers and thinkers1 the classical   
epoch would seem as much a dark age as  
does the epoch that succeeded it4  ,but 
immediately we are met with the         
question3 ,why do no great original     
investigators appear during all these   

later centuries8 ,we have already       
offered a part explanation in the fact  
that the borders of civilization1 where 
racial mingling naturally took place1   
were peopled with semi-barbarians4 ,but 
we must not forget that in the centres  
of civilization all along there were    
many men of powerful intellect4 ,indeed1
 it would violate the principle of      
historical continuity to suppose that   
there was any sudden change in the level
 of mentality of the ,roman world at the
 close of the classical period4 ,we must
 assume1 then1 that the direction in    
which the great minds turned was for    
some reason changed4 ,newton is said to 
have alleged that he made his           
discoveries by intending his mind in a  
certain direction continuously4 ,it is  
probable that the same explanation may  
be given of almost every great          
scientific discovery4 ,anaxagoras could 
not have thought out the theory of the  
moon's phases2 ,aristarchus could not   
have found out the true mechanism of the

 solar system2 ,eratosthenes could not  
have developed his plan for measuring   
the earth1 had not each of these        
investigators intended his mind         
persistently towards the problems in    
question4  ,nor can we doubt that men   
lived in every generation of the dark   
age who were capable of creative thought
 in the field of science1 bad they      
chosen similarly to intend their minds  
in the right direction4 ,the difficulty 
was that they did not so choose4 ,their 
minds had a quite different bent4 ,they 
were under the spell of different       
ideals2 all their mental efforts were   
directed into different channels4 ,what 
these different channels were cannot be 
in doubt--they were the channels of     
oriental ecclesiasticism4 ,one          
all-significant fact speaks volumes     
here4 ,it is the fact that1 as          
,professor ,robinson7#a7 points out1    
from the time of ,boethius 7died #ebd or
 #ebe ,a4,d47 to that of ,dante         
7#abfe-acba ,a4,d47 there was not a     

single writer of renown in western      
,europe who was not a professional      
churchman4 ,all the learning of the     
time1 then1 centred in the priesthood4  
,we know that the same condition of     
things pertained in ,egypt1 when science
 became static there4 ,but1             
contrariwise1 we have seen that in      
,greece and early ,rome the scientific  
workers were largely physicians or      
professional teachers2 there was        
scarcely a professional theologian among
 them4  ,similarly1 as we shall see in  
the ,arabic world1 where alone there was
 progress in the mediaeval epoch1 the   
learned men were1 for the most part1    
physicians4 ,now the meaning of this    
must be self-evident4 ,the physician    
naturally intends his mind towards the  
practicalities4 ,his professional       
studies tend to make him an investigator
 of the operations of nature4 ,he is    
usually a sceptic1 with a spontaneous   
interest in practical science4 ,but the 
theologian intends his mind away from   

practicalities and towards mysticism4   
,he is a professional believer in the   
supernatural2 he discounts the value of 
merely natural phenomena4 ,his whole    
attitude of mind is unscientific2 the   
fundamental tenets of his faith are     
based on alleged occurrences which      
inductive science cannot admit--namely1 
miracles4 ,and so the minds intended    
towards the supernatural achieved only  
the hazy mysticism of mediaeval thought4
 ,instead of investigating natural laws1
 they paid heed 7as1 for example1       
,thomas ,aquinas does in his ,summa     
,theologia7 to the acts of angels1 the  
speaking of angels1 the subordination of
 angels1 the deeds of guardian angels1  
and the like4 ,they disputed such       
important questions as1 ,how many angels
 can stand upon the point of a needle8  
,they argued pro and con as to whether  
,christ were coeval with ,god1 or       
whether he had been merely created in   
the beginning1 perhaps ages before the  
creation of the world4 ,how could it be 

expected that science should flourish   
when the greatest minds of the age could
 concern themselves with problems such  
as these8  ,despite our preconceptions  
or prejudices1 there can be but one     
answer to that question4 ,oriental      
superstition cast its blight upon the   
fair field of science1 whatever         
compensation it may or may not have     
brought in other fields4 ,but we must be
 on our guard lest we overestimate or   
incorrectly estimate this influence4    
,posterity1 in glancing backward1 is    
always prone to stamp any given age of  
the past with one idea1 and to desire to
 characterize it with a single phrase2  
whereas in reality all ages are         
diversified1 and any generalization     
regarding an epoch is sure to do that   
epoch something less or something more  
than justice4 ,we may be sure1 then1    
that the ideal of ecclesiasticism is not
 solely responsible for the scientific  
stasis of the dark age4 ,indeed1 there  
was another influence of a totally      

different character that is too patent  
to be overlooked--the influence1 namely1
 of the economic condition of western   
,europe during this period4 ,as ,i have 
elsewhere pointed out17#b7 ,italy1 the  
centre of western civilization1 was at  
this time impoverished1 and hence could 
not provide the monetary stimulus so    
essential to artistic and scientific no 
less than to material progress4 ,there  
were no patrons of science and          
literature such as the ,ptolemies of    
that elder ,alexandrian day4 ,there were
 no great libraries2 no colleges to     
supply opportunities and afford stimuli 
to the rising generation4 ,worst of all1
 it became increasingly difficult to    
secure books4  ,this phase of the       
subject is often overlooked4 ,yet a     
moment's consideration will show its    
importance4 ,how should we fare to-day  
if no new scientific books were being   
produced1 and if the records of former  
generations were destroyed8 ,that is    
what actually happened in ,europe during

 the ,middle ,ages4 ,at an earlier day  
books were made and distributed much    
more abundantly than is sometimes       
supposed4 ,bookmaking had1 indeed1 been 
an important profession in ,rome1 the   
actual makers of books being slaves who 
worked under the direction of a         
publisher4 ,it was through the efforts  
of these workers that the classical     
works in ,greek and ,latin were         
multiplied and disseminated4            
,unfortunately the climate of ,europe   
does not conduce to the indefinite      
preservation of a book2 hence very few  
remnants of classical works have come   
down to us in the original from a remote
 period4 ,the rare exceptions are       
certain papyrus fragments1 found in     
,egypt1 some of which are ,greek        
manuscripts dating from the third       
century ,b4,c4 ,even from these sources 
the output is meagre2 and the only other
 repository of classical books is a     
single room in the buried city of       
,herculaneum1 which contained several   

hundred manuscripts1 mostly in a charred
 condition1 a considerable number of    
which1 however1 have been unrolled and  
found more or less legible4 ,this       
library in the buried city was chiefly  
made up of philosophical works1 some of 
which were quite unknown to the modern  
world until discovered there4  ,but this
 find1 interesting as it was from an    
archaeological stand-point1 had no very 
important bearing on our knowledge of   
the literature of antiquity4 ,our chief 
dependence for our knowledge of that    
literature must still be placed in such 
copies of books as were made in the     
successive generations4 ,comparatively  
few of the extant manuscripts are older 
than the tenth century of our era4 ,it  
requires but a momentary consideration  
of the conditions under which ancient   
books were produced to realize how slow 
and difficult the process was before the
 invention of printing4 ,the taste of   
the book-buying public demanded a       
clearly written text1 and in the ,middle

 ,ages it became customary to produce a 
richly ornamented text as well4 ,the    
script employed being the prototype of  
the modern printed text1 it will be     
obvious that a scribe could produce but 
a few pages at best in a day4 ,a large  
work would therefore require the labor  
of a scribe for many months or even for 
several years4 ,we may assume1 then1    
that it would be a very flourishing     
publisher who could produce a hundred   
volumes all told per annum2 and probably
 there were not many publishers at any  
given time1 even in the period of       
,rome's greatest glory1 who had anything
 like this output4  ,as there was a     
large number of authors in every        
generation of the classical period1 it  
follows that most of these authors must 
have been obliged to content themselves 
with editions numbering very few copies2
 and it goes without saying that the    
greater number of books were never      
reproduced in what might be called a    
second edition4 ,even books that        

retained their popularity for several   
generations would presently fail to     
arouse sufficient interest to be copied2
 and in due course such works would pass
 out of existence altogether4 ,doubtless
 many hundreds of books were thus lost  
before the close of the classical       
period1 the names of their authors being
 quite forgotten1 or preserved only     
through a chance reference2 and of      
course the work of elimination went on  
much more rapidly during the ,middle    
,ages1 when the interest in classical   
literature sank to so low an ebb in the 
,west4 ,such collections of references  
and quotations as the ,greek ,anthology 
and the famous anthologies of ,stobaeus 
and ,athanasius and ,eusebius give us   
glimpses of a host of writers--more than
 seven hundred are quoted by            
,stobaeus--a very large proportion of   
whom are quite unknown except through   
these brief excerpts from their lost    
works4  ,quite naturally the scientific 
works suffered at least as largely as   

any others in an age given over to      
ecclesiastical dreamings4 ,yet in some  
regards there is matter for surprise as 
to the works preserved4 ,thus1 as we    
have seen1 the very extensive works of  
,aristotle on natural history1 and the  
equally extensive natural history of    
,pliny1 which were preserved throughout 
this period1 and are still extant1 make 
up relatively bulky volumes4 ,these     
works seem to have interested the monks 
of the ,middle ,ages1 while many much   
more important scientific books were    
allowed to perish4 ,a considerable bulk 
of scientific literature was also       
preserved through the curious channels  
of ,arabic and ,armenian translations4  
,reference has already been made to the 
,almagest of ,ptolemy1 which1 as we have
 seen1 was translated into ,arabic1 and 
which was at a later day brought by the 
,arabs into western ,europe and 7at the 
instance of ,frederick ,,ii of ,sicily7 
translated out of their language into   
mediaeval ,latin4  ,it remains to       

inquire1 however1 through what channels 
the ,greek works reached the ,arabs     
themselves4 ,to gain an answer to this  
question we must follow the stream of   
history from its ,roman course eastward 
to the new seat of the ,roman empire in 
,byzantium4 ,here civilization centred  
from about the fifth century ,a4,d41 and
 here the ,european came in contact with
 the civilization of the ,syrians1 the  
,persians1 the ,armenians1 and finally  
of the ,arabs4 ,the ,byzantines         
themselves1 unlike the inhabitants of   
western ,europe1 did not ignore the     
literature of old ,greece2 the ,greek   
language became the regular speech of   
the ,byzantine people1 and their writers
 made a strenuous effort to perpetuate  
the idiom and style of the classical    
period4 ,naturally they also made       
transcriptions of the classical authors1
 and thus a great mass of literature was
 preserved1 while the corresponding     
works were quite forgotten in western   
,europe4  ,meantime many of these works 

were translated into ,syriac1 ,armenian1
 and ,persian1 and when later on the    
,byzantine civilization degenerated1    
many works that were no longer to be had
 in the ,greek originals continued to be
 widely circulated in ,syriac1 ,persian1
 ,armenian1 and1 ultimately1 in ,arabic 
translations4 ,when the ,arabs started  
out in their conquests1 which carried   
them through ,egypt and along the       
southern coast of the ,mediterranean1   
until they finally invaded ,europe from 
the west by way of ,gibraltar1 they     
carried with them their translations of 
many a ,greek classical author1 who was 
introduced anew to the western world    
through this strange channel4  ,we are  
told1 for example1 that ,averrhoes1 the 
famous commentator of ,aristotle1 who   
lived in ,spain in the twelfth century1 
did not know a word of ,greek and was   
obliged to gain his knowledge of the    
master through a ,syriac translation2   
or1 as others alleged 7denying that he  
knew even ,syriac71 through an ,arabic  

version translated from the ,syriac4 ,we
 know1 too1 that the famous chronology  
of ,eusebius was preserved through an   
,armenian translation2 and reference has
 more than once been made to the ,arabic
 translation of ,ptolemy's great work1  
to which we still apply its ,arabic     
title of ,almagest4  ,the familiar story
 that when the ,arabs invaded ,egypt    
they burned the ,alexandrian library is 
now regarded as an invention of later   
times4 ,it seems much more probable that
 the library bad been largely scattered 
before the coming of the ,moslems4      
,indeed1 it has even been suggested that
 the ,christians of an earlier day      
removed the records of pagan thought4   
,be that as it may1 the famous          
,alexandrian library had disappeared    
long before the revival of interest in  
classical learning4 ,meanwhile1 as we   
have said1 the ,arabs1 far from         
destroying the western literature1 were 
its chief preservers4 ,partly at least  
because of their regard for the records 

of the creative work of earlier         
generations of alien peoples1 the ,arabs
 were enabled to outstrip their         
contemporaries4 ,for it cannot be in    
doubt that1 during that long stretch of 
time when the western world was ignoring
 science altogether or at most          
contenting itself with the casual       
reading of ,aristotle and ,pliny1 the   
,arabs had the unique distinction of    
attempting original investigations in   
science4 ,to them were due all important
 progressive steps which were made in   
any scientific field whatever for about 
a thousand years after the time of      
,ptolemy and ,galen4 ,the progress made 
even by the ,arabs during this long     
period seems meagre enough1 yet it has  
some significant features4 ,these will  
now demand our attention4     ,,ii4     
,,mediaeval ,,science ,,among ,,the     
,,arabians  ,the successors of ,mohammed
 showed themselves curiously receptive  
of the ideas of the western people whom 
they conquered4 ,they came in contact   

with the ,greeks in western ,asia and in
 ,egypt1 and1 as has been said1 became  
their virtual successors in carrying    
forward the torch of learning4 ,it must 
not be inferred1 however1 that the      
,arabian scholars1 as a class1 were     
comparable to their predecessors in     
creative genius4 ,on the contrary1 they 
retained much of the conservative       
oriental spirit4 ,they were under the   
spell of tradition1 and1 in the main1   
what they accepted from the ,greeks they
 regarded as almost final in its        
teaching4 ,there were1 however1 a few   
notable exceptions among their men of   
science1 and to these must be ascribed  
several discoveries of some importance4 
,the chief subjects that excited the    
interest and exercised the ingenuity of 
the ,arabian scholars were astronomy1   
mathematics1 and medicine4 ,the         
practical phases of all these subjects  
were given particular attention4 ,thus  
it is well known that our so-called     
,arabian numerals date from this period4

 ,the revolutionary effect of these     
characters1 as applied to practical     
mathematics1 can hardly be              
overestimated2 but it is generally      
considered1 and in fact was admitted by 
the ,arabs themselves1 that these       
numerals were really borrowed from the  
,hindoos1 with whom the ,arabs came in  
contact on the east4 ,certain of the    
,hindoo alphabets1 notably that of the  
,battaks of ,sumatra1 give us clews to  
the originals of the numerals4 ,it does 
not seem certain1 however1 that the     
,hindoos employed these characters      
according to the decimal system1 which  
is the prime element of their           
importance4 ,knowledge is not           
forthcoming as to just when or by whom  
such application was made4 ,if this was 
an ,arabic innovation1 it was perhaps   
the most important one with which that  
nation is to be credited4 ,another      
mathematical improvement was the        
introduction into trigonometry of the   
sine--the half-chord of the double      

arc--instead of the chord of the arc    
itself which the ,greek astronomers had 
employed4 ,this improvement was due to  
the famous ,albategnius1 whose work in  
other fields we shall examine in a      
moment4  ,another evidence of           
practicality was shown in the ,arabian  
method of attempting to advance upon    
,eratosthenes' measurement of the earth4
 ,instead of trusting to the measurement
 of angles1 the ,arabs decided to       
measure directly a degree of the earth's
 surface--or rather two degrees4        
,selecting a level plain in ,mesopotamia
 for the experiment1 one party of the   
surveyors progressed northward1 another 
party southward1 from a given point to  
the distance of one degree of arc1 as   
determined by astronomical observations4
 ,the result found was fifty-six miles  
for the northern degree1 and fifty-six  
and two-third miles for the southern4   
,unfortunately1 we do not know the      
precise length of the mile in question1 
and therefore cannot be assured as to   

the accuracy of the measurement4 ,it is 
interesting to note1 however1 that the  
two degrees were found of unequal       
lengths1 suggesting that the earth is   
not a perfect sphere--a suggestion the  
validity of which was not to be put to  
the test of conclusive measurements     
until about the close of the eighteenth 
century4 ,the ,arab measurement was made
 in the time of ,caliph ,abdallah       
al-,mamun1 the son of the famous        
,harun-al-,rashid4 ,both father and son 
were famous for their interest in       
science4 ,harun-al-,rashid was1 it will 
be recalled1 the friend of ,charlemagne4
 ,it is said that he sent that ruler1 as
 a token of friendship1 a marvellous    
clock which let fall a metal ball to    
mark the hours4 ,this mechanism1 which  
is alleged to have excited great wonder 
in the ,west1 furnishes yet another     
instance of ,arabian practicality4      
,perhaps the greatest of the ,arabian   
astronomers was ,mohammed ben ,jabir    
,albategnius1 or ,el-batani1 who was    

born at ,batan1 in ,mesopotamia1 about  
the year #hej ,a4,d41 and died in #ibi4 
,albategnius was a student of the       
,ptolemaic astronomy1 but he was also a 
practical observer4 ,he made the        
important discovery of the motion of the
 solar apogee4 ,that is to say1 he found
 that the position of the sun among the 
stars1 at the time of its greatest      
distance from the earth1 was not what it
 had been in the time of ,ptolemy4 ,the 
,greek astronomer placed the sun in     
longitude #fe degrees1 but ,albategnius 
found it in longitude #hb degrees1 a    
distance too great to be accounted for  
by inaccuracy of measurement4 ,the      
modern inference from this observation  
is that the solar system is moving      
through space2 but of course this       
inference could not well be drawn while 
the earth was regarded as the fixed     
centre of the universe4  ,in the        
eleventh century another ,arabian       
discoverer1 ,arzachel1 observing the sun
 to be less advanced than ,albategnius  

had found it1 inferred incorrectly that 
the sun had receded in the mean time4   
,the modern explanation of this         
observation is that the measurement of  
,albategnius was somewhat in error1     
since we know that the sun's motion is  
steadily progressive4 ,arzachel1        
however1 accepting the measurement of   
his predecessor1 drew the false         
inference of an oscillatory motion of   
the stars1 the idea of the motion of the
 solar system not being permissible4    
,this assumed phenomenon1 which really  
has no existence in point of fact1 was  
named the trepidation of the fixed      
stars1 and was for centuries accepted as
 an actual phenomenon4 ,arzachel        
explained this supposed phenomenon by   
assuming that the equinoctial points1 or
 the points of intersection of the      
equator and the ecliptic1 revolve in    
circles of eight degrees' radius4 ,the  
first points of ,aries and ,libra were  
supposed to describe the circumference  
of these circles in about eight hundred 

years4 ,all of which illustrates how a  
difficult and false explanation may take
 the place of a simple and correct one4 
,the observations of later generations  
have shown conclusively that the sun's  
shift of position is regularly          
progressive1 hence that there is no     
trepidation of the stars and no         
revolution of the equinoctial points4   
,if the ,arabs were wrong as regards    
this supposed motion of the fixed stars1
 they made at least one correct         
observation as to the inequality of     
motion of the moon4 ,two inequalities of
 the motion of this body were already   
known4 ,a third1 called the moon's      
variation1 was discovered by an ,arabian
 astronomer who lived at ,cairo and     
observed at ,bagdad in #ige1 and who    
bore the formidable name of ,mohammed   
,aboul ,wefaal-,bouzdjani4 ,the         
inequality of motion in question1 in    
virtue of which the moon moves quickest 
when she is at new or full1 and slowest 
at the first and third quarter1 was     

rediscovered by ,tycho ,brahe six       
centuries later2 a fact which in itself 
evidences the neglect of the ,arabian   
astronomer's discovery by his immediate 
successors4  ,in the ninth and tenth    
centuries the ,arabian city of ,cordova1
 in ,spain1 was another important centre
 of scientific influence4 ,there was a  
library of several hundred thousand     
volumes here1 and a college where       
mathematics and astronomy were taught4  
,granada1 ,toledo1 and ,salamanca were  
also important centres1 to which        
students flocked from western ,europe4  
,it was the proximity of these ,arabian 
centres that stimulated the scientific  
interests of ,alfonso ,x4 of ,castile1  
at whose instance the celebrated        
,alfonsine tables were constructed4 ,a  
familiar story records that ,alfonso1   
pondering the complications of the      
,ptolemaic cycles and epicycles1 was led
 to remark that1 had he been consulted  
at the time of creation1 he could have  
suggested a much better and simpler plan

 for the universe4 ,some centuries were 
to elapse before ,copernicus was to show
 that it was not the plan of the        
universe1 but man's interpretation of   
it1 that was at fault4  ,another royal  
personage who came under ,arabian       
influence was ,frederick ,,ii4 of       
,sicily--the ,wonder of the ,world1 as  
he was called by his contemporaries4    
,the ,almagest of ,ptolemy was          
translated into ,latin at his instance1 
being introduced to the ,western world  
through this curious channel4 ,at this  
time it became quite usual for the      
,italian and ,spanish scholars to       
understand ,arabic although they were   
totally ignorant of ,greek4  ,in the    
field of physical science one of the    
most important of the ,arabian          
scientists was ,alhazen4 ,his work1     
published about the year #aajj ,a4,d41  
had great celebrity throughout the      
mediaeval period4 ,the original         
investigations of ,alhazen had to do    
largely with optics4 ,he made particular

 studies of the eye itself1 and the     
names given by him to various parts of  
the eye1 as the vitreous humor1 the     
cornea1 and the retina1 are still       
retained by anatomists4 ,it is known    
that ,ptolemy had studied the refraction
 of light1 and that he1 in common with  
his immediate predecessors1 was aware   
that atmospheric refraction affects the 
apparent position of stars near the     
horizon4 ,alhazen carried forward these 
studies1 and was led through them to    
make the first recorded scientific      
estimate of the phenomena of twilight   
and of the height of the atmosphere4    
,the persistence of a glow in the       
atmosphere after the sun has disappeared
 beneath the horizon is so familiar a   
phenomenon that the ancient philosophers
 seem not to have thought of it as      
requiring an explanation4 ,yet a        
moment's consideration makes it clear   
that1 if light travels in straight lines
 and the rays of the sun were in no wise
 deflected1 the complete darkness of    

night should instantly succeed to day   
when the sun passes below the horizon4  
,that this sudden change does not occur1
 ,alhazen explained as due to the       
reflection of light by the earth's      
atmosphere4  ,alhazen appears to have   
conceived the atmosphere as a sharply   
defined layer1 and1 assuming that       
twilight continues only so long as rays 
of the sun reflected from the outer     
surface of this layer can reach the     
spectator at any given point1 he hit    
upon a means of measurement that seemed 
to solve the hitherto inscrutable       
problem as to the atmospheric depth4    
,like the measurements of ,aristarchus  
and ,eratosthenes1 this calculation of  
,alhazen is simple enough in theory4    
,its defect consists largely in the     
difficulty of fixing its terms with     
precision1 combined with the further    
fact that the rays of the sun1 in taking
 the slanting course through the earth's
 atmosphere1 are really deflected from a
 straight line in virtue of the         

constantly increasing density of the air
 near the earth's surface4 ,alhazen must
 have been aware of this latter fact1   
since it was known to the later         
,alexandrian astronomers1 but he takes  
no account of it in the present         
measurement4 ,the diagram will make the 
method of ,alhazen clear4  ,his         
important premises are two3 first1 the  
well-recognized fact that1 when light is
 reflected from any surface1 the angle  
of incidence is equal to the angle of   
reflection2 and1 second1 the much more  
doubtful observation that twilight      
continues until such time as the sun1   
according to a simple calculation1 is   
nineteen degrees below the horizon4     
,referring to the diagram1 let the inner
 circle represent the earth's surface1  
the outer circle the limits of the      
atmosphere1 ,c being the earth's centre1
 and ,,rr radii of the earth4 ,then the 
observer at the point ,a will continue  
to receive the reflected rays of the sun
 until that body reaches the point ,s1  

which is1 according to the hypothesis1  
nineteen degrees below the horizon line 
of the observer at ,a4 ,this horizon    
line1 being represented by ,,ah1 and the
 sun's ray by ,,sm1 the angle ,,hms is  
an angle of nineteen degrees4 ,the      
complementary angle ,,sma is1 obviously1
 an angle of 7#ahj-ai7 one hundred and  
sixty-one degrees4 ,but since ,m is the 
reflecting surface and the angle of     
incidence equals the angle of           
reflection1 the angle ,,amc is an angle 
of one-half of one hundred and sixty-one
 degrees1 or eighty degrees and thirty  
minutes4 ,now this angle ,,amc1 being   
known1 the right-angled triangle ,,mac  
is easily resolved1 since the side ,,ac 
of that triangle1 being the radius of   
the earth1 is a known dimension4        
,resolution of this triangle gives us   
the length of the hypotenuse ,,mc1 and  
the difference between this and the     
radius 7,,ac71 or ,,cd1 is obviously the
 height of the atmosphere 7h71 which was
 the measurement desired4 ,according to 

the calculation of ,alhazen1 this h1 or 
the height of the atmosphere1 represents
 from twenty to thirty miles4 ,the      
modern computation extends this to about
 fifty miles4 ,but1 considering the     
various ambiguities that necessarily    
attended the experiment1 the result was 
a remarkably close approximation to the 
truth4  ,turning from physics to        
chemistry1 we find as perhaps the       
greatest ,arabian name that of ,geber1  
who taught in the ,college of ,seville  
in the first half of the eighth century4
 ,the most important researches of this 
really remarkable experimenter had to do
 with the acids4 ,the ancient world had 
had no knowledge of any acid more       
powerful than acetic4 ,geber1 however1  
vastly increased the possibilities of   
chemical experiment by the discovery of 
sulphuric1 nitric1 and nitromuriatic    
acids4 ,he made use also of the         
processes of sublimation and filtration1
 and his works describe the water bath  
and the chemical oven4 ,among the       

important chemicals which he first      
differentiated is oxide of mercury1 and 
his studies of sulphur in its various   
compounds have peculiar interest4 ,in   
particular is this true of his          
observation that1 tinder certain        
conditions of oxidation1 the weight of a
 metal was lessened4  ,from the record  
of these studies in the fields of       
astronomy1 physics1 and chemistry1 we   
turn to a somewhat extended survey of   
the ,arabian advances in the field of   
medicine4   ,,arabian ,,medicine  ,the  
influence of ,arabian physicians rested 
chiefly upon their use of drugs rather  
than upon anatomical knowledge4 ,like   
the mediaeval ,christians1 they looked  
with horror on dissection of the human  
body2 yet there were always among them  
investigators who turned constantly to  
nature herself for hidden truths1 and   
were ready to uphold the superiority of 
actual observation to mere reading4     
,thus the physician ,abd el-,letif1     
while in ,egypt1 made careful studies of

 a mound of bones containing more than  
twenty thousand skeletons4 ,while       
examining these bones he discovered that
 the lower jaw consists of a single     
bone1 not of two1 as had been taught by 
,galen4 ,he also discovered several     
other important mistakes in ,galenic    
anatomy1 and was so impressed with his  
discoveries that he contemplated writing
 a work on anatomy which should correct 
the great classical authority's         
mistakes4  ,it was the ,arabs who       
invented the apothecary1 and their      
pharmacopoeia1 issued from the hospital 
at ,gondisapor1 and elaborated from time
 to time1 formed the basis for ,western 
pharmacopoeias4 ,just how many drugs    
originated with them1 and how many were 
borrowed from the ,hindoos1 ,jews1      
,syrians1 and ,persians1 cannot be      
determined4 ,it is certain1 however1    
that through them various new and useful
 drugs1 such as senna1 aconite1 rhubarb1
 camphor1 and mercury1 were handed down 
through the ,middle ,ages1 and that they

 are responsible for the introduction of
 alcohol in the field of therapeutics4  
,in mediaeval ,europe1 ,arabian science 
came to be regarded with superstitious  
awe1 and the works of certain ,arabian  
physicians were exalted to a position   
above all the ancient writers4 ,in      
modern times1 however1 there has been a 
reaction and a tendency to depreciation 
of their work4 ,by some they are held to
 be mere copyists or translators of     
,greek books1 and in no sense original  
investigators in medicine4 ,yet there   
can be little doubt that while the      
,arabians did copy and translate freely1
 they also originated and added         
considerably to medical knowledge4 ,it  
is certain that in the time when        
,christian monarchs in western ,europe  
were paying little attention to science 
or education1 the caliphs and vizirs    
were encouraging physicians and         
philosophers1 building schools1 and     
erecting libraries and hospitals4 ,they 
made at least a creditable effort to    

uphold and advance upon the scientific  
standards of an earlier age4  ,the first
 distinguished ,arabian physician was   
,harets ben ,kaladah1 who received his  
education in the ,nestonian school at   
,gondisapor1 about the beginning of the 
seventh century4 ,notwithstanding the   
fact that ,harets was a ,christian1 he  
was chosen by ,mohammed as his chief    
medical adviser1 and recommended as such
 to his successor1 the ,caliph ,abu     
,bekr4 ,thus1 at the very outset1 the   
science of medicine was divorced from   
religion among the ,arabians2 for if the
 prophet himself could employ the       
services of an unbeliever1 surely others
 might follow his example4 ,and that    
this example was followed is shown in   
the fact that many ,christian physicians
 were raised to honorable positions by  
succeeding generations of ,arabian      
monarchs4 ,this broad-minded view of    
medicine taken by the ,arabs undoubtedly
 assisted as much as any one single     
factor in upbuilding the science1 just  

as the narrow and superstitious view    
taken by ,western nations helped to     
destroy it4  ,the education of the      
,arabians made it natural for them to   
associate medicine with the natural     
sciences1 rather than with religion4 ,an
 ,arabian savant was supposed to be     
equally well educated in philosophy1    
jurisprudence1 theology1 mathematics1   
and medicine1 and to practise law1      
theology1 and medicine with equal skill 
upon occasion4 ,it is easy to           
understand1 therefore1 why these        
religious fanatics were willing to      
employ unbelieving physicians1 and their
 physicians themselves to turn to the   
scientific works of ,hippocrates and    
,galen for medical instruction1 rather  
than to religious works4 ,even ,mohammed
 himself professed some knowledge of    
medicine1 and often relied upon this    
knowledge in treating ailments rather   
than upon prayers or incantations4 ,he  
is said1 for example1 to have           
recommended and applied the cautery in  

the case of a friend who1 when suffering
 from angina1 had sought his aid4  ,the 
list of eminent ,arabian physicians is  
too long to be given here1 but some of  
them are of such importance in their    
influence upon later medicine that they 
cannot be entirely ignored4 ,one of the 
first of these was ,honain ben ,isaac   
7#hji-hgc ,a4,d471 a ,christian ,arab of
 ,bagdad4 ,he made translations of the  
works of ,hippocrates1 and practised the
 art along the lines indicated by his   
teachings and those of ,galen4 ,he is   
considered the greatest translator of   
the ninth century and one of the        
greatest philosophers of that period4   
,another great ,arabian physician1 whose
 work was just beginning as ,honain's   
was drawing to a close1 was ,rhazes     
7#hej-ibc ,a4,d471 who during his life  
was no less noted as a philosopher and  
musician than as a physician4 ,he       
continued the work of ,honain1 and      
advanced therapeutics by introducing    
more extensive use of chemical remedies1

 such as mercurial ointments1 sulphuric 
acid1 and aqua vitae4 ,he is also       
credited with being the first physician 
to describe small-pox and measles       
accurately4  ,while ,rhazes was still   
alive another ,arabian1 ,haly ,abbas    
7died about #iid71 was writing his      
famous encyclopaedia of medicine1 called
 ,the ,royal ,book4 ,but the names of   
all these great physicians have been    
considerably obscured by the reputation 
of ,avicenna 7#ihj-ajcg71 the ,arabian  
,prince of ,physicians1 the greatest    
name in ,arabic medicine1 and one of the
 most remarkable men in history4        
,leclerc says that he was perhaps never 
surpassed by any man in brilliancy of   
intellect and indefatigable activity4   
,his career was a most varied one4 ,he  
was at all times a boisterous reveller1 
but whether flaunting gayly among the   
guests of an emir or biding in some     
obscure apothecary cellar1 his work of  
philosophical writing was carried on    
steadily4 ,when a friendly emir was in  

power1 he taught and wrote and caroused 
at court2 but between times1 when some  
unfriendly ruler was supreme1 he was    
hiding away obscurely1 still pouring out
 his great mass of manuscripts4 ,in this
 way his entire life was spent4  ,by his
 extensive writings he revived and kept 
alive the best of the teachings of the  
,greek physicians1 adding to them such  
observations as he had made in anatomy1 
physiology1 and materia medica4 ,among  
his discoveries is that of the          
contagiousness of pulmonary             
tuberculosis4 ,his works for several    
centuries continued to be looked upon as
 the highest standard by physicians1 and
 he should undoubtedly be credited with 
having at least retarded the decline of 
mediaeval medicine4  ,but it was not the
 ,eastern ,arabs alone who were active  
in the field of medicine4 ,cordova1 the 
capital of the western caliphate1 became
 also a great centre of learning and    
produced several great physicians4 ,one 
of these1 ,albucasis 7died in #ajac     

,a4,d471 is credited with having        
published the first illustrated work on 
surgery1 this book being remarkable in  
still another way1 in that it was also  
the first book1 since classical times1  
written from the practical experience of
 the physician1 and not a mere          
compilation of ancient authors4 ,a      
century after ,albucasis came the great 
physician ,avenzoar 7#aaac-aaif71 with  
whom he divides about equally the       
medical honors of the western caliphate4
 ,among ,avenzoar's discoveries was that
 of the cause of itch--a little         
parasite1 so small that he is hardly    
visible4 ,the discovery of the cause of 
this common disease seems of minor      
importance now1 but it is of interest in
 medical history because1 had           
,avenzoar's discovery been remembered a 
hundred years ago1 itch struck in could 
hardly have been considered the cause of
 three-fourths of all diseases1 as it   
was by the famous ,hahnemann4  ,the     
illustrious pupil of ,avenzoar1         

,averrhoes1 who died in #aaih ,a4,d41   
was the last of the great ,arabian      
physicians who1 by rational conception  
of medicine1 attempted to stem the flood
 of superstition that was overwhelming  
medicine4 ,for a time he succeeded2 but 
at last the ,moslem theologians         
prevailed1 and he was degraded and      
banished to a town inhabited only by the
 despised ,jews4   ,,arabian ,,hospitals
  ,to early ,christians belong the      
credit of having established the first  
charitable institutions for caring for  
the sick2 but their efforts were soon   
eclipsed by both ,eastern and ,western  
,mohammedans4 ,as early as the eighth   
century the ,arabs had begun building   
hospitals1 but the flourishing time of  
hospital building seems to have begun   
early in the tenth century4 ,lady       
,seidel1 in #iah ,a4,d41 opened a       
hospital at ,bagdad1 endowed with an    
amount corresponding to about three     
hundred pounds sterling a month4 ,other 
similar hospitals were erected in the   

years immediately following1 and in #igg
 the ,emir ,adad-adaula established an  
enormous institution with a staff of    
twenty-four medical officers4 ,the great
 physician ,rhazes is said to have      
selected the site for one of these      
hospitals by hanging pieces of meat in  
various places about the city1 selecting
 the site near the place at which       
putrefaction was slowest in making its  
appearance4 ,by the middle of the       
twelfth century there were something    
like sixty medical institutions in      
,bagdad alone1 and these institutions   
were free to all patients and supported 
by official charity4  ,the ,emir        
,nureddin1 about the year #aafj1 founded
 a great hospital at ,damascus1 as a    
thank-offering for his victories over   
the ,crusaders4 ,this great institution 
completely overshadowed all the earlier 
,moslem hospitals in size and in the    
completeness of its equipment4 ,it was  
furnished with facilities for teaching1 
and was conducted for several centuries 

in a lavish manner1 regardless of       
expense4 ,but little over a century     
after its foundation the fame of its    
methods of treatment led to the         
establishment of a larger and still more
 luxurious institution--the ,mansuri    
hospital at ,cairo4 ,it seems that a    
certain sultan1 having been cured by    
medicines from the ,damascene hospital1 
determined to build one of his own at   
,cairo which should eclipse even the    
great ,damascene institution4  ,in a    
single year 7#abhc-abhd7 this hospital  
was begun and completed4 ,no efforts    
were spared in hurrying on the good     
work1 and no one was exempt from        
performing labor on the building if he  
chanced to pass one of the adjoining    
streets4 ,it was the order of the sultan
 that any person passing near could be  
impressed into the work1 and this order 
was carried out to the letter1 noblemen 
and beggars alike being forced to lend a
 hand4 ,very naturally1 the adjacent    
thoroughfares became unpopular and      

practically deserted1 but still the holy
 work progressed rapidly and was shortly
 completed4  ,this immense structure is 
said to have contained four courts1 each
 having a fountain in the centre2       
lecture-halls1 wards for isolating      
certain diseases1 and a department that 
corresponded to the modern hospital's   
out-patient department4 ,the yearly     
endowment amounted to something like the
 equivalent of one hundred and          
twenty-five thousand dollars4 ,a novel  
feature was a hall where musicians      
played day and night1 and another where 
story-tellers were employed1 so that    
persons troubled with insomnia were     
amused and melancholiacs cheered4 ,those
 of a religious turn of mind could      
listen to readings of the ,koran1       
conducted continuously by a staff of    
some fifty chaplains4 ,each patient on  
leaving the hospital received some gold 
pieces1 that he need not be obliged to  
attempt hard labor at once4  ,in        
considering the astonishing tales of    

these sumptuous ,arabian institutions1  
it should be borne in mind that our     
accounts of them are1 for the most part1
 from ,mohammedan sources4              
,nevertheless1 there can be little      
question that they were enormous        
institutions1 far surpassing any similar
 institutions in western ,europe4 ,the  
so-called hospitals in the ,west were1  
at this time1 branches of monasteries   
under supervision of the monks1 and did 
not compare favorably with the ,arabian 
hospitals4  ,but while the medical      
science of the ,mohammedans greatly     
overshadowed that of the ,christians    
during this period1 it did not          
completely obliterate it4 ,about the    
year #ajjj ,a4,d4 came into prominence  
the ,christian medical school at        
,salerno1 situated on the ,italian      
coast1 some thirty miles southeast of   
,naples4 ,just how long this school had 
been in existence1 or by whom it was    
founded1 cannot be determined1 but its  
period of greatest influence was the    

eleventh1 twelfth1 and thirteenth       
centuries4 ,the members of this school  
gradually adopted ,arabic medicine1     
making use of many drugs from the       
,arabic pharmacopoeia1 and this formed  
one of the stepping-stones to the       
introduction of ,arabian medicine all   
through western ,europe4  ,it was not   
the adoption of ,arabian medicines1     
however1 that has made the school at    
,salerno famous both in rhyme and prose1
 but rather the fact that women there   
practised the healing art4 ,greatest    
among them was ,trotula1 who lived in   
the eleventh century1 and whose learning
 is reputed to have equalled that of the
 greatest physicians of the day4 ,she is
 accredited with a work on ,diseases of 
,women1 still extant1 and many of her   
writings on general medical subjects    
were quoted through two succeeding      
centuries4 ,if we may judge from these  
writings1 she seemed to have had many   
excellent ideas as to the proper methods
 of treating diseases1 but it is        

difficult to determine just which of the
 writings credited to her are in reality
 hers4 ,indeed1 the uncertainty is even 
greater than this implies1 for1         
according to some writers1 ,trotula is  
merely the title of a book4 ,such an    
authority as ,malgaigne1 however1       
believed that such a woman existed1 and 
that the works accredited to her are    
authentic4 ,the truth of the matter may 
perhaps never be fully established1 but 
this at least is certain--the tradition 
in regard to ,trotula could never have  
arisen had not women held a far         
different position among the ,arabians  
of this period from that accorded them  
in contemporary ,christendom4     ,,iii4
 ,,mediaeval ,,science ,,in ,,the ,,west
  ,we have previously referred to the   
influence of the ,byzantine civilization
 in transmitting the learning of        
antiquity across the abysm of the dark  
age4 ,it must be admitted1 however1 that
 the importance of that civilization did
 not extend much beyond the task of the 

common carrier4 ,there were no great    
creative scientists in the later ,roman 
empire of the ,east any more than in the
 corresponding empire of the ,west4     
,there was1 however1 one field in which 
the ,byzantine made respectable progress
 and regarding which their efforts      
require a few words of special comment4 
,this was the field of medicine4  ,the  
,byzantines of this time could boast of 
two great medical men1 ,aetius of ,amida
 7about #ejb-ege ,a4,d47 and ,paul of   
,aegina 7about #fbj-fij74 ,the works of 
,aetius were of value largely because   
they recorded the teachings of many of  
his eminent predecessors1 but he was not
 entirely lacking in originality1 and   
was perhaps the first physician to      
mention diphtheria1 with an allusion to 
some observations of the paralysis of   
the palate which sometimes follows this 
disease4  ,paul of ,aegina1 who came    
from the ,alexandrian school about a    
century later1 was one of those         
remarkable men whose ideas are centuries

 ahead of their time4 ,this was         
particularly true of ,paul in regard to 
surgery1 and his attitude towards the   
supernatural in the causation and       
treatment of diseases4 ,he was          
essentially a surgeon1 being            
particularly familiar with military     
surgery1 and some of his descriptions of
 complicated and difficult operations   
have been little improved upon even in  
modern times4 ,in his books he describes
 such operations as the removal of      
foreign bodies from the nose1 ear1 and  
esophagus2 and he recognizes foreign    
growths such as polypi in the           
air-passages1 and gives the method of   
their removal4 ,such operations as      
tracheotomy1 tonsillotomy1 bronchotomy1 
staphylotomy1 etc41 were performed by   
him1 and he even advocated and described
 puncture of the abdominal cavity1      
giving careful directions as to the     
location in which such punctures should 
be made4 ,he advocated amputation of the
 breast for the cure of cancer1 and     

described extirpation of the uterus4    
,just how successful this last operation
 may have been as performed by him does 
not appear2 but he would hardly have    
recommended it if it had not been       
sometimes1 at least1 successful4 ,that  
he mentions it at all1 however1 is      
significant1 as this difficult operation
 is considered one of the great triumphs
 of modern surgery4  ,but ,paul of      
,aegina is a striking exception to the  
rule among ,byzantine surgeons1 and as  
he was their greatest1 so he was also   
their last important surgeon4 ,the      
energies of all ,byzantium were so      
expended in religious controversies that
 medicine1 like the other sciences1 was 
soon relegated to a place among the     
other superstitions1 and the influence  
of the ,byzantine school was presently  
replaced by that of the conquering      
,arabians4   ,,thirteenth-,,century     
,,medicine  ,the thirteenth century     
marks the beginning of a gradual change 
in medicine1 and a tendency to leave the

 time-worn rut of superstitious dogmas  
that so long retarded the progress of   
science4 ,it is thought that the great  
epidemics which raged during the ,middle
 ,ages acted powerfully in diverting the
 medical thought of the times into new  
and entirely different channels4 ,it    
will be remembered that the teachings of
 ,galen were handed through mediaeval   
times as the highest and best authority 
on the subject of all diseases4 ,when1  
however1 the great epidemics made their 
appearance1 the medical men appealed to 
the works of ,galen in vain for         
enlightenment1 as these works1 having   
been written several centuries before   
the time of the plagues1 naturally      
contained no information concerning     
them4 ,it was evident1 therefore1 that  
on this subject1 at least1 ,galen was   
not infallible2 and it would naturally  
follow that1 one fallible point having  
been revealed1 others would be sought   
for4 ,in other words1 scepticism in     
regard to accepted methods would be     

aroused1 and would lead naturally1 as   
such scepticism usually does1 to        
progress4 ,the devastating effects of   
these plagues1 despite prayers and      
incantations1 would arouse doubt in the 
minds of many as to the efficacy of     
superstitious rites and ceremonies in   
curing diseases4 ,they had seen         
thousands and tens of thousands of their
 fellow-beings swept away by these awful
 scourges4 ,they had seen the ravages of
 these epidemics continue for months or 
even years1 notwithstanding the fact    
that multitudes of ,god-fearing people  
prayed hourly that such ravages might be
 checked4 ,and they must have observed  
also that when even very simple rules of
 cleanliness and hygiene were followed  
there was a diminution in the ravages of
 the plague1 even without the aid of    
incantations4 ,such observations as     
these would have a tendency to awaken a 
suspicion in the minds of many of the   
physicians that disease was not a       
manifestation of the supernatural1 but a

 natural phenomenon1 to be treated by   
natural methods4  ,but1 be the causes   
what they may1 it is a fact that the    
thirteenth century marks a              
turning-point1 or the beginning of an   
attitude of mind which resulted in      
bringing medicine to a much more        
rational position4 ,among the           
thirteenth-century physicians1 two men  
are deserving of special mention4 ,these
 are ,arnald of ,villanova 7#abce-acab7 
and ,peter of ,abano 7#abej-acae74 ,both
 these men suffered persecution for     
expressing their belief in natural1 as  
against the supernatural1 causes of     
disease1 and at one time ,arnald was    
obliged to flee from ,barcelona for     
declaring that the bulls of popes were  
human works1 and that acts of charity   
were dearer to ,god than hecatombs4 ,he 
was also accused of alchemy4 ,fleeing   
from persecution1 he finally perished by
 shipwreck4  ,arnald was the first great
 representative of the school of        
,montpellier4 ,he devoted much time to  

the study of chemicals1 and was active  
in attempting to re-establish the       
teachings of ,hippocrates and ,galen4   
,he was one of the first of a long line 
of alchemists who1 for several          
succeeding centuries1 expended so much  
time and energy in attempting to find   
the elixir of life4 ,the ,arab discovery
 of alcohol first deluded him into the  
belief that the elixir had at last been 
found2 but later he discarded it and    
made extensive experiments with brandy1 
employing it in the treatment of certain
 diseases--the first record of the      
administration of this liquor as a      
medicine4 ,arnald also revived the      
search for some anaesthetic that would  
produce insensibility to pain in        
surgical operations4 ,this idea was not 
original with him1 for since very early 
times physicians had attempted to       
discover such an anaesthetic1 and even  
so early a writer as ,herodotus tells   
how the ,scythians1 by inhalation of the
 vapors of some kind of hemp1 produced  

complete insensibility4 ,it may have    
been these writings that stimulated     
,arnald to search for such an           
anaesthetic4 ,in a book usually credited
 to him1 medicines are named and methods
 of administration described which will 
make the patient insensible to pain1 so 
that he may be cut and feel nothing1 as 
though he were dead4 ,for this purpose a
 mixture of opium1 mandragora1 and      
henbane is to be used4 ,this mixture was
 held at the patient's nostrils much as 
ether and chloroform are administered by
 the modern surgeon4 ,the method was    
modified by ,hugo of ,lucca 7died in    
#abeb or #abfh71 who added certain other
 narcotics1 such as hemlock1 to the     
mixture1 and boiled a new sponge in this
 decoction4 ,after boiling for a certain
 time1 this sponge was dried1 and when  
wanted for use was dipped in hot water  
and applied to the nostrils4  ,just how 
frequently patients recovered from the  
administration of such a combination of 
powerful poisons does not appear1 but   

the percentage of deaths must have been 
very high1 as the practice was generally
 condemned4 ,insensibility could have   
been produced only by swallowing large  
quantities of the liquid1 which dripped 
into the nose and mouth when the sponge 
was applied1 and a lethal quantity might
 thus be swallowed4 ,the method was     
revived1 with various modifications1    
from time to time1 but as often fell    
into disuse4 ,as late as #aghb it was   
sometimes attempted1 and in that year   
the ,king of ,poland is said to have    
been completely anaesthetized and to    
have recovered1 after a painless        
amputation had been performed by the    
surgeons4  ,peter of ,abano was one of  
the first great men produced by the     
,university of ,padua4 ,his fate would  
have been even more tragic than that of 
the shipwrecked ,arnald had he not      
cheated the purifying fagots of the     
church by dying opportunely on the eve  
of his execution for heresy4 ,but if his
 spirit had cheated the fanatics1 his   

body could not1 and his bones were      
burned for his heresy4 ,he had dared to 
deny the existence of a devil1 and had  
suggested that the case of a patient who
 lay in a trance for three days might   
help to explain some miracles1 like the 
raising of ,lazarus4  ,his great work   
was ,conciliator ,differentiarum1 an    
attempt to reconcile physicians and     
philosophers4 ,but his researches were  
not confined to medicine1 for he seems  
to have had an inkling of the hitherto  
unknown fact that air possesses weight1 
and his calculation of the length of the
 year at three hundred and sixty-five   
days1 six hours1 and four minutes1 is   
exceptionally accurate for the age in   
which he lived4 ,he was probably the    
first of the ,western writers to teach  
that the brain is the source of the     
nerves1 and the heart the source of the 
vessels4 ,from this it is seen that he  
was groping in the direction of an      
explanation of the circulation of the   
blood1 as demonstrated by ,harvey three 

centuries later4  ,the work of ,arnald  
and ,peter of ,abano in reviving        
medicine was continued actively by      
,mondino 7#abgf-acbf7 of ,bologna1 the  
restorer of anatomy1 and by ,guy of     
,chauliac3 7born about #acjj71 the      
restorer of surgery4 ,all through the   
early ,middle ,ages dissections of human
 bodies had been forbidden1 and even    
dissection of the lower animals         
gradually fell into disrepute because   
physicians detected in such practices   
were sometimes accused of sorcery4      
,before the close of the thirteenth     
century1 however1 a reaction had begun1 
physicians were protected1 and          
dissections were occasionally sanctioned
 by the ruling monarch4 ,thus ,emperor  
,frederick ,h4 7#aaid-abej              
,a4,d47--whose services to science we   
have already had occasion to            
mention--ordered that at least one human
 body should be dissected by physicians 
in his kingdom every five years4 ,by the
 time of ,mondino dissections were      

becoming more frequent1 and he himself  
is known to have dissected and          
demonstrated several bodies4 ,his       
writings on anatomy have been called    
merely plagiarisms of ,galen1 but in all
 probability be made many discoveries   
independently1 and on the whole1 his    
work may be taken as more advanced than 
,galen's4 ,his description of the heart 
is particularly accurate1 and he seems  
to have come nearer to determining the  
course of the blood in its circulation  
than any of his predecessors4 ,in this  
quest he was greatly handicapped by the 
prevailing belief in the idea that      
blood-vessels must contain air as well  
as blood1 and this led him to assume    
that one of the cavities of the heart   
contained spirits1 or air4 ,it is       
probable1 however1 that his accurate    
observations1 so far as they went1 were 
helpful stepping-stones to ,harvey in   
his discovery of the circulation4  ,guy 
of ,chauliac1 whose innovations in      
surgery reestablished that science on a 

firm basis1 was not only one of the most
 cultured1 but also the most practical  
surgeon of his time4 ,he had great      
reverence for the works of ,galen1      
,albucasis1 and others of his noted     
predecessors2 but this reverence did not
 blind him to their mistakes nor prevent
 him from using rational methods of     
treatment far in advance of theirs4 ,his
 practicality is shown in some of his   
simple but useful inventions for the    
sick-room1 such as the device of a rope1
 suspended from the ceiling over the    
bed1 by which a patient may move himself
 about more easily2 and in some of his  
improvements in surgical dressings1 such
 as stiffening bandages by dipping them 
in the white of an egg so that they are 
held firmly4 ,he treated broken limbs in
 the suspended cradle still in use1 and 
introduced the method of making traction
 on a broken limb by means of a weight  
and pulley1 to prevent deformity through
 shortening of the member4 ,he was one  
of the first physicians to recognize the

 utility of spectacles1 and recommended 
them in cases not amenable to treatment 
with lotions and eye-waters4 ,in some of
 his surgical operations1 such as       
trephining for fracture of the skull1   
his technique has been little improved  
upon even in modern times4 ,in one of   
these operations he successfully removed
 a portion of a man's brain4   ,surgery 
was undoubtedly stimulated greatly at   
this period by the constant wars4 ,lay  
physicians1 as a class1 had been looked 
down upon during the ,dark ,ages2 but   
with the beginning of the return to     
rationalism1 the services of surgeons on
 the battle-field1 to remove missiles   
from wounds1 and to care for wounds and 
apply dressings1 came to be more fully  
appreciated4 ,in return for his labors  
the surgeon was thus afforded better    
opportunities for observing wounds and  
diseases1 which led naturally to a      
gradual improvement in surgical methods4
   ,,fifteenth-,,century ,,medicine     
,the thirteenth and fourteenth centuries

 had seen some slight advancement in the
 science of medicine2 at least1 certain 
surgeons and physicians1 if not the     
generality1 had made advances2 but it   
was not until the fifteenth century that
 the general revival of medical learning
 became assured4 ,in this movement1     
naturally1 the printing-press played an 
all-important part4 ,medical books1     
hitherto practically inaccessible to the
 great mass of physicians1 now became   
common1 and this output of reprints of  
,greek and ,arabic treatises revealed   
the fact that many of the supposed true 
copies were spurious4 ,these discoveries
 very naturally aroused all manner of   
doubt and criticism1 which in turn      
helped in the development of independent
 thought4  ,a certain manuscript of the 
great ,cornelius ,celsus1 the ,de       
,medicine1 which had been lost for many 
centuries1 was found in the church of   
,st4 ,ambrose1 at ,milan1 in #addc1 and 
was at once put into print4 ,the effect 
of the publication of this book1 which  

had lain in hiding for so many          
centuries1 was a revelation1 showing the
 medical profession how far most of     
their supposed true copies of ,celsus   
had drifted away from the original4 ,the
 indisputable authenticity of this      
manuscript1 discovered and vouched for  
by the man who shortly after became     
,pope ,nicholas ,v41 made its           
publication the more impressive4 ,the   
output in book form of other authorities
 followed rapidly1 and the manifest     
discrepancies between such teachers as  
,celsus1 ,hippocrates1 ,galen1 and      
,pliny heightened still more the growing
 spirit of criticism4  ,these doubts    
resulted in great controversies as to   
the proper treatment of certain         
diseases1 some physicians following     
,hippocrates1 others ,galen or ,celsus1 
still others the ,arabian masters4 ,one 
of the most bitter of these contests was
 over the question of revulsion1 and    
derivation--that is1 whether in cases of
 pleurisy treated by bleeding1 the      

venesection should be made at a point   
distant from the seat of the disease1 as
 held by the revulsionists1 or at a     
point nearer and on the same side of the
 body1 as practised by the              
derivationists4 ,that any great point   
for discussion could be raised in the   
fifteenth or sixteenth centuries on so  
simple a matter as it seems to-day shows
 how necessary to the progress of       
medicine was the discovery of the       
circulation of the blood made by ,harvey
 two centuries later4 ,after ,harvey's  
discovery no such discussion could have 
been possible1 because this discovery   
made it evident that as far as the      
general effect upon the circulation is  
concerned1 it made little difference    
whether the bleeding was done near a    
diseased part or remote from it4 ,but in
 the sixteenth century this question was
 the all-absorbing one among the        
doctors4 ,at one time the faculty of    
,paris condemned derivation2 but the    
supporters of this method carried the   

war still higher1 and ,emperor ,charles 
,v4 himself was appealed to4 ,he        
reversed the decision of the ,paris     
faculty1 and decided in favor of        
derivation4 ,his decision was further   
supported by ,pope ,clement ,,vii41     
although the discussion dragged on until
 cut short by ,harvey's discovery4  ,but
 a new form of injury now claimed the   
attention of the surgeons1 something    
that could be decided by neither ,greek 
nor ,arabian authors1 as the treatment  
of gun-shot wounds was1 for obvious     
reasons1 not given in their writings4   
,about this time1 also1 came the great  
epidemics1 the sweating sickness and    
scurvy2 and upon these subjects1 also1  
the ,greeks and ,arabians were silent4  
,john of ,vigo1 in his book1 the        
,practica ,copiosa1 published in #aead1 
and repeated in many editions1 became   
the standard authority on all these     
subjects1 and thus supplanted the works 
of the ancient writers4  ,according to  
,vigo1 gun-shot wounds differed from the

 wounds made by ordinary weapons--that  
is1 spear1 arrow1 sword1 or axe--in that
 the bullet1 being round1 bruised rather
 than cut its way through the tissues2  
it burned the flesh2 and1 worst of all1 
it poisoned it4 ,vigo laid especial     
stress upon treating this last          
condition1 recommending the use of the  
cautery or the oil of elder1 boiling    
hot4 ,it is little wonder that gun-shot 
wounds were so likely to prove fatal4   
,yet1 after all1 here was the germ of   
the idea of antisepsis4   ,,new         
,,beginnings ,,in ,,general ,,science   
,we have dwelt thus at length on the    
subject of medical science1 because it  
was chiefly in this field that progress 
was made in the ,western world during   
the mediaeval period1 and because these 
studies furnished the point of departure
 for the revival all along the line4 ,it
 will be understood1 however1 from what 
was stated in the preceding chapter1    
that the ,arabian influences in         
particular were to some extent making   

themselves felt along other lines4 ,the 
opportunity afforded a portion of the   
,western world--notably ,spain and      
,sicily--to gain access to the          
scientific ideas of antiquity through   
,arabic translations could not fail of  
influence4 ,of like character1 and      
perhaps even more pronounced in degree1 
was the influence wrought by the        
,byzantine refugees1 who1 when          
,constantinople began to be threatened  
by the ,turks1 migrated to the ,west in 
considerable numbers1 bringing with them
 a knowledge of ,greek literature and a 
large number of precious works which for
 centuries had been quite forgotten or  
absolutely ignored in ,italy4 ,now      
,western scholars began to take an      
interest in the ,greek language1 which  
had been utterly neglected since the    
beginning of the ,middle ,ages4         
,interesting stories are told of the    
efforts made by such men as ,cosmo de'  
,medici to gain possession of classical 
manuscripts4 ,the revival of learning   

thus brought about had its first        
permanent influence in the fields of    
literature and art1 but its effect on   
science could not be long delayed4      
,quite independently of the ,byzantine  
influence1 however1 the striving for    
better intellectual things had          
manifested itself in many ways before   
the close of the thirteenth century4 ,an
 illustration of this is found in the   
almost simultaneous development of      
centres of teaching1 which developed    
into the universities of ,italy1        
,france1 ,england1 and1 a little later1 
of ,germany4  ,the regular list of      
studies that came to be adopted         
everywhere comprised seven nominal      
branches1 divided into two groups--the  
so-called quadrivium1 comprising music1 
arithmetic1 geometry1 and astronomy2 and
 the trivium comprising grammar1        
rhetoric1 and logic4 ,the vagueness of  
implication of some of these branches   
gave opportunity to the teacher for the 
promulgation of almost any knowledge of 

which he might be possessed1 but there  
can be no doubt that1 in general1       
science had but meagre share in the     
curriculum4 ,in so far as it was given  
representation1 its chief field must    
have been ,ptolemaic astronomy4 ,the    
utter lack of scientific thought and    
scientific method is illustrated most   
vividly in the works of the greatest men
 of that period--such men as ,albertus  
,magnus1 ,thomas ,aquinas1 ,bonaventura1
 and the hosts of other scholastics of  
lesser rank4 ,yet the mental awakening  
implied in their efforts was sure to    
extend to other fields1 and in point of 
fact there was at least one contemporary
 of these great scholastics whose mind  
was intended towards scientific         
subjects1 and who produced writings     
strangely at variance in tone and in    
content with the others4 ,this          
anachronistic thinker was the ,english  
monk1 ,roger ,bacon4   ,,roger ,,bacon  
,bacon was born in #abad and died in    
#abib4 ,by some it is held that he was  

not appreciated in his own time because 
he was really a modern scientist living 
in an age two centuries before modern   
science or methods of modern scientific 
thinking were known4 ,such an estimate1 
however1 is a manifest exaggeration of  
the facts1 although there is probably a 
grain of truth in it withal4 ,his       
learning certainly brought him into     
contact with the great thinkers of the  
time1 and his writings caused him to be 
imprisoned by his fellow-churchmen at   
different times1 from which             
circumstances we may gather that he was 
advanced thinker1 even if not a modern  
scientist4  ,although ,bacon was at     
various times in durance1 or under      
surveillance1 and forbidden to write1 he
 was nevertheless a marvellously        
prolific writer1 as is shown by the     
numerous books and unpublished          
manuscripts of his still extant4 ,his   
master-production was the ,opus ,majus4 
,in ,part ,,iv4 of this work he attempts
 to show that all sciences rest         

ultimately on mathematics2 but ,part    
,v41 which treats of perspective1 is of 
particular interest to modern           
scientists1 because in this he discusses
 reflection and refraction1 and the     
properties of mirrors and lenses4 ,in   
this part1 also1 it is evident that he  
is making use of such ,arabian writers  
as ,alkindi and ,alhazen1 and this is of
 especial interest1 since it has been   
used by his detractors1 who accuse him  
of lack of originality1 to prove that   
his seeming inventions and discoveries  
were in reality adaptations of the ,arab
 scientists4 ,it is difficult to        
determine just how fully such criticisms
 are justified4 ,it is certain1 however1
 that in this part he describes the     
anatomy of the eye with great accuracy1 
and discusses mirrors and lenses4  ,the 
magnifying power of the segment of a    
glass sphere had been noted by ,alhazen1
 who had observed also that the         
magnification was increased by          
increasing the size of the segment used4

 ,bacon took up the discussion of the   
comparative advantages of segments1 and 
in this discussion seems to show that he
 understood how to trace the progress of
 the rays of light through a spherical  
transparent body1 and how to determine  
the place of the image4 ,he also        
described a method of constructing a    
telescope1 but it is by no means clear  
that he had ever actually constructed   
such an instrument4 ,it is also a mooted
 question as to whether his instructions
 as to the construction of such an      
instrument would have enabled any one to
 construct one4 ,the vagaries of the    
names of terms as he uses them allow    
such latitude in interpretation that    
modern scientists are not agreed as to  
the practicability of ,bacon's          
suggestions4 ,for example1 he constantly
 refers to force under such names as    
virtus1 species1 imago1 agentis1 and a  
score of other names1 and this naturally
 gives rise to the great differences in 
the interpretations of his writings1    

with corresponding differences in       
estimates of them4  ,the claim that     
,bacon originated the use of lenses1 in 
the form of spectacles1 cannot be       
proven4 ,smith has determined that as   
early as the opening years of the       
fourteenth century such lenses were in  
use1 but this proves nothing as regards 
,bacon's connection with their          
invention4 ,the knowledge of lenses     
seems to be very ancient1 if we may     
judge from the convex lens of rock      
crystal found by ,layard in his         
excavations at ,nimrud4 ,there is       
nothing to show1 however1 that the      
ancients ever thought of using them to  
correct defects of vision4 ,neither1    
apparently1 is it feasible to determine 
whether the idea of such an application 
originated with ,bacon4  ,another       
mechanical discovery about which there  
has been a great deal of discussion is  
,bacon's supposed invention of          
gunpowder4 ,it appears that in a certain
 passage of his work he describes the   

process of making a substance that is1  
in effect1 ordinary gunpowder2 but it is
 more than doubtful whether he          
understood the properties of the        
substance he describes4 ,it is fairly   
well established1 however1 that in      
,bacon's time gunpowder was known to the
 ,arabs1 so that it should not be       
surprising to find references made to it
 in ,bacon's work1 since there is reason
 to believe that he constantly consulted
 ,arabian writings4  ,the great merit of
 ,bacon's work1 however1 depends on the 
principles taught as regards experiment 
and the observation of nature1 rather   
than on any single invention4 ,he had   
the all-important idea of breaking with 
tradition4 ,he championed unfettered    
inquiry in every field of thought4 ,he  
had the instinct of a scientific        
worker--a rare instinct indeed in that  
age4 ,nor need we doubt that to the best
 of his opportunities he was himself an 
original investigator4   ,,leonardo ,,da
 ,,vinci  ,the relative infertility of  

,bacon's thought is shown by the fact   
that he founded no school and left no   
trace of discipleship4 ,the entire      
century after his death shows no single 
,european name that need claim the      
attention of the historian of science4  
,in the latter part of the fifteenth    
century1 however1 there is evidence of a
 renaissance of science no less than of 
art4 ,the ,german ,muller became famous 
under the latinized named of ,regio     
,montanus 7#adcg-adgb71 although his    
actual scientific attainments would     
appear to have been important only in   
comparison with the utter ignorance of  
his contemporaries4 ,the most           
distinguished worker of the new era was 
the famous ,italian ,leonardo da        
,vinci--a man who has been called by    
,hamerton the most universal genius that
 ever lived4 ,leonardo's position in the
 history of art is known to every one4  
,with that1 of course1 we have no       
present concern2 but it is worth our    
while to inquire at some length as to   

the famous painter's accomplishments as 
a scientist4  ,from a passage in the    
works of ,leonardo1 first brought to    
light by ,venturi17#a7 it would seem    
that the great painter anticipated      
,copernicus in determining the movement 
of the earth4 ,he made mathematical     
calculations to prove this1 and appears 
to have reached the definite conclusion 
that the earth does move--or what       
amounts to the same thing1 that the sun 
does not move4 ,muntz is authority for  
the statement that in one of his        
writings he declares1 ,il sole non si   
mouve--the sun does not move47#b7       
,among his inventions is a dynamometer  
for determining the traction power of   
machines and animals1 and his           
experiments with steam have led some of 
his enthusiastic partisans to claim for 
him priority to ,watt in the invention  
of the steam-engine4 ,in these          
experiments1 however1 ,leonardo seems to
 have advanced little beyond ,hero of   
,alexandria and his steam toy4 ,hero's  

steam-engine did nothing but rotate     
itself by virtue of escaping jets of    
steam forced from the bent tubes1 while 
,leonardo's steam-engine drove a ball   
weighing one talent over a distance of  
six stadia4 ,in a manuscript now in the 
library of the ,institut de ,france1 ,da
 ,vinci describes this engine minutely4 
,the action of this machine was due to  
the sudden conversion of small          
quantities of water into steam 7smoke1  
as he called it7 by coming suddenly in  
contact with a heated surface in a      
proper receptacle1 the rapidly formed   
steam acting as a propulsive force after
 the manner of an explosive4 ,it is     
really a steam-gun1 rather than a       
steam-engine1 and it is not unlikely    
that the study of the action of         
gunpowder may have suggested it to      
,leonardo4  ,it is believed that        
,leonardo is the true discoverer of the 
camera-obscura1 although the ,neapolitan
 philosopher1 ,giambattista ,porta1 who 
was not born until some twenty years    

after the death of ,leonardo1 is usually
 credited with first describing this    
device4 ,there is little doubt1 however1
 that ,da ,vinci understood the         
principle of this mechanism1 for he     
describes how such a camera can be made 
by cutting a small1 round hole through  
the shutter of a darkened room1 the     
reversed image of objects outside being 
shown on the opposite wall4  ,like other
 philosophers in all ages1 he had       
observed a great number of facts which  
he was unable to explain correctly4 ,but
 such accumulations of scientific       
observations are always interesting1 as 
showing how many centuries of           
observation frequently precede correct  
explanation4 ,he observed many facts    
about sounds1 among others that blows   
struck upon a bell produced sympathetic 
sounds in a bell of the same kind2 and  
that striking the string of a lute      
produced vibration in corresponding     
strings of lutes strung to the same     
pitch4 ,he knew1 also1 that sounds could

 be heard at a distance at sea by       
listening at one end of a tube1 the     
other end of which was placed in the    
water2 and that the same expedient      
worked successfully on land1 the end of 
the tube being placed against the       
ground4  ,the knowledge of this great   
number of unexplained facts is often    
interpreted by the admirers of ,da      
,vinci1 as showing an almost occult     
insight into science many centuries in  
advance of his time4 ,such              
interpretations1 however1 are illusive4 
,the observation1 for example1 that a   
tube placed against the ground enables  
one to hear movements on the earth at a 
distance1 is not in itself evidence of  
anything more than acute scientific     
observation1 as a similar method is in  
use among almost every race of savages1 
notably the ,american ,indians4 ,on the 
other hand1 one is inclined to give     
credence to almost any story of the     
breadth of knowledge of the man who came
 so near anticipating ,hutton1 ,lyell1  

and ,darwin in his interpretation of the
 geological records as he found them    
written on the rocks4  ,it is in this   
field of geology that ,leonardo is      
entitled to the greatest admiration by  
modern scientists4 ,he had observed the 
deposit of fossil shells in various     
strata of rocks1 even on the tops of    
mountains1 and he rejected once for all 
the theory that they had been deposited 
there by the ,deluge4 ,he rightly       
interpreted their presence as evidence  
that they had once been deposited at the
 bottom of the sea4 ,this process he    
assumed bad taken hundreds and thousands
 of centuries1 thus tacitly rejecting   
the biblical tradition as to the date of
 the creation4  ,notwithstanding the    
obvious interest that attaches to the   
investigations of ,leonardo1 it must be 
admitted that his work in science       
remained almost as infertile as that of 
his great precursor1 ,bacon4 ,the really
 stimulative work of this generation was
 done by a man of affairs1 who knew     

little of theoretical science except in 
one line1 but who pursued that one      
practical line until he achieved a      
wonderful result4 ,this man was         
,christopher ,columbus4 ,it is not      
necessary here to tell the trite story  
of his accomplishment4 ,suffice it that 
his practical demonstration of the      
rotundity of the earth is regarded by   
most modern writers as marking an epoch 
in history4 ,with the year of his voyage
 the epoch of the ,middle ,ages is      
usually regarded as coming to an end4   
,it must not be supposed that any very  
sudden change came over the aspect of   
scholarship of the time1 but the        
preliminaries of great things had been  
achieved1 and when ,columbus made his   
famous voyage in #adib1 the man was     
already alive who was to bring forward  
the first great vitalizing thought in   
the field of pure science that the      
,western world had originated for more  
than a thousand years4 ,this man bore   
the name of ,kopernik1 or in its        

familiar ,anglicized form1 ,copernicus4 
,his life work and that of his disciples
 will claim our attention in the        
succeeding chapter4     ,,iv4 ,,the     
,,new ,,cosmology--,,copernicus ,,to    
,,kepler ,,and ,,galileo  ,we have seen 
that the ,ptolemaic astronomy1 which was
 the accepted doctrine throughout the   
,middle ,ages1 taught that the earth is 
round4 ,doubtless there was a popular   
opinion current which regarded the earth
 as flat1 but it must be understood that
 this opinion had no champions among men
 of science during the ,middle ,ages4   
,when1 in the year #adib1 ,columbus     
sailed out to the west on his memorable 
voyage1 his expectation of reaching     
,india had full scientific warrant1     
however much it may have been scouted by
 certain ecclesiastics and by the       
average man of the period4              
,nevertheless1 we may well suppose that 
the successful voyage of ,columbus1 and 
the still more demonstrative one made   
about thirty years later by ,magellan1  

gave the theory of the earth's rotundity
 a certainty it could never previously  
have had4 ,alexandrian geographers had  
measured the size of the earth1 and had 
not hesitated to assert that by sailing 
westward one might reach ,india4 ,but   
there is a wide gap between theory and  
practice1 and it required the voyages of
 ,columbus and his successors to bridge 
that gap4  ,after the companions of     
,magellan completed the circumnavigation
 of the globe1 the general shape of our 
earth would1 obviously1 never again be  
called in question4 ,but demonstration  
of the sphericity of the earth had1 of  
course1 no direct bearing upon the      
question of the earth's position in the 
universe4 ,therefore the voyage of      
,magellan served to fortify1 rather than
 to dispute1 the ,ptolemaic theory4     
,according to that theory1 as we have   
seen1 the earth was supposed to lie     
immovable at the centre of the universe2
 the various heavenly bodies1 including 
the sun1 revolving about it in eccentric

 circles4 ,we have seen that several of 
the ancient ,greeks1 notably            
,aristarchus1 disputed this conception1 
declaring for the central position of   
the sun in the universe1 and the motion 
of the earth and other planets about    
that body4 ,but this revolutionary      
theory seemed so opposed to the ordinary
 observation that1 having been          
discountenanced by ,hipparchus and      
,ptolemy1 it did not find a single      
important champion for more than a      
thousand years after the time of the    
last great ,alexandrian astronomer4     
,the first man1 seemingly1 to hark back 
to the ,aristarchian conception in the  
new scientific era that was now dawning 
was the noted cardinal1 ,nikolaus of    
,cusa1 who lived in the first half of   
the fifteenth century1 and was          
distinguished as a philosophical writer 
and mathematician4 ,his ,de ,docta      
,ignorantia expressly propounds the     
doctrine of the earth's motion4 ,no one1
 however1 paid the slightest attention  

to his suggestion1 which1 therefore1    
merely serves to furnish us with another
 interesting illustration of the        
futility of propounding even a correct  
hypothesis before the time is ripe to   
receive it--particularly if the         
hypothesis is not fully fortified by    
reasoning based on experiment or        
observation4  ,the man who was destined 
to put forward the theory of the earth's
 motion in a way to command attention   
was born in #adgc1 at the village of    
,thorn1 in eastern ,prussia4 ,his name  
was ,nicholas ,copernicus4 ,there is no 
more famous name in the entire annals of
 science than this1 yet posterity has   
never been able fully to establish the  
lineage of the famous expositor of the  
true doctrine of the solar system4 ,the 
city of ,thorn lies in a province of    
that border territory which was then    
under control of ,poland1 but which     
subsequently became a part of ,prussia4 
,it is claimed that the aspects of the  
city were essentially ,german1 and it is

 admitted that the mother of ,copernicus
 belonged to that race4 ,the nationality
 of the father is more in doubt1 but it 
is urged that ,copernicus used ,german  
as his mother-tongue4 ,his great work   
was1 of course1 written in ,latin1      
according to the custom of the time2 but
 it is said that1 when not employing    
that language1 he always wrote in       
,german4 ,the disputed nationality of   
,copernicus strongly suggests that he   
came of a mixed racial lineage1 and we  
are reminded again of the influences of 
those ethnical minglings to which we    
have previously more than once referred4
 ,the acknowledged centres of           
civilization towards the close of the   
fifteenth century were ,italy and       
,spain4 ,therefore1 the birthplace of   
,copernicus lay almost at the confines  
of civilization1 reminding us of that   
earlier period when ,greece was the     
centre of culture1 but when the great   
,greek thinkers were born in ,asia      
,minor and in ,italy4  ,as a young man1 

,copernicus made his way to ,vienna to  
study medicine1 and subsequently he     
journeyed into ,italy and remained there
 many years1 ,about the year #aejj he   
held the chair of mathematics in a      
college at ,rome4 ,subsequently he      
returned to his native land and passed  
his remaining years there1 dying at     
,domkerr1 in ,frauenburg1 ,east         
,prussia1 in the year #aedc4  ,it would 
appear that ,copernicus conceived the   
idea of the heliocentric system of the  
universe while he was a comparatively   
young man1 since in the introduction to 
his great work1 which he addressed to   
,pope ,paul ,,iii41 he states that he   
has pondered his system not merely nine 
years1 in accordance with the maxim of  
,horace1 but well into the fourth period
 of nine years4 ,throughout a           
considerable portion of this period the 
great work of ,copernicus was in        
manuscript1 but it was not published    
until the year of his death4 ,the       
reasons for the delay are not very fully

 established4 ,copernicus undoubtedly   
taught his system throughout the later  
decades of his life4 ,he himself tells  
us that he had even questioned whether  
it were not better for him to confine   
himself to such verbal teaching1        
following thus the example of           
,pythagoras4 ,just as his life was      
drawing to a close1 he decided to pursue
 the opposite course1 and the first copy
 of his work is said to have been placed
 in his hands as he lay on his deathbed4
  ,the violent opposition which the new 
system met from ecclesiastical sources  
led subsequent commentators to suppose  
that ,copernicus had delayed publication
 of his work through fear of the church 
authorities4 ,there seems1 however1 to  
be no direct evidence for this opinion4 
,it has been thought significant that   
,copernicus addressed his work to the   
pope4 ,it is1 of course1 quite          
conceivable that the aged astronomer    
might wish by this means to demonstrate 
that he wrote in no spirit of hostility 

to the church4 ,his address to the pope 
might have been considered as a         
desirable shield precisely because the  
author recognized that his work must    
needs meet with ecclesiastical          
criticism4 ,be that as it may1          
,copernicus was removed by death from   
the danger of attack1 and it remained   
for his disciples of a later generation 
to run the gauntlet of criticism and    
suffer the charges of heresy4  ,the work
 of ,copernicus1 published thus in the  
year #aedc at ,nuremberg1 bears the     
title ,de ,orbium ,coelestium           
,revolutionibus4  ,it is not necessary  
to go into details as to the            
cosmological system which ,copernicus   
advocated1 since it is familiar to every
 one4 ,in a word1 he supposed the sun to
 be the centre of all the planetary     
motions1 the earth taking its place     
among the other planets1 the list of    
which1 as known at that time1 comprised 
,mercury1 ,venus1 the ,earth1 ,mars1    
,jupiter1 and ,saturn4 ,the fixed stars 

were alleged to be stationary1 and it   
was necessary to suppose that they are  
almost infinitely distant1 inasmuch as  
they showed to the observers of that    
time no parallax2 that is to say1 they  
preserved the same apparent position    
when viewed from the opposite points of 
the earth's orbit4  ,but let us allow   
,copernicus to speak for himself        
regarding his system1 ,his exposition is
 full of interest4 ,we quote first the  
introduction just referred to1 in which 
appeal is made directly to the pope4  ,i
 can well believe1 most holy father1    
that certain people1 when they hear of  
my attributing motion to the earth in   
these books of mine1 will at once       
declare that such an opinion ought to be
 rejected4 ,now1 my own theories do not 
please me so much as not to consider    
what others may judge of them4          
,accordingly1 when ,i began to reflect  
upon what those persons who accept the  
stability of the earth1 as confirmed by 
the opinion of many centuries1 would say

 when ,i claimed that the earth moves1  
,i hesitated for a long time as to      
whether ,i should publish that which ,i 
have written to demonstrate its motion1 
or whether it would not be better to    
follow the example of the ,pythagoreans1
 who used to hand down the secrets of   
philosophy to their relatives and       
friends only in oral form4 ,as ,i well  
considered all this1 ,i was almost      
impelled to put the finished work wholly
 aside1 through the scorn ,i had reason 
to anticipate on account of the newness 
and apparent contrariness to reason of  
my theory4  ,my friends1 however1       
dissuaded me from such a course and     
admonished me that ,i ought to publish  
my book1 which had lain concealed in my 
possession not only nine years1 but     
already into four times the ninth year4 
,not a few other distinguished and very 
learned men asked me to do the same     
thing1 and told me that ,i ought not1 on
 account of my anxiety1 to delay any    
longer in consecrating my work to the   

general service of mathematicians4  ,but
 your holiness will perhaps not so much 
wonder that ,i have dared to bring the  
results of my night labors to the light 
of day1 after having taken so much care 
in elaborating them1 but is waiting     
instead to hear how it entered my mind  
to imagine that the earth moved1        
contrary to the accepted opinion of     
mathematicians--nay1 almost contrary to 
ordinary human understanding4 ,therefore
 ,i will not conceal from your holiness 
that what moved me to consider another  
way of reckoning the motions of the     
heavenly bodies was nothing else than   
the fact that the mathematicians do not 
agree with one another in their         
investigations4 ,in the first place1    
they are so uncertain about the motions 
of the sun and moon that they cannot    
find out the length of a full year4 ,in 
the second place1 they apply neither the
 same laws of cause and effect1 in      
determining the motions of the sun and  
moon and of the five planets1 nor the   

same proofs4 ,some employ only          
concentric circles1 others use eccentric
 and epicyclic ones1 with which1        
however1 they do not fully attain the   
desired end4 ,they could not even       
discover nor compute the main           
thing--namely1 the form of the universe 
and the symmetry of its parts4 ,it was  
with them as if some should1 from       
different places1 take hands1 feet1     
head1 and other parts of the body1      
which1 although very beautiful1 were not
 drawn in their proper relations1 and1  
without making them in any way          
correspond1 should construct a monster  
instead of a human being4  ,accordingly1
 when ,i had long reflected on this     
uncertainty of mathematical tradition1  
,i took the trouble to read again the   
books of all the philosophers ,i could  
get hold of1 to see if some one of them 
had not once believed that there were   
other motions of the heavenly bodies4   
,first ,i found in ,cicero that         
,niceties had believed in the motion of 

the earth4 ,afterwards ,i found in      
,plutarch1 likewise1 that some others   
had held the same opinion4 ,this induced
 me also to begin to consider the       
movability of the earth1 and1 although  
the theory appeared contrary to reason1 
,i did so because ,i knew that others   
before me had been allowed to assume    
rotary movements at will1 in order to   
explain the phenomena of these celestial
 bodies4 ,i was of the opinion that ,i1 
too1 might be permitted to see whether1 
by presupposing motion in the earth1    
more reliable conclusions than hitherto 
reached could not be discovered for the 
rotary motions of the spheres4 ,and     
thus1 acting on the hypothesis of the   
motion which1 in the following book1 ,i 
ascribe to the earth1 and by long and   
continued observations1 ,i have finally 
discovered that if the motion of the    
other planets be carried over to the    
relation of the earth and this is made  
the basis for the rotation of every     
star1 not only will the phenomena of the

 planets be explained thereby1 but also 
the laws and the size of the stars2 all 
their spheres and the heavens themselves
 will appear so harmoniously connected  
that nothing could be changed in any    
part of them without confusion in the   
remaining parts and in the whole        
universe4 ,i do not doubt that clever   
and learned men will agree with me if   
they are willing fully to comprehend and
 to consider the proofs which ,i advance
 in the book before us4 ,in order1      
however1 that both the learned and the  
unlearned may see that ,i fear no man's 
judgment1 ,i wanted to dedicate these1  
my night labors1 to your holiness1      
rather than to any one else1 because    
you1 even in this remote corner of the  
earth where ,i live1 are held to be the 
greatest in dignity of station and in   
love for all sciences and for           
mathematics1 so that you1 through your  
position and judgment1 can easily       
suppress the bites of slanderers1       
although the proverb says that there is 

no remedy against the bite of calumny4  
,in chapter ,x4 of book ,i41 ,on the    
,order of the ,spheres1 occurs a more   
detailed presentation of the system1 as 
follows3  ,that which ,martianus        
,capella1 and a few other ,latins1 very 
well knew1 appears to me extremely      
noteworthy4 ,he believed that ,venus and
 ,mercury revolve about the sun as their
 centre and that they cannot go farther 
away from it than the circles of their  
orbits permit1 since they do not revolve
 about the earth like the other planets4
 ,according to this theory1 then1       
,mercury's orbit would be included      
within that of ,venus1 which is more    
than twice as great1 and would find room
 enough within it for its revolution4   
,if1 acting upon this supposition1 we   
connect ,saturn1 ,jupiter1 and ,mars    
with the same centre1 keeping in mind   
the greater extent of their orbits1     
which include the earth's sphere besides
 those of ,mercury and ,venus1 we cannot
 fail to see the explanation of the     

regular order of their motions4 ,he is  
certain that ,saturn1 ,jupiter1 and     
,mars are always nearest the earth when 
they rise in the evening--that is1 when 
they appear over against the sun1 or the
 earth stands between them and the      
sun--but that they are farthest from the
 earth when they set in the             
evening--that is1 when we have the sun  
between them and the earth4 ,this proves
 sufficiently that their centre belongs 
to the sun and is the same about which  
the orbits of ,venus and ,mercury       
circle4 ,since1 however1 all have one   
centre1 it is necessary for the space   
intervening between the orbits of ,venus
 and ,mars to include the earth with her
 accompanying moon and all that is      
beneath the moon2 for the moon1 which   
stands unquestionably nearest the earth1
 can in no way be separated from her1   
especially as there is sufficient room  
for the moon in the aforesaid space4    
,hence we do not hesitate to claim that 
the whole system1 which includes the    

moon with the earth for its centre1     
makes the round of that great circle    
between the planets1 in yearly motion   
about the sun1 and revolves about the   
centre of the universe1 in which the sun
 rests motionless1 and that all which   
looks like motion in the sun is         
explained by the motion of the earth4   
,the extent of the universe1 however1 is
 so great that1 whereas the distance of 
the earth from the sun is considerable  
in comparison with the size of the other
 planetary orbits1 it disappears when   
compared with the sphere of the fixed   
stars4 ,i hold this to be more easily   
comprehensible than when the mind is    
confused by an almost endless number of 
circles1 which is necessarily the case  
with those who keep the earth in the    
middle of the universe4 ,although this  
may appear incomprehensible and contrary
 to the opinion of many1 ,i shall1 if   
,god wills1 make it clearer than the    
sun1 at least to those who are not      
ignorant of mathematics4  ,the order of 

the spheres is as follows3 ,the first   
and lightest of all the spheres is that 
of the fixed stars1 which includes      
itself and all others1 and hence is     
motionless as the place in the universe 
to which the motion and position of all 
other stars is referred4  ,then follows 
the outermost planet1 ,saturn1 which    
completes its revolution around the sun 
in thirty years2 next comes ,jupiter    
with a twelve years' revolution2 then   
,mars1 which completes its course in two
 years4 ,the fourth one in order is the 
yearly revolution which includes the    
earth with the moon's orbit as an       
epicycle4 ,in the fifth place is ,venus 
with a revolution of nine months4 ,the  
sixth place is taken by ,mercury1 which 
completes its course in eighty days4 ,in
 the middle of all stands the sun1 and  
who could wish to place the lamp of this
 most beautiful temple in another or    
better place4 ,thus1 in fact1 the sun1  
seated upon the royal throne1 controls  
the family of the stars which circle    

around him4 ,we find in their order a   
harmonious connection which cannot be   
found elsewhere4 ,here the attentive    
observer can see why the waxing and     
waning of ,jupiter seems greater than   
with ,saturn and smaller than with      
,mars1 and again greater with ,venus    
than with ,mercury4 ,also1 why ,saturn1 
,jupiter1 and ,mars are nearer to the   
earth when they rise in the evening than
 when they disappear in the rays of the 
sun4 ,more prominently1 however1 is it  
seen in the case of ,mars1 which when it
 appears in the heavens at night1 seems 
to equal ,jupiter in size1 but soon     
afterwards is found among the stars of  
second magnitude4 ,all of this results  
from the same cause--namely1 from the   
earth's motion4 ,the fact that nothing  
of this is to be seen in the case of the
 fixed stars is a proof of their        
immeasurable distance1 which makes even 
the orbit of yearly motion or its       
counterpart invisible to us47#a7   ,the 
fact that the stars show no parallax had

 been regarded as an important argument 
against the motion of the earth1 and it 
was still so considered by the opponents
 of the system of ,copernicus4 ,it had1 
indeed1 been necessary for ,aristarchus 
to explain the fact as due to the       
extreme distance of the stars2 a        
perfectly correct explanation1 but one  
that implies distances that are         
altogether inconceivable4 ,it remained  
for nineteenth-century astronomers to   
show1 with the aid of instruments of    
greater precision1 that certain of the  
stars have a parallax4 ,but long before 
this demonstration had been brought     
forward1 the system of ,copernicus had  
been accepted as a part of common       
knowledge4  ,while ,copernicus          
postulated a cosmical scheme that was   
correct as to its main features1 he did 
not altogether break away from certain  
defects of the ,ptolemaic hypothesis4   
,indeed1 he seems to have retained as   
much of this as practicable1 in         
deference to the prejudice of his time4 

,thus he records the planetary orbits as
 circular1 and explains their           
eccentricities by resorting to the      
theory of epicycles1 quite after the    
,ptolemaic method4 ,but now1 of course1 
a much more simple mechanism sufficed to
 explain the planetary motions1 since   
the orbits were correctly referred to   
the central sun and not to the earth4   
,needless to say1 the revolutionary     
conception of ,copernicus did not meet  
with immediate acceptance4 ,a number of 
prominent astronomers1 however1 took it 
up almost at once1 among these being    
,rhaeticus1 who wrote a commentary on   
the evolutions2 ,erasmus ,reinhold1 the 
author of the ,prutenic tables2         
,rothmann1 astronomer to the ,landgrave 
of ,hesse1 and ,maestlin1 the instructor
 of ,kepler4 ,the ,prutenic tables1 just
 referred to1 so called because of their
 ,prussian origin1 were considered an   
improvement on the tables of            
,copernicus1 and were highly esteemed by
 the astronomers of the time4 ,the      

commentary of ,rhaeticus gives us the   
interesting information that it was the 
observation of the orbit of ,mars and of
 the very great difference between his  
apparent diameters at different times   
which first led ,copernicus to conceive 
the heliocentric idea4 ,of ,reinhold it 
is recorded that he considered the orbit
 of ,mercury elliptical1 and that he    
advocated a theory of the moon1         
according to which her epicycle revolved
 on an elliptical orbit1 thus in a      
measure anticipating one of the great   
discoveries of ,kepler to which we shall
 refer presently4 ,the ,landgrave of    
,hesse was a practical astronomer1 who  
produced a catalogue of fixed stars     
which has been compared with that of    
,tycho ,brahe4 ,he was assisted by      
,rothmann and by ,justus ,byrgius4      
,maestlin1 the preceptor of ,kepler1 is 
reputed to have been the first modern   
observer to give a correct explanation  
of the light seen on portions of the    
moon not directly illumined by the sun4 

,he explained this as not due to any    
proper light of the moon itself1 but as 
light reflected from the earth4 ,certain
 of the ,greek philosophers1 however1   
are said to have given the same         
explanation1 and it is alleged also that
 ,leonardo da ,vinci anticipated        
,maestlin in this regard47#b7  ,while1  
various astronomers of some eminence    
thus gave support to the ,copernican    
system1 almost from the beginning1 it   
unfortunately chanced that by far the   
most famous of the immediate successors 
of ,copernicus declined to accept the   
theory of the earth's motion4 ,this was 
,tycho ,brahe1 one of the greatest      
observing astronomers of any age4 ,tycho
 ,brahe was a ,dane1 born at ,knudstrup 
in the year #aedf4 ,he died in #afja at 
,prague1 in ,bohemia4 ,during a         
considerable portion of his life he     
found a patron in ,frederick1 ,king of  
,denmark1 who assisted him to build a   
splendid observatory on the ,island of  
,huene4 ,on the death of his patron     

,tycho moved to ,germany1 where1 as good
 luck would have it1 he came in contact 
with the youthful ,kepler1 and thus1 no 
doubt1 was instrumental in stimulating  
the ambitions of one who in later years 
was to be known as a far greater        
theorist than himself4 ,as has been     
said1 ,tycho rejected the ,copernican   
theory of the earth's motion4 ,it should
 be added1 however1 that he accepted    
that part of the ,copernican theory     
which makes the sun the centre of all   
the planetary motions1 the earth being  
excepted4 ,he thus developed a system of
 his own1 which was in some sort a      
compromise between the ,ptolemaic and   
the ,copernican systems4 ,as ,tycho     
conceived it1 the sun revolves about the
 earth1 carrying with it the            
planets-,mercury1 ,venus1 ,mars1        
,jupiter1 and ,saturn1 which planets    
have the sun and not the earth as the   
centre of their orbits4 ,this cosmical  
scheme1 it should be added1 may be made 
to explain the observed motions of the  

heavenly bodies1 but it involves a much 
more complex mechanism than is          
postulated by the ,copernican theory4   
,various explanations have been offered 
of the conservatism which held the great
 ,danish astronomer back from full      
acceptance of the relatively simple and1
 as we now know1 correct ,copernican    
doctrine4 ,from our latter-day point of 
view1 it seems so much more natural to  
accept than to reject the ,copernican   
system1 that we find it difficult to put
 ourselves in the place of a            
sixteenth-century observer4 ,yet if we  
recall that the traditional view1 having
 warrant of acceptance by nearly all    
thinkers of every age1 recorded the     
earth as a fixed1 immovable body1 we    
shall see that our surprise should be   
excited rather by the thinker who can   
break away from this view than by the   
one who still tends to cling to it4     
,moreover1 it is useless to attempt to  
disguise the fact that something more   
than a mere vague tradition was supposed

 to support the idea of the earth's     
overshadowing importance in the cosmical
 scheme4 ,the sixteenth-century mind was
 overmastered by the tenets of          
ecclesiasticism1 and it was a dangerous 
heresy to doubt that the ,hebrew        
writings1 upon which ecclesiasticism    
based its claim1 contained the last word
 regarding matters of science4 ,but the 
writers of the ,hebrew text had been    
under the influence of that ,babylonian 
conception of the universe which        
accepted the earth as unqualifiedly     
central--which1 indeed1 had never so    
much as conceived a contradictory       
hypothesis2 and so the ,western world1  
which had come to accept these writings 
as actually supernatural in origin1 lay 
under the spell of ,oriental ideas of a 
pre-scientific era4 ,in our own day1 no 
one speaking with authority thinks of   
these ,hebrew writings as having any    
scientific weight whatever4 ,their      
interest in this regard is purely       
antiquarian2 hence from our changed     

point of view it seems scarcely credible
 that ,tycho ,brahe can have been in    
earnest when he quotes the ,hebrew      
traditions as proof that the sun        
revolves about the earth4 ,yet we shall 
see that for almost three centuries     
after the time of ,tycho1 these same    
dreamings continued to be cited in      
opposition to those scientific advances 
which new observations made necessary2  
and this notwithstanding the fact that  
the ,oriental phrasing is1 for the most 
part1 poetically ambiguous and          
susceptible of shifting interpretations1
 as the criticism of successive         
generations has amply testified4  ,as we
 have said1 ,tycho ,brahe1 great        
observer as he was1 could not shake     
himself free from the ,oriental incubus4
 ,he began his objections1 then1 to the 
,copernican system by quoting the       
adverse testimony of a ,hebrew prophet  
who lived more than a thousand years    
,b4,c4 ,all of this shows sufficiently  
that ,tycho ,brahe was not a great      

theorist4 ,he was essentially an        
observer1 but in this regard he won a   
secure place in the very first rank4    
,indeed1 he was easily the greatest     
observing astronomer since ,hipparchus1 
between whom and himself there were many
 points of resemblance4 ,hipparchus1 it 
will be recalled1 rejected the          
,aristarchian conception of the universe
 just as ,tycho rejected the conception 
of ,copernicus4  ,but if ,tycho         
propounded no great generalizations1 the
 list of specific advances due to him is
 a long one1 and some of these were to  
prove important aids in the hands of    
later workers to the secure             
demonstration of the ,copernican idea4  
,one of his most important series of    
studies had to do with comets4          
,regarding these bodies there had been  
the greatest uncertainty in the minds of
 astronomers4 ,the greatest variety of  
opinions regarding them prevailed2 they 
were thought on the one hand to be      
divine messengers1 and on the other to  

be merely igneous phenomena of the      
earth's atmosphere4 ,tycho ,brahe       
declared that a comet which he observed 
in the year #aegg had no parallax1      
proving its extreme distance4 ,the      
observed course of the comet intersected
 the planetary orbits1 which fact gave a
 quietus to the long-mooted question as 
to whether the ,ptolemaic spheres were  
transparent solids or merely imaginary2 
since the comet was seen to intersect   
these alleged spheres1 it was obvious   
that they could not be the solid        
substance that they were commonly       
imagined to be1 and this fact in itself 
went far towards discrediting the       
,ptolemaic system4 ,it should be        
recalled1 however1 that this supposition
 of tangible spheres for the various    
planetary and stellar orbits was a      
mediaeval interpretation of ,ptolemy's  
theory rather than an interpretation of 
,ptolemy himself1 there being nothing to
 show that the ,alexandrian astronomer  
regarded his cycles and epicycles as    

other than theoretical4  ,an interesting
 practical discovery made by ,tycho was 
his method of determining the latitude  
of a place by means of two observations 
made at an interval of twelve hours4    
,hitherto it had been necessary to      
observe the sun's angle on the          
equinoctial days1 a period of six months
 being therefore required4 ,tycho       
measured the angle of elevation of some 
star situated near the pole1 when on the
 meridian1 and then1 twelve hours later1
 measured the angle of elevation of the 
same star when it again came to the     
meridian at the opposite point of its   
apparent circle about the polestar4     
,half the sum of these angles gives the 
latitude of the place of observation4   
,as illustrating the accuracy of        
,tycho's observations1 it may be noted  
that he rediscovered a third inequality 
of the moon's motion at its variation1  
he1 in common with other ,european      
astronomers1 being then quite unaware   
that this inequality had been observed  

by an ,arabian astronomer4 ,tycho proved
 also that the angle of inclination of  
the moon's orbit to the ecliptic is     
subject to slight variation4  ,the very 
brilliant new star which shone forth    
suddenly in the constellation of        
,cassiopeia in the year #aegb1 was made 
the object of special studies by ,tycho1
 who proved that the star had no        
sensible parallax and consequently was  
far beyond the planetary regions4 ,the  
appearance of a new star was a          
phenomenon not unknown to the ancients1 
since ,pliny records that ,hipparchus   
was led by such an appearance to make   
his catalogue of the fixed stars4 ,but  
the phenomenon is sufficiently uncommon 
to attract unusual attention4 ,a similar
 phenomenon occurred in the year #afjd1 
when the new star--in this case         
appearing in the constellation of       
,serpentarius--was explained by ,kepler 
as probably proceeding from a vast      
combustion4 ,this explanation--in which 
,kepler is said to have followed4       

,tycho--is fully in accord with the most
 recent theories on the subject1 as we  
shall see in due course4 ,it is         
surprising to hear ,tycho credited with 
so startling a theory1 but1 on the other
 hand1 such an explanation is precisely 
what should be expected from the other  
astronomer named4 ,for ,johann ,kepler1 
or1 as he was originally named1 ,johann 
von ,kappel1 was one of the most        
speculative astronomers of any age4 ,he 
was forever theorizing1 but such was the
 peculiar quality of his mind that his  
theories never satisfied him for long   
unless he could put them to the test of 
observation4 ,thanks to this happy      
combination of qualities1 ,kepler became
 the discoverer of three famous laws of 
planetary motion which lie at the very  
foundation of modern astronomy1 and     
which were to be largely instrumental in
 guiding ,newton to his still greater   
generalization4 ,these laws of planetary
 motion were vastly important as        
corroborating the ,copernican theory of 

the universe1 though their position in  
this regard was not immediately         
recognized by contemporary thinkers4    
,let us examine with some detail into   
their discovery1 meantime catching a    
glimpse of the life history of the      
remarkable man whose name they bear4    
,,johann ,,kepler ,,and ,,the ,,laws    
,,of ,,planetary ,,motion  ,johann      
,kepler was born the #bgth of ,december1
 #aega1 in the little town of ,weil1 in 
,wurtemburg4 ,he was a weak1 sickly     
child1 further enfeebled by a severe    
attack of small-pox4 ,it would seem     
paradoxical to assert that the parents  
of such a genius were mismated1 but     
their home was not a happy one1 the     
mother being of a nervous temperament1  
which perhaps in some measure accounted 
for the genius of the child4 ,the father
 led the life of a soldier1 and finally 
perished in the campaign against the    
,turks4 ,young ,kepler's studies were   
directed with an eye to the ministry4   
,after a preliminary training he        

attended the university at ,tubingen1   
where he came under the influence of the
 celebrated ,maestlin and became his    
life-long friend4  ,curiously enough1 it
 is recorded that at first ,kepler had  
no taste for astronomy or for           
mathematics4 ,but the doors of the      
ministry being presently barred to him1 
he turned with enthusiasm to the study  
of astronomy1 being from the first an   
ardent advocate of the ,copernican      
system4 ,his teacher1 ,maestlin1        
accepted the same doctrine1 though he   
was obliged1 for theological reasons1 to
 teach the ,ptolemaic system1 as also to
 oppose the ,gregorian reform of the    
calendar4  ,the ,gregorian calendar1 it 
should be explained1 is so called       
because it was instituted by ,pope      
,gregory ,,xiii41 who put it into effect
 in the year #aehb1 up to which time the
 so-called ,julian calendar1 as         
introduced by ,julius ,caesar1 had been 
everywhere accepted in ,christendom4    
,this ,julian calendar1 as we have seen1

 was a great improvement on preceding   
ones1 but still lacked something of     
perfection inasmuch as its theoretical  
day differed appreciably from the actual
 day4 ,in the course of fifteen hundred 
years1 since the time of ,caesar1 this  
defect amounted to a discrepancy of     
about eleven days4 ,pope ,gregory       
proposed to correct this by omitting ten
 days from the calendar1 which was done 
in ,september1 #aehb4 ,to prevent       
similar inaccuracies in the future1 the 
,gregorian calendar provided that once  
in four centuries the additional day to 
make a leap-year should be omitted1 the 
date selected for such omission being   
the last year of every fourth century4  
,thus the years #aejj1 #aijj1 and #bcjj1
 ,a4,d41 would not be leap-years4 ,by   
this arrangement an approximate         
rectification of the calendar was       
effected1 though even this does not make
 it absolutely exact4  ,such a          
rectification as this was obviously     
desirable1 but there was really no      

necessity for the omission of the ten   
days from the calendar4 ,the equinoctial
 day had shifted so that in the year    
#aehb it fell on the #ajth of ,march and
 ,september4 ,there was no reason why it
 should not have remained there4 ,it    
would greatly have simplified the task  
of future historians had ,gregory       
contented himself with providing for the
 future stability of the calendar       
without making the needless shift in    
question4 ,we are so accustomed to think
 of the #bast of ,march and #bast of    
,september as the natural periods of the
 equinox1 that we are likely to forget  
that these are purely arbitrary dates   
for which the #ajth might have been     
substituted without any inconvenience or
 inconsistency4  ,but the opposition to 
the new calendar1 to which reference has
 been made1 was not based on any such   
considerations as these4 ,it was due1   
largely at any rate1 to the fact that   
,germany at this time was under sway of 
the ,lutheran revolt against the papacy4

 ,so effective was the opposition that  
the ,gregorian calendar did not come    
into vogue in ,germany until the year   
#afii4 ,it may be added that ,england1  
under stress of the same manner of      
prejudice1 held out against the new     
reckoning until the year #agea1 while   
,russia does not accept it even now4    
,as the ,protestant leaders thus opposed
 the papal attitude in a matter of so   
practical a character as the calendar1  
it might perhaps have been expected that
 the ,lutherans would have had a leaning
 towards the ,copernican theory of the  
universe1 since this theory was opposed 
by the papacy4 ,such1 however1 was not  
the case4 ,luther himself pointed out   
with great strenuousness1 as a final and
 demonstrative argument1 the fact that  
,joshua commanded the sun and not the   
earth to stand still2 and his followers 
were quite as intolerant towards the new
 teaching as were their ultramontane    
opponents4 ,kepler himself was1 at      
various times1 to feel the restraint of 

ecclesiastical opposition1 though he was
 never subjected to direct persecution1 
as was his friend and contemporary1     
,galileo4 ,at the very outset of        
,kepler's career there was1 indeed1     
question as to the publication of a work
 he had written1 because that work took 
for granted the truth of the ,copernican
 doctrine4 ,this work appeared1 however1
 in the year #aeif4 ,it bore the title  
,mysterium ,cosmographium1 and it       
attempted to explain the positions of   
the various planetary bodies4           
,copernicus had devoted much time to    
observation of the planets with         
reference to measuring their distance1  
and his efforts had been attended with  
considerable success4 ,he did not1      
indeed1 know the actual distance of the 
sun1 and1 therefore1 was quite unable to
 fix the distance of any planet2 but1 on
 the other hand1 he determined the      
relative distance of all the planets    
then known1 as measured in terms of the 
sun's distance1 with remarkable         

accuracy4  ,with these measurements as a
 guide1 ,kepler was led to a very       
fanciful theory1 according to which the 
orbits of the five principal planets    
sustain a peculiar relation to the five 
regular solids of geometry4 ,his theory 
was this3 ,around the orbit of the earth
 describe a dodecahedron--the circle    
comprising it will be that of ,mars2    
around ,mars describe a tetrahedron--the
 circle comprising it will be that of   
,jupiter2 around ,jupiter describe a    
cube--the circle comprising it will be  
that of ,saturn2 now within the earth's 
orbit inscribe an icosahedron--the      
inscribed circle will be that of ,venus2
 in the orbit of ,venus inscribe an     
octahedron--the circle inscribed will be
 that of ,mercury47#c7  ,though this    
arrangement was a fanciful one1 which no
 one would now recall had not the       
theorizer obtained subsequent fame on   
more substantial grounds1 yet it        
evidenced a philosophical spirit on the 
part of the astronomer which1           

misdirected as it was in this instance1 
promised well for the future4 ,tycho    
,brahe1 to whom a copy of the work was  
sent1 had the acumen to recognize it as 
a work of genius4 ,he summoned the young
 astronomer to be his assistant at      
,prague1 and no doubt the association   
thus begun was instrumental in          
determining the character of ,kepler's  
future work4 ,it was precisely the      
training in minute observation that     
could avail most for a mind which1 like 
,kepler's1 tended instinctively to the  
formulation of theories4 ,when ,tycho   
,brahe died1 in #afja1 ,kepler became   
his successor4 ,in due time he secured  
access to all the unpublished           
observations of his great predecessor1  
and these were of inestimable value to  
him in the progress of his own studies4 
,kepler was not only an ardent worker   
and an enthusiastic theorizer1 but he   
was an indefatigable writer1 and it     
pleased him to take the public fully    
into his confidence1 not merely as to   

his successes1 but as to his failures4  
,thus his works elaborate false theories
 as well as correct ones1 and detail the
 observations through which the         
incorrect guesses were refuted by their 
originator4 ,some of these accounts are 
highly interesting1 but they must not   
detain us here4 ,for our present purpose
 it must suffice to point out the three 
important theories1 which1 as culled    
from among a score or so of incorrect   
ones1 ,kepler was able to demonstrate to
 his own satisfaction and to that of    
subsequent observers4 ,stated in a few  
words1 these theories1 which have come  
to bear the name of ,kepler's ,laws1 are
 the following3  #a4 ,that the planetary
 orbits are not circular1 but           
elliptical1 the sun occupying one focus 
of the ellipses4  #b4 ,that the speed of
 planetary motion varies in different   
parts of the orbit in such a way that an
 imaginary line drawn from the sun to   
the planet--that is to say1 the radius  
vector of the planet's orbit--always    

sweeps the same area in a given time4   
,these two laws ,kepler published as    
early as #afji4 ,many years more of     
patient investigation were required     
before he found out the secret of the   
relation between planetary distances and
 times of revolution which his third law
 expresses4 ,in #afah1 however1 he was  
able to formulate this relation also1 as
 follows3  #c4 ,the squares of the      
distance of the various planets from the
 sun are proportional to the cubes of   
their periods of revolution about the   
sun4   ,all these laws1 it will be      
observed1 take for granted the fact that
 the sun is the centre of the planetary 
orbits4 ,it must be understood1 too1    
that the earth is constantly regarded1  
in accordance with the ,copernican      
system1 as being itself a member of the 
planetary system1 subject to precisely  
the same laws as the other planets4     
,long familiarity has made these        
wonderful laws of ,kepler seem such a   
matter of course that it is difficult   

now to appreciate them at their full    
value4 ,yet1 as has been already pointed
 out1 it was the knowledge of these     
marvellously simple relations between   
the planetary orbits that laid the      
foundation for the ,newtonian law of    
universal gravitation4 ,contemporary    
judgment could not1 of course1          
anticipate this culmination of a later  
generation4 ,what it could understand   
was that the first law of ,kepler       
attacked one of the most time-honored of
 metaphysical conceptions--namely1 the  
,aristotelian idea that the circle is   
the perfect figure1 and hence that the  
planetary orbits must be circular4 ,not 
even ,copernicus had doubted the        
validity of this assumption4 ,that      
,kepler dared dispute so firmly fixed a 
belief1 and one that seemingly had so   
sound a philosophical basis1 evidenced  
the iconoclastic nature of his genius4  
,that he did not rest content until he  
had demonstrated the validity of his    
revolutionary assumption shows how truly

 this great theorizer made his          
hypotheses subservient to the most rigid
 inductions4   ,,galileo ,,galilei      
,while ,kepler was solving these riddles
 of planetary motion1 there was an even 
more famous man in ,italy whose         
championship of the ,copernican doctrine
 was destined to give the greatest      
possible publicity to the new ideas4    
,this was ,galileo ,galilei1 one of the 
most extraordinary scientific observers 
of any age4 ,galileo was born at ,pisa1 
on the #ahth of ,february 7old style71  
#aefd4 ,the day of his birth is doubly  
memorable1 since on the same day the    
greatest ,italian of the preceding      
epoch1 ,michael ,angelo1 breathed his   
last4 ,persons fond of symbolism have   
found in the coincidence a forecast of  
the transit from the artistic to the    
scientific epoch of the later           
,renaissance4 ,galileo came of an       
impoverished noble family4 ,he was      
educated for the profession of medicine1
 but did not progress far before his    

natural proclivities directed him       
towards the physical sciences4 ,meeting 
with opposition in ,pisa1 he early      
accepted a call to the chair of natural 
philosophy in the ,university of ,padua1
 and later in life he made his home at  
,florence4 ,the mechanical and physical 
discoveries of ,galileo will claim our  
attention in another chapter4 ,our      
present concern is with his contribution
 to the ,copernican theory4  ,galileo   
himself records in a letter to ,kepler  
that he became a convert to this theory 
at an early day4 ,he was not enabled1   
however1 to make any marked contribution
 to the subject1 beyond the influence of
 his general teachings1 until about the 
year #afaj4 ,the brilliant contributions
 which he made were due largely to a    
single discovery--namely1 that of the   
telescope4 ,hitherto the astronomical   
observations had been made with the     
unaided eye4 ,glass lenses had been     
known since the thirteenth century1 but1
 until now1 no one had thought of their 

possible use as aids to distant vision4 
,the question of priority of discovery  
has never been settled4 ,it is admitted1
 however1 that the chief honors belong  
to the opticians of the ,netherlands4   
,as early as the year #aeij the ,dutch  
optician ,zacharias ,jensen placed a    
concave and a convex lens respectively  
at the ends of a tube about eighteen    
inches long1 and used this instrument   
for the purpose of magnifying small     
objects--producing1 in short1 a crude   
microscope4 ,some years later1 ,johannes
 ,lippershey1 of whom not much is known 
except that he died in #afai1           
experimented with a somewhat similar    
combination of lenses1 and made the     
startling observation that the          
weather-vane on a distant church-steeple
 seemed to be brought much nearer when  
viewed through the lens4 ,the           
combination of lenses he employed is    
that still used in the construction of  
opera-glasses2 the ,germans still call  
such a combination a ,dutch telescope4  

,doubtless a large number of            
experimenters took the matter up and the
 fame of the new instrument spread      
rapidly abroad4 ,galileo1 down in       
,italy1 heard rumors of this remarkable 
contrivance1 through the use of which it
 was said distant objects might be seen 
as clearly as those near at hand4 ,he at
 once set to work to construct for      
himself a similar instrument1 and his   
efforts were so far successful that at  
first he saw objects three times as near
 and nine times enlarged4 ,continuing   
his efforts1 he presently so improved   
his glass that objects were enlarged    
almost a thousand times and made to     
appear thirty times nearer than when    
seen with the naked eye4 ,naturally     
enough1 ,galileo turned this fascinating
 instrument towards the skies1 and he   
was almost immediately rewarded by      
several startling discoveries4 ,at the  
very outset1 his magnifying-glass       
brought to view a vast number of stars  
that are invisible to the naked eye1 and

 enabled the observer to reach the      
conclusion that the hazy light of the   
,milky ,way is merely due to the        
aggregation of a vast number of tiny    
stars4  ,turning his telescope towards  
the moon1 ,galileo found that body rough
 and earth-like in contour1 its surface 
covered with mountains1 whose height    
could be approximately measured through 
study of their shadows4 ,this was       
disquieting1 because the current        
,aristotelian doctrine supposed the     
moon1 in common with the planets1 to be 
a perfectly spherical1 smooth body4 ,the
 metaphysical idea of a perfect universe
 was sure to be disturbed by this       
seemingly rough workmanship of the moon4
 ,thus far1 however1 there was nothing  
in the observations of ,galileo to bear 
directly upon the ,copernican theory2   
but when an inspection was made of the  
planets the case was quite different4   
,with the aid of his telescope1 ,galileo
 saw that ,venus1 for example1 passes   
through phases precisely similar to     

those of the moon1 due1 of course1 to   
the same cause4 ,here1 then1 was        
demonstrative evidence that the planets 
are dark bodies reflecting the light of 
the sun1 and an explanation was given of
 the fact1 hitherto urged in opposition 
to the ,copernican theory1 that the     
inferior planets do not seem many times 
brighter when nearer the earth than when
 in the most distant parts of their     
orbits2 the explanation being1 of       
course1 that when the planets are       
between the earth and the sun only a    
small portion of their illumined        
surfaces is visible from the earth4  ,on
 inspecting the planet ,jupiter1 a still
 more striking revelation was made1 as  
four tiny stars were observed to occupy 
an equatorial position near that planet1
 and were seen1 when watched night after
 night1 to be circling about the planet1
 precisely as the moon circles about the
 earth4 ,here1 obviously1 was a         
miniature solar system--a tangible      
object-lesson in the ,copernican theory4

 ,in honor of the ruling ,florentine    
house of the period1 ,galileo named     
these moons of ,jupiter1 ,medicean      
stars4  ,turning attention to the sun   
itself1 ,galileo observed on the surface
 of that luminary a spot or blemish     
which gradually changed its shape1      
suggesting that changes were taking     
place in the substance of the           
sun--changes obviously incompatible with
 the perfect condition demanded by the  
metaphysical theorists4 ,but however    
disquieting for the conservative1 the   
sun's spots served a most useful purpose
 in enabling ,galileo to demonstrate    
that the sun itself revolves on its     
axis1 since a given spot was seen to    
pass across the disk and after          
disappearing to reappear in due course4 
,the period of rotation was found to be 
about twenty-four days4  ,it must be    
added that various observers disputed   
priority of discovery of the sun's spots
 with ,galileo4 ,unquestionably a       
sun-spot had been seen by earlier       

observers1 and by them mistaken for the 
transit of an inferior planet4 ,kepler  
himself had made this mistake4 ,before  
the day of the telescope1 he had viewed 
the image of the sun as thrown on a     
screen in a camera-obscura1 and had     
observed a spot on the disk which be    
interpreted as representing the planet  
,mercury1 but which1 as is now known1   
must have been a sun-spot1 since the    
planetary disk is too small to have been
 revealed by this method4 ,such         
observations as these1 however          
interesting1 cannot be claimed as       
discoveries of the sun-spots4 ,it is    
probable1 however1 that several         
discoverers 7notably ,johann ,fabricius7
 made the telescopic observation of the 
spots1 and recognized them as having to 
do with the sun's surface1 almost       
simultaneously with ,galileo4 ,one of   
these claimants was a ,jesuit named     
,scheiner1 and the jealousy of this man 
is said to have had a share in bringing 
about that persecution to which we must 

now refer4  ,there is no more famous    
incident in the history of science than 
the heresy trial through which ,galileo 
was led to the nominal renunciation of  
his cherished doctrines4 ,there is      
scarcely another incident that has been 
commented upon so variously4 ,each      
succeeding generation has put its own   
interpretation on it4 ,the facts1       
however1 have been but little           
questioned4 ,it appears that in the year
 #afaf the church became at last aroused
 to the implications of the heliocentric
 doctrine of the universe4 ,apparently  
it seemed clear to the church           
authorities that the authors of the     
,bible believed the world to be         
immovably fixed at the centre of the    
universe4 ,such1 indeed1 would seem to  
be the natural inference from various   
familiar phrases of the ,hebrew text1   
and what we now know of the status of   
,oriental science in antiquity gives    
full warrant to this interpretation4    
,there is no reason to suppose that the 

conception of the subordinate place of  
the world in the solar system had ever  
so much as occurred1 even as a vague    
speculation1 to the authors of ,genesis4
 ,in common with their contemporaries1  
they believed the earth to be the       
all-important body in the universe1 and 
the sun a luminary placed in the sky for
 the sole purpose of giving light to the
 earth4 ,there is nothing strange1      
nothing anomalous1 in this view2 it     
merely reflects the current notions of  
,oriental peoples in antiquity4 ,what is
 strange and anomalous is the fact that 
the ,oriental dreamings thus expressed  
could have been supposed to represent   
the acme of scientific knowledge4 ,yet  
such a hold had these writings taken    
upon the ,western world that not even a 
,galileo dared contradict them openly2  
and when the church fathers gravely     
declared the heliocentric theory        
necessarily false1 because contradictory
 to ,scripture1 there were probably few 
people in ,christendom whose mental     

attitude would permit them justly to    
appreciate the humor of such a          
pronouncement4 ,and1 indeed1 if here and
 there a man might have risen to such an
 appreciation1 there were abundant      
reasons for the repression of the       
impulse1 for there was nothing humorous 
about the response with which the       
authorities of the time were wont to    
meet the expression of iconoclastic     
opinions4 ,the burning at the stake of  
,giordano ,bruno1 in the year #afjj1    
was1 for example1 an object-lesson well 
calculated to restrain the enthusiasm of
 other similarly minded teachers4       
,doubtless it was such considerations   
that explained the relative silence of  
the champions of the ,copernican theory1
 accounting for the otherwise           
inexplicable fact that about eighty     
years elapsed after the death of        
,copernicus himself before a single     
text-book expounded his theory4 ,the    
text-book which then appeared1 under    
date of #afbb1 was written by the famous

 ,kepler1 who perhaps was shielded in a 
measure from the papal consequences of  
such hardihood by the fact of residence 
in a ,protestant country4 ,not that the 
,protestants of the time favored the    
heliocentric doctrine--we have already  
quoted ,luther in an adverse sense--but 
of course it was characteristic of the  
,reformation temper to oppose any papal 
pronouncement1 hence the ultramontane   
declaration of #afaf may indirectly have
 aided the doctrine which it attacked1  
by making that doctrine less obnoxious  
to ,lutheran eyes4 ,be that as it may1  
the work of ,kepler brought its author  
into no direct conflict with the        
authorities4 ,but the result was quite  
different when1 in #afcb1 ,galileo at   
last broke silence and gave the world1  
under cover of the form of dialogue1 an 
elaborate exposition of the ,copernican 
theory4 ,galileo1 it must be explained1 
had previously been warned to keep      
silent on the subject1 hence his        
publication doubly offended the         

authorities4 ,to be sure1 he could reply
 that his dialogue introduced a champion
 of the ,ptolemaic system to dispute    
with the upholder of the opposite view1 
and that1 both views being presented    
with full array of argument1 the reader 
was left to reach a verdict for himself1
 the author having nowhere pointedly    
expressed an opinion4 ,but such an      
argument1 of course1 was specious1 for  
no one who read the dialogue could be in
 doubt as to the opinion of the author4 
,moreover1 it was hinted that           
,simplicio1 the character who upheld the
 ,ptolemaic doctrine and who was        
everywhere worsted in the argument1 was 
intended to represent the pope          
himself--a suggestion which probably did
 no good to ,galileo's cause4  ,the     
character of ,galileo's artistic        
presentation may best be judged from an 
example1 illustrating the vigorous      
assault of ,salviati1 the champion of   
the new theory1 and the feeble retorts  
of his conservative antagonist3         

,salviati4 ,let us then begin our       
discussion with the consideration that1 
whatever motion may be attributed to the
 earth1 yet we1 as dwellers upon it1 and
 hence as participators in its motion1  
cannot possibly perceive anything of it1
 presupposing that we are to consider   
only earthly things4 ,on the other hand1
 it is just as necessary that this same 
motion belong apparently to all other   
bodies and visible objects1 which1 being
 separated from the earth1 do not take  
part in its motion4 ,the correct method 
to discover whether one can ascribe     
motion to the earth1 and what kind of   
motion1 is1 therefore1 to investigate   
and observe whether in bodies outside   
the earth a perceptible motion may be   
discovered which belongs to all alike4  
,because a movement which is perceptible
 only in the moon1 for instance1 and has
 nothing to do with ,venus or ,jupiter  
or other stars1 cannot possibly be      
peculiar to the earth1 nor can its seat 
be anywhere else than in the moon4 ,now 

there is one such universal movement    
which controls all others--namely1 that 
which the sun1 moon1 the other planets1 
the fixed stars--in short1 the whole    
universe1 with the single exception of  
the earth--appears to execute from east 
to west in the space of twenty-four     
hours4 ,this now1 as it appears at the  
first glance anyway1 might just as well 
be a motion of the earth alone as of all
 the rest of the universe with the      
exception of the earth1 for the same    
phenomena would result from either      
hypothesis4 ,beginning with the most    
general1 ,i will enumerate the reasons  
which seem to speak in favor of the     
earth's motion4 ,when we merely consider
 the immensity of the starry sphere in  
comparison with the smallness of the    
terrestrial ball1 which is contained    
many million times in the former1 and   
then think of the rapidity of the motion
 which completes a whole rotation in one
 day and night1 ,i cannot persuade      
myself how any one can hold it to be    

more reasonable and credible that it is 
the heavenly sphere which rotates1 while
 the earth stands still4  ,simplicio4 ,i
 do not well understand how that        
powerful motion may be said to as good  
as not exist for the sun1 the moon1 the 
other planets1 and the innumerable host 
of fixed stars4 ,do you call that       
nothing when the sun goes from one      
meridian to another1 rises up over this 
horizon and sinks behind that one1      
brings now day1 and now night2 when the 
moon goes through similar changes1 and  
the other planets and fixed stars in the
 same way8  ,salviati4 ,all the changes 
you mention are such only in respect to 
the earth4 ,to convince yourself of it1 
only imagine the earth out of existence4
 ,there would then be no rising and     
setting of the sun or of the moon1 no   
horizon1 no meridian1 no day1 no        
night--in short1 the said motion causes 
no change of any sort in the relation of
 the sun to the moon or to any of the   
other heavenly bodies1 be they planets  

or fixed stars4 ,all changes are rather 
in respect to the earth2 they may all be
 reduced to the simple fact that the sun
 is first visible in ,china1 then in    
,persia1 afterwards in ,egypt1 ,greece1 
,france1 ,spain1 ,america1 etc41 and    
that the same thing happens with the    
moon and the other heavenly bodies4     
,exactly the same thing happens and in  
exactly the same way if1 instead of     
disturbing so large a part of the       
universe1 you let the earth revolve     
about itself4 ,the difficulty is1       
however1 doubled1 inasmuch as a second  
very important problem presents itself4 
,if1 namely1 that powerful motion is    
ascribed to the heavens1 it is          
absolutely necessary to regard it as    
opposed to the individual motion of all 
the planets1 every one of which         
indubitably has its own very leisurely  
and moderate movement from west to east4
 ,if1 on the other hand1 you let the    
earth move about itself1 this opposition
 of motion disappears4  ,the            

improbability is tripled by the complete
 overthrow of that order which rules all
 the heavenly bodies in which the       
revolving motion is definitely          
established4 ,the greater the sphere is 
in such a case1 so much longer is the   
time required for its revolution2 the   
smaller the sphere the shorter the time4
 ,saturn1 whose orbit surpasses those of
 all the planets in size1 traverses it  
in thirty years4 ,jupiter7#d7 completes 
its smaller course in twelve years1     
,mars in two2 the moon performs its much
 smaller revolution within a month4     
,just as clearly in the ,medicean stars1
 we see that the one nearest ,jupiter   
completes its revolution in a very short
 time--about forty-two hours2 the next  
in about three and one-half days1 the   
third in seven1 and the most distant one
 in sixteen days4 ,this rule1 which is  
followed throughout1 will still remain  
if we ascribe the twenty-four-hourly    
motion to a rotation of the earth4 ,if1 
however1 the earth is left motionless1  

we must go first from the very short    
rule of the moon to ever greater        
ones--to the two-yearly rule of ,mars1  
from that to the twelve-yearly one of   
,jupiter1 from here to the thirty-yearly
 one of ,saturn1 and then suddenly to an
 incomparably greater sphere1 to which  
also we must ascribe a complete rotation
 in twenty-four hours4 ,if1 however1 we 
assume a motion of the earth1 the       
rapidity of the periods is very well    
preserved2 from the slowest sphere of   
,saturn we come to the wholly motionless
 fixed stars4 ,we also escape thereby a 
fourth difficulty1 which arises as soon 
as we assume that there is motion in the
 sphere of the stars4 ,i mean the great 
unevenness in the movement of these very
 stars1 some of which would have to     
revolve with extraordinary rapidity in  
immense circles1 while others moved very
 slowly in small circles1 since some of 
them are at a greater1 others at a less1
 distance from the pole4 ,that is       
likewise an inconvenience1 for1 on the  

one hand1 we see all those stars1 the   
motion of which is indubitable1 revolve 
in great circles1 while1 on the other   
hand1 there seems to be little object in
 placing bodies1 which are to move in   
circles1 at an enormous distance from   
the centre and then let them move in    
very small circles4 ,and not only are   
the size of the different circles and   
therewith the rapidity of the movement  
very different in the different fixed   
stars1 but the same stars also change   
their orbits and their rapidity of      
motion4 ,therein consists the fifth     
inconvenience4 ,those stars1 namely1    
which were at the equator two thousand  
years ago1 and hence described great    
circles in their revolutions1 must      
to-day move more slowly and in smaller  
circles1 because they are many degrees  
removed from it4 ,it will even happen1  
after not so very long a time1 that one 
of those which have hitherto been       
continually in motion will finally      
coincide with the pole and stand still1 

but after a period of repose will again 
begin to move4 ,the other stars in the  
mean while1 which unquestionably move1  
all have1 as was said1 a great circle   
for an orbit and keep this unchangeably4
  ,the improbability is further         
increased--this may be considered the   
sixth inconvenience--by the fact that it
 is impossible to conceive what degree  
of solidity those immense spheres must  
have1 in the depths of which so many    
stars are fixed so enduringly that they 
are kept revolving evenly in spite of   
such difference of motion without       
changing their respective positions4 ,or
 if1 according to the much more probable
 theory1 the heavens are fluid1 and     
every star describes an orbit of its    
own1 according to what law then1 or for 
what reason1 are their orbits so        
arranged that1 when looked at from the  
earth1 they appear to be contained in   
one single sphere8 ,to attain this it   
seems to me much easier and more        
convenient to make them motionless      

instead of moving1 just as the          
paving-stones on the market-place1 for  
instance1 remain in order more easily   
than the swarms of children running     
about on them4  ,finally1 the seventh   
difficulty3 ,if we attribute the daily  
rotation to the higher region of the    
heavens1 we should have to endow it with
 force and power sufficient to carry    
with it the innumerable host of the     
fixed stars--every one a body of very   
great compass and much larger than the  
earth--and all the planets1 although the
 latter1 like the earth1 move naturally 
in an opposite direction4 ,in the midst 
of all this the little earth1 single and
 alone1 would obstinately and wilfully  
withstand such force--a supposition     
which1 it appears to me1 has much       
against it4 ,i could also not explain   
why the earth1 a freely poised body1    
balancing itself about its centre1 and  
surrounded on all sides by a fluid      
medium1 should not be affected by the   
universal rotation4 ,such difficulties1 

however1 do not confront us if we       
attribute motion to the earth--such a   
small1 insignificant body in comparison 
with the whole universe1 and which for  
that very reason cannot exercise any    
power over the latter4  ,simplicio4 ,you
 support your arguments throughout1 it  
seems to me1 on the greater ease and    
simplicity with which the said effects  
are produced4 ,you mean that as a cause 
the motion of the earth alone is just as
 satisfactory as the motion of all the  
rest of the universe with the exception 
of the earth2 you hold the actual event 
to be much easier in the former case    
than in the latter4 ,for the ruler of   
the universe1 however1 whose might is   
infinite1 it is no less easy to move the
 universe than the earth or a straw     
balm4 ,but if his power is infinite1 why
 should not a greater1 rather than a    
very small1 part of it be revealed to   
me8  ,salviati4 ,if ,i had said that the
 universe does not move on account of   
the impotence of its ruler1 ,i should   

have been wrong and your rebuke would   
have been in order4 ,i admit that it is 
just as easy for an infinite power to   
move a hundred thousand as to move one4 
,what ,i said1 however1 does not refer  
to him who causes the motion1 but to    
that which is moved4 ,in answer to your 
remark that it is more fitting for an   
infinite power to reveal a large part of
 itself rather than a little1 ,i answer 
that1 in relation to the infinite1 one  
part is not greater than another1 if    
both are finite4 ,hence it is           
unallowable to say that a hundred       
thousand is a larger part of an infinite
 number than two1 although the former is
 fifty thousand times greater than the  
latter4 ,if1 therefore1 we consider the 
moving bodies1 we must unquestionably   
regard the motion of the earth as a much
 simpler process than that of the       
universe2 if1 furthermore1 we direct our
 attention to so many other             
simplifications which may be reached    
only by this theory1 the daily movement 

of the earth must appear much more      
probable than the motion of the universe
 without the earth1 for1 according to   
,aristotle's just axiom1 ',frustra fit  
per plura1 quod potest fieri per p      
auciora' 7,it is vain to expend many    
means where a few are sufficient747#b7  
,the work was widely circulated1 and it 
was received with an interest which     
bespeaks a wide-spread undercurrent of  
belief in the ,copernican doctrine4     
,naturally enough1 it attracted         
immediate attention from the church     
authorities4 ,galileo was summoned to   
appear at ,rome to defend his conduct4  
,the philosopher1 who was now in his    
seventieth year1 pleaded age and        
infirmity4 ,he had no desire for        
personal experience of the tribunal of  
the ,inquisition2 but the mandate was   
repeated1 and ,galileo went to ,rome4   
,there1 as every one knows1 he disavowed
 any intention to oppose the teachings  
of ,scripture1 and formally renounced   
the heretical doctrine of the earth's   

motion4 ,according to a tale which so   
long passed current that every historian
 must still repeat it though no one now 
believes it authentic1 ,galileo         
qualified his renunciation by muttering 
to himself1 ,e pur si muove 7,it does   
move1 none the less71 as he rose to his 
feet and retired from the presence of   
his persecutors4 ,the tale is one of    
those fictions which the dramatic sense 
of humanity is wont to impose upon      
history1 but1 like most such fictions1  
it expresses the spirit if not the      
letter of truth2 for just as no one     
believes that ,galileo's lips uttered   
the phrase1 so no one doubts that the   
rebellious words were in his mind4      
,after his formal renunciation1 ,galileo
 was allowed to depart1 but with the    
injunction that he abstain in future    
from heretical teaching4 ,the remaining 
ten years of his life were devoted      
chiefly to mechanics1 where his         
experiments fortunately opposed the     
,aristotelian rather than the ,hebrew   

teachings4 ,galileo's death occurred in 
#afdb1 a hundred years after the death  
of ,copernicus4 ,kepler had died        
thirteen years before1 and there        
remained no astronomer in the field who 
is conspicuous in the history of science
 as a champion of the ,copernican       
doctrine4 ,but in truth it might be said
 that the theory no longer needed a     
champion4 ,the researches of ,kepler and
 ,galileo had produced a mass of        
evidence for the ,copernican theory     
which amounted to demonstration4 ,a     
generation or two might be required for 
this evidence to make itself everywhere 
known among men of science1 and of      
course the ecclesiastical authorities   
must be expected to stand by their guns 
for a somewhat longer period4 ,in point 
of fact1 the ecclesiastical ban was not 
technically removed by the striking of  
the ,copernican books from the list of  
the ,index ,expurgatorius until the year
 #ahbb1 almost two hundred years after  
the date of ,galileo's dialogue4 ,but   

this1 of course1 is in no sense a guide 
to the state of general opinion         
regarding the theory4 ,we shall gain a  
true gauge as to this if we assume that 
the greater number of important thinkers
 had accepted the heliocentric doctrine 
before the middle of the seventeenth    
century1 and that before the close of   
that century the old ,ptolemaic idea had
 been quite abandoned4 ,a wonderful     
revolution in man's estimate of the     
universe had thus been effected within  
about two centuries after the birth of  
,copernicus4     ,v4 ,,galileo ,,and    
,,the ,,new ,,physics  ,after ,galileo  
had felt the strong hand of the         
,inquisition1 in #afcb1 he was careful  
to confine his researches1 or at least  
his publications1 to topics that seemed 
free from theological implications4 ,in 
doing so he reverted to the field of his
 earliest studies--namely1 the field of 
mechanics2 and the ,dialoghi delle      
,nuove ,scienze1 which he finished in   
#afcf1 and which was printed two years  

later1 attained a celebrity no less than
 that of the heretical dialogue that had
 preceded it4 ,the later work was free  
from all apparent heresies1 yet perhaps 
it did more towards the establishment of
 the ,copernican doctrine1 through the  
teaching of correct mechanical          
principles1 than the other work had     
accomplished by a more direct method4   
,galileo's astronomical discoveries     
were1 as we have seen1 in a sense       
accidental2 at least1 they received     
their inception through the inventive   
genius of another4 ,his mechanical      
discoveries1 on the other hand1 were the
 natural output of his own creative     
genius4 ,at the very beginning of his   
career1 while yet a very young man1     
though a professor of mathematics at    
,pisa1 he had begun that onslaught upon 
the old ,aristotelian ideas which he was
 to continue throughout his life4 ,at   
the famous leaning tower in ,pisa1 the  
young iconoclast performed1 in the year 
#aeij1 one of the most theatrical       

demonstrations in the history of        
science4 ,assembling a multitude of     
champions of the old ideas1 he proposed 
to demonstrate the falsity of the       
,aristotelian doctrine that the velocity
 of falling bodies is proportionate to  
their weight4 ,there is perhaps no fact 
more strongly illustrative of the temper
 of the ,middle ,ages than the fact that
 this doctrine1 as taught by the        
,aristotelian philosopher1 should so    
long have gone unchallenged4 ,now1      
however1 it was put to the test2        
,galileo released a half-pound weight   
and a hundred-pound cannon-ball from    
near the top of the tower1 and1 needless
 to say1 they reached the ground        
together4 ,of course1 the spectators    
were but little pleased with what they  
saw4 ,they could not doubt the evidence 
of their own senses as to the particular
 experiment in question2 they could     
suggest1 however1 that the experiment   
involved a violation of the laws of     
nature through the practice of magic4   

,to controvert so firmly established an 
idea savored of heresy4 ,the young man  
guilty of such iconoclasm was naturally 
looked at askance by the scholarship of 
his time4 ,instead of being applauded1  
he was hissed1 and he found it expedient
 presently to retire from ,pisa4        
,fortunately1 however1 the new spirit of
 progress had made itself felt more     
effectively in some other portions of   
,italy1 and so ,galileo found a refuge  
and a following in ,padua1 and          
afterwards in ,florence2 and while1 as  
we have seen1 he was obliged to curb his
 enthusiasm regarding the subject that  
was perhaps nearest his heart--the      
promulgation of the ,copernican         
theory--yet he was permitted in the main
 to carry on his experimental           
observations unrestrained4 ,these       
experiments gave him a place of         
unquestioned authority among his        
contemporaries1 and they have           
transmitted his name to posterity as    
that of one of the greatest of          

experimenters and the virtual founder of
 modern mechanical science4 ,the        
experiments in question range over a    
wide field2 but for the most part they  
have to do with moving bodies and with  
questions of force1 or1 as we should now
 say1 of energy4 ,the experiment at the 
leaning tower showed that the velocity  
of falling bodies is independent of the 
weight of the bodies1 provided the      
weight is sufficient to overcome the    
resistance of the atmosphere4 ,later    
experiments with falling bodies led to  
the discovery of laws regarding the     
accelerated velocity of fall4 ,such     
velocities were found to bear a simple  
relation to the period of time from the 
beginning of the fall4 ,other           
experiments1 in which balls were allowed
 to roll down inclined planes1          
corroborated the observation that the   
pull of gravitation gave a velocity     
proportionate to the length of fall1    
whether such fall were direct or in a   
slanting direction4  ,these studies were

 associated with observations on        
projectiles1 regarding which ,galileo   
was the first to entertain correct      
notions4 ,according to the current idea1
 a projectile fired1 for example1 from a
 cannon1 moved in a straight horizontal 
line until the propulsive force was     
exhausted1 and then fell to the ground  
in a perpendicular line4 ,galileo taught
 that the projectile begins to fall at  
once on leaving the mouth of the cannon 
and traverses a parabolic course4       
,according to his idea1 which is now    
familiar to every one1 a cannon-ball    
dropped from the level of the cannon's  
muzzle will strike the ground           
simultaneously with a ball fired        
horizontally from the cannon4 ,as to the
 paraboloid course pursued by the       
projectile1 the resistance of the air is
 a factor which ,galileo could not      
accurately compute1 and which interferes
 with the practical realization of his  
theory4 ,but this is a minor            
consideration4 ,the great importance of 

his idea consists in the recognition    
that such a force as that of gravitation
 acts in precisely the same way upon all
 unsupported bodies1 whether or not such
 bodies be at the same time acted upon  
by a force of translation4  ,out of     
these studies of moving bodies was      
gradually developed a correct notion of 
several important general laws of       
mechanics--laws a knowledge of which was
 absolutely essential to the progress of
 physical science4 ,the belief in the   
rotation of the earth made necessary a  
clear conception that all bodies at the 
surface of the earth partake of that    
motion quite independently of their     
various observed motions in relation to 
one another4 ,this idea was hard to     
grasp1 as an oft-repeated argument      
shows4 ,it was asserted again and again 
that1 if the earth rotates1 a stone     
dropped from the top of a tower could   
not fall at the foot of the tower1 since
 the earth's motion would sweep the     
tower far away from its original        

position while the stone is in transit4 
,this was one of the stock arguments    
against the earth's motion1 yet it was  
one that could be refuted with the      
greatest ease by reasoning from strictly
 analogous experiments4 ,it might       
readily be observed1 for example1 that a
 stone dropped from a moving cart does  
not strike the ground directly below the
 point from which it is dropped1 but    
partakes of the forward motion of the   
cart4 ,if any one doubt this he has but 
to jump from a moving cart to be given a
 practical demonstration of the fact    
that his entire body was in some way    
influenced by the motion of translation4
 ,similarly1 the simple experiment of   
tossing a ball from the deck of a moving
 ship will convince any one that the    
ball partakes of the motion of the ship1
 so that it can be manipulated precisely
 as if the manipulator were standing on 
the earth4 ,in short1 every-day         
experience gives us illustrations of    
what might be called compound motion1   

which makes it seem altogether plausible
 that1 if the earth is in motion1       
objects at its surface will partake of  
that motion in a way that does not      
interfere with any other movements to   
which they may be subjected4 ,as the    
,copernican doctrine made its way1 this 
idea of compound motion naturally       
received more and more attention1 and   
such experiments as those of ,galileo   
prepared the way for a new              
interpretation of the mechanical        
principles involved4  ,the great        
difficulty was that the subject of      
moving bodies had all along been        
contemplated from a wrong point of view4
 ,since force must be applied to an     
object to put it in motion1 it was      
perhaps not unnaturally assumed that    
similar force must continue to be       
applied to keep the object in motion4   
,when1 for example1 a stone is thrown   
from the hand1 the direct force applied 
necessarily ceases as soon as the       
projectile leaves the hand4 ,the stone1 

nevertheless1 flies on for a certain    
distance and then falls to the ground4  
,how is this flight of the stone to be  
explained8 ,the ancient philosophers    
puzzled more than a little over this    
problem1 and the ,aristotelians reached 
the conclusion that the motion of the   
hand had imparted a propulsive motion to
 the air1 and that this propulsive      
motion was transmitted to the stone1    
pushing it on4 ,just how the air took on
 this propulsive property was not       
explained1 and the vagueness of thought 
that characterized the time did not     
demand an explanation4 ,possibly the    
dying away of ripples in water may have 
furnished1 by analogy1 an explanation of
 the gradual dying out of the impulse   
which propels the stone4  ,all of this  
was1 of course1 an unfortunate          
maladjustment of the point of view4 ,as 
every one nowadays knows1 the air       
retards the progress of the stone1      
enabling the pull of gravitation to drag
 it to the earth earlier than it        

otherwise could4 ,were the resistance of
 the air and the pull of gravitation    
removed1 the stone as projected from the
 hand would fly on in a straight line1  
at an unchanged velocity1 forever4 ,but 
this fact1 which is expressed in what we
 now term the first law of motion1 was  
extremely difficult to grasp4 ,the first
 important step towards it was perhaps  
implied in ,galileo's study of falling  
bodies4 ,these studies1 as we have seen1
 demonstrated that a half-pound weight  
and a hundred-pound weight fall with the
 same velocity4 ,it is1 however1 matter 
of common experience that certain       
bodies1 as1 for example1 feathers1 do   
not fall at the same rate of speed with 
these heavier bodies4 ,this anomaly     
demands an explanation1 and the         
explanation is found in the resistance  
offered the relatively light object by  
the air4 ,once the idea that the air may
 thus act as an impeding force was      
grasped1 the investigator of mechanical 
principles had entered on a new and     

promising course4  ,galileo could not   
demonstrate the retarding influence of  
air in the way which became familiar a  
generation or two later2 he could not   
put a feather and a coin in a vacuum    
tube and prove that the two would there 
fall with equal velocity1 because1 in   
his day1 the air-pump had not yet been  
invented4 ,the experiment was made only 
a generation after the time of ,galileo1
 as we shall see2 but1 meantime1 the    
great ,italian had fully grasped the    
idea that atmospheric resistance plays a
 most important part in regard to the   
motion of falling and projected bodies4 
,thanks largely to his own experiments1 
but partly also to the efforts of       
others1 he had come1 before the end of  
his life1 pretty definitely to realize  
that the motion of a projectile1 for    
example1 must be thought of as inherent 
in the projectile itself1 and that the  
retardation or ultimate cessation of    
that motion is due to the action of     
antagonistic forces4 ,in other words1 he

 had come to grasp the meaning of the   
first law of motion4 ,it remained1      
however1 for the great ,frenchman       
,descartes to give precise expression to
 this law two years after ,galileo's    
death4 ,as ,descartes expressed it in   
his ,principia ,philosophiae1 published 
in #afdd1 any body once in motion tends 
to go on in a straight line1 at a       
uniform rate of speed1 forever4         
,contrariwise1 a stationary body will   
remain forever at rest unless acted on  
by some disturbing force4  ,this        
all-important law1 which lies at the    
very foundation of all true conceptions 
of mechanics1 was thus worked out during
 the first half of the seventeenth      
century1 as the outcome of numberless   
experiments for which ,galileo's        
experiments with failing bodies         
furnished the foundation4 ,so numerous  
and so gradual were the steps by which  
the reversal of view regarding moving   
bodies was effected that it is          
impossible to trace them in detail4 ,we 

must be content to reflect that at the  
beginning of the ,galilean epoch utterly
 false notions regarding the subject    
were entertained by the very greatest   
philosophers--by ,galileo himself1 for  
example1 and by ,kepler--whereas at the 
close of that epoch the correct and     
highly illuminative view had been       
attained4  ,we must now consider some   
other experiments of ,galileo which led 
to scarcely less-important results4 ,the
 experiments in question had to do with 
the movements of bodies passing down an 
inclined plane1 and with the allied     
subject of the motion of a pendulum4    
,the elaborate experiments of ,galileo  
regarding the former subject were made  
by measuring the velocity of a ball     
rolling down a plane inclined at various
 angles4 ,he found that the velocity    
acquired by a ball was proportional to  
the height from which the ball descended
 regardless of the steepness of the     
incline4 ,experiments were made also    
with a ball rolling down a curved       

gutter1 the curve representing the are  
of a circle4 ,these experiments led to  
the study of the curvilinear motions of 
a weight suspended by a cord2 in other  
words1 of the pendulum4  ,regarding the 
motion of the pendulum1 some very       
curious facts were soon ascertained4    
,galileo found1 for example1 that a     
pendulum of a given length performs its 
oscillations with the same frequency    
though the arc described by the pendulum
 be varied greatly47#a7 ,he found1 also1
 that the rate of oscillation for       
pendulums of different lengths varies   
according to a simple law4 ,in order    
that one pendulum shall oscillate       
one-half as fast as another1 the length 
of the pendulums must be as four to one4
 ,similarly1 by lengthening the         
pendulums nine times1 the oscillation is
 reduced to one-third1 ,in other words1 
the rate of oscillation of pendulums    
varies inversely as the square of their 
length4 ,here1 then1 is a simple        
relation between the motions of swinging

 bodies which suggests the relation     
which ,kepler bad discovered between the
 relative motions of the planets4 ,every
 such discovery coming in this age of   
the rejuvenation of experimental science
 had a peculiar force in teaching men   
the all-important lesson that simple    
laws lie back of most of the diverse    
phenomena of nature1 if only these laws 
can be discovered4  ,galileo further    
observed that his pendulum might be     
constructed of any weight sufficiently  
heavy readily to overcome the           
atmospheric resistance1 and that1 with  
this qualification1 neither the weight  
nor the material had any influence upon 
the time of oscillation1 this being     
solely determined by the length of the  
cord4 ,naturally1 the practical utility 
of these discoveries was not overlooked 
by ,galileo4 ,since a pendulum of a     
given length oscillates with unvarying  
rapidity1 here is an obvious means of   
measuring time4 ,galileo1 however1      
appears not to have met with any great  

measure of success in putting this idea 
into practice4 ,it remained for the     
mechanical ingenuity of ,huyghens to    
construct a satisfactory pendulum clock4
  ,as a theoretical result of the       
studies of rolling and oscillating      
bodies1 there was developed what is     
usually spoken of as the third law of   
motion--namely1 the law that a given    
force operates upon a moving body with  
an effect proportionate to its effect   
upon the same body when at rest4 ,or1 as
 ,whewell states the law3 ,the dynamical
 effect of force is as the statical     
effect2 that is1 the velocity which any 
force generates in a given time1 when it
 puts the body in motion1 is            
proportional to the pressure which this 
same force produces in a body at        
rest47#b7 ,according to the second law  
of motion1 each one of the different    
forces1 operating at the same time upon 
a moving body1 produces the same effect 
as if it operated upon the body while at
 rest4   ,,stevinus ,,and ,,the ,,law   

,,of ,,equilibrium  ,it appears1 then1  
that the mechanical studies of ,galileo1
 taken as a whole1 were nothing less    
than revolutionary4 ,they constituted   
the first great advance upon the dynamic
 studies of ,archimedes1 and then led to
 the secure foundation for one of the   
most important of modern sciences4 ,we  
shall see that an important company of  
students entered the field immediately  
after the time of ,galileo1 and carried 
forward the work he had so well begun4  
,but before passing on to the           
consideration of their labors1 we must  
consider work in allied fields of two   
men who were contemporaries of ,galileo 
and whose original labors were in some  
respects scarcely less important than   
his own4 ,these men are the ,dutchman   
,stevinus1 who must always be remembered
 as a co-laborer with ,galileo in the   
foundation of the science of dynamics1  
and the ,englishman ,gilbert1 to whom is
 due the unqualified praise of first    
subjecting the phenomenon of magnetism  

to a strictly scientific investigation4 
,stevinus was born in the year #aedh1   
and died in #afbj4 ,he was a man of a   
practical genius1 and he attracted the  
attention of his non-scientific         
contemporaries1 among other ways1 by the
 construction of a curious land-craft1  
which1 mounted on wheels1 was to be     
propelled by sails like a boat4 ,not    
only did he write a book on this curious
 horseless carriage1 but he put his idea
 into practical application1 producing a
 vehicle which actually traversed the   
distance between ,scheveningen and      
,petton1 with no fewer than twenty-seven
 passengers1 one of them being ,prince  
,maurice of ,orange4 ,this demonstration
 was made about the year #afjj4 ,it does
 not appear1 however1 that any important
 use was made of the strange vehicle2   
but the man who invented it put his     
mechanical ingenuity to other use with  
better effect4 ,it was he who solved the
 problem of oblique forces1 and who     
discovered the important hydrostatic    

principle that the pressure of fluids is
 proportionate to their depth1 without  
regard to the shape of the including    
vessel4  ,the study of oblique forces   
was made by ,stevinus with the aid of   
inclined planes4 ,his most demonstrative
 experiment was a very simple one1 in   
which a chain of balls of equal weight  
was hung from a triangle2 the triangle  
being so constructed as to rest on a    
horizontal base1 the oblique sides      
bearing the relation to each other of   
two to one4 ,stevinus found that his    
chain of balls just balanced when four  
balls were on the longer side and two on
 the shorter and steeper side4 ,the     
balancing of force thus brought about   
constituted a stable equilibrium1       
,stevinus being the first to            
discriminate between such a condition   
and the unbalanced condition called     
unstable equilibrium4 ,by this simple   
experiment was laid the foundation of   
the science of statics4 ,stevinus had a 
full grasp of the principle which his   

experiment involved1 and he applied it  
to the solution of oblique forces in all
 directions4 ,earlier investigations of 
,stevinus were published in #afjh4 ,his 
collected works were published at       
,leyden in #afcd4  ,this study of the   
equilibrium of pressure of bodies at    
rest led ,stevinus1 not unnaturally1 to 
consider the allied subject of the      
pressure of liquids4 ,he is to be       
credited with the explanation of the    
so-called hydrostatic paradox4 ,the     
familiar modern experiment which        
illustrates this paradox is made by     
inserting a long perpendicular tube of  
small caliber into the top of a tight   
barrel4 ,on filling the barrel and tube 
with water1 it is possible to produce a 
pressure which will burst the barrel1   
though it be a strong one1 and though   
the actual weight of water in the tube  
is comparatively insignificant4 ,this   
illustrates the fact that the pressure  
at the bottom of a column of liquid is  
proportionate to the height of the      

column1 and not to its bulk1 this being 
the hydrostatic paradox in question4    
,the explanation is that an enclosed    
fluid under pressure exerts an equal    
force upon all parts of the             
circumscribing wall2 the aggregate      
pressure may1 therefore1 be increased   
indefinitely by increasing the surface4 
,it is this principle1 of course1 which 
is utilized in the familiar hydrostatic 
press4 ,theoretical explanations of the 
pressure of liquids were supplied a     
generation or two later by numerous     
investigators1 including ,newton1 but   
the practical refoundation of the       
science of hydrostatics in modern times 
dates from the experiments of ,stevinus4
   ,,galileo ,,and ,,the ,,equilibrium  
,,of ,,fluids  ,experiments of an allied
 character1 having to do with the       
equilibrium of fluids1 exercised the    
ingenuity of ,galileo4 ,some of his most
 interesting experiments have to do with
 the subject of floating bodies4 ,it    
will be recalled that ,archimedes1 away 

back in the ,alexandrian epoch1 had     
solved the most important problems of   
hydrostatic equilibrium4 ,now1 however1 
his experiments were overlooked or      
forgotten1 and ,galileo was obliged to  
make experiments anew1 and to combat    
fallacious views that ought long since  
to have been abandoned4 ,perhaps the    
most illuminative view of the spirit of 
the times can be gained by quoting at   
length a paper of ,galileo's1 in which  
he details his own experiments with     
floating bodies and controverts the     
views of his opponents4 ,the paper has  
further value as illustrating ,galileo's
 methods both as experimenter and as    
speculative reasoner4  ,the current     
view1 which ,galileo here undertakes to 
refute1 asserts that water offers       
resistance to penetration1 and that this
 resistance is instrumental in          
determining whether a body placed in    
water will float or sink4 ,galileo      
contends that water is non-resistant1   
and that bodies float or sink in virtue 

of their respective weights4 ,this1 of  
course1 is merely a restatement of the  
law of ,archimedes4 ,but it remains to  
explain the fact that bodies of a       
certain shape will float1 while bodies  
of the same material and weight1 but of 
a different shape1 will sink4 ,we shall 
see what explanation ,galileo finds of  
this anomaly as we proceed4  ,in the    
first place1 ,galileo makes a cone of   
wood or of wax1 and shows that when it  
floats with either its point or its base
 in the water1 it displaces exactly the 
same amount of fluid1 although the apex 
is by its shape better adapted to       
overcome the resistance of the water1 if
 that were the cause of buoyancy4       
,again1 the experiment may be varied by 
tempering the wax with filings of lead  
till it sinks in the water1 when it will
 be found that in any figure the same   
quantity of cork must be added to it to 
raise the surface4  ,but1 says ,galileo1
 this silences not my antagonists2 they 
say that all the discourse hitherto made

 by me imports little to them1 and that 
it serves their turn2 that they have    
demonstrated in one instance1 and in    
such manner and figure as pleases them  
best--namely1 in a board and in a ball  
of ebony--that one when put into the    
water sinks to the bottom1 and that the 
other stays to swim on the top2 and the 
matter being the same1 and the two      
bodies differing in nothing but in      
figure1 they affirm that with all       
perspicuity they have demonstrated and  
sensibly manifested what they undertook4
 ,nevertheless1 ,i believe1 and think ,i
 can prove1 that this very experiment   
proves nothing against my theory4 ,and  
first1 it is false that the ball sinks  
and the board not2 for the board will   
sink1 too1 if you do to both the figures
 as the words of our question require2  
that is1 if you put them both in the    
water2 for to be in the water implies to
 be placed in the water1 and by         
,aristotle's own definition of place1 to
 be placed imports to be environed by   

the surface of the ambient body2 but    
when my antagonists show the floating   
board of ebony1 they put it not into the
 water1 but upon the water2 where1 being
 detained by a certain impediment 7of   
which more anon71 it is surrounded1     
partly with water1 partly with air1     
which is contrary to our agreement1 for 
that was that bodies should be in the   
water1 and not part in the water1 part  
in the air4  ,i will not omit another   
reason1 founded also upon experience1   
and1 if ,i deceive not myself1          
conclusive against the notion that      
figure1 and the resistance of the water 
to penetration1 have anything to do with
 the buoyancy of bodies4 ,choose a piece
 of wood or other matter1 as1 for       
instance1 walnut-wood1 of which a ball  
rises from the bottom of the water to   
the surface more slowly than a ball of  
ebony of the same size sinks1 so that1  
clearly1 the ball of ebony divides the  
water more readily in sinking than the  
ball of wood does in rising4 ,then take 

a board of walnut-tree equal to and like
 the floating one of my antagonists2 and
 if it be true that this latter floats  
by reason of the figure being unable to 
penetrate the water1 the other of       
walnut-tree1 without a question1 if     
thrust to the bottom1 ought to stay     
there1 as having the same impeding      
figure1 and being less apt to overcome  
the said resistance of the water4 ,but  
if we find by experience that not only  
the thin board1 but every other figure  
of the same walnut-tree1 will return to 
float1 as unquestionably we shall1 then 
,i must desire my opponents to forbear  
to attribute the floating of the ebony  
to the figure of the board1 since the   
resistance of the water is the same in  
rising as in sinking1 and the force of  
ascension of the walnut-tree is less    
than the ebony's force for going to the 
bottom4  ,now let us return to the thin 
plate of gold or silver1 or the thin    
board of ebony1 and let us lay it       
lightly upon the water1 so that it may  

stay there without sinking1 and         
carefully observe the effect4 ,it will  
appear clearly that the plates are a    
considerable matter lower than the      
surface of the water1 which rises up and
 makes a kind of rampart round them on  
every side4 ,but if it has already      
penetrated and overcome the continuity  
of the water1 and is of its own nature  
heavier than the water1 why does it not 
continue to sink1 but stop and suspend  
itself in that little dimple that its   
weight has made in the water8 ,my answer
 is1 because in sinking till its surface
 is below the water1 which rises up in a
 bank round it1 it draws after and      
carries along with it the air above it1 
so that that which1 in this case1       
descends in the water is not only the   
board of ebony or the plate of iron1 but
 a compound of ebony and air1 from which
 composition results a solid no longer  
specifically heavier than the water1 as 
was the ebony or gold alone4 ,but1      
gentlemen1 we want the same matter2 you 

are to alter nothing but the shape1 and1
 therefore1 have the goodness to remove 
this air1 which may be done simply by   
washing the surface of the board1 for   
the water having once got between the   
board and the air will run together1 and
 the ebony will go to the bottom2 and if
 it does not1 you have won the day4     
,but methinks ,i hear some of my        
antagonists cunningly opposing this1 and
 telling me that they will not on any   
account allow their boards to be wetted1
 because the weight of the water so     
added1 by making it heavier than it was 
before1 draws it to the bottom1 and that
 the addition of new weight is contrary 
to our agreement1 which was that the    
matter should be the same4  ,to this ,i 
answer1 first1 that nobody can suppose  
bodies to be put into the water without 
their being wet1 nor do ,i wish to do   
more to the board than you may do to the
 ball4 ,moreover1 it is not true that   
the board sinks on account of the weight
 of the water added in the washing2 for 

,i will put ten or twenty drops on the  
floating board1 and so long as they     
stand separate it shall not sink2 but if
 the board be taken out and all that    
water wiped off1 and the whole surface  
bathed with one single drop1 and put it 
again upon the water1 there is no       
question but it will sink1 the other    
water running to cover it1 being no     
longer hindered by the air4 ,in the next
 place1 it is altogether false that     
water can in any way increase the weight
 of bodies immersed in it1 for water has
 no weight in water1 since it does not  
sink4 ,now just as he who should say    
that brass by its own nature sinks1 but 
that when formed into the shape of a    
kettle it acquires from that figure the 
virtue of lying in water without        
sinking1 would say what is false1       
because that is not purely brass which  
then is put into the water1 but a       
compound of brass and air2 so is it     
neither more nor less false that a thin 
plate of brass or ebony swims by virtue 

of its dilated and broad figure4 ,also1 
,i cannot omit to tell my opponents that
 this conceit of refusing to bathe the  
surface of the board might beget an     
opinion in a third person of a poverty  
of argument on their side1 especially as
 the conversation began about flakes of 
ice1 in which it would be simple to     
require that the surfaces should be kept
 dry2 not to mention that such pieces of
 ice1 whether wet or dry1 always float1 
and so my antagonists say1 because of   
their shape4  ,some may wonder that ,i  
affirm this power to be in the air of   
keeping plate of brass or silver above  
water1 as if in a certain sense ,i would
 attribute to the air a kind of magnetic
 virtue for sustaining heavy bodies with
 which it is in contact4 ,to satisfy all
 these doubts ,i have contrived the     
following experiment to demonstrate how 
truly the air does support these bodies2
 for ,i have found1 when one of these   
bodies which floats when placed lightly 
on the water is thoroughly bathed and   

sunk to the bottom1 that by carrying    
down to it a little air without         
otherwise touching it in the least1 ,i  
am able to raise and carry it back to   
the top1 where it floats as before4 ,to 
this effect1 ,i take a ball of wax1 and 
with a little lead make it just heavy   
enough to sink very slowly to the       
bottom1 taking care that its surface be 
quite smooth and even4 ,this1 if put    
gently into the water1 submerges almost 
entirely1 there remaining visible only a
 little of the very top1 which1 so long 
as it is joined to the air1 keeps the   
ball afloat2 but if we take away the    
contact of the air by wetting this top1 
the ball sinks to the bottom and remains
 there4 ,now to make it return to the   
surface by virtue of the air which      
before sustained it1 thrust into the    
water a glass with the mouth downward1  
which will carry with it the air it     
contains1 and move this down towards the
 ball until you see1 by the transparency
 of the glass1 that the air has reached 

the top of it2 then gently draw the     
glass upward1 and you will see the ball 
rise1 and afterwards stay on the top of 
the water1 if you carefully part the    
glass and water without too much        
disturbing it47#c7  ,it will be seen    
that ,galileo1 while holding in the main
 to a correct thesis1 yet mingles with  
it some false ideas4 ,at the very       
outset1 of course1 it is not true that  
water has no resistance to penetration2 
it is true1 however1 in the sense in    
which ,galileo uses the term--that is to
 say1 the resistance of the water to    
penetration is not the determining      
factor ordinarily in deciding whether a 
body sinks or floats4 ,yet in the case  
of the flat body it is not altogether   
inappropriate to say that the water     
resists penetration and thus supports   
the body4 ,the modern physicist explains
 the phenomenon as due to               
surface-tension of the fluid4 ,of       
course1 ,galileo's disquisition on the  
mixing of air with the floating body is 

utterly fanciful4 ,his experiments were 
beautifully exact2 his theorizing from  
them was1 in this instance1 altogether  
fallacious4 ,thus1 as already intimated1
 his paper is admirably adapted to      
convey a double lesson to the student of
 science4   ,,william ,,gilbert ,,and   
,,the ,,study ,,of ,,magnetism  ,it will
 be observed that the studies of        
,galileo and ,stevinus were chiefly     
concerned with the force of gravitation4
 ,meanwhile1 there was an ,english      
philosopher of corresponding genius1    
whose attention was directed towards    
investigation of the equally mysterious 
force of terrestrial magnetism4 ,with   
the doubtful exception of ,bacon1       
,gilbert was the most distinguished man 
of science in ,england during the reign 
of ,queen ,elizabeth4 ,he was for many  
years court physician1 and ,queen       
,elizabeth ultimately settled upon him a
 pension that enabled him to continue   
his researches in pure science4  ,his   
investigations in chemistry1 although   

supposed to be of great importance1 are 
mostly lost2 but his great work1 ,de    
,magnete1 on which he labored for       
upwards of eighteen years1 is a work of 
sufficient importance1 as ,hallam says1 
to raise a lasting reputation for its   
author4 ,from its first appearance it   
created a profound impression upon the  
learned men of the continent1 although  
in ,england ,gilbert's theories seem to 
have been somewhat less favorably       
received4 ,galileo freely expressed his 
admiration for the work and its author2 
,bacon1 who admired the author1 did not 
express the same admiration for his     
theories2 but ,dr4 ,priestley1 later1   
declared him to be the father of modern 
electricity4  ,strangely enough1        
,gilbert's book had never been          
translated into ,english1 or apparently 
into any other language1 until recent   
years1 although at the time of its      
publication certain learned men1 unable 
to read the book in the original1 had   
asked that it should be4 ,by this       

neglect1 or oversight1 a great number of
 general readers as well as many        
scientists1 through succeeding          
centuries1 have been deprived of the    
benefit of writings that contained a    
good share of the fundamental facts     
about magnetism as known to-day4        
,gilbert was the first to discover that 
the earth is a great magnet1 and he not 
only gave the name of pole to the       
extremities of the magnetic needle1 but 
also spoke of these poles as north and  
south pole1 although he used these names
 in the opposite sense from that in     
which we now use them1 his south pole   
being the extremity which pointed       
towards the north1 and vice versa4 ,he  
was also first to make use of the terms 
electric force1 electric emanations1 and
 electric attractions4  ,it is hardly   
necessary to say that some of the views 
taken by ,gilbert1 many of his theories1
 and the accuracy of some of his        
experiments have in recent times been   
found to be erroneous4 ,as a pioneer in 

an unexplored field of science1 however1
 his work is remarkably accurate4 ,on   
the whole1 says ,dr4 ,john ,robinson1   
this performance contains more real     
information than any writing of the age 
in which he lived1 and is scarcely      
exceeded by any that has appeared       
since47#d7  ,in the preface to his work 
,gilbert says3 ,since in the discovery  
of secret things1 and in the            
investigation of hidden causes1 stronger
 reasons are obtained from sure         
experiments and demonstrated arguments  
than from probable conjectures and the  
opinions of philosophical speculators of
 the common sort1 therefore1 to the end 
of that noble substance of that great   
loadstone1 our common mother 7the       
earth71 still quite unknown1 and also   
that the forces extraordinary and       
exalted of this globe may the better be 
understood1 we have decided1 first1 to  
begin with the common stony and         
ferruginous matter1 and magnetic bodies1
 and the part of the earth that we may  

handle and may perceive with senses1 and
 then to proceed with plain magnetic    
experiments1 and to penetrate to the    
inner parts of the earth47#e7  ,before  
taking up the demonstration that the    
earth is simply a giant loadstone1      
,gilbert demonstrated in an ingenious   
way that every loadstone1 of whatever   
size1 has definite and fixed poles4 ,he 
did this by placing the stone in a metal
 lathe and converting it into a sphere1 
and upon this sphere demonstrated how   
the poles can be found4 ,to this round  
loadstone he gave the name of           
terrella--that is1 little earth4  ,to   
find1 then1 poles answering to the      
earth1 he says1 take in your hand the   
round stone1 and lay on it a needle or a
 piece of iron wire3 the ends of the    
wire move round their middle point1 and 
suddenly come to a standstill4 ,now1    
with ochre or with chalk1 mark where the
 wire lies still and sticks4 ,then move 
the middle or centre of the wire to     
another spot1 and so to a third and     

fourth1 always marking the stone along  
the length of the wire where it stands  
still2 the lines so marked will exhibit 
meridian circles1 or circles like       
meridians1 on the stone or terrella2 and
 manifestly they will all come together 
at the poles of the stone4 ,the circle  
being continued in this way1 the poles  
appear1 both the north and the south1   
and betwixt these1 midway1 we may draw a
 large circle for an equator1 as is done
 by the astronomer in the heavens and on
 his spheres1 and by the geographer on  
the terrestrial globe47#f7  ,gilbert had
 tried the familiar experiment of       
placing the loadstone on a float in     
water1 and observed that the poles      
always revolved until they pointed north
 and south1 which he explained as due to
 the earth's magnetic attraction4 ,in   
this same connection he noticed that a  
piece of wrought iron mounted on a cork 
float was attracted by other metals to a
 slight degree1 and he observed also    
that an ordinary iron bar1 if suspended 

horizontally by a thread1 assumes       
invariably a north and south direction4 
,these1 with many other experiments of a
 similar nature1 convinced him that the 
earth is a magnet and a loadstone1 which
 he says is a new and till now          
unheard-of view of the earth4  ,fully to
 appreciate ,gilbert's revolutionary    
views concerning the earth as a magnet1 
it should be remembered that numberless 
theories to explain the action of the   
electric needle had been advanced4      
,columbus and ,paracelsus1 for example1 
believed that the magnet was attracted  
by some point in the heavens1 such as a 
magnetic star4 ,gilbert himself tells of
 some of the beliefs that had been held 
by his predecessors1 many of whom he    
declares wilfully falsify4 ,one of his  
first steps was to refute by experiment 
such assertions as that of ,cardan1 that
 a wound by a magnetized needle was     
painless2 and also the assertion of     
,fracastoni that loadstone attracts     
silver2 or that of ,scalinger1 that the 

diamond will attract iron2 and the      
statement of ,matthiolus that iron      
rubbed with garlic is no longer         
attracted to the loadstone4  ,gilbert   
made extensive experiments to explain   
the dipping of the needle1 which had    
been first noticed by ,william ,norman4 
,his deduction as to this phenomenon led
 him to believe that this was also      
explained by the magnetic attraction of 
the earth1 and to predict where the     
vertical dip would be found4 ,these     
deductions seem the more wonderful      
because at the time he made them the dip
 had just been discovered1 and had not  
been studied except at ,london4 ,his    
theory of the dip was1 therefore1 a     
scientific prediction1 based on a       
preconceived hypothesis4 ,gilbert found 
the dip to be #gb degrees at ,london2   
eight years later ,hudson found the dip 
at #ge degrees #bb' north latitude to be
 #hi degrees #cj'2 but it was not until 
over two hundred years later1 in #ahca1 
that the vertical dip was first observed

 by ,sir ,james ,ross at about #gj      
degrees #e' north latitude1 and #if     
degrees #dc' west longitude4 ,this was  
not the exact point assumed by ,gilbert1
 and his scientific predictions1        
therefore1 were not quite correct2 but  
such comparatively slight and excusable 
errors mar but little the excellence of 
his work as a whole4  ,a brief epitome  
of some of his other important          
discoveries suffices to show that the   
exalted position in science accorded him
 by contemporaries1 as well as          
succeeding generations of scientists1   
was well merited4 ,he was first to      
distinguish between magnetism and       
electricity1 giving the latter its name4
 ,he discovered also the electrical     
charge1 and pointed the way to the      
discovery of insulation by showing that 
the charge could be retained some time  
in the excited body by covering it with 
some non-conducting substance1 such as  
silk2 although1 of course1 electrical   
conduction can hardly be said to have   

been more than vaguely surmised1 if     
understood at all by him4 ,the first    
electrical instrument ever made1 and    
known as such1 was invented by him1 as  
was also the first magnetometer1 and the
 first electrical indicating device4    
,although three centuries have elapsed  
since his death1 the method of          
magnetizing iron first introduced by him
 is in common use to-day4  ,he made     
exhaustive experiments with a needle    
balanced on a pivot to see how many     
substances he could find which1 like    
amber1 on being rubbed affected the     
needle4 ,in this way he discovered that 
light substances were attracted by alum1
 mica1 arsenic1 sealing-wax1 lac        
sulphur1 slags1 beryl1 amethyst1        
rock-crystal1 sapphire1 jet1 carbuncle1 
diamond1 opal1 ,bristol stone1 glass1   
glass of antimony1 gum-mastic1 hard     
resin1 rock-salt1 and1 of course1 amber4
 ,he discovered also that atmospheric   
conditions affected the production of   
electricity1 dryness being unfavorable  

and moisture favorable4  ,galileo's     
estimate of this first electrician is   
the verdict of succeeding generations4  
,i extremely admire and envy this       
author1 he said4 ,i think him worthy of 
the greatest praise for the many new and
 true observations which he has made1 to
 the disgrace of so many vain and       
fabling authors4   ,,studies ,,of       
,,light1 ,,heat1 ,,and ,,atmospheric    
,,pressure  ,we have seen that ,gilbert 
was by no means lacking in versatility1 
yet the investigations upon which his   
fame is founded were all pursued along  
one line1 so that the father of         
magnetism may be considered one of the  
earliest of specialists in physical     
science4 ,most workers of the time1 on  
the other band1 extended their          
investigations in many directions4 ,the 
sum total of scientific knowledge of    
that day had not bulked so large as to  
exclude the possibility that one man    
might master it all4 ,so we find a      
,galileo1 for example1 making           

revolutionary discoveries in astronomy1 
and performing fundamental experiments  
in various fields of physics4 ,galileo's
 great contemporary1 ,kepler1 was almost
 equally versatile1 though his          
astronomical studies were of such       
pre-eminent importance that his other   
investigations sink into relative       
insignificance4 ,yet he performed some  
notable experiments in at least one     
department of physics4 ,these           
experiments had to do with the          
refraction of light1 a subject which    
,kepler was led to investigate1 in part 
at least1 through his interest in the   
telescope4  ,we have seen that ,ptolemy 
in the ,alexandrian time1 and ,alhazen1 
the ,arab1 made studies of refraction4  
,kepler repeated their experiments1 and1
 striving as always to generalize his   
observations1 he attempted to find the  
law that governed the observed change of
 direction which a ray of light assumes 
in passing from one medium to another4  
,kepler measured the angle of refraction

 by means of a simple yet ingenious     
trough-like apparatus which enabled him 
to compare readily the direct and       
refracted rays4 ,he discovered that when
 a ray of light passes through a glass  
plate1 if it strikes the farther surface
 of the glass at an angle greater than  
#de degrees it will be totally refracted
 instead of passing through into the    
air4 ,he could not well fail to know    
that different mediums refract light    
differently1 and that for the same      
medium the amount of light valies with  
the change in the angle of incidence4   
,he was not able1 however1 to generalize
 his observations as he desired1 and to 
the last the law that governs refraction
 escaped him4 ,it remained for          
,willebrord ,snell1 a ,dutchman1 about  
the year #afba1 to discover the law in  
question1 and for ,descartes1 a little  
later1 to formulate it4 ,descartes1     
indeed1 has sometimes been supposed to  
be the discoverer of the law4 ,there is 
reason to believe that he based his     

generalizations on the experiment of    
,snell1 though he did not openly        
acknowledge his indebtedness4 ,the law1 
as ,descartes expressed it1 states that 
the sine of the angle of incidence bears
 a fixed ratio to the sine of the angle 
of refraction for any given medium4     
,here1 then1 was another illustration of
 the fact that almost infinitely varied 
phenomena may be brought within the     
scope of a simple law4 ,once the law had
 been expressed1 it could be tested and 
verified with the greatest ease2 and1 as
 usual1 the discovery being made1 it    
seems surprising that earlier           
investigators--in particular so         
sagacious a guesser as ,kepler--should  
have missed it4  ,galileo himself must  
have been to some extent a student of   
light1 since1 as we have seen1 he made  
such notable contributions to practical 
optics through perfecting the telescope2
 but he seems not to have added anything
 to the theory of light4 ,the subject of
 heat1 however1 attracted his attention 

in a somewhat different way1 and he was 
led to the invention of the first       
contrivance for measuring temperatures4 
,his thermometer was based on the       
afterwards familiar principle of the    
expansion of a liquid under the         
influence of heat2 but as a practical   
means of measuring temperature it was a 
very crude affair1 because the tube that
 contained the measuring liquid was     
exposed to the air1 hence barometric    
changes of pressure vitiated the        
experiment4 ,it remained for ,galileo's 
,italian successors of the ,accademia   
del ,cimento of ,florence to improve    
upon the apparatus1 after the           
experiments of ,torricelli--to which we 
shall refer in a moment--had thrown new 
light on the question of atmospheric    
pressure4 ,still later the celebrated   
,huygens hit upon the idea of using the 
melting and the boiling point of water  
as fixed points in a scale of           
measurements1 which first gave          
definiteness to thermometric tests4     

,,torricelli  ,in the closing years of  
his life ,galileo took into his family1 
as his adopted disciple in science1 a   
young man1 ,evangelista ,torricelli     
7#afjh-afdg71 who proved himself1 during
 his short lifetime1 to be a worthy     
follower of his great master4 ,not only 
worthy on account of his great          
scientific discoveries1 but grateful as 
well1 for when he had made the great    
discovery that the suction made by a    
vacuum was really nothing but air       
pressure1 and not suction at all1 he    
regretted that so important a step in   
science might not have been made by his 
great teacher1 ,galileo1 instead of by  
himself4 ,this generosity of            
,torricelli1 says ,playfair1 was1       
perhaps1 rarer than his genius3 there   
are more who might have discovered the  
suspension of mercury in the barometer  
than who would have been willing to part
 with the honor of the discovery to a   
master or a friend4  ,torricelli's      
discovery was made in #afdc1 less than  

two years after the death of his master4
 ,galileo had observed that water will  
not rise in an exhausted tube1 such as a
 pump1 to a height greater than         
thirty-three feet1 but he was never able
 to offer a satisfactory explanation of 
the principle4 ,torricelli was able to  
demonstrate that the height at which the
 water stood depended upon nothing but  
its weight as compared with the weight  
of air4 ,if this be true1 it is evident 
that any fluid will be supported at a   
definite height1 according to its       
relative weight as compared with air4   
,thus mercury1 which is about thirteen  
times more dense than water1 should only
 rise to one-thirteenth the height of a 
column of water--that is1 about thirty  
inches4 ,reasoning in this way1         
,torricelli proceeded to prove that his 
theory was correct4 ,filling a long     
tube1 closed at one end1 with mercury1  
he inverted the tube with its open      
orifice in a vessel of mercury4 ,the    
column of mercury fell at once1 but at a

 height of about thirty inches it       
stopped and remained stationary1 the    
pressure of the air on the mercury in   
the vessel maintaining it at that       
height4 ,this discovery was a shattering
 blow to the old theory that had        
dominated that field of physics for so  
many centuries4 ,it was completely      
revolutionary to prove that1 instead of 
a mysterious something within the tube  
being responsible for the suspension of 
liquids at certain heights1 it was      
simply the ordinary atmospheric pressure
 mysterious enough1 it is true--pushing 
upon them from without4 ,the pressure   
exerted by the atmosphere was but little
 understood at that time1 but           
,torricelli's discovery aided materially
 in solving the mystery4 ,the whole     
class of similar phenomena of air       
pressure1 which had been held in the    
trammel of long-established but false   
doctrines1 was now reduced to one simple
 law1 and the door to a solution of a   
host of unsolved problems thrown open4  

,it had long been suspected and believed
 that the density of the atmosphere     
varies at certain times4 ,that the air  
is sometimes heavy and at other times   
light is apparent to the senses without 
scientific apparatus for demonstration4 
,it is evident1 then1 that ,torricelli's
 column of mercury should rise and fall 
just in proportion to the lightness or  
heaviness of the air4 ,a short series of
 observations proved that it did so1 and
 with those observations went naturally 
the observations as to changes in the   
weather4 ,it was only necessary1        
therefore1 to scratch a scale on the    
glass tube1 indicating relative         
atmospheric pressures1 and the          
,torricellian barometer was complete4   
,such a revolutionary theory and such an
 important discovery were1 of course1   
not to be accepted without controversy1 
but the feeble arguments of the         
opponents showed how untenable the old  
theory had become4 ,in #afdh ,pascal    
suggested that if the theory of the     

pressure of air upon the mercury was    
correct1 it could be demonstrated by    
ascending a mountain with the mercury   
tube4 ,as the air was known to get      
progressively lighter from base to      
summit1 the height of the column should 
be progressively lessened as the ascent 
was made1 and increase again on the     
descent into the denser air4 ,the       
experiment was made on the mountain     
called the ,puy-de-,dome1 in ,auvergne1 
and the column of mercury fell and rose 
progressively through a space of about  
three inches as the ascent and descent  
were made4  ,this experiment practically
 sealed the verdict on the new theory1  
but it also suggested something more4   
,if the mercury descended to a certain  
mark on the scale on a mountain-top     
whose height was known1 why was not this
 a means of measuring the heights of all
 other elevations8 ,and so the beginning
 was made which1 with certain           
modifications and corrections in        
details1 is now the basis of            

barometrical measurements of heights4   
,in hydraulics1 also1 ,torricelli seems 
to have taken one of the first steps4   
,he did this by showing that the water  
which issues from a hole in the side or 
bottom of a vessel does so at the same  
velocity as that which a body would     
acquire by falling from the level of the
 surface of the water to that of the    
orifice4 ,this discovery was of the     
greatest importance to a correct        
understanding of the science of the     
motions of fluids4 ,he also discovered  
the valuable mechanical principle that  
if any number of bodies be connected so 
that by their motion there is neither   
ascent nor descent of their centre of   
gravity1 these bodies are in            
equilibrium4  ,besides making these     
discoveries1 he greatly improved the    
microscope and the telescope1 and       
invented a simple microscope made of a  
globule of glass4 ,in #afdd he published
 a tract on the properties of the       
cycloid in which he suggested a solution

 of the problem of its quadrature4 ,as  
soon as this pamphlet appeared its      
author was accused by ,gilles ,roberval 
7#afjb-afge7 of having appropriated a   
solution already offered by him4 ,this  
led to a long debate1 during which      
,torricelli was seized with a fever1    
from the effects of which he died1 in   
,florence1 ,october #be1 #afdg4 ,there  
is reason to believe1 however1 that     
while ,roberval's discovery was made    
before ,torricelli's1 the latter reached
 his conclusions independently4         
,,vi4 ,,two                             
,,pseudo-,,sciences--,,alchemy ,,and    
,,astrology  ,in recent chapters we have
 seen science come forward with         
tremendous strides4 ,a new era is       
obviously at hand4 ,but we shall        
misconceive the spirit of the times if  
we fail to understand that in the midst 
of all this progress there was still    
room for mediaeval superstition and for 
the pursuit of fallacious ideals4 ,two  
forms of pseudo-science were peculiarly 

prevalent--alchemy and astrology4       
,neither of these can with full         
propriety be called a science1 yet both 
were pursued by many of the greatest    
scientific workers of the period4       
,moreover1 the studies of the alchemist 
may with some propriety be said to have 
laid the foundation for the latter-day  
science of chemistry2 while astrology   
was closely allied to astronomy1 though 
its relations to that science are not as
 intimate as has sometimes been         
supposed4  ,just when the study of      
alchemy began is undetermined4 ,it was  
certainly of very ancient origin1       
perhaps ,egyptian1 but its most         
flourishing time was from about the     
eighth century ,a4,d4 to the eighteenth 
century4 ,the stories of the ,old       
,testament formed a basis for some of   
the strange beliefs regarding the       
properties of the magic elixir1 or      
philosopher's stone4 ,alchemists        
believed that most of the antediluvians1
 perhaps all of them1 possessed a       

knowledge of this stone4 ,how1          
otherwise1 could they have prolonged    
their lives to nine and a half          
centuries8 ,and ,moses was surely a     
first-rate alchemist1 as is proved by   
the story of the ,golden ,calf47#a7     
,after ,aaron had made the calf of gold1
 ,moses performed the much more         
difficult task of grinding it to powder 
and strewing it upon the waters1 thus   
showing that he had transmuted it into  
some lighter substance4  ,but           
antediluvians and ,biblical characters  
were not the only persons who were      
thought to have discovered the coveted  
elixir4 ,hundreds of aged mediaeval     
chemists were credited with having made 
the discovery1 and were thought to be   
living on through the centuries by its  
means4 ,alaies de ,lisle1 for example1  
who died in #abih1 at the age of #aaj1  
was alleged to have been at the point of
 death at the age of fifty1 but just at 
this time he made the fortunate         
discovery of the magic stone1 and so    

continued to live in health and         
affluence for sixty years more4 ,and ,de
 ,lisle was but one case among hundreds4
  ,an aged and wealthy alchemist could  
claim with seeming plausibility that he 
was prolonging his life by his magic2   
whereas a younger man might assert that1
 knowing the great secret1 he was       
keeping himself young through the       
centuries4 ,in either case such a       
statement1 or rumor1 about a learned and
 wealthy alchemist was likely to be     
believed1 particularly among strangers2 
and as such a man would1 of course1 be  
the object of much attention1 the claim 
was frequently made by persons seeking  
notoriety4 ,one of the most celebrated  
of these impostors was a certain ,count 
de ,saint-,germain1 who was connected   
with the court of ,louis ,,xv4 ,his     
statements carried the more weight      
because1 having apparently no means of  
maintenance1 he continued to live in    
affluence year after year--for two      
thousand years1 as he himself           

admitted--by means of the magic stone4  
,if at any time his statements were     
doubted1 he was in the habit of         
referring to his valet for confirmation1
 this valet being also under the        
influence of the elixir of life4  ,upon 
one occasion his master was telling a   
party of ladies and gentlemen1 at       
dinner1 some conversation he had had in 
,palestine1 with ,king ,richard ,i41 of 
,england1 whom he described as a very   
particular friend of his4 ,signs of     
astonishment and incredulity were       
visible on the faces of the company1    
upon which ,saint-,germain very coolly  
turned to his servant1 who stood behind 
his chair1 and asked him if he had not  
spoken the truth4 ',i really cannot     
say1' replied the man1 without moving a 
muscle2 'you forget1 sir1 ,i have been  
only five hundred years in your         
service4' ',ah1 true1' said his master1 
',i remember now2 it was a little before
 your time6'7#b7  ,in the time of       
,saint-,germain1 only a little over a   

century ago1 belief in alchemy had      
almost disappeared1 and his             
extraordinary tales were probably       
regarded in the light of amusing        
stories4 ,still there was undoubtedly a 
lingering suspicion in the minds of many
 that this man possessed some peculiar  
secret4 ,a few centuries earlier his    
tales would hardly have been questioned1
 for at that time the belief in the     
existence of this magic something was so
 strong that the search for it became   
almost a form of mania2 and once a man  
was seized with it1 lie gambled away    
health1 position1 and life itself in    
pursuing the coveted stake4 ,an example 
of this is seen in ,albertus ,magnus1   
one of the most learned men of his time1
 who it is said resigned his position as
 bishop of ,ratisbon in order that he   
might pursue his researches in alchemy4 
,if self-sacrifice was not sufficient to
 secure the prize1 crime would naturally
 follow1 for there could be no limit to 
the price of the stakes in this game4   

,the notorious ,marechal de ,reys1      
failing to find the coveted stone by    
ordinary methods of laboratory research1
 was persuaded by an impostor that if he
 would propitiate the friendship of the 
devil the secret would be revealed4 ,to 
this end ,de ,reys began secretly       
capturing young children as they passed 
his castle and murdering them4 ,when he 
was at last brought to justice it was   
proved that he had murdered something   
like a hundred children within a period 
of three years4 ,so1 at least1 runs one 
version of the story of this perverted  
being4  ,naturally monarchs1 constantly 
in need of funds1 were interested in    
these alchemists4 ,even sober ,england  
did not escape1 and ,raymond ,lully1 one
 of the most famous of the thirteenth   
and fourteenth century alchemists1 is   
said to have been secretly invited by   
,king ,edward ,i4 7or ,,ii47 to leave   
,milan and settle in ,england4          
,according to some accounts1 apartments 
were assigned to his use in the ,tower  

of ,london1 where he is alleged to have 
made some six million pounds sterling   
for the monarch1 out of iron1 mercury1  
lead1 and pewter4  ,pope ,john ,,xxii41 
a friend and pupil of the alchemist     
,arnold de ,villeneuve1 is reported to  
have learned the secrets of alchemy from
 his master4 ,later he issued two bulls 
against pretenders in the art1 which1   
far from showing his disbelief1 were    
cited by alchemists as proving that he  
recognized pretenders as distinct from  
true masters of magic4  ,to moderns the 
attitude of mind of the alchemist is    
difficult to comprehend4 ,it is1        
perhaps1 possible to conceive of animals
 or plants possessing souls1 but the    
early alchemist attributed the same     
thing--or something kin to it--to metals
 also4 ,furthermore1 just as plants     
germinated from seeds1 so metals were   
supposed to germinate also1 and hence a 
constant growth of metals in the ground4
 ,to prove this the alchemist cited     
cases where previously exhausted        

gold-mines were found1 after a lapse of 
time1 to contain fresh quantities of    
gold4 ,the seed of the remaining        
particles of gold had multiplied and    
increased4 ,but this germinating process
 could only take place under favorable  
conditions1 just as the seed of a plant 
must have its proper surroundings before
 germinating2 and it was believed that  
the action of the philosopher's stone   
was to hasten this process1 as man may  
hasten the growth of plants by          
artificial means4 ,gold was looked upon 
as the most perfect metal1 and all other
 metals imperfect1 because not yet      
purified4 ,by some alchemists they were 
regarded as lepers1 who1 when cured of  
their leprosy1 would become gold4 ,and  
since nature intended that all things   
should be perfect1 it was the aim of the
 alchemist to assist her in this        
purifying process1 and incidentally to  
gain wealth and prolong his life4  ,by  
other alchemists the process of         
transition from baser metals into gold  

was conceived to be like a process of   
ripening fruit4 ,the ripened product was
 gold1 while the green fruit1 in various
 stages of maturity1 was represented by 
the base metals4 ,silver1 for example1  
was more nearly ripe than lead2 but the 
difference was only one of digestion1   
and it was thought that by further      
digestion lead might first become silver
 and eventually gold4 ,in other words1  
,nature had not completed her work1 and 
was wofully slow at it at best2 but man1
 with his superior faculties1 was to    
hasten the process in his               
laboratories--if he could but hit upon  
the right method of doing so4  ,it      
should not be inferred that the         
alchemist set about his task of         
assisting nature in a haphazard way1 and
 without training in the various        
alchemic laboratory methods4 ,on the    
contrary1 he usually served a long      
apprenticeship in the rudiments of his  
calling4 ,he was obliged to learn1 in a 
general way1 many of the same things    

that must be understood in either       
chemical or alchemical laboratories4    
,the general knowledge that certain     
liquids vaporize at lower temperatures  
than others1 and that the melting-points
 of metals differ greatly1 for example1 
was just as necessary to alchemy as to  
chemistry4 ,the knowledge of the gross  
structure1 or nature1 of materials was  
much the same to the alchemist as to the
 chemist1 and1 for that matter1 many of 
the experiments in calcining1           
distilling1 etc41 were practically      
identical4  ,to the alchemist there were
 three principles--salt1 sulphur1 and   
mercury--and the sources of these       
principles were the four                
elements--earth1 water1 fire1 and air4  
,these four elements were accountable   
for every substance in nature4 ,some of 
the experiments to prove this were so   
illusive1 and yet apparently so simple1 
that one is not surprised that it took  
centuries to disprove them4 ,that water 
was composed of earth and air seemed    

easily proven by the simple process of  
boiling it in a tea-kettle1 for the     
residue left was obviously an earthy    
substance1 whereas the steam driven off 
was supposed to be air4 ,the fact that  
pure water leaves no residue was not    
demonstrated until after alchemy had    
practically ceased to exist4 ,it was    
possible also to demonstrate that water 
could be turned into fire by thrusting a
 red-hot poker under a bellglass        
containing a dish of water4 ,not only   
did the quantity of water diminish1 but1
 if a lighted candle was thrust under   
the glass1 the contents ignited and     
burned1 proving1 apparently1 that water 
had been converted into fire4 ,these1   
and scores of other similar experiments1
 seemed so easily explained1 and to     
accord so well with the four elements   
theory1 that they were seldom questioned
 until a later age of inductive science4
  ,but there was one experiment to which
 the alchemist pinned his faith in      
showing that metals could be killed and 

revived1 when proper means were         
employed4 ,it had been known for many   
centuries that if any metal1 other than 
gold or silver1 were calcined in an open
 crucible1 it turned1 after a time1 into
 a peculiar kind of ash4 ,this ash was  
thought by the alchemist to represent   
the death of the metal4 ,but if to this 
same ash a few grains of wheat were     
added and heat again applied to the     
crucible1 the metal was seen to rise    
from its ashes and resume its original  
form--a well-known phenomenon of        
reducing metals from oxides by the use  
of carbon1 in the form of wheat1 or1 for
 that matter1 any other carbonaceous    
substance4 ,wheat was1 therefore1 made  
the symbol of the resurrection of the   
life eternal4 ,oats1 corn1 or a piece of
 charcoal would have revived the metals 
from the ashes equally well1 but the    
mediaeval alchemist seems not to have   
known this4 ,however1 in this experiment
 the metal seemed actually to be        
destroyed and revivified1 and1 as       

science had not as yet explained this   
striking phenomenon1 it is little wonder
 that it deceived the alchemist4  ,since
 the alchemists pursued their search of 
the magic stone in such a methodical    
way1 it would seem that they must have  
some idea of the appearance of the      
substance they sought4 ,probably they   
did1 each according to his own mental   
bias2 but1 if so1 they seldom committed 
themselves to writing1 confining their  
discourses largely to speculations as to
 the properties of this illusive        
substance4 ,furthermore1 the desire for 
secrecy would prevent them from         
expressing so important a piece of      
information4 ,but on the subject of the 
properties1 if not on the appearance of 
the essence1 they were voluminous       
writers4 ,it was supposed to be the only
 perfect substance in existence1 and to 
be confined in various substances1 in   
quantities proportionate to the state of
 perfection of the substance4 ,thus1    
gold being most nearly perfect would    

contain more1 silver less1 lead still   
less1 and so on4 ,the essence contained 
in the more nearly perfect metals was   
thought to be more potent1 a very small 
quantity of it being capable of creating
 large quantities of gold and of        
prolonging life indefinitely4  ,it would
 appear from many of the writings of the
 alchemists that their conception of    
nature and the supernatural was so      
confused and entangled in an            
inexplicable philosophy that they       
themselves did not really understand the
 meaning of what they were attempting to
 convey4 ,but it should not be forgotten
 that alchemy was kept as much as       
possible from the ignorant general      
public1 and the alchemists themselves   
had knowledge of secret words and       
expressions which conveyed a definite   
meaning to one of their number1 but     
which would appear a meaningless jumble 
to an outsider4 ,some of these writers  
declared openly that their writings were
 intended to convey an entirely         

erroneous impression1 and were sent out 
only for that purpose4  ,however1 while 
it may have been true that the vagaries 
of their writings were made purposely1  
the case is probably more correctly     
explained by saying that the very nature
 of the art made definite statements    
impossible4 ,they were dealing with     
something that did not exist--could not 
exist4 ,their attempted descriptions    
became1 therefore1 the language of      
romance rather than the language of     
science4  ,but if the alchemists        
themselves were usually silent as to the
 appearance of the actual substance of  
the philosopher's stone1 there were     
numberless other writers who were less  
reticent4 ,by some it was supposed to be
 a stone1 by others a liquid or elixir1 
but more commonly it was described as a 
black powder4 ,it also possessed        
different degrees of efficiency         
according to its degrees of purity1     
certain forms only possessing the power 
of turning base metals into gold1 while 

others gave eternal youth and life or   
different degrees of health4 ,thus an   
alchemist1 who had made a partial       
discovery of this substance1 could      
prolong life a certain number of years  
only1 or1 possessing only a small and   
inadequate amount of the magic powder1  
he was obliged to give up the ghost when
 the effect of this small quantity had  
passed away4  ,this belief in the       
supernatural power of the philosopher's 
stone to prolong life and heal diseases 
was probably a later phase of alchemy1  
possibly developed by attempts to       
connect the power of the mysterious     
essence with ,biblical teachings4 ,the  
early ,roman alchemists1 who claimed to 
be able to transmute metals1 seem not to
 have made other claims for their magic 
stone4  ,by the fifteenth century the   
belief in the philosopher's stone had   
become so fixed that governments began  
to be alarmed lest some lucky possessor 
of the secret should flood the country  
with gold1 thus rendering the existing  

coin of little value4 ,some little      
consolation was found in the thought    
that in case all the baser metals were  
converted into gold iron would then     
become the precious metal1 and would    
remain so until some new philosopher's  
stone was found to convert gold back    
into iron--a much more difficult feat1  
it was thought4 ,however1 to be on the  
safe side1 the ,english ,parliament1 in 
#adjd1 saw fit to pass an act declaring 
the making of gold and silver to be a   
felony4 ,nevertheless1 in #adee1 ,king  
,henry ,,vi4 granted permission to      
several knights1 citizens of ,london1   
chemists1 and monks to find the         
philosopher's stone1 or elixir1 that the
 crown might thus be enabled to pay off 
its debts4 ,the monks and ecclesiastics 
were supposed to be most likely to      
discover the secret process1 since they 
were such good artists in               
transubstantiating bread and wine4  ,in 
,germany the emperors ,maximilian ,i41  
,rudolf ,,ii41 and ,frederick ,,ii4 gave

 considerable attention to the search1  
and the example they set was followed by
 thousands of their subjects4 ,it is    
said that some noblemen developed the   
unpleasant custom of inviting to their  
courts men who were reputed to have     
found the stone1 and then imprisoning   
the poor alchemists until they had made 
a certain quantity of gold1 stimulating 
their activity with tortures of the most
 atrocious kinds4 ,thus this danger of  
being imprisoned and held for ransom    
until some fabulous amount of gold      
should be made became the constant      
menace of the alchemist4 ,it was useless
 for an alchemist to plead poverty once 
it was noised about that he had learned 
the secret4 ,for how could such a man be
 poor when1 with a piece of metal and a 
few grains of magic powder1 he was able 
to provide himself with gold8 ,it was1  
therefore1 a reckless alchemist indeed  
who dared boast that he had made the    
coveted discovery4  ,the fate of a      
certain indiscreet alchemist1 supposed  

by many to have been ,seton1 a          
,scotchman1 was not an uncommon one4    
,word having been brought to the elector
 of ,saxony that this alchemist was in  
,dresden and boasting of his powers1 the
 elector caused him to be arrested and  
imprisoned4 ,forty guards were stationed
 to see that he did not escape and that 
no one visited him save the elector     
himself4 ,for some time the elector     
tried by argument and persuasion to     
penetrate his secret or to induce him to
 make a certain quantity of gold2 but as
 ,seton steadily refused1 the rack was  
tried1 and for several months he        
suffered torture1 until finally1 reduced
 to a mere skeleton1 he was rescued by a
 rival candidate of the elector1 a ,pole
 named ,michael ,sendivogins1 who       
drugged the guards4 ,however1 before    
,seton could be persuaded by his new    
captor1 he died of his injuries4  ,but  
,sendivogins was also ambitious in      
alchemy1 and1 since ,seton was beyond   
his reach1 he took the next best step   

and married his widow4 ,from her1 as the
 story goes1 he received an ounce of    
black powder--the veritable             
philosopher's stone4 ,with this he      
manufactured great quantities of gold1  
even inviting ,emperor ,rudolf ,,ii4 to 
see him work the miracle4 ,that monarch 
was so impressed that he caused a tablet
 to be inserted in the wall of the room 
in which he had seen the gold made4     
,sendivogins had learned discretion from
 the misfortune of ,seton1 so that he   
took the precaution of concealing most  
of the precious powder in a secret      
chamber of his carriage when he         
travelled1 having only a small quantity 
carried by his steward in a gold box4   
,in particularly dangerous places1 he is
 said to have exchanged clothes with his
 coachman1 making the servant take his  
place in the carriage while he mounted  
the box4   ,about the middle of the     
seventeenth century alchemy took such   
firm root in the religious field that it
 became the basis of the sect known as  

the ,rosicrucians4 ,the name was derived
 from the teaching of a ,german         
philosopher1 ,rosenkreutz1 who1 having  
been healed of a dangerous illness by an
 ,arabian supposed to possess the       
philosopher's stone1 returned home and  
gathered about him a chosen band of     
friends1 to whom he imparted the secret4
 ,this sect came rapidly into           
prominence1 and for a short time at     
least created a sensation in ,europe1   
and at the time were credited with      
having refined and spiritualized        
alchemy4 ,but by the end of the         
seventeenth century their number had    
dwindled to a mere handful1 and         
henceforth they exerted little          
influence4  ,another and earlier        
religious sect was the ,aureacrucians1  
founded by ,jacob ,bohme1 a shoemaker1  
born in ,prussia in #aege4 ,according to
 his teachings the philosopher's stone  
could be discovered by a diligent search
 of the ,old and the ,new ,testaments1  
and more particularly the ,apocalypse1  

which contained all the secrets of      
alchemy4 ,this sect found quite a number
 of followers during the life of ,bohme1
 but gradually died out after his death2
 not1 however1 until many of its members
 had been tortured for heresy1 and one  
at least1 ,kuhlmann1 of ,moscow1 burned 
as a sorcerer4  ,the names of the       
different substances that at various    
times were thought to contain the large 
quantities of the essence during the    
many centuries of searching for it1 form
 a list of practically all substances   
that were known1 discovered1 or invented
 during the period4 ,some believed that 
acids contained the substance2 others   
sought it in minerals or in animal or   
vegetable products2 while still others  
looked to find it among the distilled   
spirits--the alcoholic liquors and      
distilled products4 ,on the introduction
 of alcohol by the ,arabs that substance
 became of all-absorbing interest1 and  
for a long time allured the alchemist   
into believing that through it they were

 soon to be rewarded4 ,they rectified   
and refined it until sometimes it was so
 strong that it broke the vessels       
containing it1 but still it failed in   
its magic power4 ,later1 brandy was     
substituted for it1 and this in turn    
discarded for more recent discoveries4  
,there were always1 of course1 two      
classes of alchemists3 serious          
investigators whose honesty could not be
 questioned1 and clever impostors whose 
legerdemain was probably largely        
responsible for the extended belief in  
the existence of the philosopher's      
stone4 ,sometimes an alchemist practised
 both1 using the profits of his         
sleight-of-hand to procure the means of 
carrying on his serious alchemical      
researches4 ,the impostures of some of  
these jugglers deceived even the most   
intelligent and learned men of the time1
 and so kept the flame of hope          
constantly burning4 ,the age of cold    
investigation had not arrived1 and it is
 easy to understand how an unscrupulous 

mediaeval ,hermann or ,kellar might     
completely deceive even the most        
intelligent and thoughtful scholars4 ,in
 scoffing at the credulity of such an   
age1 it should not be forgotten that the
 ,keely motor was a late                
nineteenth-century illusion4  ,but long 
before the belief in the philosopher's  
stone had died out1 the methods of the  
legerdemain alchemist had been          
investigated and reported upon          
officially by bodies of men appointed to
 make such investigations1 although it  
took several generations completely to  
overthrow a superstition that had been  
handed down through several thousand    
years4 ,in ,april of #aggb ,monsieur    
,geoffroy made a report to the ,royal   
,academy of ,sciences1 at ,paris1 on the
 alchemic cheats principally of the     
sixteenth and seventeenth centuries4 ,in
 this report he explains many of the    
seemingly marvellous feats of the       
unscrupulous alchemists4 ,a very common 
form of deception was the use of a      

double-bottomed crucible4 ,a copper or  
brass crucible was covered on the inside
 with a layer of wax1 cleverly painted  
so as to resemble the ordinary metal4   
,between this layer of wax and the      
bottom of the crucible1 however1 was a  
layer of gold dust or silver4 ,when the 
alchemist wished to demonstrate his     
power1 he had but to place some mercury 
or whatever substance he chose in the   
crucible1 heat it1 throw in a grain or  
two of some mysterious powder1 pronounce
 a few equally mysterious phrases to    
impress his audience1 and1 behold1 a    
lump of precious metal would be found in
 the bottom of his pot4 ,this was the   
favorite method of mediocre performers1 
but was1 of course1 easily detected4    
,an equally successful but more         
difficult way was to insert             
surreptitiously a lump of metal into the
 mixture1 using an ordinary crucible4   
,this required great dexterity1 but was 
facilitated by the use of many          
mysterious ceremonies on the part of the

 operator while performing1 just as the 
modern vaudeville performer diverts the 
attention of the audience to his right  
hand while his left is engaged in the   
trick4 ,such ceremonies were not        
questioned1 for it was the common belief
 that the whole process lay in the      
spirit as much as in the substance1     
many1 as we have seen1 regarding the    
whole process as a divine manifestation4
  ,sometimes a hollow rod was used for  
stirring the mixture in the crucible1   
this rod containing gold dust1 and      
having the end plugged either with wax  
or soft metal that was easily melted4   
,again1 pieces of lead were used which  
had been plugged with lumps of gold     
carefully covered over2 and a very      
simple and impressive demonstration was 
making use of a nugget of gold that had 
been coated over with quicksilver and   
tarnished so as to resemble lead or some
 base metal4 ,when this was thrown into 
acid the coating was removed by chemical
 action1 leaving the shining metal in   

the bottom of the vessel4 ,in order to  
perform some of these tricks1 it is     
obvious that the alchemist must have    
been well supplied with gold1 as some of
 them1 when performing before a royal   
audience1 gave the products to their    
visitors4 ,but it was always a paying   
investment1 for once his reputation was 
established the gold-maker found an     
endless variety of ways of turning his  
alleged knowledge to account1 frequently
 amassing great wealth4  ,some of the   
cleverest of the charlatans often       
invited royal or other distinguished    
guests to bring with them iron nails to 
be turned into gold ones4 ,they were    
transmuted in the alchemist's crucible  
before the eyes of the visitors1 the    
juggler adroitly extracting the iron    
nail and inserting a gold one without   
detection4 ,it mattered little if the   
converted gold nail differed in size and
 shape from the original1 for this      
change in shape could be laid to the    
process of transmutation2 and even the  

very critical were hardly likely to find
 fault with the exchange thus made4     
,furthermore1 it was believed that gold 
possessed the property of changing its  
bulk under certain conditions1 some of  
the more conservative alchemists        
maintaining that gold was only increased
 in bulk1 not necessarily created1 by   
certain forms of the magic stone4 ,thus 
a very proficient operator was thought  
to be able to increase a grain of gold  
into a pound of pure metal1 while one   
less expert could only double1 or       
possibly treble1 its original weight4   
,the actual number of useful discoveries
 resulting from the efforts of the      
alchemists is considerable1 some of them
 of incalculable value4 ,roger ,bacon1  
who lived in the thirteenth century1    
while devoting much of his time to      
alchemy1 made such valuable discoveries 
as the theory1 at least1 of the         
telescope1 and probably gunpowder4 ,of  
this latter we cannot be sure that the  
discovery was his own and that he had   

not learned of it through the source of 
old manuscripts4 ,but it is not         
impossible nor improbable that he may   
have hit upon the mixture that makes the
 explosives while searching for the     
philosopher's stone in his laboratory4  
,von ,helmont1 in the same pursuit1     
discovered the properties of gas1 says  
,mackay2 ,geber made discoveries in     
chemistry1 which were equally important2
 and ,paracelsus1 amid his perpetual    
visions of the transmutation of metals1 
found that mercury was a remedy for one 
of the most odious and excruciating of  
all the diseases that afflict humanity4'
 ,as we shall see a little farther on1  
alchemy finally evolved into modern     
chemistry1 but not until it had passed  
through several important transitional  
stages4   ,,astrology  ,in a general way
 modern astronomy may be considered as  
the outgrowth of astrology1 just as     
modern chemistry is the result of       
alchemy4 ,it is quite possible1 however1
 that astronomy is the older of the two2

 but astrology must have developed very 
shortly after4 ,the primitive           
astronomer1 having acquired enough      
knowledge from his observations of the  
heavenly bodies to make correct         
predictions1 such as the time of the    
coming of the new moon1 would be led1   
naturally1 to believe that certain      
predictions other than purely           
astronomical ones could be made by      
studying the heavens4 ,even if the      
astronomer himself did not believe this1
 some of his superstitious admirers     
would2 for to the unscientific mind     
predictions of earthly events would     
surely seem no more miraculous than     
correct predictions as to the future    
movements of the sun1 moon1 and stars4  
,when astronomy had reached a stage of  
development so that such things as      
eclipses could be predicted with        
anything like accuracy1 the occult      
knowledge of the astronomer would be    
unquestioned4 ,turning this apparently  
occult knowledge to account in a        

mercenary way would then be the         
inevitable result1 although it cannot be
 doubted that many of the astrologers1  
in all ages1 were sincere in their      
beliefs4  ,later1 as the business of    
astrology became a profitable one1      
sincere astronomers would find it       
expedient to practise astrology as a    
means of gaining a livelihood4 ,such a  
philosopher as ,kepler freely admitted  
that he practised astrology to keep from
 starving1 although he confessed no     
faith in such predictions4 ,ye otherwise
 philosophers1 he said1 ye censure this 
daughter of astronomy beyond her        
deserts2 know ye not that she must      
support her mother by her charms4  ,once
 astrology had become an established    
practice1 any considerable knowledge of 
astronomy was unnecessary1 for as it was
 at best but a system of good guessing  
as to future events1 clever impostors   
could thrive equally well without       
troubling to study astronomy4 ,the      
celebrated astrologers1 however1 were   

usually astronomers as well1 and        
undoubtedly based many of their         
predictions on the position and         
movements of the heavenly bodies4 ,thus1
 the casting of a horoscope that is1 the
 methods by which the astrologers       
ascertained the relative position of the
 heavenly bodies at the time of a       
birth--was a simple but fairly exact    
procedure4 ,its basis was the zodiac1 or
 the path traced by the sun in his      
yearly course through certain           
constellations4 ,at the moment of the   
birth of a child1 the first care of the 
astrologer was to note the particular   
part of the zodiac that appeared on the 
horizon4 ,the zodiac was then divided   
into houses--that is1 into twelve       
spaces--on a chart4 ,in these houses    
were inserted the places of the planets1
 sun1 and moon1 with reference to the   
zodiac4 ,when this chart was completed  
it made a fairly correct diagram of the 
heavens and the position of the heavenly
 bodies as they would appear to a person

 standing at the place of birth at a    
certain time4  ,up to this point the    
process was a simple one of astronomy4  
,but the next step--the really important
 one--that of interpreting this chart1  
was the one which called forth the skill
 and imagination of the astrologer4 ,in 
this interpretation1 not in his mere    
observations1 lay the secret of his     
success4 ,nor did his task cease with   
simply foretelling future events that   
were to happen in the life of the newly 
born infant4 ,he must not only point out
 the dangers1 but show the means whereby
 they could be averted1 and his         
prophylactic measures1 like his         
predictions1 were alleged to be based on
 his reading of the stars4  ,but casting
 a horoscope at the time of births was1 
of course1 only a small part of the     
astrologer's duty4 ,his offices were    
sought by persons of all ages for       
predictions as to their futures1 the    
movements of an enemy1 where to find    
stolen goods1 and a host of everyday    

occurrences4 ,in such cases it is more  
than probable that the astrologers did  
very little consulting of the stars in  
making their predictions4 ,they became  
expert physiognomists and excellent     
judges of human nature1 and were thus   
able to foretell futures with the same  
shrewdness and by the same methods as   
the modern mediums1 palmists1 and       
fortune-tellers4 ,to strengthen belief  
in their powers1 it became a common     
thing for some supposedly lost document 
of the astrologer to be mysteriously    
discovered after an important event1    
this document purporting to foretell    
this very event4 ,it was also a common  
practice with astrologers to retain1 or 
have access to1 their original charts1  
cleverly altering them from time to time
 to fit conditions4  ,the dangers       
attendant upon astrology were of such a 
nature that the lot of the astrologer   
was likely to prove anything but an     
enviable one4 ,as in the case of the    
alchemist1 the greater the reputation of

 an astrologer the greater dangers he   
was likely to fall into4 ,if he became  
so famous that he was employed by kings 
or noblemen1 his too true or too false  
prophecies were likely to bring him into
 disrepute--even to endanger his life4  
,throughout the dark age the astrologers
 flourished1 but the sixteenth and      
seventeenth centuries were the golden   
age of these impostors4 ,a skilful      
astrologer was as much an essential to  
the government as the highest official1 
and it would have been a bold monarch1  
indeed1 who would undertake any         
expedition of importance unless         
sanctioned by the governing stars as    
interpreted by these officials4  ,it    
should not be understood1 however1 that 
belief in astrology died with the advent
 of the ,copernican doctrine4 ,it did   
become separated from astronomy very    
shortly after1 to be sure1 and          
undoubtedly among the scientists it lost
 much of its prestige4 ,but it cannot be
 considered as entirely passed away1    

even to-day1 and even if we leave out of
 consideration street-corner astrologers
 and fortune-tellers1 whose signs may be
 seen in every large city1 there still  
remains quite a large class of          
relatively intelligent people who       
believe in what they call the science of
 astrology4 ,needless to say1 such      
people are not found among the          
scientific thinkers2 but it is          
significant that scarcely a year passes 
that some book or pamphlet is not       
published by some ardent believer in    
astrology1 attempting to prove by the   
illogical dogmas characteristic of      
unscientific thinkers that astrology is 
a science4 ,the arguments contained in  
these pamphlets are very much the same  
as those of the astrologers three       
hundred years ago1 except that they lack
 the quaint form of wording which is one
 of the features that lends interest to 
the older documents4 ,these pamphlets   
need not be taken seriously1 but they   
are interesting as exemplifying how     

difficult it is1 even in an age of      
science1 to entirely stamp out firmly   
established superstitions4 ,here are    
some of the arguments advanced in       
defence of astrology1 taken from a      
little brochure entitled ,astrology     
,vindicated1 published in #ahih3 ,it    
will be found that a person born when   
the ,sun is in twenty degrees ,scorpio  
has the left ear as his exceptional     
feature and the nose 7,sagittarius7 bent
 towards the left ear4 ,a person born   
when the ,sun is in any of the latter   
degrees of ,taurus1 say the twenty-fifth
 degree1 will have a small1 sharp1 weak 
chin1 curved up towards ,gemini1 the two
 vertical lines on the upper lip47#d7   
,the time was when science went out of  
its way to prove that such statements   
were untrue2 but that time is past1 and 
such writers are usually classed among  
those energetic but misguided persons   
who are unable to distinguish between   
logic and sophistry4   ,in ,england1    
from the time of ,elizabeth to the reign

 of ,william and ,mary1 judicial        
astrology was at its height4 ,after the 
great ,london fire1 in #afff1 a         
committee of the ,house of ,commons     
publicly summoned the famous astrologer1
 ,lilly1 to come before ,parliament and 
report to them on his alleged prediction
 of the calamity that had befallen the  
city4 ,lilly1 for some reason best known
 to himself1 denied having made such a  
prediction1 being1 as he explained1 more
 interested in determining affairs of   
much more importance to the future      
welfare of the country4 ,some of the    
explanations of his interpretations will
 suffice to show their absurdities1     
which1 however1 were by no means        
regarded as absurdities at that time1   
for ,lilly was one of the greatest      
astrologers of his day4 ,he said that in
 #aehh a prophecy had been printed in   
,greek characters which foretold exactly
 the troubles of ,england between the   
years #afda4 and #affj4 ,and after him  
shall come a dreadful dead man1 ran the 

prophecy1 and with him a royal ,g of the
 best blood in the world1 and he shall  
have the crown and shall set ,england on
 the right way and put out all heresies4
 ,his interpretation of this was that1  
,monkery being extinguished above eighty
 or ninety years1 and the ,lord         
,general's name being ,monk1 is the dead
 man4 ,the royal ,g or ,c 7it is gamma  
in the ,greek1 intending ,c in the      
,latin1 being the third letter in the   
alphabet7 is ,charles ,,ii41 who1 for   
his extraction1 may be said to be of the
 best blood of the world47#e7  ,this may
 be taken as a fair sample of ,lilly's  
interpretations of astrological         
prophesies1 but many of his own         
writings1 while somewhat more definite  
and direct1 are still left sufficiently 
vague to allow his skilful              
interpretations to set right an apparent
 mistake4 ,one of his famous documents  
was ,the ,starry ,messenger1 a little   
pamphlet purporting to explain the      
phenomenon of a strange apparition of   

three suns that were seen in ,london on 
,november #ai1 #afdd---the anniversary  
of the birth of ,charles ,i41 then the  
reigning monarch4 ,this phenomenon      
caused a great stir among the ,english  
astrologers1 coming1 as it did1 at a    
time of great political disturbance4    
,prophecies were numerous1 and ,lilly's 
brochure is only one of many that       
appeared at that time1 most of which1   
however1 have been lost4 ,lilly1 in his 
preface1 says3 ,if there be any of so   
prevaricate a judgment as to think that 
the apparition of these three ,suns doth
 intimate no ,novelle thing to happen in
 our own ,climate1 where they were      
manifestly visible1 ,i shall lament     
their indisposition1 and conceive their 
brains to be shallow1 and voyde of      
understanding humanity1 or notice of    
common ,history4  ,having thus forgiven 
his few doubting readers1 who were by no
 means in the majority in his day1 he   
takes up in review the records of the   
various appearances of three suns as    

they have occurred during the ,christian
 era1 showing how such phenomena have   
governed certain human events in a very 
definite manner4 ,some of these are     
worth recording4  ,anno #ff4 ,a comet   
was seen1 and also three ,suns3 ,in     
which yeer1 ,florus ,president of the   
,jews was by them slain4 ,paul writes to
 ,timothy4 ,the ,christians are warned  
by a divine ,oracle1 and depart out of  
,jerusalem4 ,boadice a ,british ,queen1 
killeth seventy thousand ,romans4 ,the  
,nazareni1 a scurvie ,sect1 begun1 that 
boasted much of ,revelations and        
,visions4 ,about a year after ,nero was 
proclaimed enemy to the ,state of ,rome4
  ,again1 ,anno #aaeg1 in ,september1   
there were seen three ,suns together1 in
 as clear weather as could be3 ,and a   
few days after1 in the same month1 three
 ,moons1 and1 in the ,moon that stood in
 the middle1 a white ,crosse4 ,sueno1   
,king of ,denmark1 at a great ,feast1   
killeth ,canutus3 ,sueno is himself     
slain1 in pursuit of ,waldemar4 ,the    

,order of ,eremites1 according to the   
rule of ,saint ,augustine1 begun this   
year2 and in the next1 the ,pope submits
 to the ,emperour3 7was not this        
miraculous87 ,lombardy was also adjudged
 to the ,emperour4  ,continuing this    
list of peculiar phenomena he comes down
 to within a few years of his own time4 
,anno #afbb1 three ,suns appeared at    
,heidelberg4 ,the woful ,calamities that
 have ever since fallen upon the        
,palatinate1 we are all sensible of1 and
 of the loss of it1 for any thing ,i    
see1 for ever1 from the right ,heir4    
,osman the great ,turk is strangled that
 year2 and ,spinola besiegeth ,bergen up
 ,zoom1 etc4  ,fortified by the         
enumeration of these past events1 he    
then proceeds to make his deductions4   
,only this ,i must tell thee1 he writes1
 that the interpretation ,i write is1 ,i
 conceive1 grounded upon probable       
foundations2 and who lives to see a few 
years over his head1 will easily        
perceive ,i have unfolded as much as was

 fit to discover1 and that my judgment  
was not a mile and a half from truth4   
,there is a great significance in this  
as much as was fit to discover--a       
mysterious something that ,lilly thinks 
it expedient not to divulge4 ,but1      
nevertheless1 one would imagine that he 
was about to make some definite         
prediction about ,charles ,i41 since    
these three suns appeared upon his      
birthday and surely must portend        
something concerning him4 ,but after    
rambling on through many pages of       
dissertations upon planets and          
prophecies1 he finally makes his own    
indefinite prediction4  ,o all you      
,emperors1 ,kings1 ,princes1 ,rulers and
 ,magistrates of ,europe1 this          
unaccustomed ,apparition is like the    
,handwriting in ,daniel to some of you2 
it premonisheth you1 above all other    
people1 to make your peace with ,god in 
time4 ,you shall every one of you smart1
 and every one of you taste 7none       
excepted7 the heavie hand of ,god1 who  

will strengthen your subjects with      
invincible courage to suppress your     
misgovernments and ,oppressions in      
,church or ,common-wealth2444 ,those    
words are general3 a word for my own    
country of ,england4444 ,look to        
yourselves2 here's some monstrous death 
towards you4 ,but to whom8 wilt thou    
say4 ,herein we consider the ,signe1    
,lord thereof1 and the ,house2 ,the ,sun
 signifies in that ,royal ,signe1 great 
ones2 the ,house signifies captivity1   
poison1 ,treachery3 ,from which is      
derived thus much1 ,that some very great
 man1 what ,king1 ,prince1 ,duke1 or the
 like1 ,i really affirm ,i perfectly    
know not1 shall1 ,i say1 come to some   
such untimely end47#f7  ,here is shown a
 typical example of astrological        
prophecy1 which seems to tell something 
or nothing1 according to the point of   
view of the reader4 ,according to a     
believer in astrology1 after the        
execution of ,charles ,i41 five years   
later1 this could be made to seem a     

direct and exact prophecy4 ,for example1
 he says3 ,you ,kings1 ,princes1        
etc41444 it premonisheth you444 to make 
your peace with ,god4444 ,look to       
yourselves2 here's some monstrous death 
towards you4444 ,that some very great   
man1 what ,king1 ,prince14 shall1 ,i    
say1 come to such untimely end4  ,but by
 the doubter the complete prophecy could
 be shown to be absolutely indefinite1  
and applicable as much to the king of   
,france or ,spain as to ,charles ,i41 or
 to any king in the future1 since no    
definite time is stated4 ,furthermore1  
,lilly distinctly states1 ,what ,king1  
,prince1 ,duke1 or the like1 ,i really  
affirm ,i perfectly know not--which     
last1 at least1 was a most truthful     
statement4 ,the same ingenuity that made
 ,gen4 ,monk the dreadful dead man1     
could easily make such a prediction     
apply to the execution of ,charles ,i4  
,such a definite statement that1 on such
 and such a day a certain number of     
years in the future1 the monarch of     

,england would be beheaded--such an     
exact statement can scarcely be found in
 any of the works on astrology4 ,it     
should be borne in mind1 also1 that     
,lilly was of the ,cromwell party and   
opposed to the king4  ,after the death  
of ,charles ,i41 ,lilly admitted that   
the monarch had given him a thousand    
pounds to cast his horoscope4 ,i advised
 him1 says ,lilly1 to proceed eastwards2
 he went west1 and all the world knows  
the result4 ,it is an unfortunate thing 
for the cause of astrology that ,lilly  
failed to mention this until after the  
downfall of the monarch4 ,in fact1 the  
sudden death1 or decline in power1 of   
any monarch1 even to-day1 brings out the
 perennial post-mortem predictions of   
astrologers4  ,we see how ,lilly1 an    
opponent of the king1 made his so-called
 prophecy of the disaster of the king   
and his army4 ,at the same time another 
celebrated astrologer and rival of      
,lilly1 ,george ,wharton1 also made some
 predictions about the outcome of the   

eventful march from ,oxford4 ,wharton1  
unlike ,lilly1 was a follower of the    
king's party1 but that1 of course1      
should have had no influence in his     
scientific reading of the stars4        
,wharton's predictions are much less    
verbose than ,lilly's1 much more        
explicit1 and1 incidentally1 much more  
incorrect in this particular instance4  
,the ,moon ,lady of the #ab1 he wrote1  
and moving betwixt the #h degree1 #cd   
min41 and #ba degree1 #bf min4 of       
,aquarius1 gives us to understand that  
,his ,majesty shall receive much        
contentment by certain ,messages brought
 him from foreign parts2 and that he    
shall receive some sudden and unexpected
 supply of444 by the means of some that 
assimilate the condition of his         
,enemies3 ,and withal this comfort2 that
 ,his ,majesty shall be exceeding       
successful in ,besieging ,towns1        
,castles1 or ,forts1 and in persuing the
 enemy4  ,mars his ,sextile to the ,sun1
 ,lord of the ,ascendant 7which         

happeneth the #ah day of ,may7 will     
encourage our ,soldiers to advance with 
much alacrity and cheerfulness of       
spirit2 to show themselves gallant in   
the most dangerous attempt4444 ,and now 
to sum up all3 ,it is most apparent to  
every impartial and ingenuous judgment2 
,that although ,his ,majesty cannot     
expect to be secured from every trivial 
disaster that may befall his army1      
either by the too much ,presumption1    
,ignorance1 or ,negligence of some      
particular ,persons 7which is frequently
 incident and unavoidable in the best of
 ,armies71 yet the several positions of 
the ,heavens duly considered and        
compared among themselves1 as well in   
the prefixed ,scheme as at the          
,quarterly ,ingresses1 do generally     
render ,his ,majesty and his whole ,army
 unexpectedly victorious and successful 
in all his designs2 ,believe it         
7,london71 thy ,miseries approach1 they 
are like to be many1 great1 and         
grievous1 and not to be diverted1 unless

 thou seasonably crave ,pardon of ,god  
for being ,nurse to this present        
,rebellion1 and speedily submit to thy  
,prince's ,mercy2 ,which shall be the   
daily ,prayer of ,geo4 ,wharton47#g7    
,in the light of after events1 it is    
probable that ,wharton's stock as an    
astrologer was not greatly enhanced by  
this document1 at least among members of
 the ,royal family4 ,lilly's book1 on   
the other hand1 became a favorite with  
the ,parliamentary army4  ,after the    
downfall and death of ,napoleon there   
were unearthed many alleged authentic   
astrological documents foretelling his  
ruin4 ,and on the death of ,george      
,,iv41 in #ahcj1 there appeared a       
document 7unknown1 as usual1 until that 
time7 purporting to foretell the death  
of the monarch to the day1 and this     
without the astrologer knowing that his 
horoscope was being cast for a monarch4 
,a full account of this prophecy is     
told1 with full belief1 by ,roback1 a   
nineteenth-century astrologer4 ,he says3

  ,in the year #ahbh1 a stranger of     
noble mien1 advanced in life1 but       
possessing the most bland manners1      
arrived at the abode of a celebrated    
astrologer in ,london1 asking that the  
learned man foretell his future4 ,the   
astrologer complied with the request of 
the mysterious visitor1 drew forth his  
tables1 consulted his ephemeris1 and    
cast the horoscope or celestial map for 
the hour and the moment of the inquiry1 
according to the established rules of   
his art4  ,the elements of his          
calculation were adverse1 and a feeling 
of gloom cast a shade of serious        
thought1 if not dejection1 over his     
countenance4  ',you are of high rank1'  
said the astrologer1 as he calculated   
and looked on the stranger1 'and of     
illustrious title4' ,the stranger made a
 graceful inclination of the head in    
token of acknowledgment of the          
complimentary remarks1 and the          
astrologer proceeded with his mission4  
,the celestial signs were ominous of    

calamity to the stranger1 who1 probably 
observing a sudden change in the        
countenance of the astrologer1 eagerly  
inquired what evil or good fortune had  
been assigned him by the celestial orbs4
  ',to the first part of your inquiry1' 
said the astrologer1 ',i can readily    
reply4 ,you have been a favorite of     
fortune2 her smiles on you have been    
abundant1 her frowns but few2 you have  
had1 perhaps now possess1 wealth and    
power2 the impossibility of their       
accomplishment is the only limit to the 
fulfilment of your desires4'  ',you have
 spoken truly of the past1' said the    
stranger4 ',i have full faith in your   
revelations of the future3 what say you 
of my pilgrimage in this life--is it    
short or long8'  ',i regret1' replied   
the astrologer1 in answer to this       
inquiry1 'to be the herald of ill1      
though ,,true1 fortune2 your sojourn on 
earth will be short4'  ',how short8'    
eagerly inquired the excited and anxious
 stranger4  ',give me a momentary       

truce1' said the astrologer2 ',i will   
consult the horoscope1 and may possibly 
find some mitigating circumstances4'    
,having cast his eyes over the celestial
 map1 and paused for some moments1 he   
surveyed the countenance of the stranger
 with great sympathy1 and said1 ',i am  
sorry that ,i can find no planetary     
influences that oppose your             
destiny--your death will take place in  
two years4'  ,the event justified the   
astrologic prediction3 ,george ,,iv4    
died on ,may #ah1 #ahcj1 exactly two    
years from the day on which he had      
visited the astrologer47#h7  ,this makes
 a very pretty story1 but it hardly     
seems like occult insight that an       
astrologer should have been able to     
predict an early death of a man nearly  
seventy years old1 or to have guessed   
that his well-groomed visitor had1      
perhaps now possesses1 wealth and power4
 ,here again1 however1 the point of view
 of each individual plays the governing 
part in determining the importance of   

such a document4 ,to the scientist it   
proves nothing2 to the believer in      
astrology1 everything4 ,the significant 
thing is that it appeared shortly       
,,after the death of the monarch4   ,on 
the ,continent astrologers were even    
more in favor than in ,england4         
,charlemagne1 and some of his immediate 
successors1 to be sure1 attempted to    
exterminate them1 but such rulers as    
,louis ,,xi4 and ,catherine de' ,medici 
patronized and encouraged them1 and it  
was many years after the time of        
,copernicus before their influence was  
entirely stamped out even in official   
life4 ,there can be no question that    
what gave the color of truth to many of 
the predictions was the fact that so    
many of the prophecies of sudden deaths 
and great conflagrations were known to  
have come true--in many instances were  
made to come true by the astrologer     
himself4 ,and so it happened that when  
the prediction of a great conflagration 
at a certain time culminated in such a  

conflagration1 many times a second but  
less-important burning took place1 in   
which the ambitious astrologer1 or his  
followers1 took a central part about a  
stake1 being convicted of incendiarism1 
which they had committed in order that  
their prophecies might be fulfilled4    
,but1 on the other hand1 these          
predictions were sometimes turned to    
account by interested friends to warn   
certain persons of approaching dangers4 
,for example1 a certain astrologer      
foretold the death of ,prince ,alexander
 de' ,medici4 ,he not only foretold the 
death1 but described so minutely the    
circumstances that would attend it1 and 
gave such a correct description of the  
assassin who should murder the prince1  
that he was at once suspected of having 
a hand in the assassination4 ,it        
developed later1 however1 that such was 
probably not the case2 but that some    
friend of ,prince ,alexander1 knowing of
 the plot to take his life1 had induced 
the astrologer to foretell the event in 

order that the prince might have timely 
warning and so elude the conspirators4  
,the cause of the decline of astrology  
was the growing prevalence of the new   
spirit of experimental science4         
,doubtless the most direct blow was     
dealt by the ,copernican theory4 ,so    
soon as this was established1 the       
recognition of the earth's subordinate  
place in the universe must have made it 
difficult for astronomers to be longer  
deceived by such coincidences as had    
sufficed to convince the observers of a 
more credulous generation4 ,tycho ,brahe
 was1 perhaps1 the last astronomer of   
prominence who was a conscientious      
practiser of the art of the astrologer4 
,,vii4 ,,from ,,paracelsus ,,to ,,harvey
  ,,paracelsus  ,in the year #aebf there
 appeared a new lecturer on the platform
 at the ,university at ,basel--a small1 
beardless1 effeminate-looking           
person--who had already inflamed all    
,christendom with his peculiar          
philosophy1 his revolutionary methods of

 treating diseases1 and his unparalleled
 success in curing them4 ,a man who was 
to be remembered in after-time by some  
as the father of modern chemistry and   
the founder of modern medicine2 by      
others as madman1 charlatan1 impostor2  
and by still others as a combination of 
all these4 ,this soft-cheeked1          
effeminate1 woman-hating man1 whose very
 sex has been questioned1 was           
,theophrastus von ,hohenheim1 better    
known as ,paracelsus 7#adic-aeda74  ,to 
appreciate his work1 something must be  
known of the life of the man4 ,he was   
born near ,maria-,einsiedeln1 in        
,switzerland1 the son of a poor         
physician of the place4 ,he began the   
study of medicine under the instruction 
of his father1 and later on came under  
the instruction of several learned      
churchmen4 ,at the age of sixteen he    
entered the ,university of ,basel1 but1 
soon becoming disgusted with the        
philosophical teachings of the time1 he 
quitted the scholarly world of dogmas   

and theories and went to live among the 
miners in the ,tyrol1 in order that he  
might study nature and men at first     
hand4 ,ordinary methods of study were   
thrown aside1 and he devoted his time to
 personal observation--the only true    
means of gaining useful knowledge1 as he
 preached and practised ever after4     
,here he became familiar with the art of
 mining1 learned the physical properties
 of minerals1 ores1 and metals1 and     
acquired some knowledge of mineral      
waters4 ,more important still1 he came  
in contact with such diseases1 wounds1  
and injuries as miners are subject to1  
and he tried his hand at the practical  
treatment of these conditions1          
untrammelled by the traditions of a     
profession in which his training had    
been so scant4  ,having acquired some   
empirical skill in treating diseases1   
,paracelsus set out wandering from place
 to place all over ,europe1 gathering   
practical information as he went1 and   
learning more and more of the medicinal 

virtues of plants and minerals4 ,his    
wanderings covered a period of about ten
 years1 at the end of which time he     
returned to ,basel1 where he was soon   
invited to give a course of lectures in 
the university4  ,these lectures were   
revolutionary in two respects--they were
 given in ,german instead of            
time-honored ,latin1 and they were based
 upon personal experience rather than   
upon the works of such writers as ,galen
 and ,avicenna4 ,indeed1 the            
iconoclastic teacher spoke with open    
disparagement of these revered masters1 
and openly upbraided his                
fellow-practitioners for following their
 tenets4 ,naturally such teaching raised
 a storm of opposition among the older  
physicians1 but for a time the          
unparalleled success of ,paracelsus in  
curing diseases more than offset his    
unpopularity4 ,gradually1 however1 his  
bitter tongue and his coarse personality
 rendered him so unpopular1 even among  
his patients1 that1 finally1 his liberty

 and life being jeopardized1 he was     
obliged to flee from ,basel1 and became 
a wanderer4 ,he lived for brief periods 
in ,colmar1 ,nuremberg1 ,appenzell1     
,zurich1 ,pfeffers1 ,augsburg1 and      
several other cities1 until finally at  
,salzburg his eventful life came to a   
close in #aeda4 ,his enemies said that  
he had died in a tavern from the effects
 of a protracted debauch2 his supporters
 maintained that he had been murdered at
 the instigation of rival physicians and
 apothecaries4  ,but the effects of his 
teachings had taken firm root1 and      
continued to spread after his death4 ,he
 had shown the fallibility of many of   
the teachings of the hitherto standard  
methods of treating diseases1 and had   
demonstrated the advantages of          
independent reasoning based on          
observation4 ,in his ,magicum he gives  
his reasons for breaking with tradition4
 ,i did1 he says1 embrace at the        
beginning these doctrines1 as my        
adversaries 7followers of ,galen7 have  

done1 but since ,i saw that from their  
procedures nothing resulted but death1  
murder1 stranglings1 anchylosed limbs1  
paralysis1 and so forth1 that they held 
most diseases incurable4444 therefore   
have ,i quitted this wretched art1 and  
sought for truth in any other direction4
 ,i asked myself if there were no such  
thing as a teacher in medicine1 where   
could ,i learn this art best8 ,nowhere  
better than the open book of nature1    
written with ,god's own finger4 ,we     
shall see1 however1 that this book of   
nature taught ,paracelsus some very     
strange lessons4 ,modesty was not one of
 these4 ,now at this time1 he declares1 
,i1 ,theophrastus ,paracelsus1 ,bombast1
 ,monarch of the ,arcana1 was endowed by
 ,god with special gifts for this end1  
that every searcher after this supreme  
philosopher's work may be forced to     
imitate and to follow me1 be he         
,italian1 ,pole1 ,gaul1 ,german1 or     
whatsoever or whosoever he be4 ,come    
hither after me1 all ye philosophers1   

astronomers1 and spagirists4444 ,i will 
show and open to you444 this corporeal  
regeneration47#a7  ,paracelsus based his
 medical teachings on four              
pillars--philosophy1 astronomy1 alchemy1
 and virtue of the physician--a         
strange-enough equipment surely1 and    
yet1 properly interpreted1 not quite so 
anomalous as it seems at first blush4   
,philosophy was the gate of medicine1   
whereby the physician entered rightly   
upon the true course of learning2       
astronomy1 the study of the stars1 was  
all-important because they 7the stars7  
caused disease by their exhalations1 as1
 for instance1 the sun by excessive     
heat2 alchemy1 as he interpreted it1    
meant the improvement of natural        
substances for man's benefit2 while     
virtue in the physician was necessary   
since only the virtuous are permitted to
 penetrate into the innermost nature of 
man and the universe4  ,all his writings
 aim to promote progress in medicine1   
and to hold before the physician a grand

 ideal of his profession4 ,in this his  
views are wide and far-reaching1 based  
on the relationship which man bears to  
nature as a whole2 but in his sweeping  
condemnations he not only rejected      
,galenic therapeutics and ,galenic      
anatomy1 but condemned dissections of   
any kind4 ,he laid the cause of all     
diseases at the door of the three mystic
 elements--salt1 sulphur1 and mercury4  
,in health he supposed these to be      
mingled in the body so as to be         
indistinguishable2 a slight separation  
of them produced disease2 and death he  
supposed to be the result of their      
complete separation4 ,the spiritual     
agencies of diseases1 he said1 had      
nothing to do with either angels or     
devils1 but were the spirits of human   
beings4  ,he believed that all food     
contained poisons1 and that the function
 of digestion was to separate the       
poisonous from the nutritious4 ,in the  
stomach was an archaeus1 or alchemist1  
whose duty was to make this separation4 

,in digestive disorders the archaeus    
failed to do this1 and the poisons thus 
gaining access to the system were       
coagulated and deposited in the joints  
and various other parts of the body4    
,thus the deposits in the kidneys and   
tartar on the teeth were formed2 and the
 stony deposits of gout were            
particularly familiar examples of this4 
,all this is visionary enough1 yet it   
shows at least a groping after rational 
explanations of vital phenomena4  ,like 
most others of his time1 ,paracelsus    
believed firmly in the doctrine of      
signatures--a belief that every organ   
and part of the body had a corresponding
 form in nature1 whose function was to  
heal diseases of the organ it resembled4
 ,the vagaries of this peculiar doctrine
 are too numerous and complicated for   
lengthy discussion1 and varied greatly  
from generation to generation4 ,in      
general1 however1 the theory may be     
summed up in the words of ,paracelsus3  
,as a woman is known by her shape1 so   

are the medicines4 ,hence the physicians
 were constantly searching for some     
object of corresponding shape to an     
organ of the body4 ,the most natural    
application of this doctrine would be   
the use of the organs of the lower      
animals for the treatment of the        
corresponding diseased organs in man4   
,thus diseases of the heart were to be  
treated with the hearts of animals1     
liver disorders with livers1 and so on4 
,but this apparently simple form of     
treatment had endless modifications and 
restrictions1 for not all animals were  
useful4 ,for example1 it was useless to 
give the stomach of an ox in gastric    
diseases when the indication in such    
cases was really for the stomach of a   
rat4 ,nor were the organs of animals the
 only signatures in nature4 ,plants also
 played a very important role1 and the  
herb-doctors devoted endless labor to   
searching for such plants4 ,thus the    
blood-root1 with its red juice1 was     
supposed to be useful in blood diseases1

 in stopping hemorrhage1 or in subduing 
the redness of an inflammation4         
,paracelsus's system of signatures1     
however1 was so complicated by his      
theories of astronomy and alchemy that  
it is practically beyond comprehension4 
,it is possible that he himself may have
 understood it1 but it is improbable    
that any one else did--as shown by the  
endless discussions that have taken     
place about it4 ,but with all the       
vagaries of his theories he was still   
rational in his applications1 and he    
attacked to good purpose the complicated
 shot-gun prescriptions of his          
contemporaries1 advocating more simple  
methods of treatment4  ,the             
ever-fascinating subject of electricity1
 or1 more specifically1 magnetism1 found
 great favor with him1 and with properly
 adjusted magnets he claimed to be able 
to cure many diseases4 ,in epilepsy and 
lockjaw1 for example1 one had but to    
fasten magnets to the four extremities  
of the body1 and then1 when the proper  

medicines were given1 the cure would be 
effected4 ,the easy loop-hole for       
excusing failure on the ground of       
improper medicines is obvious1 but      
,paracelsus declares that this one      
prescription is of more value than all  
the humoralists have ever written or    
taught4  ,since ,paracelsus condemned   
the study of anatomy as useless1 he     
quite naturally regarded surgery in the 
same light4 ,in this he would have done 
far better to have studied some of his  
predecessors1 such as ,galen1 ,paul of  
,aegina1 and ,avicenna4 ,but instead of 
cutting men to pieces1 he taught that   
surgeons would gain more by devoting    
their time to searching for the         
universal panacea which would cure all  
diseases1 surgical as well as medical4  
,in this we detect a taint of the       
popular belief in the philosopher's     
stone and the magic elixir of life1 his 
belief in which have been stoutly denied
 by some of his followers4 ,he did      
admit1 however1 that one operation alone

 was perhaps permissible--lithotomy1 or 
the cutting for stone4  ,his influence  
upon medicine rests undoubtedly upon his
 revolutionary attitude1 rather than on 
any great or new discoveries made by    
him4 ,it is claimed by many that he     
brought prominently into use opium and  
mercury1 and if this were indisputably  
proven his services to medicine could   
hardly be overestimated4 ,unfortunately1
 however1 there are good grounds for    
doubting that he was particularly       
influential in reintroducing these      
medicines4 ,his chief influence may     
perhaps be summed up in a single        
phrase--he overthrew old traditions4    
,to ,paracelsus's endeavors1 however1 if
 not to the actual products of his work1
 is due the credit of setting in motion 
the chain of thought that developed     
finally into scientific chemistry4 ,nor 
can the ultimate aim of the modern      
chemist seek a higher object than that  
of this sixteenth-century alchemist1 who
 taught that true alchemy has but one   

aim and object1 to extract the          
quintessence of things1 and to prepare  
arcana1 tinctures1 and elixirs which may
 restore to man the health and soundness
 he has lost4   ,,the ,,great           
,,anatomists  ,about the beginning of   
the sixteenth century1 while ,paracelsus
 was scoffing at the study of anatomy as
 useless1 and using his influence       
against it1 there had already come upon 
the scene the first of the great        
anatomists whose work was to make the   
century conspicuous in that branch of   
medicine4  ,the young anatomist ,charles
 etienne 7#aejc-aefd7 made one of the   
first noteworthy discoveries1 pointing  
out for the first time that the spinal  
cord contains a canal1 continuous       
throughout its length4 ,he also made    
other minor discoveries of some         
importance1 but his researches were     
completely overshadowed and obscured by 
the work of a young ,fleming who came   
upon the scene a few years later1 and   
who shone with such brilliancy in the   

medical world that he obscured          
completely the work of his contemporary 
until many years later4 ,this young     
physician1 who was destined to lead such
 an eventful career and meet such an    
untimely end as a martyr to science1 was
 ,andrew ,vesalius 7#aead-aefd71 who is 
called the greatest of anatomists4 ,at  
the time he came into the field medicine
 was struggling against the dominating  
,galenic teachings and the theories of  
,paracelsus1 but perhaps most of all    
against the superstitions of the time4  
,in ,france human dissections were      
attended with such dangers that the     
young ,vesalius transferred his field of
 labors to ,italy1 where such           
investigations were covertly permitted1 
if not openly countenanced4  ,from the  
very start the young ,fleming looked    
askance at the accepted teachings of the
 day1 and began a series of independent 
investigations based upon his own       
observations4 ,the results of these     
investigations he gave in a treatise on 

the subject which is regarded as the    
first comprehensive and systematic work 
on human anatomy4 ,this remarkable work 
was published in the author's           
twenty-eighth or twenty-ninth year4     
,soon after this ,vesalius was invited  
as imperial physician to the court of   
,emperor ,charles ,v4 ,he continued to  
act in the same capacity at the court of
 ,philip ,,ii41 after the abdication of 
his patron4 ,but in spite of this royal 
favor there was at work a factor more   
powerful than the influence of the      
monarch himself--an instrument that did 
so much to retard scientific progress1  
and by which so many lives were brought 
to a premature close4  ,vesalius had    
received permission from the kinsmen of 
a certain grandee to perform an autopsy4
 ,while making his observations the     
heart of the outraged body was seen to  
palpitate--so at least it was reported4 
,this was brought immediately to the    
attention of the ,inquisition1 and it   
was only by the intervention of the king

 himself that the anatomist escaped the 
usual fate of those accused by that     
tribunal4 ,as it was1 he was obliged to 
perform a pilgrimage to the ,holy ,land4
 ,while returning from this he was      
shipwrecked1 and perished from hunger   
and exposure on the island of ,zante4   
,at the very time when the anatomical   
writings of ,vesalius were startling the
 medical world1 there was living and    
working contemporaneously another great 
anatomist1 ,eustachius 7died #aegd71    
whose records of his anatomical         
investigations were ready for           
publication only nine years after the   
publication of the work of ,vesalius4   
,owing to the unfortunate circumstances 
of the anatomist1 however1 they were    
never published during his              
lifetime--not1 in fact1 until #agad4    
,when at last they were given to the    
world as ,anatomical ,engravings1 they  
showed conclusively that ,eustachius was
 equal1 if not superior to ,vesalius in 
his knowledge of anatomy4 ,it has been  

said of this remarkable collection of   
engravings that if they had been        
published when they were made in the    
sixteenth century1 anatomy would have   
been advanced by at least two centuries4
 ,but be this as it may1 they certainly 
show that their author was a most       
careful dissector and observer4         
,eustachius described accurately for the
 first time certain structures of the   
middle ear1 and rediscovered the tube   
leading from the ear to the throat that 
bears his name4 ,he also made careful   
studies of the teeth and the phenomena  
of first and second dentition4 ,he was  
not baffled by the minuteness of        
structures and where he was unable to   
study them with the naked eye he used   
glasses for the purpose1 and resorted to
 macerations and injections for the     
study of certain complicated structures4
 ,but while the fruit of his pen and    
pencil were lost for more than a century
 after his death1 the effects of his    
teachings were not2 and his two pupils1 

,fallopius and ,columbus1 are almost as 
well known to-day as their illustrious  
teacher4 ,columbus 7#adij-aeei7 did much
 in correcting the mistakes made in the 
anatomy of the bones as described by    
,vesalius4 ,he also added much to the   
science by giving correct accounts of   
the shape and cavities of the heart1 and
 made many other discoveries of minor   
importance4 ,fallopius 7#aebc-aefb7     
added considerably to the general       
knowledge of anatomy1 made several      
discoveries in the anatomy of the ear1  
and also several organs in the abdominal
 cavity4  ,at this time a most vitally  
important controversy was in progress as
 to whether or not the veins of the     
bodies were supplied with valves1 many  
anatomists being unable to find them4   
,etienne had first described these      
structures1 and ,vesalius had confirmed 
his observations4 ,it would seem as if  
there could be no difficulty in settling
 the question as to the fact of such    
valves being present in the vessels1 for

 the demonstration is so simple that it 
is now made daily by medical students in
 all physiological laboratories and     
dissecting-rooms4 ,but many of the great
 anatomists of the sixteenth century    
were unable to make this demonstration1 
even when it had been brought to their  
attention by such an authority as       
,vesalius4 ,fallopius1 writing to       
,vesalius on the subject in #aefb1      
declared that he was unable to find such
 valves4 ,others1 however1 such as      
,eustachius and ,fabricius 7#aecg-afai71
 were more successful1 and found and    
described these structures4 ,but the    
purpose served by these valves was      
entirely misinterpreted4 ,that they act 
in preventing the backward flow of the  
blood in the veins on its way to the    
heart1 just as the valves of the heart  
itself prevent regurgitation1 has been  
known since the time of ,harvey2 but the
 best interpretation that could be given
 at that time1 even by such a man as    
,fabricius1 was that they acted in      

retarding the flow of the blood as it   
comes from the heart1 and thus prevent  
its too rapid distribution throughout   
the body4 ,the fact that the blood might
 have been going towards the heart1     
instead of coming from it1 seems never  
to have been considered seriously until 
demonstrated so conclusively by ,harvey4
  ,of this important and remarkable     
controversy over the valves in veins1   
,withington has this to say3 ,this is   
truly a marvellous story4 ,a great      
,galenic anatomist is first to give a   
full and correct description of the     
valves and their function1 but fails to 
see that any modification of the old    
view as to the motion of the blood is   
required4 ,two able dissectors carefully
 test their action by experiment1 and   
come to a result1 the exact reverse of  
the truth4 ,urged by them1 the two      
foremost anatomists of the age make a   
special search for valves and fail to   
find them4 ,finally1 passing over lesser
 peculiarities1 an aged and honorable   

professor1 who has lived through all    
this1 calmly asserts that no anatomist1 
ancient or modern1 has ever mentioned   
valves in veins till he discovered them 
in #aegd67b7  ,among the anatomists who 
probably discovered these valves was    
,michael ,servetus 7#aeaa-aeec72 but if 
this is somewhat in doubt1 it is certain
 that he discovered and described the   
pulmonary circulation1 and had a very   
clear idea of the process of respiration
 as carried on in the lungs4 ,the       
description was contained in a famous   
document sent to ,calvin in #aede--;a   
document which the reformer carefully   
kept for seven years in order that he   
might make use of some of the heretical 
statements it contained to accomplish   
his desire of bringing its writer to the
 stake4 ,the awful fate of ,servetus1   
the interesting character of the man1   
and the fact that he came so near to    
anticipating the discoveries of ,harvey 
make him one of the most interesting    
figures in medical history4  ,in this   

document which was sent to ,calvin1     
,servetus rejected the doctrine of      
natural1 vital1 and animal spirits1 as  
contained in the veins1 arteries1 and   
nerves respectively1 and made the       
all-important statement that the fluids 
contained in veins and arteries are the 
same4 ,he showed also that the blood is 
purged from fume and purified by        
respiration in the lungs1 and declared  
that there is a new vessel in the lungs1
 formed out of vein and artery4 ,even at
 the present day there is little to add 
to or change in this description of     
,servetus's4  ,by keeping this document1
 pregnant with advanced scientific      
views1 from the world1 and in the end   
only using it as a means of destroying  
its author1 the great reformer showed   
the same jealousy in retarding          
scientific progress as had his          
arch-enemies of the ,inquisition1 at    
whose dictates ,vesalius became a martyr
 to science1 and in whose dungeons      
etienne perished4   ,,the ,,coming ,,of 

,,harvey  ,the time was ripe for the    
culminating discovery of the circulation
 of the blood2 but as yet no one had    
determined the all-important fact that  
there are two currents of blood in the  
body1 one going to the heart1 one coming
 from it4 ,the valves in the veins would
 seem to show conclusively that the     
venous current did not come from the    
heart1 and surgeons must have observed  
thousands of times the every-day        
phenomenon of congested veins at the    
distal extremity of a limb around which 
a ligature or constriction of any kind  
had been placed1 and the simultaneous   
depletion of the vessels at the proximal
 points above the ligature4 ,but it     
should be remembered that inductive     
science was in its infancy4 ,this was   
the sixteenth1 not the nineteenth       
century1 and few men had learned to put 
implicit confidence in their            
observations and convictions when       
opposed to existing doctrines4 ,the time
 was at hand1 however1 when such a man  

was to make his appearance1 and1 as in  
the case of so many revolutionary       
doctrines in science1 this man was an   
,englishman4 ,it remained for ,william  
,harvey 7#aegh-afeg7 to solve the great 
mystery which had puzzled the medical   
world since the beginning of history2   
not only to solve it1 but to prove his  
case so conclusively and so simply that 
for all time his little booklet must he 
handed down as one of the great         
masterpieces of lucid and almost        
faultless demonstration4  ,harvey1 the  
son of a prosperous ,kentish yeoman1 was
 born at ,folkestone4 ,his education was
 begun at the grammar-school of         
,canterbury1 and later he became a      
pensioner of ,caius ,college1           
,cambridge4 ,soon after taking his      
degree of ,b4,a41 at the age of         
nineteen1 he decided upon the profession
 of medicine1 and went to ,padua as a   
pupil of ,fabricius and ,casserius4     
,returning to ,england at the age of    
twenty-four1 he soon after 7#afji7      

obtained the reversion of the post of   
physician to ,st4 ,bartholomew's        
,hospital1 his application being        
supported by ,james ,i4 himself4 ,even  
at this time he was a popular physician1
 counting among his patients such men as
 ,francis ,bacon4 ,in #afah he was      
appointed physician extraordinary to the
 king1 and1 a little later1 physician in
 ordinary4 ,he was in attendance upon   
,charles ,i4 at the battle of ,edgehill1
 in #afdb1 where1 with the young ,prince
 of ,wales and the ,duke of ,york1 after
 seeking shelter under a hedge1 he drew 
a book out of his pocket and1 forgetful 
of the battle1 became absorbed in study1
 until finally the cannon-balls from the
 enemy's artillery made him seek a more 
sheltered position4  ,on the fall of    
,charles ,i4 he retired from practice1  
and lived in retirement with his        
brother4 ,he was then well along in     
years1 but still pursued his scientific 
researches with the same vigor as       
before1 directing his attention chiefly 

to the study of embryology4 ,on ,june   
#c1 #afeg1 he was attacked by paralysis 
and died1 in his eightieth year4 ,he had
 lived to see his theory of the         
circulation accepted1 several years     
before1 by all the eminent anatomists of
 the civilized world4  ,a keenness in   
the observation of facts1 characteristic
 of the mind of the man1 had led ,harvey
 to doubt the truth of existing         
doctrines as to the phenomena of the    
circulation4 ,galen had taught that the 
arteries are filled1 like bellows1      
because they are expanded1 but ,harvey  
thought that the action of spurting     
blood from a severed vessel disproved   
this4 ,for the spurting was remittant1  
now with greater1 now with less impetus1
 and its greater force always           
corresponded to the expansion           
7diastole71 not the contraction         
7systole7 of the vessel4 ,furthermore1  
it was evident that contraction of the  
heart and the arteries was not          
simultaneous1 as was commonly taught1   

because in that case there would be no  
marked propulsion of the blood in any   
direction2 and there was no gainsaying  
the fact that the blood was forcibly    
propelled in a definite direction1 and  
that direction away from the heart4     
,harvey's investigations led him to     
doubt also the accepted theory that     
there was a porosity in the septum of   
tissue that divides the two ventricles  
of the heart4 ,it seemed unreasonable to
 suppose that a thick fluid like the    
blood could find its way through pores  
so small that they could not be         
demonstrated by any means devised by    
man4 ,in evidence that there could be no
 such openings he pointed out that1     
since the two ventricles contract at the
 same time1 this process would impede   
rather than facilitate such an          
intra-ventricular passage of blood4 ,but
 what seemed the most conclusive proof  
of all was the fact that in the foetus  
there existed a demonstrable opening    
between the two ventricles1 and yet this

 is closed in the fully developed heart4
 ,why should ,nature1 if she intended   
that blood should pass between the two  
cavities1 choose to close this opening  
and substitute microscopic openings in  
place of it8 ,it would surely seem more 
reasonable to have the small            
perforations in the thin1 easily        
permeable membrane of the foetus1 and   
the opening in the adult heart1 rather  
than the reverse4 ,from all this ,harvey
 drew his correct conclusions1 declaring
 earnestly1 ,by ,hercules1 there ,,are  
no such porosities1 and they cannot be  
demonstrated4  ,having convinced himself
 that no intra-ventricular opening      
existed1 he proceeded to study the      
action of the heart itself1 untrammelled
 by too much faith in established       
theories1 and1 as yet1 with no theory of
 his own4 ,he soon discovered that the  
commonly accepted theory of the heart   
striking against the chest-wall during  
the period of relaxation was entirely   
wrong1 and that its action was exactly  

the reverse of this1 the heart striking 
the chest-wall during contraction4      
,having thus disproved the accepted     
theory concerning the heart's action1 he
 took up the subject of the action of   
arteries1 and soon was able to          
demonstrate by vivisection that the     
contraction of the arteries was not     
simultaneous with contractions of the   
heart4 ,his experiments demonstrated    
that these vessels were simply elastic  
tubes whose pulsations were nothing else
 than the impulse of the blood within   
them4 ,the reason that the arterial     
pulsation was not simultaneous with the 
heart-beat he found to be because of the
 time required to carry the impulse     
along the tube4  ,by a series of further
 careful examinations and experiments1  
which are too extended to be given here1
 he was soon able further to demonstrate
 the action and course of the blood     
during the contractions of the heart4   
,his explanations were practically the  
same as those given to-day--first the   

contraction of the auricle1 sending     
blood into the ventricle2 then          
ventricular contraction1 making the     
pulse1 and sending the blood into the   
arteries4 ,he had thus demonstrated what
 had not been generally accepted before1
 that the heart was an organ for the    
propulsion of blood4 ,to make such a    
statement to-day seems not unlike the   
sober announcement that the earth is    
round or that the sun does not revolve  
about it4 ,before ,harvey's time1       
however1 it was considered as an organ  
that was in some mysterious way the     
source of vitality and warmth1 as an    
animated crucible for the concoction of 
blood and the generation of vital       
spirits47#c7  ,in watching the rapid and
 ceaseless contractions of the heart1   
,harvey was impressed with the fact     
that1 even if a very small amount of    
blood was sent out at each pulsation1 an
 enormous quantity must pass through the
 organ in a day1 or even in an hour4    
,estimating the size of the cavities of 

the heart1 and noting that at least a   
drachm must be sent out with each       
pulsation1 it was evident that the two  
thousand beats given by a very slow     
human heart in an hour must send out    
some forty pounds of blood--more than   
twice the amount in the entire body4    
,the question was1 what became of it    
all8 ,for it should be remembered that  
the return of the blood by the veins was
 unknown1 and nothing like a circulation
 more than vaguely conceived even by    
,harvey himself4 ,once it could be shown
 that the veins were constantly         
returning blood to the heart1 the       
discovery that the blood in some way    
passes from the arteries to the veins   
was only a short step4 ,harvey1 by      
resorting to vivisections of lower      
animals and reptiles1 soon demonstrated 
beyond question the fact that the veins 
do carry the return blood4 ,but this1 in
 particular1 can be shown clearer than  
daylight1 says ,harvey4 ,the vena cava  
enters the heart at an inferior portion1

 while the artery passes out above4 ,now
 if the vena cava be taken up with      
forceps or the thumb and finger1 and the
 course of the blood intercepted for    
some distance below the heart1 you will 
at once see it almost emptied between   
the fingers and the heart1 the blood    
being exhausted by the heart's          
pulsation1 the heart at the same time   
becoming much paler even in its         
dilatation1 smaller in size1 owing to   
the deficiency of blood1 and at length  
languid in pulsation1 as if about to    
die4 ,on the other hand1 when you       
release the vein the heart immediately  
regains its color and dimensions4 ,after
 that1 if you leave the vein free and   
tie and compress the arteries at some   
distance from the heart1 you will see1  
on the contrary1 their included portion 
grow excessively turgid1 the heart      
becoming so beyond measure1 assuming a  
dark-red color1 even to lividity1 and at
 length so overloaded with blood as to  
seem in danger of suffocation2 but when 

the obstruction is removed it returns to
 its normal condition1 in size1 color1  
and movement47#d7  ,this conclusive     
demonstration that the veins return the 
blood to the heart must have been most  
impressive to ,harvey1 who had been     
taught to believe that the blood current
 in the veins pursued an opposite       
course1 and must have tended to shake   
his faith in all existing doctrines of  
the day4  ,his next step was the natural
 one of demonstrating that the blood    
passes from the arteries to the veins4  
,he demonstrated conclusively that this 
did occur1 but for once his rejection of
 the ancient writers and one modern one 
was a mistake4 ,for ,galen had taught1  
and had attempted to demonstrate1 that  
there are sets of minute vessels        
connecting the arteries and the veins2  
and ,servetus had shown that there must 
be such vessels1 at least in the lungs4 
,however1 the little flaw in the        
otherwise complete demonstration of     
,harvey detracts nothing from the main  

issue at stake4 ,it was for others who  
followed to show just how these small   
vessels acted in effecting the transfer 
of the blood from artery to vein1 and   
the grand general statement that such a 
transfer does take place was1 after all1
 the all-important one1 and the exact   
method of how it takes place a detail4  
,harvey's experiments to demonstrate    
that the blood passes from the arteries 
to the veins are so simply and concisely
 stated that they may best be given in  
his own words4  ,i have here to cite    
certain experiments1 he wrote1 from     
which it seems obvious that the blood   
enters a limb by the arteries1 and      
returns from it by the veins2 that the  
arteries are the vessels carrying the   
blood from the heart1 and the veins the 
returning channels of the blood to the  
heart2 that in the limbs and extreme    
parts of the body the blood passes      
either by anastomosis from the arteries 
into the veins1 or immediately by the   
pores of the flesh1 or in both ways1 as 

has already been said in speaking of the
 passage of the blood through the lungs2
 whence it appears manifest that in the 
circuit the blood moves from thence     
hither1 and hence thither2 from the     
centre to the extremities1 to wit1 and  
from the extreme parts back again to the
 centre4 ,finally1 upon grounds of      
circulation1 with the same elements as  
before1 it will be obvious that the     
quantity can neither be accounted for by
 the ingesta1 nor yet be held necessary 
to nutrition4  ,now let any one make an 
experiment on the arm of a man1 either  
using such a fillet as is employed in   
blood-letting or grasping the limb      
tightly with his hand1 the best subject 
for it being one who is lean1 and who   
has large veins1 and the best time after
 exercise1 when the body is warm1 the   
pulse is full1 and the blood carried in 
large quantities to the extremities1 for
 all then is more conspicuous2 under    
such circumstances let a ligature be    
thrown about the extremity and drawn as 

tightly as can be borne3 it will first  
be perceived that beyond the ligature   
neither in the wrist nor anywhere else  
do the arteries pulsate1 that at the    
same time immediately above the ligature
 the artery begins to rise higher at    
each diastole1 to throb more violently1 
and to swell in its vicinity with a kind
 of tide1 as if it strove to break      
through and overcome the obstacle to its
 current2 the artery here1 in short1    
appears as if it were permanently full4 
,the hand under such circumstances      
retains its natural color and           
appearances2 in the course of time it   
begins to fall somewhat in temperature1 
indeed1 but nothing is ,,drawn into it4 
,after the bandage has been kept on some
 short time in this way1 let it be      
slackened a little1 brought to the state
 or term of middling tightness which is 
used in bleeding1 and it will be seen   
that the whole hand and arm will        
instantly become deeply suffused and    
distended1 injected1 gorged with blood1 

,,drawn1 as it is said1 by this middling
 ligature1 without pain1 or heat1 or any
 horror of a vacuum1 or any other cause 
yet indicated4  ,as we have noted1 in   
connection with the tight ligature1 that
 the artery above the bandage was       
distended and pulsated1 not below it1   
so1 in the case of the moderately tight 
bandage1 on the contrary1 do we find    
that the veins below1 never above1 the  
fillet swell and become dilated1 while  
the arteries shrink2 and such is the    
degree of distention of the veins here  
that it is only very strong pressure    
that will force the blood beyond the    
fillet and cause any of the veins in the
 upper part of the arm to rise4  ,from  
these facts it is easy for any careful  
observer to learn that the blood enters 
an extremity by the arteries2 for when  
they are effectively compressed nothing 
is ,,drawn to the member2 the hand      
preserves its color2 nothing flows into 
it1 neither is it distended2 but when   
the pressure is diminished1 as it is    

with the bleeding fillet1 it is manifest
 that the blood is instantly thrown in  
with force1 for then the hand begins to 
swell2 which is as much as to say that  
when the arteries pulsate the blood is  
flowing through them1 as it is when the 
moderately tight ligature is applied2   
but when they do not pulsate1 or when a 
tight ligature is used1 they cease from 
transmitting anything2 they are only    
distended above the part where the      
ligature is applied4 ,the veins again   
being compressed1 nothing can flow      
through them2 the certain indication of 
which is that below the ligature they   
are much more tumid than above it1 and  
than they usually appear when there is  
no bandage upon the arm4  ,it therefore 
plainly appears that the ligature       
prevents the return of the blood through
 the veins to the parts above it1 and   
maintains those beneath it in a state of
 permanent distention4 ,but the         
arteries1 in spite of the pressure1 and 
under the force and impulse of the      

heart1 send on the blood from the       
internal parts of the body to the parts 
beyond the bandage47#e7   ,this use of  
ligatures is very significant1 because1 
as shown1 a very tight ligature stops   
circulation in both arteries and veins1 
while a loose one1 while checking the   
circulation in the veins1 which lie     
nearer the surface and are not so       
directly influenced by the force of the 
heart1 does not stop the passage of     
blood in the arteries1 which are usually
 deeply imbedded in the tissues1 and not
 so easily influenced by pressure from  
without4  ,the last step of ,harvey's   
demonstration was to prove that the     
blood does flow along the veins to the  
heart1 aided by the valves that had been
 the cause of so much discussion and    
dispute between the great               
sixteenth-century anatomists4 ,harvey   
not only demonstrated the presence of   
these valves1 but showed conclusively1  
by simple experiments1 what their       
function was1 thus completing his       

demonstration of the phenomena of the   
circulation4  ,the final ocular         
demonstration of the passage of the     
blood from the arteries to the veins was
 not to be made until four years after  
,harvey's death4 ,this process1 which   
can be observed easily in the web of a  
frog's foot by the aid of a low-power   
lens1 was first demonstrated by         
,marcello ,malpighi 7#afbh-afid7 in     
#affa4 ,by the aid of a lens he first   
saw the small capillary vessels         
connecting the veins and arteries in a  
piece of dried lung4 ,taking his cue    
from this1 he examined the lung of a    
turtle1 and was able to see in it the   
passage of the corpuscles through these 
minute vessels1 making their way along  
these previously unknown channels from  
the arteries into the veins on their    
journey back to the heart4 ,thus the    
work of ,harvey1 all but complete1 was  
made absolutely entire by the great     
,italian4 ,and all this in a single     
generation4   ,,leeuwenhoek ,,discovers 

,,bacteria  ,the seventeenth century was
 not to close1 however1 without another 
discovery in science1 which1 when       
applied to the causation of disease     
almost two centuries later1             
revolutionized therapeutics more        
completely than any one discovery4 ,this
 was the discovery of microbes1 by      
,antonius von ,leeuwenhoek 7#afcb-agbc71
 in #afhc4 ,von ,leeuwenhoek discovered 
that in the white matter between his    
teeth there were millions of microscopic
 animals--more1 in fact1 than there were
 human beings in the united             
,netherlands1 and all moving in the most
 delightful manner4 ,there can be no    
question that he saw them1 for we can   
recognize in his descriptions of these  
various forms of little animals the four
 principal forms of microbes--the long  
and short rods of bacilli and bacteria1 
the spheres of micrococci1 and the      
corkscrew spirillum4  ,the presence of  
these microbes in his mouth greatly     
annoyed ,antonius1 and he tried various 

methods of getting rid of them1 such as 
using vinegar and hot coffee4 ,in doing 
this he little suspected that he was    
anticipating modern antiseptic surgery  
by a century and three-quarters1 and to 
be attempting what antiseptic surgery is
 now able to accomplish4 ,for the       
fundamental principle of antisepsis is  
the use of medicines for ridding wounds 
of similar microscopic organisms4 ,von  
,leenwenhoek was only temporarily       
successful in his attempts1 however1 and
 took occasion to communicate his       
discovery to the ,royal ,society of     
,england1 hoping that they would be     
interested in this novelty4 ,probably   
they were1 but not sufficiently so for  
any member to pursue any protracted     
investigations or reach any satisfactory
 conclusions1 and the whole matter was  
practically forgotten until the middle  
of the nineteenth century4     ,,viii4  
,,medicine ,,in ,,the ,,sixteenth ,,and 
,,seventeenth ,,centuries  ,of the      
half-dozen surgeons who were prominent  

in the sixteenth century1 ,ambroise     
,pare 7#aeag-aeij71 called the father of
 ,french surgery1 is perhaps the most   
widely known4 ,he rose from the position
 of a common barber to that of surgeon  
to three ,french monarchs1 ,henry ,,ii41
 ,francis ,,ii41 and ,charles ,,ix4     
,some of his mottoes are still first    
principles of the medical man4 ,among   
others are3 ,he who becomes a surgeon   
for the sake of money1 and not for the  
sake of knowledge1 will accomplish      
nothing2 and ,a tried remedy is better  
than a newly invented4 ,on his statue is
 his modest estimate of his work in     
caring for the wounded1 ,je le pansay1  
,dieu le guarit--,i dressed him1 ,god   
cured him4  ,it was in this dressing of 
wounds on the battlefield that he       
accidentally discovered how useless and 
harmful was the terribly painful        
treatment of applying boiling oil to    
gunshot wounds as advocated by ,john of 
,vigo4 ,it happened that after a certain
 battle1 where there was an unusually   

large number of casualties1 ,pare found1
 to his horror1 that no more boiling oil
 was available for the surgeons1 and    
that he should be obliged to dress the  
wounded by other simpler methods4 ,to   
his amazement the results proved        
entirely satisfactory1 and from that day
 he discarded the hot-oil treatment4    
,as ,pare did not understand ,latin he  
wrote his treatises in ,french1 thus    
inaugurating a custom in ,france that   
was begun by ,paracelsus in ,germany    
half a century before4 ,he reintroduced 
the use of the ligature in controlling  
hemorrhage1 introduced the figure of    
eight suture in the operation for       
hare-lip1 improved many of the          
medico-legal doctrines1 and advanced the
 practice of surgery generally4 ,he is  
credited with having successfully       
performed the operation for strangulated
 hernia1 but he probably borrowed it    
from ,peter ,franco 7#aeje-aegj71 who   
published an account of this operation  
in #aeef4 ,as this operation is         

considered by some the most important   
operation in surgery1 its discoverer is 
entitled to more than passing notice1   
although he was despised and ignored by 
the surgeons of his time4  ,franco was  
an illiterate travelling lithotomist--a 
class of itinerant physicians who were  
very generally frowned down by the      
regular practitioners of medicine4 ,but 
,franco possessed such skill as an      
operator1 and appears to have been so   
earnest in the pursuit of what he       
considered a legitimate calling1 that he
 finally overcame the popular prejudice 
and became one of the salaried surgeons 
of the republic of ,bern4 ,he was the   
first surgeon to perform the suprapubic 
lithotomy operation--the removal of     
stone through the abdomen instead of    
through the perineum4 ,his works1 while 
written in an illiterate style1 give the
 clearest descriptions of any of the    
early modern writers4  ,as the fame of  
,franco rests upon his operation for    
prolonging human life1 so the fame of   

his ,italian contemporary1 ,gaspar      
,tagliacozzi 7#aede-aeii71 rests upon   
his operation for increasing human      
comfort and happiness by restoring      
amputated noses4 ,at the time in which  
he lived amputation of the nose was very
 common1 partly from disease1 but also  
because a certain pope had fixed the    
amputation of that member as the penalty
 for larceny4 ,tagliacozzi probably     
borrowed his operation from the ,east2  
but he was the first ,western surgeon to
 perform it and describe it4 ,so great  
was the fame of his operations that     
patients flocked to him from all over   
,europe1 and each went away with as many
 noses as he liked4 ,naturally1 the man 
who directed his efforts to restoring   
structures that bad been removed by     
order of the ,church was regarded in the
 light of a heretic by many theologians2
 and though he succeeded in cheating the
 stake or dungeon1 and died a natural   
death1 his body was finally cast out of 
the church in which it had been buried4 

,in the sixteenth century ,germany      
produced a surgeon1 ,fabricius ,hildanes
 7#aefj-afci71 whose work compares      
favorably with that of ,pare1 and whose 
name would undoubtedly have been much   
better known had not the circumstances  
of the time in which he lived tended to 
obscure his merits4 ,the blind followers
 of ,paracelsus could see nothing       
outside the pale of their master's      
teachings1 and the disastrous ,thirty   
,years' ,war tended to obscure and      
retard all scientific advances in       
,germany4 ,unlike many of his           
fellow-surgeons1 ,hildanes was well     
versed in ,latin and ,greek2 and1       
contrary to the teachings of            
,paracelsus1 he laid particular stress  
upon the necessity of the surgeon having
 a thorough knowledge of anatomy4 ,he   
had a helpmate in his wife1 who was also
 something of a surgeon1 and she is     
credited with having first made use of  
the magnet in removing particles of     
metal from the eye4 ,hildanes tells of a

 certain man who had been injured by a  
small piece of steel in the cornea1     
which resisted all his efforts to remove
 it4 ,after observing ,hildanes'        
fruitless efforts for a time1 it        
suddenly occurred to his wife to attempt
 to make the extraction with a piece of 
loadstone4 ,while the physician held    
open the two lids1 his wife attempted to
 withdraw the steel with the magnet held
 close to the cornea1 and after several 
efforts she was successful--which       
,hildanes enumerates as one of the      
advantages of being a married man4      
,hildanes was particularly happy in his 
inventions of surgical instruments1 many
 of which were designed for locating and
 removing the various missiles recently 
introduced in warfare4   ,the           
seventeenth century1 which was such a   
flourishing one for anatomy and         
physiology1 was not as productive of    
great surgeons or advances in surgery as
 the sixteenth had been or the          
eighteenth was to be4 ,there was a      

gradual improvement all along the line1 
however1 and much of the work begun by  
such surgeons as ,pare and ,hildanes was
 perfected or improved4 ,perhaps the    
most progressive surgeon of the century 
was an ,englishman1 ,richard ,wiseman   
7#afbe-afhf71 who1 like ,harvey1 enjoyed
 royal favor1 being in the service of   
all the ,stuart kings4 ,he was the first
 surgeon to advocate primary amputation1
 in gunshot wounds1 of the limbs1 and   
also to introduce the treatment of      
aneurisms by compression2 but he is     
generally rated as a conservative       
operator1 who favored medication rather 
than radical operations1 where possible4
  ,in ,italy1 ,marcus ,aurelius         
,severinus 7#aehj-afef7 and ,peter      
,marchettis 7#aehi-afge7 were the       
leading surgeons of their nation4 ,like 
many of his predecessors in ,europe1    
,severinus ran amuck with the ,holy     
,inquisition and fled from ,naples4 ,but
 the waning of the powerful arm of the  
,church is shown by the fact that he was

 brought back by the unanimous voice of 
the grateful citizens1 and lived in     
safety despite the frowns of the        
theologians4   ,the sixteenth century   
cannot be said to have added much of    
importance in the field of practical    
medicine1 and1 as in the preceding and  
succeeding centuries1 was at best only  
struggling along in the wake of anatomy1
 physiology1 and surgery4 ,in the       
seventeenth century1 however1 at least  
one discovery in therapeutics was made  
that has been an inestimable boon to    
humanity ever since4 ,this was the      
introduction of cinchona bark 7from     
which quinine is obtained7 in #afdj4    
,but this century was productive of many
 medical ,,systems1 and could boast of  
many great names among the medical      
profession1 and1 on the whole1 made     
considerably more progress than the     
preceding century4  ,of the founders of 
medical systems1 one of the most widely 
known is ,jan ,baptista van ,helmont    
7#aegh-afdd71 an eccentric genius who   

constructed a system of medicine of his 
own and for a time exerted considerable 
influence4 ,but in the end his system   
was destined to pass out of existence1  
not very long after the death of its    
author4 ,van ,helmont was not only a    
physician1 but was master of all the    
other branches of learning of the time1 
taking up the study of medicine and     
chemistry as an after-thought1 but      
devoting himself to them with the       
greatest enthusiasm once he had begun   
his investigations4 ,his attitude       
towards existing doctrines was as       
revolutionary as that of ,paracelsus1   
and he rejected the teachings of ,galen 
and all the ancient writers1 although   
retaining some of the views of          
,paracelsus4 ,he modified the archaeus  
of ,paracelsus1 and added many          
complications to it4 ,he believed the   
whole body to be controlled by an       
archaeus influus1 the soul by the       
archaei insiti1 and these in turn       
controlled by the central archeus4 ,his 

system is too elaborate and complicated 
for full explanation1 but its chief     
service to medicine was in introducing  
new chemical methods in the preparation 
of drugs4 ,in this way he was indirectly
 connected with the establishment of the
 ,iatrochemical school4 ,it was he who  
first used the word gas--a word coined  
by him1 along with many others that soon
 fell into disuse4  ,the principles of  
the ,iatrochemical school were the use  
of chemical medicines1 and a theory of  
pathology different from the prevailing 
humoral pathology4 ,the founder of this 
school was ,sylvius 7,franz de le ,boe1 
#afad-afgb71 professor of medicine at   
,leyden4 ,he attempted to establish a   
permanent system of medicine based on   
the newly discovered theory of the      
circulation and the new chemistry1 but  
his name is remembered by medical men   
because of the fissure in the brain     
7fissure of ,sylvius7 that bears it4 ,he
 laid great stress on the cause of      
fevers and other diseases as originating

 in the disturbances of the process of  
fermentation in the stomach4 ,the       
doctrines of ,sylvius spread widely over
 the continent1 but were not generally  
accepted in ,england until modified by  
,thomas ,willis 7#afbb-afge71 whose     
name1 like that of ,sylvius1 is         
perpetuated by a structure in the brain 
named after him1 the circle of ,willis4 
,willis's descriptions of certain       
nervous diseases1 and an account of     
diabetes1 are the first recorded1 and   
added materially to scientific medicine4
 ,these schools of medicine lasted until
 the end of the seventeenth century1    
when they were finally overthrown by    
,sydenham4  ,the ,iatrophysical school  
7also called iatromathematical1         
iatromechanical1 or physiatric7 was     
founded on theories of physiology1      
probably by ,borelli1 of ,naples        
7#afjh-afgi71 although ,sanctorius2     
,sanctorius1 a professor at ,padua1 was 
a precursor1 if not directly interested 
in establishing it4 ,sanctorius         

discovered the fact that an insensible  
perspiration is being given off by the  
body continually1 and was amazed to find
 that loss of weight in this way far    
exceeded the loss of weight by all other
 excretions of the body combined4 ,he   
made this discovery by means of a       
peculiar weighing-machine to which a    
chair was attached1 and in which he     
spent most of his time4 ,very naturally 
he overestimated the importance of this 
discovery1 but it was1 nevertheless1 of 
great value in pointing out the hygienic
 importance of the care of the skin4 ,he
 also introduced a thermometer which he 
advocated as valuable in cases of fever1
 but the instrument was probably not his
 own invention1 but borrowed from his   
friend ,galileo4  ,harvey's discovery of
 the circulation of the blood laid the  
foundation of the ,iatrophysical school 
by showing that this vital process was  
comparable to a hydraulic system4 ,in   
his ,on the ,motive of ,animals1        
,borelli first attempted to account for 

the phenomena of life and diseases on   
these principles4 ,the iatromechanics   
held that the great cause of disease is 
due to different states of elasticity of
 the solids of the body interfering with
 the movements of the fluids1 which are 
themselves subject to changes in        
density1 one or both of these conditions
 continuing to cause stagnation or      
congestion4 ,the school thus founded by 
,borelli was the outcome of the         
unbounded enthusiasm1 with its          
accompanying exaggeration of certain    
phenomena with the corresponding        
belittling of others that naturally     
follows such a revolutionary discovery  
as that of ,harvey4 ,having such a      
founder as the brilliant ,italian       
,borelli1 it was given a sufficient     
impetus by his writings to carry it some
 distance before it finally collapsed4  
,some of the exaggerated mathematical   
calculations of ,borelli himself are    
worth noting4 ,each heart-beat1 as he   
calculated it1 overcomes a resistance   

equal to one hundred and eighty thousand
 pounds2--the modern physiologist       
estimates its force at from five to nine
 ounces6   ,,thomas ,,sydenham  ,but    
while the ,continent was struggling with
 these illusive systems1 and dabbling in
 mystic theories that were to scarcely  
outlive the men who conceived them1     
there appeared in ,england--the land of 
common-sense1 as a ,german scientist has
 called it--a cool1 clear1 and          
unprejudiced spirit1 who in the golden  
age of systems declined to be like the  
man who builds the chambers of the upper
 story of his house before he had laid  
securely the foundation walls47#a7 ,this
 man was ,thomas ,sydenham 7#afbd-afhi71
 who1 while the great ,harvey was       
serving the king as surgeon1 was        
fighting as a captain in the            
parliamentary army4 ,sydenham took for  
his guide the teachings of ,hippocrates1
 modified to suit the advances that had 
been made in scientific knowledge since 
the days of the great ,greek1 and       

established1 as a standard1 observation 
and experience4 ,he cared little for    
theory unless confirmed by practice1 but
 took the ,hippocratic view that nature 
cured diseases1 assisted by the         
physician4 ,he gave due credit1 however1
 to the importance of the part played by
 the assistant4 ,as he saw it1 medicine 
could be advanced in three ways3 7#a7   
,by accurate descriptions or natural    
histories of diseases2 7#b7 by          
establishing a fixed principle or method
 of treatment1 founded upon experience2 
7#c7 by searching for specific remedies1
 which he believes must exist in        
considerable numbers1 though he admits  
that the only one yet discovered is     
,peruvian bark47#b7 ,as it happened1    
another equally specific remedy1        
mercury1 when used in certain diseases1 
was already known to him1 but he        
evidently did not recognize it as such4 
,the influence on future medicine of    
,sydenham's teachings was most          
pronounced1 due mostly to his teaching  

of careful observation4 ,to most        
physicians1 however1 he is now          
remembered chiefly for his introduction 
of the use of laudanum1 still considered
 one of the most valuable remedies of   
modern pharmacopoeias4 ,the ,german     
gives the honor of introducing this     
preparation to ,paracelsus1 but the     
,english-speaking world will always     
believe that the credit should be given 
to ,sydenham4     ,,ix4                 
,,philosopher-,,scientists ,,and ,,new  
,,institutions ,,of ,,learning  ,we saw 
that in the old ,greek days there was no
 sharp line of demarcation between the  
field of the philosopher and that of the
 scientist4 ,in the ,hellenistic epoch1 
however1 knowledge became more          
specialized1 and our recent chapters    
have shown us scientific investigators  
whose efforts were far enough removed   
from the intangibilities of the         
philosopher4 ,it must not be overlooked1
 however1 that even in the present epoch
 there were men whose intellectual      

efforts were primarily directed towards 
the subtleties of philosophy1 yet who   
had also a penchant for strictly        
scientific imaginings1 if not indeed for
 practical scientific experiments4 ,at  
least three of these men were of        
sufficient importance in the history of 
the development of science to demand    
more than passing notice4 ,these three  
are the ,englishman ,francis ,bacon     
7#aefa-afbf71 the ,frenchman ,rene      
,descartes 7#aeif-afej72 and the ,german
 ,gottfried ,leibnitz 7#afdf-agaf74     
,bacon1 as the earliest path-breaker1   
showed the way1 theoretically at least1 
in which the sciences should be studied2
 ,descartes1 pursuing the methods       
pointed out by ,bacon1 carried the same 
line of abstract reason into practice as
 well2 while ,leibnitz1 coming some     
years later1 and having the advantage of
 the wisdom of his two great            
predecessors1 was naturally influenced  
by both in his views of abstract        
scientific principles4  ,bacon's career 

as a statesman and his faults and       
misfortunes as a man do not concern us  
here4 ,our interest in him begins with  
his entrance into ,trinity ,college1    
,cambridge1 where he took up the study  
of all the sciences taught there at that
 time4 ,during the three years he became
 more and more convinced that science   
was not being studied in a profitable   
manner1 until at last1 at the end of his
 college course1 he made ready to       
renounce the old ,aristotelian methods  
of study and advance his theory of      
inductive study4 ,for although he was a 
great admirer of ,aristotle's work1 he  
became convinced that his methods of    
approaching study were entirely wrong4  
,the opinion of ,aristotle1 he says1 in 
his ,de ,argumentum ,scientiarum1       
seemeth to me a negligent opinion1 that 
of those things which exist by nature   
nothing can be changed by custom2 using 
for example1 that if a stone be thrown  
ten thousand times up it will not learn 
to ascend2 and that by often seeing or  

hearing we do not learn to see or hear  
better4 ,for though this principle be   
true in things wherein nature is        
peremptory 7the reason whereof we cannot
 now stand to discuss71 yet it is       
otherwise in things wherein nature      
admitteth a latitude4 ,for he might see 
that a straight glove will come more    
easily on with use2 and that a wand will
 by use bend otherwise than it grew2 and
 that by use of the voice we speak      
louder and stronger2 and that by use of 
enduring heat or cold we endure it the  
better1 and the like2 which latter sort 
have a nearer resemblance unto that     
subject of manners he handleth than     
those instances which he allegeth47#a7  
,these were his opinions1 formed while a
 young man in college1 repeated at      
intervals through his maturer years1 and
 reiterated and emphasized in his old   
age4 ,masses of facts were to be        
obtained by observing nature at first   
hand1 and from such accumulations of    
facts deductions were to be made4 ,in   

short1 reasoning was to be from the     
specific to the general1 and not vice   
versa4  ,it was by his teachings alone  
that ,bacon thus contributed to the     
foundation of modern science2 and1 while
 he was constantly thinking and writing 
on scientific subjects1 he contributed  
little in the way of actual discoveries4
 ,i only sound the clarion1 he said1 but
 ,i enter not the battle4  ,the case of 
,descartes1 however1 is different4 ,he  
both sounded the clarion and entered    
into the fight4 ,he himself freely      
acknowledges his debt to ,bacon for his 
teachings of inductive methods of study1
 but modern criticism places his work on
 the same plane as that of the great    
,englishman4 ,if you lay hold of any    
characteristic product of modern ways of
 thinking1 says ,huxley1 either in the  
region of philosophy or in that of      
science1 you find the spirit of that    
thought1 if not its form1 has been      
present in the mind of the great        
,frenchman47#b7  ,descartes1 the son of 

a noble family of ,france1 was educated 
by ,jesuit teachers4 ,like ,bacon1 he   
very early conceived the idea that the  
methods of teaching and studying science
 were wrong1 but be pondered the matter 
well into middle life before putting    
into writing his ideas of philosophy and
 science4 ,then1 in his ,discourse      
,touching the ,method of ,using ,one's  
,reason ,rightly and of ,seeking        
,scientific ,truth1 he pointed out the  
way of seeking after truth4 ,his central
 idea in this was to emphasize the      
importance of ,,doubt1 and avoidance of 
accepting as truth anything that does   
not admit of absolute and unqualified   
proof4 ,in reaching these conclusions he
 had before him the striking examples of
 scientific deductions by ,galileo1 and 
more recently the discovery of the      
circulation of the blood by ,harvey4    
,this last came as a revelation to      
scientists1 reducing this seemingly     
occult process1 as it did1 to the field 
of mechanical phenomena4 ,the same      

mechanical laws that governed the       
heavenly bodies1 as shown by ,galileo1  
governed the action of the human heart1 
and1 for aught any one knew1 every part 
of the body1 and even the mind itself4  
,having once conceived this idea1       
,descartes began a series of dissections
 and experiments upon the lower animals1
 to find1 if possible1 further proof of 
this general law4 ,to him the human body
 was simply a machine1 a complicated    
mechanism1 whose functions were         
controlled just as any other piece of   
machinery4 ,he compared the human body  
to complicated machinery run by         
water-falls and complicated pipes4 ,the 
nerves of the machine which ,i am       
describing1 he says1 may very well be   
compared to the pipes of these          
waterworks2 its muscles and its tendons 
to the other various engines and springs
 which seem to move them2 its animal    
spirits to the water which impels them1 
of which the heart is the fountain2     
while the cavities of the brain are the 

central office4 ,moreover1 respiration  
and other such actions as are natural   
and usual in the body1 and which depend 
on the course of the spirits1 are like  
the movements of a clock1 or a mill1    
which may be kept up by the ordinary    
flow of water47#c7  ,in such passages as
 these ,descartes anticipates the ideas 
of physiology of the present time4 ,he  
believed that the functions are         
performed by the various organs of the  
bodies of animals and men as a          
mechanism1 to which in man was added the
 soul4 ,this soul he located in the     
pineal gland1 a degenerate and          
presumably functionless little organ in 
the brain4 ,for years ,descartes's idea 
of the function of this gland was held  
by many physiologists1 and it was only  
the introduction of modern high-power   
microscopy that reduced this also to a  
mere mechanism1 and showed that it is   
apparently the remains of a ,cyclopean  
eye once common to man's remote         
ancestors4  ,descartes was the          

originator of a theory of the movements 
of the universe by a mechanical         
process--the ,cartesian theory of       
vortices--which for several decades     
after its promulgation reigned supreme  
in science4 ,it is the ingenuity of this
 theory1 not the truth of its           
assertions1 that still excites          
admiration1 for it has long since been  
supplanted4 ,it was certainly the best  
hitherto advanced--the best that the    
observations of the age admitted1       
according to ,d',alembert4  ,according  
to this theory the infinite universe is 
full of matter1 there being no such     
thing as a vacuum4 ,matter1 as          
,descartes believed1 is uniform in      
character throughout the entire         
universe1 and since motion cannot take  
place in any part of a space completely 
filled1 without simultaneous movement in
 all other parts1 there are constant    
more or less circular movements1        
vortices1 or whirlpools of particles1   
varying1 of course1 in size and         

velocity4 ,as a result of this circular 
movement the particles of matter tend to
 become globular from contact with one  
another4 ,two species of matter are thus
 formed1 one larger and globular1 which 
continue their circular motion with a   
constant tendency to fly from the centre
 of the axis of rotation1 the other     
composed of the clippings resulting from
 the grinding process4 ,these smaller   
filings from the main bodies1 becoming  
smaller and smaller1 gradually lose     
their velocity and accumulate in the    
centre of the vortex4 ,this collection  
of the smaller matter in the centre of  
the vortex constitutes the sun or star1 
while the spherical particles propelled 
in straight lines from the centre       
towards the circumference of the vortex 
produce the phenomenon of light         
radiating from the central star4 ,thus  
this matter becomes the atmosphere      
revolving around the accumulation at the
 centre4 ,but the small particles being 
constantly worn away from the revolving 

spherical particles in the vortex1      
become entangled in their passage1 and  
when they reach the edge of the inner   
strata of solar dust they settle upon it
 and form what we call sun-spots4 ,these
 are constantly dissolved and reformed1 
until sometimes they form a crust round 
the central nucleus4  ,as the expansive 
force of the star diminishes in the     
course of time1 it is encroached upon by
 neighboring vortices4 ,if the part of  
the encroaching star be of a less       
velocity than the star which it has     
swept up1 it will presently lose its    
hold1 and the smaller star pass out of  
range1 becoming a comet4 ,but if the    
velocity of the vortex into which the   
incrusted star settles be equivalent to 
that of the surrounded vortex1 it will  
hold it as a captive1 still revolving   
and wrapt in its own firmament4 ,thus   
the several planets of our solar system 
have been captured and held by the      
sun-vortex1 as have the moon and other  
satellites4  ,but although these new    

theories at first created great         
enthusiasm among all classes of         
philosophers and scientists1 they soon  
came under the ban of the ,church4      
,while no actual harm came to ,descartes
 himself1 his writings were condemned by
 the ,catholic and ,protestant churches 
alike4 ,the spirit of philosophical     
inquiry he had engendered1 however1     
lived on1 and is largely responsible for
 modern philosophy4  ,in many ways the  
life and works of ,leibnitz remind us of
 ,bacon rather than ,descartes4 ,his    
life was spent in filling high political
 positions1 and his philosophical and   
scientific writings were by-paths of his
 fertile mind4 ,he was a theoretical    
rather than a practical scientist1 his  
contributions to science being in the   
nature of philosophical reasonings      
rather than practical demonstrations4   
,had he been able to withdraw from      
public life and devote himself to       
science alone1 as ,descartes did1 he    
would undoubtedly have proved himself   

equally great as a practical worker4    
,but during the time of his greatest    
activity in philosophical fields1       
between the years #afij and #agaf1 he   
was all the time performing             
extraordinary active duties in entirely 
foreign fields4 ,his work may be        
regarded1 perhaps1 as doing for ,germany
 in particular what ,bacon's did for    
,england and the rest of the world in   
general4  ,only a comparatively small   
part of his philosophical writings      
concern us here4 ,according to his      
theory of the ultimate elements of the  
universe1 the entire universe is        
composed of individual centres1 or      
monads4 ,to these monads he ascribed    
numberless qualities by which every     
phase of nature may be accounted4 ,they 
were supposed by him to be percipient1  
self-acting beings1 not under arbitrary 
control of the deity1 and yet ,god      
himself was the original monad from     
which all the rest are generated4 ,with 
this conception as a basis1 ,leibnitz   

deduced his doctrine of pre-established 
harmony1 whereby the numerous           
independent substances composing the    
world are made to form one universe4 ,he
 believed that by virtue of an inward   
energy monads develop themselves        
spontaneously1 each being independent of
 every other4 ,in short1 each monad is a
 kind of deity in itself--a microcosm   
representing all the great features of  
the macrocosm4  ,it would be impossible 
clearly to estimate the precise value of
 the stimulative influence of these     
philosophers upon the scientific thought
 of their time4 ,there was one way1     
however1 in which their influence was   
made very tangible--namely1 in the      
incentive they gave to the foundation of
 scientific societies4   ,,scientific   
,,societies  ,at the present time1 when 
the elements of time and distance are   
practically eliminated in the           
propagation of news1 and when cheap     
printing has minimized the difficulties 
of publishing scientific discoveries1 it

 is difficult to understand the isolated
 position of the scientific             
investigation of the ages that preceded 
steam and electricity4 ,shut off from   
the world and completely out of touch   
with fellow-laborers perhaps only a few 
miles away1 the investigators were      
naturally seriously handicapped2 and    
inventions and discoveries were not made
 with the same rapidity that they would 
undoubtedly have been had the same men  
been receiving daily1 weekly1 or monthly
 communications from fellow-laborers all
 over the world1 as they do to-day4     
,neither did they have the advantage of 
public or semi-public laboratories1     
where they were brought into contact    
with other men1 from whom to gather     
fresh trains of thought and receive the 
stimulus of their successes or failures4
 ,in the natural course of events1      
however1 neighbors who were interested  
in somewhat similar pursuits1 not of the
 character of the rivalry of trade or   
commerce1 would meet more or less       

frequently and discuss their progress4  
,the mutual advantages of such          
intercourse would be at once            
appreciated2 and it would be but a short
 step from the casual meeting of two    
neighborly scientists to the            
establishment of societies1 meeting at  
fixed times1 and composed of members    
living within reasonable travelling     
distance4 ,there would1 perhaps1 be the 
weekly or monthly meetings of men in a  
limited area2 and as the natural        
outgrowth of these little local         
societies1 with frequent meetings1 would
 come the formation of larger societies1
 meeting less often1 where members      
travelled a considerable distance to    
attend4 ,and1 finally1 with increased   
facilities for communication and travel1
 the great international societies of   
to-day would be produced--the natural   
outcome of the neighborly meetings of   
the primitive mediaeval investigators4  
,in ,italy1 at about the time of        
,galileo1 several small societies were  

formed4 ,one of the most important of   
these was the ,lyncean ,society1 founded
 about the year #afaa1 ,galileo himself 
being a member4 ,this society was       
succeeded by the ,accademia del         
,cimento1 at ,florence1 in #afeg1 which 
for a time flourished1 with such a      
famous scientist as ,torricelli as one  
of its members4  ,in ,england an impetus
 seems to have been given by ,sir       
,francis ,bacon's writings in criticism 
and censure of the system of teaching in
 colleges4 ,it is supposed that his     
suggestions as to what should be the    
aims of a scientific society led        
eventually to the establishment of the  
,royal ,society4 ,he pointed out how    
little had really been accomplished by  
the existing institutions of learning in
 advancing science1 and asserted that   
little good could ever come from them   
while their methods of teaching remained
 unchanged4 ,he contended that the      
system which made the lectures and      
exercises of such a nature that no      

deviation from the established routine  
could be thought of was pernicious4 ,but
 he showed that if any teacher had the  
temerity to turn from the traditional   
paths1 the daring pioneer was likely to 
find insurmountable obstacles placed in 
the way of his advancement4 ,the studies
 were imprisoned within the limits of a 
certain set of authors1 and originality 
in thought or teaching was to be neither
 contemplated nor tolerated4  ,the words
 of ,bacon1 given in strong and         
unsparing terms of censure and          
condemnation1 but nevertheless with     
perfect justification1 soon bore fruit4 
,as early as the year #afde a small     
company of scientists had been in the   
habit of meeting at some place in       
,london to discuss philosophical and    
scientific subjects for mental          
advancement4 ,in #afdh1 owing to the    
political disturbances of the time1 some
 of the members of these meetings       
removed to ,oxford1 among them ,boyle1  
,wallis1 and ,wren1 where the meetings  

were continued1 as were also the        
meetings of those left in ,london4 ,in  
#affb1 however1 when the political      
situation bad become more settled1 these
 two bodies of men were united under a  
charter from ,charles ,,ii41 and        
,bacon's ideas were practically         
expressed in that learned body1 the     
,royal ,society of ,london4 ,and it     
matters little that in some respects    
,bacon's views were not followed in the 
practical workings of the society1 or   
that the division of labor in the early 
stages was somewhat different than at   
present4 ,the aim of the society has    
always been one for the advancement of  
learning2 and if ,bacon himself could   
look over its records1 he would surely  
have little fault to find with the aid  
it has given in carrying out his ideas  
for the promulgation of useful          
knowledge4  ,ten years after the charter
 was granted to the ,royal ,society of  
,london1 ,lord ,bacon's words took      
practical effect in ,germany1 with the  

result that the ,academia ,naturae      
,curiosorum was founded1 under the      
leadership of ,professor ,j4 ,c4 ,sturm4
 ,the early labors of this society were 
devoted to a repetition of the most     
notable experiments of the time1 and the
 work of the embryo society was         
published in two volumes1 in #afgb and  
#afhe respectively1 which were          
practically text-books of the physics of
 the period4 ,it was not until #agjj    
that ,frederick ,i4 founded the ,royal  
,academy of ,sciences at ,berlin1 after 
the elaborate plan of ,leibnitz1 who was
 himself the first president4  ,perhaps 
the nearest realization of ,bacon's     
ideal1 however1 is in the ,royal        
,academy of ,sciences at ,paris1 which  
was founded in #afff under the          
administration of ,colbert1 during the  
reign of ,louis ,,xiv4 ,this institution
 not only recognized independent        
members1 but had besides twenty         
pensionnaires who received salaries from
 the government4 ,in this way a select  

body of scientists were enabled to      
pursue their investigations without     
being obliged to give thought to the    
morrow for their sustenance4 ,in return 
they were to furnish the meetings with  
scientific memoirs1 and once a year give
 an account of the work they were       
engaged upon4 ,thus a certain number of 
the brightest minds were encouraged to  
devote their entire time to scientific  
research1 delivered alike from the      
temptations of wealth or the            
embarrassments of poverty4 ,that such a 
plan works well is amply attested by the
 results emanating from the ,french     
academy4 ,pensionnaires in various      
branches of science1 however1 either    
paid by the state or by learned         
societies1 are no longer confined to    
,france4  ,among the other early        
scientific societies was the ,imperial  
,academy of ,sciences at ,st4           
,petersburg1 projected by ,peter the    
,great1 and established by his widow1   
,catharine ,i41 in #agbe2 and also the  

,royal ,swedish ,academy1 incorporated  
in #agha1 and counting among its early  
members such men as the celebrated      
,linnaeus4 ,but after the first impulse 
had resulted in a few learned societies1
 their manifest advantage was so evident
 that additional numbers increased      
rapidly1 until at present almost every  
branch of every science is represented  
by more or less important bodies2 and   
these are1 individually and             
collectively1 adding to knowledge and   
stimulating interest in the many fields 
of science1 thus vindicating ,lord      
,bacon's asseverations that knowledge   
could be satisfactorily promulgated in  
this manner4     ,x4 ,,the ,,successors 
,,of ,,galileo ,,in ,,physical ,,science
  ,we have now to witness the           
diversified efforts of a company of men 
who1 working for the most part          
independently1 greatly added to the data
 of the physical sciences--such men as  
,boyle1 ,huygens1 ,von ,gericke1 and    
,hooke4 ,it will be found that the      

studies of these men covered the whole  
field of physical sciences as then      
understood--the field of so-called      
natural philosophy4 ,we shall best treat
 these successors of ,galileo and       
precursors of ,newton somewhat          
biographically1 pointing out the        
correspondences and differences between 
their various accomplishments as we     
proceed4 ,it will be noted in due course
 that the work of some of them was      
anticipatory of great achievements of a 
later century4   ,,robert ,,boyle       
7#afbg-afia7  ,some of ,robert ,boyle's 
views as to the possible structure of   
atmospheric air will be considered a    
little farther on in this chapter1 but  
for the moment we will take up the      
consideration of some of his experiments
 upon that as well as other gases4      
,boyle was always much interested in    
alchemy1 and carried on extensive       
experiments in attempting to accomplish 
the transmutation of metals2 but he did 
not confine himself to these            

experiments1 devoting himself to        
researches in all the fields of natural 
philosophy4 ,he was associated at       
,oxford with a company of scientists1   
including ,wallis and ,wren1 who held   
meetings and made experiments together1 
these gatherings being the beginning1 as
 mentioned a moment ago1 of what finally
 became the ,royal ,society4 ,it was    
during this residence at ,oxford that   
many of his valuable researches upon air
 were made1 and during this time be     
invented his air-pump1 now exhibited in 
the ,royal ,society rooms at ,burlington
 ,house47#a7  ,his experiments to prove 
the atmospheric pressure are most       
interesting and conclusive4 ,having     
three small1 round glass bubbles1 blown 
at the flame of a lamp1 about the size  
of hazel-nuts1 he says1 each of them    
with a short1 slender stem1 by means    
whereof they were so exactly poised in  
water that a very small change of weight
 would make them either emerge or sink2 
at a time when the atmosphere was of    

convenient weight1 ,i put them into a   
wide-mouthed glass of common water1 and 
leaving them in a quiet place1 where    
they were frequently in my eye1 ,i      
observed that sometimes they would be at
 the top of the water1 and remain there 
for several days1 or perhaps weeks1     
together1 and sometimes fall to the     
bottom1 and after having continued there
 for some time rise again4 ,and         
sometimes they would rise or fall as the
 air was hot or cold47#b7  ,it was in   
the course of these experiments that the
 observations made by ,boyle led to the 
invention of his statical barometer1 the
 mercurial barometer having been        
invented1 as we have seen1 by           
,torricelli1 in #afdc4 ,in describing   
this invention he says3 ,making choice  
of a large1 thin1 and light glass       
bubble1 blown at the flame of a lamp1 ,i
 counterpoised it with a metallic       
weight1 in a pair of scales that were   
suspended in a frame1 that would turn   
with the thirtieth part of a grain4     

,both the frame and the balance were    
then placed near a good barometer1      
whence ,i might learn the present weight
 of the atmosphere2 when1 though the    
scales were unable to show all the      
variations that appeared in the         
mercurial barometer1 yet they gave      
notice of those that altered the height 
of the mercury half a quarter of an     
inch47#c7 ,a fairly sensitive barometer1
 after all4 ,this statical barometer    
suggested several useful applications to
 the fertile imagination of its         
inventor1 among others the measuring of 
mountain-peaks1 as with the mercurial   
barometer1 the rarefication of the air  
at the top giving a definite ratio to   
the more condensed air in the valley4   
,another of his experiments was made to 
discover the atmospheric pressure to the
 square inch4 ,after considerable       
difficulty he determined that the       
relative weight of a cubic inch of water
 and mercury was about one to fourteen1 
and computing from other known weights  

he determined that when a column of     
quicksilver thirty inches high is       
sustained in the barometer1 as it       
frequently happens1 a column of air that
 presses upon an inch square near the   
surface of the earth must weigh about   
fifteen avoirdupois pounds47#d7 ,as the 
pressure of air at the sea-level is now 
estimated at #ad4gcjd pounds to the     
square inch1 it will be seen that       
,boyle's calculation was not far wrong4 
,from his numerous experiments upon the 
air1 ,boyle was led to believe that     
there were many latent qualities due to 
substances contained in it that science 
had as yet been unable to fathom1       
believing that there is not a more      
heterogeneous body in the world4 ,he    
believed that contagious diseases were  
carried by the air1 and suggested that  
eruptions of the earth1 such as those   
made by earthquakes1 might send up      
venomous exhalations that produced      
diseases4 ,he suggested also that the   
air might play an important part in some

 processes of calcination1 which1 as we 
shall see1 was proved to be true by     
,lavoisier late in the eighteenth       
century4 ,boyle's notions of the exact  
chemical action in these phenomena were 
of course vague and indefinite1 but he  
had observed that some part was played  
by the air1 and he was right in         
supposing that the air may have a great 
share in varying the salts obtainable   
from calcined vitriol47#e7  ,although he
 was himself such a painstaking observer
 of facts1 he had the fault of his age  
of placing too much faith in hear-say   
evidence of untrained observers4 ,thus1 
from the numerous stories he heard      
concerning the growth of metals in      
previously exhausted mines1 he believed 
that the air was responsible for        
producing this growth--in which he      
undoubtedly believed4 ,the story of a   
tin-miner that1 in his own time1 after a
 lapse of only twenty-five years1 a     
heap1 of earth previously exhausted of  
its ore became again even more richly   

impregnated than before by lying exposed
 to the air1 seems to have been believed
 by the philosopher4  ,as ,boyle was an 
alchemist1 and undoubtedly believed in  
the alchemic theory that metals have    
spirits and various other qualities that
 do not exist1 it is not surprising that
 he was credulous in the matter of      
beliefs concerning peculiar phenomena   
exhibited by them4 ,furthermore1 he     
undoubtedly fell into the error common  
to specialists1 or persons working for  
long periods of time on one subject--the
 error of over-enthusiasm in his        
subject4 ,he had discovered so many     
remarkable qualities in the air that it 
is not surprising to find that he       
attributed to it many more that he could
 not demonstrate4  ,boyle's work upon   
colors1 although probably of less       
importance than his experiments and     
deductions upon air1 show that he was in
 the van as far as the science of his   
day was concerned4 ,as he points out1   
the schools of his time generally taught

 that color is a penetrating quality1   
reaching to the innermost part of the   
substance1 and1 as an example of this1  
sealing-wax was cited1 which could be   
broken into minute bits1 each particle  
retaining the same color as its fellows 
or the original mass4 ,to refute this   
theory1 and to show instances to the    
contrary1 ,boyle1 among other things1   
shows that various colors--blue1 red1   
yellow--may be produced upon tempered   
steel1 and yet the metal within a       
hair's-breadth of its surface have none 
of these colors4 ,therefore1 he was led 
to believe that color1 in opaque bodies 
at least1 is superficial4  ,but before  
we descend to a more particular         
consideration of our subject1 he says1  
'tis proper to observe that colors may  
be regarded either as a quality residing
 in bodies to modify light after a      
particular manner1 or else as light     
itself so modified as to strike upon the
 organs of sight1 and cause the         
sensation we call color2 and that this  

latter is the more proper acceptation of
 the word color will appear hereafter4  
,and indeed it is the light itself1     
which after a certain manner1 either    
mixed with shades or other-wise1 strikes
 our eyes and immediately produces that 
motion in the organ which gives us the  
color of an object47#f7  ,in examining  
smooth and rough surfaces to determine  
the cause of their color1 he made use of
 the microscope1 and pointed out the    
very obvious example of the difference  
in color of a rough and a polished piece
 of the same block of stone4 ,he used   
some striking illustrations of the      
effect of light and the position of the 
eye upon colors4 ,thus the color of     
plush or velvet will appear various if  
you stroke part of it one way and part  
another1 the posture of the particular  
threads in regard to the light1 or the  
eye1 being thereby varied4 ,and 'tis    
observable that in a field of ripe corn1
 blown upon by the wind1 there will     
appear waves of a color different from  

that of the rest of the corn1 because   
the wind1 by depressing some of the ears
 more than others1 causes one to reflect
 more light from the lateral and strawy 
parts than another47#g7 ,his work upon  
color1 however1 as upon light1 was      
entirely overshadowed by the work of his
 great fellow-countryman ,newton4       
,boyle's work on electricity was a      
continuation of ,gilbert's1 to which he 
added several new facts4 ,he added      
several substances to ,gilbert's list of
 electrics1 experimented on smooth and  
rough surfaces in exciting of           
electricity1 and made the important     
discovery that amber retained its       
attractive virtue after the friction    
that excited it bad ceased4 ,for the    
attrition having caused an intestine    
motion in its parts1 he says1 the heat  
thereby excited ought not to cease as   
soon as ever the rubbing is over1 but to
 continue capable of emitting effluvia  
for some time afterwards1 longer or     
shorter according to the goodness of the

 electric and the degree of the         
commotion made2 all which1 joined       
together1 may sometimes make the effect 
considerable2 and by this means1 on a   
warm day1 ,i1 with a certain body not   
bigger than a pea1 but very vigorously  
attractive1 moved a steel needle1 freely
 poised1 about three minutes after ,i   
had left off rubbing it47#h7            
,,mariotte ,,and ,,von ,,guericke       
,working contemporaneously with ,boyle1 
and a man whose name is usually         
associated with his as the propounder of
 the law of density of gases1 was ,edme 
,mariotte 7died #afhd71 a native of     
,burgundy4 ,mariotte demonstrated that  
but for the resistance of the           
atmosphere1 all bodies1 whether light or
 heavy1 dense or thin1 would fall with  
equal rapidity1 and he proved this by   
the well-known guinea-and-feather       
experiment4 ,having exhausted the air   
from a long glass tube in which a guinea
 piece and a feather had been placed1 he
 showed that in the vacuum thus formed  

they fell with equal rapidity as often  
as the tube was reversed4 ,from his     
various experiments as to the pressure  
of the atmosphere he deduced the law    
that the density and elasticity of the  
atmosphere are precisely proportional to
 the compressing force 7the law of      
,boyle and ,mariotte74 ,he also         
ascertained that air existed in a state 
of mechanical mixture with liquids1     
existing between their particles in a   
state of condensation4 ,he made many    
other experiments1 especially on the    
collision of bodies1 but his most       
important work was upon the atmosphere4 
,but meanwhile another contemporary of  
,boyle and ,mariotte was interesting    
himself in the study of the atmosphere1 
and had made a wonderful invention and a
 most striking demonstration4 ,this was 
,otto von ,guericke 7#afjb-afhf71       
,burgomaster of ,magdeburg1 and         
councillor to his most serene and potent
 ,highness the elector of that place4   
,when not engrossed with the duties of  

public office1 he devoted his time to   
the study of the sciences1 particularly 
pneumatics and electricity1 both then in
 their infancy4 ,the discoveries of     
,galileo1 ,pascal1 and ,torricelli      
incited him to solve the problem of the 
creation of a vacuum--a desideratum     
since before the days of ,aristotle4    
,his first experiments were with a      
wooden pump and a barrel of water1 but  
he soon found that with such porous     
material as wood a vacuum could not be  
created or maintained4 ,he therefore    
made use of a globe of copper1 with pump
 and stop-cock2 and with this he was    
able to pump out air almost as easily as
 water4 ,thus1 in #afej1 the air-pump   
was invented4 ,continuing his           
experiments upon vacuums and atmospheric
 pressure with his newly discovered     
pump1 he made some startling discoveries
 as to the enormous pressure exerted by 
the air4  ,it was not his intention1    
however1 to demonstrate his newly       
acquired knowledge by words or theories 

alone1 nor by mere laboratory           
experiments2 but he chose instead an    
open field1 to which were invited       
,emperor ,ferdinand ,,iii41 and all the 
princes of the ,diet at ,ratisbon4 ,when
 they were assembled he produced two    
hollow brass hemispheres about two feet 
in diameter1 and placing their exactly  
fitting surfaces together1 proceeded to 
pump out the air from their hollow      
interior1 thus causing them to stick    
together firmly in a most remarkable    
way1 apparently without anything holding
 them4 ,this of itself was strange      
enough2 but now the worthy burgomaster  
produced teams of horses1 and harnessing
 them to either side of the hemispheres1
 attempted to pull the adhering brasses 
apart4 ,five1 ten1 fifteen teams--thirty
 horses1 in all--were attached2 but pull
 and tug as they would they could not   
separate the firmly clasped hemispheres4
 ,the enormous pressure of the          
atmosphere had been most strikingly     
demonstrated4  ,but it is one thing to  

demonstrate1 another to convince2 and   
many of the good people of ,magdeburg   
shook their heads over this devil's     
contrivance1 and predicted that ,heaven 
would punish the ,herr ,burgomaster1 as 
indeed it had once by striking his house
 with lightning and injuring some of his
 infernal contrivances4 ,they predicted 
his future punishment1 but they did not 
molest him1 for to his fellow-citizens1 
who talked and laughed1 drank and smoked
 with him1 and knew him for the honest  
citizen that he was1 he did not seem    
bewitched at all4 ,and so he lived and  
worked and added other facts to science1
 and his brass hemispheres were not     
destroyed by fanatical ,inquisitors1 but
 are still preserved in the royal       
library at ,berlin4  ,in his experiments
 with his air-pump he discovered many   
things regarding the action of gases1   
among others1 that animals cannot live  
in a vacuum4 ,he invented the anemoscope
 and the air-balance1 and being thus    
enabled to weight the air and note the  

changes that preceded storms and calms1 
he was able still further to dumfound   
his wondering fellow-,magde-burgers by  
more or less accurate predictions about 
the weather4  ,von ,guericke did not    
accept ,gilbert's theory that the earth 
was a great magnet1 but in his          
experiments along lines similar to those
 pursued by ,gilbert1 he not only       
invented the first electrical machine1  
but discovered electrical attraction and
 repulsion4 ,the electrical machine     
which he invented consisted of a sphere 
of sulphur mounted on an iron axis to   
imitate the rotation of the earth1 and  
which1 when rubbed1 manifested          
electrical reactions4 ,when this globe  
was revolved and stroked with the dry   
hand it was found that it attached to it
 all sorts of little fragments1 like    
leaves of gold1 silver1 paper1 etc4     
,thus this globe1 he says1 when brought 
rather near drops of water causes them  
to swell and puff up4 ,it likewise      
attracts air1 smoke1 etc47#i7 ,before   

the time of ,guericke's demonstrations1 
,cabaeus had noted that chaff leaped    
back from an electric1 but he did not   
interpret the phenomenon as electrical  
repulsion4 ,von ,guericke1 however1     
recognized it as such1 and refers to it 
as what he calls expulsive virtue4 ,even
 expulsive virtue is seen in this globe1
 he says1 for it not only attracts1 but 
also ,,repels again from itself little  
bodies of this sort1 nor does it receive
 them until they have touched something 
else4 ,it will be observed from this    
that he was very close to discovering   
the discharge of the electrification of 
attracted bodies by contact with some   
other object1 after which they are      
reattracted by the electric4  ,he       
performed a most interesting experiment 
with his sulphur globe and a feather1   
and in doing so came near anticipating  
,benjamin ,franklin in his discovery of 
the effects of pointed conductors in    
drawing off the discharge4 ,having      
revolved and stroked his globe until it 

repelled a bit of down1 he removed the  
globe from its rack and advancing it    
towards the now repellent down1 drove it
 before him about the room4 ,in this    
chase he observed that the down         
preferred to alight against the points  
of any object whatsoever4 ,he noticed   
that should the down chance to be driven
 within a few inches of a lighted       
candle1 its attitude towards the globe  
suddenly changed1 and instead of running
 away from it1 it now flew to it for    
protection--the charge on the down      
having been dissipated by the hot air4  
,he also noted that if one face of a    
feather had been first attracted and    
then repelled by the sulphur ball1 that 
the surface so affected was always      
turned towards the globe2 so that if the
 positions of the two were reversed1 the
 sides of the feather reversed also4    
,still another important discovery1 that
 of electrical conduction1 was made by  
,von ,guericke4 ,until his discovery no 
one had observed the transference of    

electricity from one body to another1   
although ,gilbert had some time before  
noted that a rod rendered magnetic at   
one end became so at the other4 ,von    
,guericke's experiments were made upon a
 linen thread with his sulphur globe1   
which1 he says1 having been previously  
excited by rubbing1 can exercise        
likewise its virtue through a linen     
thread an ell or more long1 and there   
attract something4 ,but this discovery1 
and his equally important one that the  
sulphur ball becomes luminous when      
rubbed1 were practically forgotten until
 again brought to notice by the         
discoveries of ,francis ,hauksbee and   
,stephen ,gray early in the eighteenth  
century4 ,from this we may gather that  
,von ,guericke himself did not realize  
the import of his discoveries1 for      
otherwise he would certainly have       
carried his investigations still        
further4 ,but as it was he turned his   
attention to other fields of research4  
,,robert ,,hooke  ,a slender1 crooked1  

shrivelled-limbed1 cantankerous little  
man1 with dishevelled hair and haggard  
countenance1 bad-tempered and irritable1
 penurious and dishonest1 at least in   
his claims for priority in              
discoveries--this is the picture usually
 drawn1 alike by friends and enemies1 of
 ,robert ,hooke 7#afce-agjc71 a man with
 an almost unparalleled genius for      
scientific discoveries in almost all    
branches of science4 ,history gives few 
examples so striking of a man whose     
really great achievements in science    
would alone have made his name immortal1
 and yet who had the pusillanimous      
spirit of a charlatan--an almost insane 
mania1 as it seems--for claiming the    
credit of discoveries made by others4   
,this attitude of mind can hardly be    
explained except as a mania3 it is      
certainly more charitable so to regard  
it4 ,for his own discoveries and        
inventions were so numerous that a few  
more or less would hardly have added to 
his fame1 as his reputation as a        

philosopher was well established4       
,admiration for his ability and his     
philosophical knowledge must always be  
marred by the recollection of his       
arrogant claims to the discoveries of   
other philosophers4  ,it seems pretty   
definitely determined that ,hooke should
 be credited with the invention of the  
balance-spring for regulating watches2  
but for a long time a heated controversy
 was waged between ,hooke and ,huygens  
as to who was the real inventor4 ,it    
appears that ,hooke conceived the idea  
of the balance-spring1 while to ,huygens
 belongs the credit of having adapted   
the ,,coiled spring in a working model4 
,he thus made practical ,hooke's        
conception1 which is without value      
except as applied by the coiled spring2 
but1 nevertheless1 the inventor1 as well
 as the perfector1 should receive       
credit4 ,in this controversy1 unlike    
many others1 the blame cannot be laid at
 ,hooke's door4  ,hooke was the first   
curator of the ,royal ,society1 and when

 anything was to be investigated1       
usually invented the mechanical devices 
for doing so4 ,astronomical apparatus1  
instruments for measuring specific      
weights1 clocks and chronometers1       
methods of measuring the velocity of    
falling bodies1 freezing and boiling    
points1 strength of gunpowder1 magnetic 
instruments--in short1 all kinds of     
ingenious mechanical devices in all     
branches of science and mechanics4 ,it  
was he who made the famous air-pump of  
,robert ,boyle1 based on ,boyle's plans4
 ,incidentally1 ,hooke claimed to be the
 inventor of the first air-pump himself1
 although this claim is now entirely    
discredited4  ,within a period of two   
years he devised no less than thirty    
different methods of flying1 all of     
which1 of course1 came to nothing1 but  
go to show the fertile imagination of   
the man1 and his tireless energy4 ,he   
experimented with electricity and made  
some novel suggestions upon the         
difference between the electric spark   

and the glow1 although on the whole his 
contributions in this field are         
unimportant4 ,he also first pointed out 
that the motions of the heavenly bodies 
must be looked upon as a mechanical     
problem1 and was almost within grasping 
distance of the exact theory of         
gravitation1 himself originating the    
idea of making use of the pendulum in   
measuring gravity4 ,likewise1 he first  
proposed the wave theory of light2      
although it was ,huygens who established
 it on its present foundation4  ,hooke  
published1 among other things1 a book of
 plates and descriptions of his         
,microscopical ,observations1 which     
gives an idea of the advance that had   
already been made in microscopy in his  
time4 ,two of these plates are given    
here1 which1 even in this age of        
microscopy1 are both interesting and    
instructive4 ,these plates are made from
 prints of ,hooke's original copper     
plates1 and show that excellent lenses  
were made even at that time4 ,they      

illustrate1 also1 how much might have   
been accomplished in the field of       
medicine if more attention had been     
given to microscopy by physicians4 ,even
 a century later1 had physicians made   
better use of their microscopes1 they   
could hardly have overlooked such an    
easily found parasite as the itch mite1 
which is quite as easily detected as the
 cheese mite1 pictured in ,hooke's book4
  ,in justice to ,hooke1 and in         
extenuation of his otherwise inexcusable
 peculiarities of mind1 it should be    
remembered that for many years he       
suffered from a painful and wasting     
disease4 ,this may have affected his    
mental equilibrium1 without appreciably 
affecting his ingenuity4 ,in his own    
time this condition would hardly have   
been considered a disease2 but to-day1  
with our advanced ideas as to mental    
diseases1 we should be more inclined to 
ascribe his unfortunate attitude of mind
 to a pathological condition1 rather    
than to any manifestation of normal     

mentality4 ,from this point of view his 
mental deformity seems not unlike that  
of ,cavendish's1 later1 except that in  
the case of ,cavendish it manifested    
itself as an abnormal sensitiveness     
instead of an abnormal irritability4    
,,christian ,,huygens  ,if for nothing  
else1 the world is indebted to the man  
who invented the pendulum clock1        
,christian ,huygens 7#afbi-afie71 of the
 ,hague1 inventor1 mathematician1       
mechanician1 astronomer1 and physicist4 
,huygens was the descendant of a noble  
and distinguished family1 his father1   
,sir ,constantine ,huygens1 being a     
well-known poet and diplomatist4 ,early 
in life young ,huygens began his career 
in the legal profession1 completing his 
education in the juridical school at    
,breda2 but his taste for mathematics   
soon led him to neglect his legal       
studies1 and his aptitude for scientific
 researches was so marked that          
,descartes predicted great things of him
 even while he was a mere tyro in the   

field of scientific investigation4  ,one
 of his first endeavors in science was  
to attempt an improvement of the        
telescope4 ,reflecting upon the process 
of making lenses then in vogue1 young   
,huygens and his brother ,constantine   
attempted a new method of grinding and  
polishing1 whereby they overcame a great
 deal of the spherical and chromatic    
aberration4 ,with this new telescope a  
much clearer field of vision was        
obtained1 so much so that ,huygens was  
able to detect1 among other things1 a   
hitherto unknown satellite of ,saturn4  
,it was these astronomical researches   
that led him to apply the pendulum to   
regulate the movements of clocks4 ,the  
need for some more exact method of      
measuring time in his observations of   
the stars was keenly felt by the young  
astronomer1 and after several           
experiments along different lines1      
,huygens hit upon the use of a swinging 
weight2 and in #afef made his invention 
of the pendulum clock4 ,the year        

following1 his clock was presented to   
the states-general4 ,accuracy as to time
 is absolutely essential in astronomy1  
but until the invention of ,huygens's   
clock there was no precise1 nor even    
approximately precise1 means of         
measuring short intervals4  ,huygens was
 one of the first to adapt the          
micrometer to the telescope--a          
mechanical device on which all the nice 
determination of minute distances       
depends4 ,he also took up the           
controversy against ,hooke as to the    
superiority of telescopic over plain    
sights to quadrants1 ,hooke contending  
in favor of the plain4 ,in this         
controversy1 the subject of which       
attracted wide attention1 ,huygens was  
completely victorious2 and ,hooke1 being
 unable to refute ,huygens's arguments1 
exhibited such irritability that he     
increased his already general           
unpopularity4 ,all of the arguments for 
and against the telescope sight are too 
numerous to be given here4 ,in          

contending in its favor ,huygens pointed
 out that the unaided eye is unable to  
appreciate an angular space in the sky  
less than about thirty seconds4 ,even in
 the best quadrant with a plain sight1  
therefore1 the altitude must be         
uncertain by that quantity4 ,if in place
 of the plain sight a telescope is      
substituted1 even if it magnify only    
thirty times1 it will enable the        
observer to fix the position to one     
second1 with progressively increased    
accuracy as the magnifying power of the 
telescope is increased4 ,this was only  
one of the many telling arguments       
advanced by ,huygens4  ,in the field of 
optics1 also1 ,huygens has added        
considerably to science1 and his work1  
,dioptrics1 is said to have been a      
favorite book with ,newton4 ,during the 
later part of his life1 however1        
,huygens again devoted himself to       
inventing and constructing telescopes1  
grinding the lenses1 and devising1 if   
not actually making1 the frame for      

holding them4 ,these telescopes were of 
enormous lengths1 three of his          
object-glasses1 now in possession of the
 ,royal ,society1 being of #abc1 #ahj1  
and #baj feet focal length respectively4
 ,such instruments1 if constructed in   
the ordinary form of the long tube1 were
 very unmanageable1 and to obviate this 
,huygens adopted the plan of dispensing 
with the tube altogether1 mounting his  
lenses on long poles manipulated by     
machinery4 ,even these were unwieldy    
enough1 but the difficulties of         
manipulation were fully compensated by  
the results obtained4  ,it had been     
discovered1 among other things1 that in 
oblique refraction light is separated   
into colors4 ,therefore1 any small      
portion of the convex lens of the       
telescope1 being a prism1 the rays      
proceed to the focus1 separated into    
prismatic colors1 which make the image  
thus formed edged with a fringe of color
 and indistinct4 ,but1 fortunately for  
the early telescope makers1 the degree  

of this aberration is independent of the
 focal length of the lens2 so that1 by  
increasing this focal length and using  
the appropriate eye-piece1 the image can
 be greatly magnified1 while the fringe 
of colors remains about the same as when
 a less powerful lens is used4 ,hence   
the advantage of ,huygens's long        
telescope4 ,he did not confine his      
efforts to simply lengthening the focal 
length of his telescopes1 however1 but  
also added to their efficiency by       
inventing an almost perfect achromatic  
eye-piece4  ,in #affc he was elected a  
fellow of the ,royal ,society of        
,london1 and in #affi he gave to that   
body a concise statement of the laws    
governing the collision of elastic      
bodies4 ,although the same views had    
been given by ,wallis and ,wren a few   
weeks earlier1 there is no doubt that   
,huygens's views were reached           
independently2 and it is probable that  
he had arrived at his conclusions       
several years before4 ,in the           

,philosophical ,transactions for #affi  
it is recorded that the society1 being  
interested in the laws of the principles
 of motion1 a request was made that ,m4 
,huygens1 ,dr4 ,wallis1 and ,sir        
,christopher ,wren submit their views on
 the subject4 ,wallis submitted his     
paper first1 ,november #ae1 #affh4 ,a   
month later1 ,december #agth1 ,wren     
imparted to the society his laws as to  
the nature of the collision of bodies4  
,and a few days later1 ,january #e1     
#affi1 ,huygens sent in his ,rules      
,concerning the ,motion of ,bodies after
 ,mutual ,impulse4 ,although ,huygens's 
report was received last1 he was        
anticipated by such a brief space of    
time1 and his views are so clearly      
stated--on the whole rather more so than
 those of the other two--that we give   
them in part here3   #a4 ,if a hard body
 should strike against a body equally   
hard at rest1 after contact the former  
will rest and the latter acquire a      
velocity equal to that of the moving    

body4  #b4 ,but if that other equal body
 be likewise in motion1 and moving in   
the same direction1 after contact they  
will move with reciprocal velocities4   
#c4 ,a body1 however great1 is moved by 
a body however small impelled with any  
velocity whatsoever4  #e4 ,the quantity 
of motion of two bodies may be either   
increased or diminished by their shock2 
but the same quantity towards the same  
part remains1 after subtracting the     
quantity of the contrary motion4  #f4   
,the sum of the products arising from   
multiplying the mass of any hard body   
into the squares of its velocity is the 
same both before and after the stroke4  
#g4 ,a hard body at rest will receive a 
greater quantity of motion from another 
hard body1 either greater or less than  
itself1 by the interposition of any     
third body of a mean quantity1 than if  
it was immediately struck by the body   
itself2 and if the interposing body be a
 mean proportional between the other    
two1 its action upon the quiescent body 

will be the greatest of all47#aj7       
,this was only one of several           
interesting and important communications
 sent to the ,royal ,society during his 
lifetime4 ,one of these was a report on 
what he calls ,pneumatical ,experiments4
 ,upon including in a vacuum an insect  
resembling a beetle1 but somewhat       
larger1 he says1 when it seemed to be   
dead1 the air was readmitted1 and soon  
after it revived2 putting it again in   
the vacuum1 and leaving it for an hour1 
after which the air was readmitted1 it  
was observed that the insect required a 
longer time to recover2 including it the
 third time for two days1 after which   
the air was admitted1 it was ten hours  
before it began to stir2 but1 putting it
 in a fourth time1 for eight days1 it   
never afterwards recovered4444 ,several 
birds1 rats1 mice1 rabbits1 and cats    
were killed in a vacuum1 but if the air 
was admitted before the engine was quite
 exhausted some of them would recover2  
yet none revived that had been in a     

perfect vacuum4444 ,upon putting the    
weight of eighteen grains of powder with
 a gauge into a receiver that held      
several pounds of water1 and firing the 
powder1 it raised the mercury an inch   
and a half2 from which it appears that  
there is one-fifth of air in gunpowder1 
upon the supposition that air is about  
one thousand times lighter than water2  
for in this experiment the mercury rose 
to the eighteenth part of the height at 
which the air commonly sustains it1 and 
consequently the weight of eighteen     
grains of powder yielded air enough to  
fill the eighteenth part of a receiver  
that contained seven pounds of water2   
now this eighteenth part contains       
forty-nine drachms of water2 wherefore  
the air1 that takes up an equal space1  
being a thousand times lighter1 weighs  
one-thousandth part of forty-nine       
drachms1 which is more than three grains
 and a half2 it follows1 therefore1 that
 the weight of eighteen grains of powder
 contains more than three and a half of 

air1 which is about one-fifth of        
eighteen grains4444  ,from #affe to     
#afha1 accepting the tempting offer made
 him through ,colbert1 by ,louis ,,xiv41
 ,huygens pursued his studies at the    
,bibliotheque du ,roi as a resident of  
,france4 ,here he published his         
,horologium ,oscillatorium1 dedicated to
 the king1 containing1 among other      
things1 his solution of the problem of  
the centre of oscillation4 ,this in     
itself was an important step in the     
history of mechanics4 ,assuming as true 
that the centre of gravity of any number
 of interdependent bodies cannot rise   
higher than the point from which it     
falls1 he reached correct conclusions as
 to the general principle of the        
conservation of vis viva1 although he   
did not actually prove his conclusions4 
,this was the first attempt to deal with
 the dynamics of a system4 ,in this     
work1 also1 was the true determination  
of the relation between the length of a 
pendulum and the time of its            

oscillation4  ,in #afha he returned to  
,holland1 influenced1 it is believed1 by
 the attitude that was being taken in   
,france against his religion4 ,here he  
continued his investigations1 built his 
immense telescopes1 and1 among other    
things1 discovered polarization1 which  
is recorded in ,traite de la ,lumiere1  
published at ,leyden in #afij4 ,five    
years later he died1 bequeathing his    
manuscripts to the ,university of       
,leyden4 ,it is interesting to note that
 he never accepted ,newton's theory of  
gravitation as a universal property of  
matter4     ,,xi4 ,,newton ,,and ,,the  
,,composition ,,of ,,light  ,galileo1   
that giant in physical science of the   
early seventeenth century1 died in      
#afdb4 ,on ,christmas day of the same   
year there was born in ,england another 
intellectual giant who was destined to  
carry forward the work of ,copernicus1  
,kepler1 and ,galileo to a marvellous   
consummation through the discovery of   
the great unifying law in accordance    

with which the planetary motions are    
performed4 ,we refer1 of course1 to the 
greatest of ,english physical           
scientists1 ,isaac ,newton1 the         
,shakespeare of the scientific world4   
,born thus before the middle of the     
seventeenth century1 ,newton lived      
beyond the first quarter of the         
eighteenth 7#agbg74 ,for the last forty 
years of that period his was the        
dominating scientific personality of the
 world4 ,with full propriety that time  
has been spoken of as the ,age of       
,newton4  ,yet the man who was to       
achieve such distinction gave no early  
premonition of future greatness4 ,he was
 a sickly child from birth1 and a boy of
 little seeming promise4 ,he was an     
indifferent student1 yet1 on the other  
hand1 he cared little for the common    
amusements of boyhood4 ,he early        
exhibited1 however1 a taste for         
mechanical contrivances1 and spent much 
time in devising windmills1             
water-clocks1 sun-dials1 and kites4     

,while other boys were interested only  
in having kites that would fly1         
,newton--at least so the stories of a   
later time would have us                
understand--cared more for the          
investigation of the seeming principles 
involved1 or for testing the best       
methods of attaching the strings1 or the
 best materials to be used in           
construction4  ,meanwhile the future    
philosopher was acquiring a taste for   
reading and study1 delving into old     
volumes whenever he found an            
opportunity4 ,these habits convinced his
 relatives that it was useless to       
attempt to make a farmer of the youth1  
as had been their intention4 ,he was    
therefore sent back to school1 and in   
the summer of #affa he matriculated at  
,trinity ,college1 ,cambridge4 ,even at 
college ,newton seems to have shown no  
unusual mental capacity1 and in #affd1  
when examined for a scholarship by ,dr4 
,barrow1 that gentleman is said to have 
formed a poor opinion of the applicant4 

,it is said that the knowledge of the   
estimate placed upon his abilities by   
his instructor piqued ,newton1 and led  
him to take up in earnest the           
mathematical studies in which he        
afterwards attained such distinction4   
,the study of ,euclid and ,descartes's  
,geometry roused in him a latent        
interest in mathematics1 and from that  
time forward his investigations were    
carried on with enthusiasm4 ,in #affg he
 was elected ,fellow of ,trinity        
,college1 taking the degree of ,m4,a4   
the following spring4  ,it will thus    
appear that ,newton's boyhood and early 
manhood were passed during that         
troublous time in ,british political    
annals which saw the overthrow of       
,charles ,i41 the autocracy of          
,cromwell1 and the eventual restoration 
of the ,stuarts4 ,his maturer years     
witnessed the overthrow of the last     
,stuart and the reign of the ,dutchman1 
,william of ,orange4 ,in his old age he 
saw the first of the ,hanoverians mount 

the throne of ,england4 ,within a decade
 of his death such scientific           
path-finders as ,cavendish1 ,black1 and 
,priestley were born--men who lived on  
to the close of the eighteenth century4 
,in a full sense1 then1 the age of      
,newton bridges the gap from that early 
time of scientific awakening under      
,kepler and ,galileo to the time which  
we of the twentieth century think of as 
essentially modern4   ,,the             
,,composition ,,of ,,white ,,light  ,in 
,december1 #afgb1 ,newton was elected a 
,fellow of the ,royal ,society1 and at  
this meeting a paper describing his     
invention of the refracting telescope   
was read4 ,a few days later he wrote to 
the secretary1 making some inquiries as 
to the weekly meetings of the society1  
and intimating that he had an account of
 an interesting discovery that he wished
 to lay before the society4 ,when this  
communication was made public1 it proved
 to be an explanation of the discovery  
of the composition of white light4 ,we  

have seen that the question as to the   
nature of color had commanded the       
attention of such investigators as      
,huygens1 but that no very satisfactory 
solution of the question had been       
attained4 ,newton proved by             
demonstrative experiments that white    
light is composed of the blending of the
 rays of diverse colors1 and that the   
color that we ascribe to any object is  
merely due to the fact that the object  
in question reflects rays of that color1
 absorbing the rest4 ,that white light  
is really made up of many colors blended
 would seem incredible had not the      
experiments by which this composition is
 demonstrated become familiar to every  
one4 ,the experiments were absolutely   
novel when ,newton brought them forward1
 and his demonstration of the           
composition of light was one of the most
 striking expositions ever brought to   
the attention of the ,royal ,society4   
,it is hardly necessary to add that1    
notwithstanding the conclusive character

 of ,newton's work1 his explanations did
 not for a long time meet with general  
acceptance4  ,newton was led to his     
discovery by some experiments made with 
an ordinary glass prism applied to a    
hole in the shutter of a darkened room1 
the refracted rays of the sunlight being
 received upon the opposite wall and    
forming there the familiar spectrum4 ,it
 was a very pleasing diversion1 he      
wrote1 to view the vivid and intense    
colors produced thereby2 and after a    
time1 applying myself to consider them  
very circumspectly1 ,i became surprised 
to see them in varying form1 which1     
according to the received laws of       
refraction1 ,i expected should have been
 circular4 ,they were terminated at the 
sides with straight lines1 but at the   
ends the decay of light was so gradual  
that it was difficult to determine      
justly what was their figure1 yet they  
seemed semicircular4  ,comparing the    
length of this colored spectrum with its
 breadth1 ,i found it almost five times 

greater2 a disproportion so extravagant 
that it excited me to a more than       
ordinary curiosity of examining from    
whence it might proceed4 ,i could scarce
 think that the various thicknesses of  
the glass1 or the termination with      
shadow or darkness1 could have any      
influence on light to produce such an   
effect2 yet ,i thought it not amiss1    
first1 to examine those circumstances1  
and so tried what would happen by       
transmitting light through parts of the 
glass of divers thickness1 or through   
holes in the window of divers bigness1  
or by setting the prism without so that 
the light might pass through it and be  
refracted before it was transmitted     
through the hole2 but ,i found none of  
those circumstances material4 ,the      
fashion of the colors was in all these  
cases the same4  ,then ,i suspected     
whether by any unevenness of the glass  
or other contingent irregularity these  
colors might be thus dilated4 ,and to   
try this ,i took another prism like the 

former1 and so placed it that the light1
 passing through them both1 might be    
refracted contrary ways1 and so by the  
latter returned into that course from   
which the former diverted it4 ,for1 by  
this means1 ,i thought1 the regular     
effects of the first prism would be     
destroyed by the second prism1 but the  
irregular ones more augmented by the    
multiplicity of refractions4 ,the event 
was that the light1 which by the first  
prism was diffused into an oblong form1 
was by the second reduced into an       
orbicular one with as much regularity as
 when it did not all pass through them4 
,so that1 whatever was the cause of that
 length1 'twas not any contingent       
irregularity4  ,i then proceeded to     
examine more critically what might be   
effected by the difference of the       
incidence of rays coming from divers    
parts of the sun2 and to that end       
measured the several lines and angles   
belonging to the image4 ,its distance   
from the hole or prism was #bb feet2 its

 utmost length #ac #a_/d inches2 its    
breadth #b #e_/h2 the diameter of the   
hole #a_/d of an inch2 the angle which  
the rays1 tending towards the middle of 
the image1 made with those lines1 in    
which they would have proceeded without 
refraction1 was #dd degrees #ef'2 and   
the vertical angle of the prism1 #fc    
degrees #ab'4 ,also the refractions on  
both sides of the prism--that is1 of the
 incident and emergent rays--were1 as   
near as ,i could make them1 equal1 and  
consequently about #ed degrees #d'2 and 
the rays fell perpendicularly upon the  
wall4 ,now1 subducting the diameter of  
the hole from the length and breadth of 
the image1 there remains #ac inches the 
length1 and #b #c_/h the breadth1       
comprehended by those rays1 which1      
passing through the centre of the said  
hole1 which that breadth subtended1 was 
about #ca'1 answerable to the sun's     
diameter2 but the angle which its length
 subtended was more than five such      
diameters1 namely #b degrees #di'4      

,having made these observations1 ,i     
first computed from them the refractive 
power of the glass1 and found it        
measured by the ratio of the sines #bj  
to #ca4 ,and then1 by that ratio1 ,i    
computed the refractions of two rays    
flowing from opposite parts of the sun's
 discus1 so as to differ #ca' in their  
obliquity of incidence1 and found that  
the emergent rays should have           
comprehended an angle of #ca'1 as they  
did1 before they were incident4  ,but   
because this computation was founded on 
the hypothesis of the proportionality of
 the sines of incidence and refraction1 
which though by my own experience ,i    
could not imagine to be so erroneous as 
to make that angle but #ca'1 which in   
reality was #b degrees #di'1 yet my     
curiosity caused me again to make my    
prism4 ,and having placed it at my      
window1 as before1 ,i observed that by  
turning it a little about its axis to   
and fro1 so as to vary its obliquity to 
the light more than an angle of #d      

degrees or #e degrees1 the colors were  
not thereby sensibly translated from    
their place on the wall1 and            
consequently by that variation of       
incidence the quantity of refraction was
 not sensibly varied4 ,by this          
experiment1 therefore1 as well as by the
 former computation1 it was evident that
 the difference of the incidence of rays
 flowing from divers parts of the sun   
could not make them after decussation   
diverge at a sensibly greater angle than
 that at which they before converged2   
which being1 at most1 but about #ca' or 
#cb'1 there still remained some other   
cause to be found out1 from whence it   
could be #b degrees #di'4  ,all this    
caused ,newton to suspect that the rays1
 after their trajection through the     
prism1 moved in curved rather than in   
straight lines1 thus tending to be cast 
upon the wall at different places       
according to the amount of this curve4  
,his suspicions were increased1 also1 by
 happening to recall that a tennis-ball 

sometimes describes such a curve when   
cut by a tennis-racket striking the ball
 obliquely4  ,for a circular as well as 
a progressive motion being communicated 
to it by the stroke1 he says1 its parts 
on that side where the motions conspire 
must press and beat the contiguous air  
more violently than on the other1 and   
there excite a reluctancy and reaction  
of the air proportionately greater4 ,and
 for the same reason1 if the rays of    
light should possibly be globular       
bodies1 and by their oblique passage out
 of one medium into another acquire a   
circulating motion1 they ought to feel  
the greater resistance from the ambient 
ether on that side where the motions    
conspire1 and thence be continually     
bowed to the other4 ,but notwithstanding
 this plausible ground of suspicion1    
when ,i came to examine it ,i could     
observe no such curvity in them4 ,and1  
besides 7which was enough for my        
purpose71 ,i observed that the          
difference 'twixt the length of the     

image and diameter of the hole through  
which the light was transmitted was     
proportionable to their distance4  ,the 
gradual removal of these suspicions at  
length led me to the experimentum       
crucis1 which was this3 ,i took two     
boards1 and1 placing one of them close  
behind the prism at the window1 so that 
the light must pass through a small     
hole1 made in it for the purpose1 and   
fall on the other board1 which ,i placed
 at about twelve feet distance1 having  
first made a small hole in it also1 for 
some of the incident light to pass      
through4 ,then ,i placed another prism  
behind this second board1 so that the   
light trajected through both the boards 
might pass through that also1 and be    
again refracted before it arrived at the
 wall4 ,this done1 ,i took the first    
prism in my hands and turned it to and  
fro slowly about its axis1 so much as to
 make the several parts of the image1   
cast on the second board1 successively  
pass through the hole in it1 that ,i    

might observe to what places on the wall
 the second prism would refract them4   
,and ,i saw by the variation of these   
places that the light1 tending to that  
end of the image towards which the      
refraction of the first prism was made1 
did in the second prism suffer a        
refraction considerably greater than the
 light tending to the other end4 ,and so
 the true cause of the length of that   
image was detected to be no other than  
that ,,light consists of ,,rays         
,,differently ,,refrangible1 which1     
without any respect to a difference in  
their incidence1 were1 according to     
their degrees of refrangibility1        
transmitted towards divers parts of the 
wall47#a7   ,,the ,,nature ,,of ,,color 
,having thus proved the composition of  
light1 ,newton took up an exhaustive    
discussion as to colors1 which cannot be
 entered into at length here4 ,some of  
his remarks on the subject of compound  
colors1 however1 may be stated in part4 
,newton's views are of particular       

interest in this connection1 since1 as  
we have already pointed out1 the        
question as to what constituted color   
could not be agreed upon by the         
philosophers4 ,some held that color was 
an integral part of the substance2      
others maintained that it was simply a  
reflection from the surface2 and no     
scientific explanation had been         
generally accepted4 ,newton concludes   
his paper as follows3  ,i might add more
 instances of this nature1 but ,i shall 
conclude with the general one that the  
colors of all natural bodies have no    
other origin than this1 that they are   
variously qualified to reflect one sort 
of light in greater plenty than another4
 ,and this ,i have experimented in a    
dark room by illuminating those bodies  
with uncompounded light of divers       
colors4 ,for by that means any body may 
be made to appear of any color4 ,they   
have there no appropriate color1 but    
ever appear of the color of the light   
cast upon them1 but yet with this       

difference1 that they are most brisk and
 vivid in the light of their own        
daylight color4 ,minium appeareth there 
of any color indifferently with which   
'tis illustrated1 but yet most luminous 
in red2 and so ,bise appeareth          
indifferently of any color with which   
'tis illustrated1 but yet most luminous 
in blue4 ,and therefore ,minium         
reflecteth rays of any color1 but most  
copiously those indued with red2 and    
consequently1 when illustrated with     
daylight--that is1 with all sorts of    
rays promiscuously blended--those       
qualified with red shall abound most in 
the reflected light1 and by their       
prevalence cause it to appear of that   
color4 ,and for the same reason1 ,bise1 
reflecting blue most copiously1 shall   
appear blue by the excess of those rays 
in its reflected light2 and the like of 
other bodies4 ,and that this is the     
entire and adequate cause of their      
colors is manifest1 because they have no
 power to change or alter the colors of 

any sort of rays incident apart1 but put
 on all colors indifferently with which 
they are enlightened47#b7  ,this        
epoch-making paper aroused a storm of   
opposition4 ,some of ,newton's opponents
 criticised his methods1 others even    
doubted the truth of his experiments4   
,there was one slight mistake in        
,newton's belief that all prisms would  
give a spectrum of exactly the same     
length1 and it was some time before he  
corrected this error4 ,meanwhile he     
patiently met and answered the arguments
 of his opponents until he began to feel
 that patience was no longer a virtue4  
,at one time he even went so far as to  
declare that1 once he was free of this  
business1 he would renounce scientific  
research forever1 at least in a public  
way4 ,fortunately for the world1        
however1 he did not adhere to this      
determination1 but went on to even      
greater discoveries--which1 it may be   
added1 involved still greater           
controversies4  ,in commenting on       

,newton's discovery of the composition  
of light1 ,voltaire said3 ,sir ,isaac   
,newton has demonstrated to the eye1 by 
the bare assistance of a prism1 that    
light is a composition of colored rays1 
which1 being united1 form white color4  
,a single ray is by him divided into    
seven1 which all fall upon a piece of   
linen or a sheet of white paper1 in     
their order one above the other1 and at 
equal distances4 ,the first is red1 the 
second orange1 the third yellow1 the    
fourth green1 the fifth blue1 the sixth 
indigo1 the seventh a violet purple4    
,each of these rays transmitted         
afterwards by a hundred other prisms    
will never change the color it bears2 in
 like manner as gold1 when completely   
purged from its dross1 will never change
 afterwards in the crucible47#c7        
,,xii4 ,,newton ,,and ,,the ,,law ,,of  
,,gravitation  ,we come now to the story
 of what is by common consent the       
greatest of scientific achievements4    
,the law of universal gravitation is the

 most far-reaching principle as yet     
discovered4 ,it has application equally 
to the minutest particle of matter and  
to the most distant suns in the         
universe1 yet it is amazing in its very 
simplicity4 ,as usually phrased1 the law
 is this3 ,that every particle of matter
 in the universe attracts every other   
particle with a force that varies       
directly with the mass of the particles 
and inversely as the squares of their   
mutual distance4 ,newton did not vault  
at once to the full expression of this  
law1 though he had formulated it fully  
before he gave the results of his       
investigations to the world4 ,we have   
now to follow the steps by which he     
reached this culminating achievement4   
,at the very beginning we must          
understand that the idea of universal   
gravitation was not absolutely original 
with ,newton4 ,away back in the old     
,greek days1 as we have seen1           
,anaxagoras conceived and clearly       
expressed the idea that the force which 

holds the heavenly bodies in their      
orbits may be the same that operates    
upon substances at the surface of the   
earth4 ,with ,anaxagoras this was       
scarcely more than a guess4 ,after his  
day the idea seems not to have been     
expressed by any one until the          
seventeenth century's awakening of      
science4 ,then the consideration of     
,kepler's ,third ,law of planetary      
motion suggested to many minds perhaps  
independently the probability that the  
force hitherto mentioned merely as      
centripetal1 through the operation of   
which the planets are held in their     
orbits is a force varying inversely as  
the square of the distance from the sun4
 ,this idea had come to ,robert ,hooke1 
to ,wren1 and perhaps to ,halley1 as    
well as to ,newton2 but as yet no one   
had conceived a method by which the     
validity of the suggestion might be     
tested4 ,it was claimed later on by     
,hooke that he had discovered a method  
demonstrating the truth of the theory of

 inverse squares1 and after the full    
announcement of ,newton's discovery a   
heated controversy was precipitated in  
which ,hooke put forward his claims with
 accustomed acrimony4 ,hooke1 however1  
never produced his demonstration1 and it
 may well be doubted whether he had     
found a method which did more than      
vaguely suggest the law which the       
observations of ,kepler had partially   
revealed4 ,newton's great merit lay not 
so much in conceiving the law of inverse
 squares as in the demonstration of the 
law4 ,he was led to this demonstration  
through considering the orbital motion  
of the moon4 ,according to the familiar 
story1 which has become one of the      
classic myths of science1 ,newton was   
led to take up the problem through      
observing the fall of an apple4         
,voltaire is responsible for the story1 
which serves as well as another2 its    
truth or falsity need not in the least  
concern us4 ,suffice it that through    
pondering on the familiar fact of       

terrestrial gravitation1 ,newton was led
 to question whether this force which   
operates so tangibly here at the earth's
 surface may not extend its influence   
out into the depths of space1 so as to  
include1 for example1 the moon4         
,obviously some force pulls the moon    
constantly towards the earth2 otherwise 
that body would fly off at a tangent and
 never return4 ,may not this so-called  
centripetal force be identical with     
terrestrial gravitation8 ,such was      
,newton's query4 ,probably many another 
man since ,anaxagoras had asked the same
 question1 but assuredly ,newton was the
 first man to find an answer4  ,the     
thought that suggested itself to        
,newton's mind was this3 ,if we make a  
diagram illustrating the orbital course 
of the moon for any given period1 say   
one minute1 we shall find that the      
course of the moon departs from a       
straight line during that period by a   
measurable distance--that3 is to say1   
the moon has been virtually pulled      

towards the earth by an amount that is  
represented by the difference between   
its actual position at the end of the   
minute under observation and the        
position it would occupy had its course 
been tangential1 as1 according to the   
first law of motion1 it must have been  
had not some force deflected it towards 
the earth4 ,measuring the deflection in 
question--which is equivalent to the    
so-called versed sine of the arc        
traversed--we have a basis for          
determining the strength of the         
deflecting force4 ,newton constructed   
such a diagram1 and1 measuring the      
amount of the moon's departure from a   
tangential rectilinear course in one    
minute1 determined this to be1 by his   
calculation1 thirteen feet4 ,obviously1 
then1 the force acting upon the moon is 
one that would cause that body to fall  
towards the earth to the distance of    
thirteen feet in the first minute of its
 fall4 ,would such be the force of      
gravitation acting at the distance of   

the moon if the power of gravitation    
varies inversely as the square of the   
distance8 ,that was the tangible form in
 which the problem presented itself to  
,newton4 ,the mathematical solution of  
the problem was simple enough4 ,it is   
based on a comparison of the moon's     
distance with the length of the earth's 
radius4 ,on making this calculation1    
,newton found that the pull of          
gravitation--if that were really the    
force that controls the moon--gives that
 body a fall of slightly over fifteen   
feet in the first minute1 instead of    
thirteen feet4 ,here was surely a       
suggestive approximation1 yet1 on the   
other band1 the discrepancy seemed to be
 too great to warrant him in the        
supposition that he had found the true  
solution4 ,he therefore dismissed the   
matter from his mind for the time being1
 nor did he return to it definitely for 
some years4  illustration caption       
,,diagram ,,to ,,illustrate ,,newton',s 
,,law ,,of ,,gravitation 7,e represents 

the earth and ,a the moon4 ,were the    
earth's pull on the moon to cease1 the  
moon's inertia would cause it to take   
the tangential course1 ,,ab4 ,on the    
other hand1 were the moon's motion to be
 stopped for an instant1 the moon would 
fall directly towards the earth1 along  
the line ,,ad4 ,the moon's actual orbit1
 resulting from these component forces1 
is ,,ac4 ,let ,,ac represent the actual 
flight of the moon in one minute4 ,then 
,,bc1 which is obviously equal to ,,ad1 
represents the distance which the moon  
virtually falls towards the earth in one
 minute4 ,actual computation1 based on  
measurements of the moon's orbit1 showed
 this distance to be about fifteen feet4
 ,another computation showed that this  
is the distance that the moon would fall
 towards the earth under the influence  
of gravity1 on the supposition that the 
force of gravity decreases inversely    
with the square of the distance2 the    
basis of comparison being furnished by  
falling bodies at the surface of the    

earth4 ,theory and observations thus    
coinciding1 ,newton was justified in    
declaring that the force that pulls the 
moon towards the earth and keeps it in  
its orbit1 is the familiar force of     
gravity1 and that this varies inversely 
as the square of the distance47  ,it was
 to appear in due time that ,newton's   
hypothesis was perfectly valid and that 
his method of attempted demonstration   
was equally so4 ,the difficulty was that
 the earth's proper dimensions were not 
at that time known4 ,a wrong estimate of
 the earth's size vitiated all the other
 calculations involved1 since the       
measurement of the moon's distance      
depends upon the observation of the     
parallax1 which cannot lead to a correct
 computation unless the length of the   
earth's radius is accurately known4     
,newton's first calculation was made as 
early as #afff1 and it was not until    
#afhb that his attention was called to a
 new and apparently accurate measurement
 of a degree of the earth's meridian    

made by the ,french astronomer ,picard4 
,the new measurement made a degree of   
the earth's surface #fi4aj miles1       
instead of sixty miles4  ,learning of   
this materially altered calculation as  
to the earth's size1 ,newton was led to 
take up again his problem of the falling
 moon4 ,as he proceeded with his        
computation1 it became more and more    
certain that this time the result was to
 harmonize with the observed facts4 ,as 
the story goes1 he was so completely    
overwhelmed with emotion that he was    
forced to ask a friend to complete the  
simple calculation4 ,that story may well
 be true1 for1 simple though the        
computation was1 its result was perhaps 
the most wonderful demonstration        
hitherto achieved in the entire field of
 science4 ,now at last it was known that
 the force of gravitation operates at   
the distance of the moon1 and holds that
 body in its elliptical orbit1 and it   
required but a slight effort of the     
imagination to assume that the force    

which operates through such a reach of  
space extends its influence yet more    
widely4 ,that such is really the case   
was demonstrated presently through      
calculations as to the moons of ,jupiter
 and by similar computations regarding  
the orbital motions of the various      
planets4 ,all results harmonizing1      
,newton was justified in reaching the   
conclusion that gravitation is a        
universal property of matter4 ,it       
remained1 as we shall see1 for          
nineteenth-century scientists to prove  
that the same force actually operates   
upon the stars1 though it should be     
added that this demonstration merely    
fortified a belief that had already     
found full acceptance4  ,having thus    
epitomized ,newton's discovery1 we must 
now take up the steps of his progress   
somewhat in detail1 and state his       
theories and their demonstration in his 
own words4 ,proposition ,,iv41 theorem  
#d1 of his ,principia is as follows3    
,that the moon gravitates towards the   

earth and by the force of gravity is    
continually drawn off from a rectilinear
 motion and retained in its orbit4  ,the
 mean distance of the moon from the     
earth1 in the syzygies in semi-diameters
 of the earth1 is1 according to ,ptolemy
 and most astronomers1 #ei2 according to
 ,vendelin and ,huygens1 #fj2 to        
,copernicus1 #fj #a_/c2 to ,street1 #fj 
#b_/c2 and to ,tycho1 #ef #a_/b4 ,but   
,tycho1 and all that follow his tables  
of refractions1 making the refractions  
of the sun and moon 7altogether against 
the nature of light7 to exceed the      
refractions of the fixed stars1 and that
 by four or five minutes ,,near ,,the   
,,horizon1 did thereby increase the     
moon's ,,horizontal parallax by a like  
number of minutes1 that is1 by a twelfth
 or fifteenth part of the whole         
parallax4 ,correct this error and the   
distance will become about #fj #a_/b    
semi-diameters of the earth1 near to    
what others have assigned4 ,let us      
assume the mean distance of #fj         

diameters in the syzygies2 and suppose  
one revolution of the moon1 in respect  
to the fixed stars1 to be completed in  
#bg;d4 #g;h4 #dc'1 as astronomers have  
determined2 and the circumference of the
 earth to amount to #abc1bdi1fjj ,paris 
feet1 as the ,french have found by      
mensuration4 ,and now1 if we imagine the
 moon1 deprived of all motion1 to be let
 go1 so as to descend towards the earth 
with the impulse of all that force by   
which 7by ,cor4 ,prop4 iii47 it is      
retained in its orb1 it will in the     
space of one minute of time describe in 
its fall #ae #a_/ab ,paris feet4 ,for   
the versed sine of that arc which the   
moon1 in the space of one minute of     
time1 would by its mean motion describe 
at the distance of sixty semi-diameters 
of the earth1 is nearly #ae #a_/ab      
,paris feet1 or more accurately #ae     
feet1 #a inch1 #a line #d_/i4           
,wherefore1 since that force1 in        
approaching the earth1 increases in the 
reciprocal-duplicate proportion of the  

distance1 and upon that account1 at the 
surface of the earth1 is #fj x #fj times
 greater than at the moon1 a body in our
 regions1 falling with that force1 ought
 in the space of one minute of time to  
describe #fj x #fj x #ae #a_/ab ,paris  
feet2 and in the space of one second of 
time1 to describe #ae #a_/ab of those   
feet1 or more accurately1 #ae feet1 #a  
inch1 #a line #d_/i4 ,and with this very
 force we actually find that bodies here
 upon earth do really descend2 for a    
pendulum oscillating seconds in the     
latitude of ,paris will be #c ,paris    
feet1 and #h lines #a_/b in length1 as  
,mr4 ,huygens has observed4 ,and the    
space which a heavy body describes by   
falling in one second of time is to half
 the length of the pendulum in the      
duplicate ratio of the circumference of 
a circle to its diameter 7as ,mr4       
,huygens has also shown71 and is        
therefore #ae ,paris feet1 #a inch1 #a  
line #d_/i4 ,and therefore the force by 
which the moon is retained in its orbit 

is that very same force which we        
commonly call gravity2 for1 were gravity
 another force different from that1 then
 bodies descending to the earth with the
 joint impulse of both forces would fall
 with a double velocity1 and in the     
space of one second of time would       
describe #cj #a_/f ,paris feet2         
altogether against experience47#a7  ,all
 this is beautifully clear1 and its     
validity has never in recent generations
 been called in question2 yet it should 
be explained that the argument does not 
amount to an actually indisputable      
demonstration4 ,it is at least possible 
that the coincidence between the        
observed and computed motion of the moon
 may be a mere coincidence and nothing  
more4 ,this probability1 however1 is so 
remote that ,newton is fully justified  
in disregarding it1 and1 as has been    
said1 all subsequent generations have   
accepted the computation as             
demonstrative4  ,let us produce now     
,newton's further computations as to the

 other planetary bodies1 passing on to  
his final conclusion that gravity is a  
universal force4                        
,,proposition ,v41 ,,theorem ,v4  ,that 
the circumjovial planets gravitate      
towards ,jupiter2 the circumsaturnal    
towards ,saturn2 the circumsolar towards
 the sun2 and by the forces of their    
gravity are drawn off from rectilinear  
motions1 and retained in curvilinear    
orbits4  ,for the revolutions of the    
circumjovial planets about ,jupiter1 of 
the circumsaturnal about ,saturn1 and of
 ,mercury and ,venus and the other      
circumsolar planets about the sun1 are  
appearances of the same sort with the   
revolution of the moon about the earth2 
and therefore1 by ,rule ii41 must be    
owing to the same sort of causes2       
especially since it has been            
demonstrated that the forces upon which 
those revolutions depend tend to the    
centres of ,jupiter1 of ,saturn1 and of 
the sun2 and that those forces1 in      
receding from ,jupiter1 from ,saturn1   

and from the sun1 decrease in the same  
proportion1 and according to the same   
law1 as the force of gravity does in    
receding from the earth4  ,,cor4        
#a4--,there is1 therefore1 a power of   
gravity tending to all the planets2 for 
doubtless ,venus1 ,mercury1 and the rest
 are bodies of the same sort with       
,jupiter and ,saturn4 ,and since all    
attraction 7by ,law iii47 is mutual1    
,jupiter will therefore gravitate       
towards all his own satellites1 ,saturn 
towards his1 the earth towards the moon1
 and the sun towards all the primary    
planets4  ,,cor4 #b4--,the force of     
gravity which tends to any one planet is
 reciprocally as the square of the      
distance of places from the planet's    
centre4  ,,cor4 #c4--;,all the planets  
do mutually gravitate towards one       
another1 by ,cor4 #a and #b1 and hence  
it is that ,jupiter and ,saturn1 when   
near their conjunction1 by their mutual 
attractions sensibly disturb each       
other's motions4 ,so the sun disturbs   

the motions of the moon2 and both sun   
and moon disturb our sea1 as we shall   
hereafter explain4            ,,scholium
  ,the force which retains the celestial
 bodies in their orbits has been        
hitherto called centripetal force2 but  
it being now made plain that it can be  
no other than a gravitating force1 we   
shall hereafter call it gravity4 ,for   
the cause of the centripetal force which
 retains the moon in its orbit will     
extend itself to all the planets by     
,rules i41 ii41 and iii4                
,,proposition ,,vi41 ,,theorem ,,vi4    
,that all bodies gravitate towards every
 planet2 and that the weights of the    
bodies towards any the same planet1 at  
equal distances from the centre of the  
planet1 are proportional to the         
quantities of matter which they         
severally contain4  ,it has been now a  
long time observed by others that all   
sorts of heavy bodies 7allowance being  
made for the inability of retardation   
which they suffer from a small power of 

resistance in the air7 descend to the   
earth ,,from ,,equal ,,heights in equal 
times2 and that equality of times we may
 distinguish to a great accuracy by help
 of pendulums4 ,i tried the thing in    
gold1 silver1 lead1 glass1 sand1 common 
salt1 wood1 water1 and wheat4 ,i        
provided two wooden boxes1 round and    
equal3 ,i filled the one with wood1 and 
suspended an equal weight of gold 7as   
exactly as ,i could7 in the centre of   
oscillation of the other4 ,the boxes    
hanging by eleven feet1 made a couple of
 pendulums exactly equal in weight and  
figure1 and equally receiving the       
resistance of the air4 ,and1 placing the
 one by the other1 ,i observed them to  
play together forward and backward1 for 
a long time1 with equal vibrations4 ,and
 therefore the quantity of matter in    
gold was to the quantity of matter in   
the wood as the action of the motive    
force 7or vis motrix7 upon all the gold 
to the action of the same upon all the  
wood--that is1 as the weight of the one 

to the weight of the other3 and the like
 happened in the other bodies4 ,by these
 experiments1 in bodies of the same     
weight1 ,i could manifestly have        
discovered a difference of matter less  
than the thousandth part of the whole1  
had any such been4 ,but1 without all    
doubt1 the nature of gravity towards the
 planets is the same as towards the     
earth4 ,for1 should we imagine our      
terrestrial bodies removed to the orb of
 the moon1 and there1 together with the 
moon1 deprived of all motion1 to be let 
go1 so as to fall together towards the  
earth1 it is certain1 from what we have 
demonstrated before1 that1 in equal     
times1 they would describe equal spaces 
with the moon1 and of consequence are to
 the moon1 in quantity and matter1 as   
their weights to its weight4  ,moreover1
 since the satellites of ,jupiter       
perform their revolutions in times which
 observe the sesquiplicate proportion of
 their distances from ,jupiter's centre1
 their accelerative gravities towards   

,jupiter will be reciprocally as the    
square of their distances from          
,jupiter's centre--that is1 equal1 at   
equal distances4 ,and1 therefore1 these 
satellites1 if supposed to fall         
,,towards ,,jupiter from equal heights1 
would describe equal spaces in equal    
times1 in like manner as heavy bodies do
 on our earth4 ,and1 by the same        
argument1 if the circumsolar planets    
were supposed to be let fall at equal   
distances from the sun1 they would1 in  
their descent towards the sun1 describe 
equal spaces in equal times4 ,but forces
 which equally accelerate unequal bodies
 must be as those bodies--that is to    
say1 the weights of the planets         
7,,towards ,,the ,,sun7 must be as their
 quantities of matter4 ,further1 that   
the weights of ,jupiter and his         
satellites towards the sun are          
proportional to the several quantities  
of their matter1 appears from the       
exceedingly regular motions of the      
satellites4 ,for if some of these bodies

 were more strongly attracted to the sun
 in proportion to their quantity of     
matter than others1 the motions of the  
satellites would be disturbed by that   
inequality of attraction4 ,if at equal  
distances from the sun any satellite1 in
 proportion to the quantity of its      
matter1 did gravitate towards the sun   
with a force greater than ,jupiter in   
proportion to his1 according to any     
given proportion1 suppose d to e2 then  
the distance between the centres of the 
sun and of the satellite's orbit would  
be always greater than the distance     
between the centres of the sun and of   
,jupiter nearly in the subduplicate of  
that proportion3 as by some computations
 ,i have found4 ,and if the satellite   
did gravitate towards the sun with a    
force1 lesser in the proportion of e to 
d1 the distance of the centre of the    
satellite's orb from the sun would be   
less than the distance of the centre of 
,jupiter from the sun in the            
subduplicate of the same proportion4    

,therefore1 if at equal distances from  
the sun1 the accelerative gravity of any
 satellite towards the sun were greater 
or less than the accelerative gravity of
 ,jupiter towards the sun by            
one-one-thousandth part of the whole    
gravity1 the distance of the centre of  
the satellite's orbit from the sun would
 be greater or less than the distance of
 ,jupiter from the sun by one           
one-two-thousandth part of the whole    
distance--that is1 by a fifth part of   
the distance of the utmost satellite    
from the centre of ,jupiter2 an         
eccentricity of the orbit which would be
 very sensible4 ,but the orbits of the  
satellites are concentric to ,jupiter1  
and therefore the accelerative gravities
 of ,jupiter and of all its satellites  
towards the sun1 at equal distances from
 the sun1 are as their several          
quantities of matter2 and the weights of
 the moon and of the earth towards the  
sun are either none1 or accurately      
proportional to the masses of matter    

which they contain4  ,,cor4 #e4--,the   
power of gravity is of a different      
nature from the power of magnetism2 for 
the magnetic attraction is not as the   
matter attracted4 ,some bodies are      
attracted more by the magnet2 others    
less2 most bodies not at all4 ,the power
 of magnetism in one and the same body  
may be increased and diminished2 and is 
sometimes far stronger1 for the quantity
 of matter1 than the power of gravity2  
and in receding from the magnet         
decreases not in the duplicate1 but     
almost in the triplicate proportion of  
the distance1 as nearly as ,i could     
judge from some rude observations4      
,,proposition ,,vii41 ,,theorem ,,vii4  
,that there is a power of gravity       
tending to all bodies1 proportional to  
the several quantities of matter which  
they contain4  ,that all the planets    
mutually gravitate one towards another  
we have proved before2 as well as that  
the force of gravity towards every one  
of them considered apart1 is            

reciprocally as the square of the       
distance of places from the centre of   
the planet4 ,and thence it follows1 that
 the gravity tending towards all the    
planets is proportional to the matter   
which they contain4  ,moreover1 since   
all the parts of any planet ,a          
gravitates towards any other planet ,b2 
and the gravity of every part is to the 
gravity of the whole as the matter of   
the part is to the matter of the whole2 
and to every action corresponds a       
reaction2 therefore the planet ,b will1 
on the other hand1 gravitate towards all
 the parts of planet ,a1 and its gravity
 towards any one part will be to the    
gravity towards the whole as the matter 
of the part to the matter of the whole4 
,q4,e4,d4   ,,hence ,,it ,,would        
,,appear ,,that the force of the whole  
must arise from the force of the        
component parts4   ,newton closes this  
remarkable ,book iii4 with the following
 words3  ,hitherto we have explained the
 phenomena of the heavens and of our sea

 by the power of gravity1 but have not  
yet assigned the cause of this power4   
,this is certain1 that it must proceed  
from a cause that penetrates to the very
 centre of the sun and planets1 without 
suffering the least diminution of its   
force2 that operates not according to   
the quantity of the surfaces of the     
particles upon which it acts 7as        
mechanical causes used to do71 but      
according to the quantity of solid      
matter which they contain1 and          
propagates its virtue on all sides to   
immense distances1 decreasing always in 
the duplicate proportions of the        
distances4 ,gravitation towards the sun 
is made up out of the gravitations      
towards the several particles of which  
the body of the sun is composed2 and in 
receding from the sun decreases         
accurately in the duplicate proportion  
of the distances as far as the orb of   
,saturn1 as evidently appears from the  
quiescence of the aphelions of the      
planets2 nay1 and even to the remotest  

aphelions of the comets1 if those       
aphelions are also quiescent4 ,but      
hitherto ,i have not been able to       
discover the cause of those properties  
of gravity from phenomena1 and ,i frame 
no hypothesis2 for whatever is not      
deduced from the phenomena is to be     
called an hypothesis2 and hypotheses1   
whether metaphysical or physical1       
whether of occult qualities or          
mechanical1 have no place in            
experimental philosophy4444 ,and to us  
it is enough that gravity does really   
exist1 and act according to the laws    
which we have explained1 and abundantly 
serves to account for all the motions of
 the celestial bodies and of our        
sea47#b7   ,the very magnitude of the   
importance of the theory of universal   
gravitation made its general acceptance 
a matter of considerable time after the 
actual discovery4 ,this opposition had  
of course been foreseen by ,newton1 and1
 much as he dreaded controversy1 he was 
prepared to face it and combat it to the

 bitter end4 ,he knew that his theory   
was right2 it remained for him to       
convince the world of its truth4 ,he    
knew that some of his contemporary      
philosophers would accept it at once2   
others would at first doubt1 question1  
and dispute1 but finally accept2 while  
still others would doubt and dispute    
until the end of their days4 ,this had  
been the history of other great         
discoveries2 and this will probably be  
the history of most great discoveries   
for all time4 ,but in this case the     
discoverer lived to see his theory      
accepted by practically all the great   
minds of his time4  ,delambre is        
authority for the following estimate of 
,newton by ,lagrange4 ,the celebrated   
,lagrange1 he says1 who frequently      
asserted that ,newton was the greatest  
genius that ever existed1 used to       
add--'and the most fortunate1 for we    
cannot find ,,more ,,than ,,once a      
system of the world to establish4' ,with
 pardonable exaggeration the admiring   

followers of the great generalizer      
pronounced this epitaph3   ,nature and  
,nature's laws lay hid in night2   ,god 
said ',let ,newton be6' and all was     
light4     ,,xiii4 ,,instruments ,,of   
,,precision ,,in ,,the ,,age ,,of       
,,newton  ,during the ,newtonian epoch  
there were numerous important inventions
 of scientific instruments1 as well as  
many improvements made upon the older   
ones4 ,some of these discoveries have   
been referred to briefly in other       
places1 but their importance in         
promoting scientific investigation      
warrants a fuller treatment of some of  
the more significant4  ,many of the     
errors that had arisen in various       
scientific calculations before the      
seventeenth century may be ascribed to  
the crudeness and inaccuracy in the     
construction of most scientific         
instruments4 ,scientists had not as yet 
learned that an approach to absolute    
accuracy was necessary in every         
investigation in the field of science1  

and that such accuracy must be extended 
to the construction of the instruments  
used in these investigations and        
observations4 ,in astronomy it is       
obvious that instruments of delicate    
exactness are most essential2 yet ,tycho
 ,brahe1 who lived in the sixteenth     
century1 is credited with being the     
first astronomer whose instruments show 
extreme care in construction4  ,it seems
 practically settled that the first     
telescope was invented in ,holland in   
#afjh2 but three men1 ,hans ,lippershey1
 ,james ,metius1 and ,zacharias ,jansen1
 have been given the credit of the      
invention at different times4 ,it would 
seem from certain papers1 now in the    
library of the ,university of ,leyden1  
and included in ,huygens's papers1 that 
,lippershey was probably the first to   
invent a telescope and to describe his  
invention4 ,the story is told that      
,lippershey1 who was a spectacle-maker1 
stumbled by accident upon the discovery 
that when two lenses are held at a      

certain distance apart1 objects at a    
distance appear nearer and larger4      
,having made this discovery1 he fitted  
two lenses with a tube so as to maintain
 them at the proper distance1 and thus  
constructed the first telescope4  ,it   
was ,galileo1 however1 as referred to in
 a preceding chapter1 who first         
constructed a telescope based on his    
knowledge of the laws of refraction4 ,in
 #afji1 having heard that an instrument 
had been invented1 consisting of two    
lenses fixed in a tube1 whereby objects 
were made to appear larger and nearer1  
he set about constructing such an       
instrument that should follow out the   
known effects of refraction4 ,his first 
telescope1 made of two lenses fixed in a
 lead pipe1 was soon followed by others 
of improved types1 ,galileo devoting    
much time and labor to perfecting lenses
 and correcting errors4 ,in fact1 his   
work in developing the instrument was so
 important that the telescope came      
gradually to be known as the ,galilean  

telescope4  ,in the construction of his 
telescope ,galileo made use of a convex 
and a concave lens2 but shortly after   
this ,kepler invented an instrument in  
which both the lenses used were convex4 
,this telescope gave a much larger field
 of view than the ,galilean telescope1  
but did not give as clear an image1 and 
in consequence did not come into general
 use until the middle of the seventeenth
 century4 ,the first powerful telescope 
of this type was made by ,huygens and   
his brother4 ,it was of twelve feet     
focal length1 and enabled ,huygens to   
discover a new satellite of ,saturn1 and
 to determine also the true explanation 
of ,saturn's ring4  ,it was ,huygens1   
together with ,malvasia and ,auzout1 who
 first applied the micrometer to the    
telescope1 although the inventor of the 
first micrometer was ,william           
,gascoigne1 of ,yorkshire1 about #afcf4 
,the micrometer as used in telescopes   
enables the observer to measure         
accurately small angular distances4     

,before the invention of the telescope  
such measurements were limited to the   
angle that could be distinguished by the
 naked eye1 and were1 of course1 only   
approximately accurate4 ,even very      
careful observers1 such as ,tycho       
,brahe1 were able to obtain only fairly 
accurate results4 ,but by applying      
,gascoigne's invention to the telescope 
almost absolute accuracy became at once 
possible4 ,the principle of ,gascoigne's
 micrometer was that of two pointers    
lying parallel1 and in this position    
pointing to zero4 ,these were arranged  
so that the turning of a single screw   
separated or approximated them at will1 
and the angle thus formed could be      
determined with absolute accuracy4      
,huygens's micrometer was a slip of     
metal of variable breadth inserted at   
the focus of the telescope4 ,by         
observing at what point this exactly    
covered an object under examination1 and
 knowing the focal length of the        
telescope and the width of the metal1 he

 could then deduce the apparent angular 
breadth of the object4 ,huygens         
discovered also that an object placed in
 the common focus of the two lenses of a
 ,kepler telescope appears distinct and 
clearly defined4 ,the micrometers of    
,malvasia1 and later of ,auzout and     
,picard1 are the development of this    
discovery4 ,malvasia's micrometer1 which
 he described in #affb1 consisted of    
fine silver wires placed at right-angles
 at the focus of his telescope4  ,as    
telescopes increased in power1 however1 
it was found that even the finest wire1 
or silk filaments1 were much too thick  
for astronomical observations1 as they  
obliterated the image1 and so1 finally1 
the spider-web came into use and is     
still used in micrometers and other     
similar instruments4 ,before that time1 
however1 the fine crossed wires had     
revolutionized astronomical             
observations4 ,we may judge how great   
was the improvement which these         
contrivances introduced into the art of 

observing1 says ,whewell1 by finding    
that ,hevelius refused to adopt them    
because they would make all the old     
observations of no value4 ,he had spent 
a laborious and active life in the      
exercise of the old methods1 and could  
not bear to think that all the treasures
 which he had accumulated had lost their
 worth by the discovery of a new mine of
 richer ones47#a7  ,until the time of   
,newton1 all the telescopes in use were 
either of the ,galilean or ,keplerian   
type1 that is1 refractors4 ,but about   
the year #afgj ,newton constructed his  
first reflecting telescope1 which was   
greatly superior to1 although much      
smaller than1 the telescopes then in    
use4 ,he was led to this invention by   
his experiments with light and colors4  
,in #afga he presented to the ,royal    
,society a second and somewhat larger   
telescope1 which he had made2 and this  
type of instrument was little improved  
upon until the introduction of the      
achromatic telescope1 invented by       

,chester ,moor ,hall in #agcc4  ,as is  
generally known1 the element of accurate
 measurements of time plays an important
 part in the measurements of the        
movements of the heavenly bodies4 ,in   
fact1 one was scarcely possible without 
the other1 and as it happened it was the
 same man1 ,huygens1 who perfected      
,kepler's telescope and invented the    
pendulum clock4 ,the general idea had   
been suggested by ,galileo2 or1 better  
perhaps1 the equal time occupied by the 
successive oscillations of the pendulum 
had been noted by him4 ,he had not been 
able1 however1 to put this discovery to 
practical account4 ,but in #afef        
,huygens invented the necessary         
machinery for maintaining the motion of 
the pendulum and perfected several      
accurate clocks4 ,these clocks were of  
invaluable assistance to the            
astronomers1 affording as they did a    
means of keeping time more accurate than
 the sun itself4 ,when ,picard had      
corrected the variation caused by heat  

and cold acting upon the pendulum rod by
 combining metals of different degrees  
of expansibility1 a high degree of      
accuracy was possible4  ,but while the  
pendulum clock was an unequalled        
stationary time-piece1 it was useless in
 such unstable situations as1 for       
example1 on shipboard4 ,but here again  
,huygens played a prominent part by     
first applying the coiled balance-spring
 for regulating watches and marine      
clocks4 ,the idea of applying a spring  
to the balance-wheel was not original   
with ,huygens1 however1 as it had been  
first conceived by ,robert ,hooke2 but  
,huygens's application made practical   
,hooke's idea4 ,in ,england the         
importance of securing accurate watches 
or marine clocks was so fully           
appreciated that a reward of ,l#bj1jjj  
sterling was offered by ,parliament as a
 stimulus to the inventor of such a     
time-piece4 ,the immediate incentive for
 this offer was the obvious fact that   
with such an instrument the             

determination of the longitude of places
 would be much simplified4 ,encouraged  
by these offers1 a certain carpenter    
named ,harrison turned his attention to 
the subject of watch-making1 and1 after 
many years of labor1 in #ageh produced a
 spring time-keeper which1 during a     
sea-voyage occupying one hundred and    
sixty-one days1 varied only one minute  
and five seconds4 ,this gained for      
,harrison a reward ,of ,l#ejjj sterling 
at once1 and a little later ,l#aj1jjj   
more1 from ,parliament4  ,while         
inventors were busy with the problem of 
accurate chronometers1 however1 another 
instrument for taking longitude at sea  
had been invented4 ,this was the        
reflecting quadrant1 or sextant1 as the 
improved instrument is now called1      
invented by ,john ,hadley in #agca1 and 
independently by ,thomas ,godfrey1 a    
poor glazier of ,philadelphia1 in #agcj4
 ,godfrey's invention1 which was        
constructed on the same principle as    
that of the ,hadley instrument1 was not 

generally recognized until two years    
after ,hadley's discovery1 although the 
instrument was finished and actually in 
use on a sea-voyage some months before  
,hadley reported his invention4 ,the    
principle of the sextant1 however1 seems
 to have been known to ,newton1 who     
constructed an instrument not very      
unlike that of ,hadley2 but this        
invention was lost sight of until       
several years after the philosopher's   
death and some time after ,hadley's     
invention4  ,the introduction of the    
sextant greatly simplified taking       
reckonings at sea as well as            
facilitating taking the correct         
longitude of distant places4 ,before    
that time the mariner was obliged to    
depend upon his compass1 a cross-staff1 
or an astrolabe1 a table of the sun's   
declination and a correction for the    
altitude of the polestar1 and very      
inadequate and incorrect charts4 ,such  
were the instruments used by ,columbus  
and ,vasco da ,gama and their immediate 

successors4  ,during the ,newtonian     
period the microscopes generally in use 
were those constructed of simple lenses1
 for although compound microscopes were 
known1 the difficulties of correcting   
aberration had not been surmounted1 and 
a much clearer field was given by the   
simple instrument4 ,the results obtained
 by the use of such instruments1        
however1 were very satisfactory in many 
ways4 ,by referring to certain plates in
 this volume1 which reproduce           
illustrations from ,robert ,hooke's work
 on the microscope1 it will be seen that
 quite a high degree of effectiveness   
had been attained4 ,and it should be    
recalled that ,antony von ,leeuwenhoek1 
whose death took place shortly before   
,newton's1 had discovered such          
micro-organisms as bacteria1 had seen   
the blood corpuscles in circulation1 and
 examined and described other           
microscopic structures of the body4     
,,xiv4 ,,progress ,,in ,,electricity    
,,from ,,gilbert ,,and ,,von ,,guericke 

,,to ,,franklin  ,we have seen how      
,gilbert1 by his experiments with       
magnets1 gave an impetus to the study of
 magnetism and electricity4 ,gilbert    
himself demonstrated some facts and     
advanced some theories1 but the system  
of general laws was to come later4 ,to  
this end the discovery of electrical    
repulsion1 as well as attraction1 by    
,von ,guericke1 with his sulphur ball1  
was a step forward2 but something like a
 century passed after ,gilbert's        
beginning before anything of much       
importance was done in the field of     
electricity4  ,in #agje1 however1       
,francis ,hauksbee began a series of    
experiments that resulted in some       
startling demonstrations4 ,for many     
years it had been observed that a       
peculiar light was seen sometimes in the
 mercurial barometer1 but ,hauksbee and 
the other scientific investigators      
supposed the radiance to be due to the  
mercury in a vacuum1 brought about1     
perhaps1 by some agitation4 ,that this  

light might have any connection with    
electricity did not1 at first1 occur to 
,hauksbee any more than it had to his   
predecessors4 ,the problem that         
interested him was whether the vacuum in
 the tube of the barometer was essential
 to the light2 and in experimenting to  
determine this1 he invented his         
mercurial fountain4 ,having exhausted   
the air in a receiver containing some   
mercury1 he found that by allowing air  
to rush through the mercury the metal   
became a jet thrown in all directions   
against the sides of the vessel1 making 
a great1 flaming shower1 like flashes of
 lightning1 as he said4 ,but it seemed  
to him that there was a difference      
between this light and the glow noted in
 the barometer4 ,this was a bright      
light1 whereas the barometer light was  
only a glow4 ,pondering over this1      
,hauksbee tried various experiments1    
revolving pieces of amber1 flint1 steel1
 and other substances in his exhausted  
air-pump receiver1 with negative1 or    

unsatisfactory1 results4 ,finally1 it   
occurred to him to revolve an exhausted 
glass tube itself4 ,mounting such a     
globe of glass on an axis so that it    
could be revolved rapidly by a belt     
running on a large wheel1 he found that 
by holding his fingers against the      
whirling globe a purplish glow appeared1
 giving sufficient light so that coarse 
print could be read1 and the walls of a 
dark room sensibly lightened several    
feet away4 ,as air was admitted to the  
globe the light gradually diminished1   
and it seemed to him that this          
diminished glow was very similar in     
appearance to the pale light seen in the
 mercurial barometer4 ,could it be that 
it was the glass1 and not the mercury1  
that caused it8 ,going to a barometer he
 proceeded to rub the glass above the   
column of mercury over the vacuum1      
without disturbing the mercury1 when1 to
 his astonishment1 the same faint light1
 to all appearances identical with the  
glow seen in the whirling globe1 was    

produced4  ,turning these demonstrations
 over in his mind1 he recalled the      
well-known fact that rubbed glass       
attracted bits of paper1 leaf-brass1 and
 other light substances1 and that this  
phenomenon was supposed to be           
electrical4 ,this led him finally to    
determine the hitherto unsuspected fact1
 that the glow in the barometer was     
electrical as was also the glow seen in 
his whirling globe4 ,continuing his     
investigations1 he soon discovered that 
solid glass rods when rubbed produced   
the same effects as the tube4 ,by mere  
chance1 happening to hold a rubbed tube 
to his cheek1 he felt the effect of     
electricity upon the skin like a number 
of fine1 limber hairs1 and this         
suggested to him that1 since the        
mysterious manifestation was so plain1  
it could be made to show its effects    
upon various substances4 ,suspending    
some woollen threads over the whirling  
glass cylinder1 he found that as soon as
 he touched the glass with his hands the

 threads1 which were waved about by the 
wind of the revolution1 suddenly        
straightened themselves in a peculiar   
manner1 and stood in a radical position1
 pointing to the axis of the cylinder4  
,encouraged by these successes1 he      
continued his experiments with          
breathless expectancy1 and soon made    
another important discovery1 that of    
induction1 although the real            
significance of this discovery was not  
appreciated by him or1 for that matter1 
by any one else for several generations 
following4 ,this discovery was made by  
placing two revolving cylinders within  
an inch of each other1 one with the air 
exhausted and the other unexhausted4    
,placing his hand on the unexhausted    
tube caused the light to appear not only
 upon it1 but on the other tube as well4
 ,a little later he discovered that it  
is not necessary to whirl the exhausted 
tube to produce this effect1 but simply 
to place it in close proximity to the   
other whirling cylinder4  ,these        

demonstrations of ,hauksbee attracted   
wide attention and gave an impetus to   
investigators in the field of           
electricity2 but still no great advance 
was made for something like a quarter of
 a century4 ,possibly the energies of   
the scientists were exhausted for the   
moment in exploring the new fields      
thrown open to investigation by the     
colossal work of ,newton4   ,,the       
,,experiments ,,of ,,stephen ,,gray  ,in
 #agbi ,stephen ,gray 7died in #agcf71  
an eccentric and irascible old pensioner
 of the ,charter ,house in ,london1     
undertook some investigations along     
lines similar to those of ,hauksbee4    
,while experimenting with a glass tube  
for producing electricity1 as ,hauksbee 
had done1 he noticed that the corks with
 which he had stopped the ends of the   
tube to exclude the dust1 seemed to     
attract bits of paper and leaf-brass as 
well as the glass itself4 ,he surmised  
at once that this mysterious            
electricity1 or virtue1 as it was       

called1 might be transmitted through    
other substances as it seemed to be     
through glass4  ,having by me an ivory  
ball of about one and three-tenths of an
 inch in diameter1 he writes1 with a    
hole through it1 this ,i fixed upon a   
fir-stick about four inches long1       
thrusting the other end into the cork1  
and upon rubbing the tube found that the
 ball attracted and repelled the feather
 with more vigor than the cork had done1
 repeating its attractions and          
repulsions for many times together4 ,i  
then fixed the ball on longer sticks1   
first upon one of eight inches1 and     
afterwards upon one of twenty-four      
inches long1 and found the effect the   
same4 ,then ,i made use of iron1 and    
then brass wire1 to fix the ball on1    
inserting the other end of the wire in  
the cork1 as before1 and found that the 
attraction was the same as when the     
fir-sticks were made use of1 and that   
when the feather was held over against  
any part of the wire it was attracted by

 it2 but though it was then nearer the  
tube1 yet its attraction was not so     
strong as that of the ball4 ,when the   
wire of two or three feet long was used1
 its vibrations1 caused by the rubbing  
of the tube1 made it somewhat           
troublesome to be managed4 ,this put me 
to thinking whether1 if the ball was    
hung by a pack-thread and suspended by a
 loop on the tube1 the electricity would
 not be carried down the line to the    
ball2 ,i found it to succeed            
accordingly2 for upon suspending the    
ball on the tube by a pack-thread about 
three feet long1 when the tube had been 
excited by rubbing1 the ivory ball      
attracted and repelled the leaf-brass   
over which it was held as freely as it  
had done when it was suspended on sticks
 or wire1 as did also a ball of cork1   
and another of lead that weighed one    
pound and a quarter4  ,gray next        
attempted to determine what other bodies
 would attract the bits of paper1 and   
for this purpose he tried coins1 pieces 

of metal1 and even a tea-kettle1 both   
empty and filled with hot or cold water2
 but he found that the attractive power 
appeared to be the same regardless of   
the substance used4  ,i next proceeded1 
he continues1 to try at what greater    
distances the electric virtues might be 
carried1 and having by me a hollow      
walking-cane1 which ,i suppose was part 
of a fishing-rod1 two feet seven inches 
long1 ,i cut the great end of it to fit 
into the bore of the tube1 into which it
 went about five inches2 then when the  
cane was put into the end of the tube1  
and this excited1 the cane drew the     
leaf-brass to the height of more than   
two inches1 as did also the ivory ball1 
when by a cork and stick it had been    
fixed to the end of the cane4444 ,with  
several pieces of ,spanish cane and     
fir-sticks ,i afterwards made a rod1    
which1 together with the tube1 was      
somewhat more than eighteen feet long1  
which was the greatest length ,i could  
conveniently use in my chamber1 and     

found the attraction very nearly1 if not
 altogether1 as strong as when the ball 
was placed on the shorter rods4  ,this  
experiment exhausted the capacity of his
 small room1 but on going to the country
 a little later he was able to continue 
his experiments4 ,to a pole of eighteen 
feet there was tied a line of           
thirty-four feet in length1 so that the 
pole and line together were fifty-two   
feet4 ,with the pole and tube ,i stood  
in the balcony1 the assistant below in  
the court1 where he held the board with 
the leaf-brass on it4 ,then the tube    
being excited1 as usual1 the electric   
virtue passed from the tube up the pole 
and down the line to the ivory ball1    
which attracted the leaf-brass1 and as  
the ball passed over it in its          
vibrations the leaf-brass would follow  
it till it was carried off the board4   
,gray next attempted to send the        
electricity over a line suspended       
horizontally4 ,to do this he suspended  
the pack-thread by pieces of string     

looped over nails driven into beams for 
that purpose4 ,but when thus suspended  
he found that the ivory ball no longer  
excited the leaf-brass1 and he guessed  
correctly that the explanation of this  
lay in the fact that when the electric  
virtue came to the loop that was        
suspended on the beam it went up the    
same to the beam1 none of it reaching   
the ball4 ,as we shall see from what    
follows1 however1 ,gray had not as yet  
determined that certain substances will 
conduct electricity while others will   
not4 ,but by a lucky accident he made   
the discovery that silk1 for example1   
was a poor conductor1 and could be      
turned to account in insulating the     
conducting-cord4  ,a certain ,mr4       
,wheler had become much interested in   
the old pensioner and his work1 and1 as 
a guest at the ,wheler house1 ,gray had 
been repeating some of his former       
experiments with the fishing-rod1 line1 
and ivory ball4 ,he had finally         
exhausted the heights from which these  

experiments could be made by climbing to
 the clock-tower and exciting bits of   
leaf-brass on the ground below4  ,as we 
had no greater heights here1 he says1   
,mr4 ,wheler was desirous to try whether
 we could not carry the electric virtue 
horizontally4 ,i then told him of the   
attempt ,i had made with that design1   
but without success1 telling him the    
method and materials made use of1 as    
mentioned above4 ,he then proposed a    
silk line to support the line by which  
the electric virtue was to pass4 ,i told
 him it might do better upon account of 
its smallness2 so that there would be   
less virtue carried from the line of    
communication4  ,the first experiment   
was made in the matted gallery1 ,july   
#b1 #agbi1 about ten in the morning4    
,about four feet from the end of the    
gallery there was a cross line that was 
fixed by its ends to each side of the   
gallery by two nails2 the middle part of
 the line was silk1 the rest at each end
 pack-thread2 then the line to which the

 ivory ball was hung and by which the   
electric virtue was to be conveyed to it
 from the tube1 being eighty and        
one-half feet in length1 was laid on the
 cross silk line1 so that the ball hung 
about nine feet below it4 ,then the     
other end of the line was by a loop     
suspended on the glass cane1 and the    
leaf-brass held under the ball on a     
piece of white paper2 when1 the tube    
being rubbed1 the ball attracted the    
leaf-brass1 and kept it suspended on it 
for some time4  ,this experiment        
succeeded so well that the string was   
lengthened until it was some two hundred
 and ninety-three feet long2 and still  
the attractive force continued1         
apparently as strong as ever4 ,on       
lengthening the string still more1      
however1 the extra weight proved too    
much for the strength of the silk       
suspending-thread4 ,upon this1 says     
,gray1 having brought with me both brass
 and iron wire1 instead of the silk we  
put up small iron wire2 but this was too

 weak to bear the weight of the line4   
,we then took brass wire of a somewhat  
larger size than that of iron4 ,this    
supported our line of communication2 but
 though the tube was well rubbed1 yet   
there was not the least motion or       
attraction given by the ball1 neither   
with the great tube1 which we made use  
of when we found the small solid cane to
 be ineffectual2 by which we were now   
convinced that the success we had before
 depended upon the lines that supported 
the line of communication being silk1   
and not upon their being small1 as      
before trial ,i had imagined it might   
be2 the same effect happening here as it
 did when the line that is to convey the
 electric virtue is supported by        
pack-thread4  ,soon after this ,gray and
 his host suspended a pack-thread six   
hundred and sixty-six feet long on poles
 across a field1 these poles being      
slightly inclined so that the thread    
could be suspended from the top by small
 silk cords1 thus securing the necessary

 insulation4 ,this pack-thread line1    
suspended upon poles along which ,gray  
was able to transmit the electricity1 is
 very suggestive of the modern          
telegraph1 but the idea of signalling or
 making use of it for communicating in  
any way seems not to have occurred to   
any one at that time4 ,even the         
successors of ,gray who constructed     
lines some thousands of feet long made  
no attempt to use them for anything but 
experimental purposes--simply to test   
the distances that the current could be 
sent4 ,nevertheless1 ,gray should       
probably be credited with the discovery 
of two of the most important properties 
of electricity--that it can be conducted
 and insulated1 although1 as we have    
seen1 ,gilbert and ,von ,guericke had an
 inkling of both these properties4      
,,experiments ,,of ,,cisternay ,,dufay  
,so far ,england had produced the two   
foremost workers in electricity4 ,it was
 now ,france's turn to take a hand1 and1
 through the efforts of ,charles        

,francois de ,cisternay ,dufay1 to      
advance the science of electricity very 
materially4 ,dufay was a highly educated
 savant1 who had been soldier and       
diplomat betimes1 but whose versatility 
and ability as a scientist is shown by  
the fact that he was the only man who   
had ever contributed to the annals of   
the academy investigations in every one 
of the six subjects admitted by that    
institution as worthy of recognition4   
,dufay upheld his reputation in this new
 field of science1 making many          
discoveries and correcting many mistakes
 of former observers4 ,in this work also
 he proved himself a great diplomat by  
remaining on terms of intimate          
friendship with ,dr4 ,gray--a thing that
 few people were able to do4  ,almost   
his first step was to overthrow the     
belief that certain bodies are electrics
 and others non-electrics--that is1 that
 some substances when rubbed show       
certain peculiarities in attracting     
pieces of paper and foil which others do

 not4 ,dufay proved that all bodies     
possess this quality in a certain       
degree4  ,i have found that all bodies  
7metallic1 soft1 or fluid ones          
excepted71 he says1 may be made electric
 by first heating them more or less and 
then rubbing them on any sort of cloth4 
,so that all kinds of stones1 as well   
precious as common1 all kinds of wood1  
and1 in general1 everything that ,i have
 made trial of1 became electric by      
beating and rubbing1 except such bodies 
as grow soft by beat1 as the gums1 which
 dissolve in water1 glue1 and such like 
substances4 ',tis also to be remarked   
that the hardest stones or marbles      
require more chafing or heating than    
others1 and that the same rule obtains  
with regard to the woods2 so that box1  
lignum vitae1 and such others must be   
chafed almost to the degree of browning1
 whereas fir1 lime-tree1 and cork       
require but a moderate heat4  ,having   
read in one of ,mr4 ,gray's letters that
 water may be made electrical by holding

 the excited glass tube near it 7a dish 
of water being fixed to a stand and that
 set on a plate of glass1 or on the brim
 of a drinking-glass1 previously chafed1
 or otherwise warmed71 ,i have found1   
upon trial1 that the same thing happened
 to all bodies without exception1       
whether solid or fluid1 and that for    
that purpose 'twas sufficient to set    
them on a glass stand slightly warmed1  
or only dried1 and then by bringing the 
tube near them they immediately became  
electrical4 ,i made this experiment with
 ice1 with a lighted wood-coal1 and with
 everything that came into my mind2 and 
,i constantly remarked that such bodies 
of themselves as were least electrical  
had the greatest degree of electricity  
communicated to them at the approval of 
the glass tube4  ,his next important    
discovery was that colors had nothing to
 do with the conduction of electricity4 
,mr4 ,gray says1 towards the end of one 
of his letters1 he writes1 that bodies  
attract more or less according to their 

colors4 ,this led me to make several    
very singular experiments4 ,i took nine 
silk ribbons of equal size1 one white1  
one black1 and the other seven of the   
seven primitive colors1 and having hung 
them all in order in the same line1 and 
then bringing the tube near them1 the   
black one was first attracted1 the white
 one next1 and others in order          
successively to the red one1 which was  
attracted least1 and the last of them   
all4 ,i afterwards cut out nine square  
pieces of gauze of the same colors with 
the ribbons1 and having put them one    
after another on a hoop of wood1 with   
leaf-gold under them1 the leaf-gold was 
attracted through all the colored pieces
 of gauze1 but not through the white or 
black4 ,this inclined me first to think 
that colors contribute much to          
electricity1 but three experiments      
convinced me to the contrary4 ,the      
first1 that by warming the pieces of    
gauze neither the black nor white pieces
 obstructed the action of the electrical

 tube more than those of the other      
colors4 ,in like manner1 the ribbons    
being warmed1 the black and white are   
not more strongly attracted than the    
rest4 ,the second is1 the gauzes and    
ribbons being wetted1 the ribbons are   
all attracted equally1 and all the      
pieces of gauze equally intercept the   
action of electric bodies4 ,the third   
is1 that the colors of a prism being    
thrown on a white gauze1 there appear no
 differences of attraction4 ,whence it  
proceeds that this difference proceeds1 
not from the color1 as a color1 but from
 the substances that are employed in the
 dyeing4 ,for when ,i colored ribbons by
 rubbing them with charcoal1 carmine1   
and such other substances1 the          
differences no longer proved the same4  
,in connection with his experiments with
 his thread suspended on glass poles1   
,dufay noted that a certain amount of   
the current is lost1 being given off to 
the surrounding air4 ,he recommended1   
therefore1 that the cords experimented  

with be wrapped with some               
non-conductor--that it should be        
insulated 7isolee71 as he said1 first   
making use of this term4   ,,dufay      
,,discovers ,,vitreous ,,and ,,resinous 
,,electricity  ,it has been shown in an 
earlier chapter how ,von ,guericke      
discovered that light substances like   
feathers1 after being attracted to the  
sulphur-ball electric-machine1 were     
repelled by it until they touched some  
object4 ,von ,guericke noted this1 but  
failed to explain it satisfactorily4    
,dufay1 repeating ,von ,guericke's      
experiments1 found that if1 while the   
excited tube or sulphur ball is driving 
the repelled feather before it1 the ball
 be touched or rubbed anew1 the feather 
comes to it again1 and is repelled      
alternately1 as1 the hand touches the   
ball1 or is withdrawn4 ,from this he    
concluded that electrified bodies first 
attract bodies not electrified1 charge  
them with electricity1 and then repel   
them1 the body so charged not being     

attracted again until it has discharged 
its electricity by touching something4  
,on making the experiment related by    
,otto von ,guericke1 he says1 which     
consists in making a ball of sulphur    
rendered electrical to repel a down     
feather1 ,i perceived that the same     
effects were produced not only by the   
tube1 but by all electric bodies        
whatsoever1 and ,i discovered that which
 accounts for a great part of the       
irregularities and1 if ,i may use the   
term1 of the caprices that seem to      
accompany most of the experiments on    
electricity4 ,this principle is that    
electric bodies attract all that are not
 so1 and repel them as soon as they are 
become electric by the vicinity or      
contact of the electric body4 ,thus     
gold-leaf is first attracted by the     
tube1 and acquires an electricity by    
approaching it1 and of consequence is   
immediately repelled by it4 ,nor is it  
reattracted while it retains its        
electric quality4 ,but if while it is   

thus sustained in the air it chance to  
light on some other body1 it straightway
 loses its electricity1 and in          
consequence is reattracted by the tube1 
which1 after having given it a new      
electricity1 repels it a second time1   
which continues as long as the tube     
keeps its electricity4 ,upon applying   
this principle to the various           
experiments of electricity1 one will be 
surprised at the number of obscure and  
puzzling facts that it clears up4 ,for  
,mr4 ,hauksbee's famous experiment of   
the glass globe1 in which silk threads  
are put1 is a necessary consequence of  
it4 ,when these threads are arranged in 
the form of rays by the electricity of  
the sides of the globe1 if the finger be
 put near the outside of the globe the  
silk threads within fly from it1 as is  
well known1 which happens only because  
the finger or any other body applied    
near the glass globe is thereby rendered
 electrical1 and consequently repels the
 silk threads which are endowed with the

 same quality4 ,with a little reflection
 we may in the same manner account for  
most of the other phenomena1 and which  
seem inexplicable without attending to  
this principle4  ,chance has thrown in  
my way another principle1 more universal
 and remarkable than the preceding one1 
and which throws a new light on the     
subject of electricity4 ,this principle 
is that there are two distinct          
electricities1 very different from each 
other1 one of which ,i call vitreous    
electricity and the other resinous      
electricity4 ,the first is that of      
glass1 rock-crystal1 precious stones1   
hair of animals1 wool1 and many other   
bodies4 ,the second is that of amber1   
copal1 gumsack1 silk thread1 paper1 and 
a number of other substances4 ,the      
characteristic of these two             
electricities is that a body of the     
vitreous electricity1 for example1      
repels all such as are of the same      
electricity1 and on the contrary        
attracts all those of the resinous      

electricity2 so that the tube1 made     
electrical1 will repel glass1 crystal1  
hair of animals1 etc41 when rendered    
electric1 and will attract silk thread1 
paper1 etc41 though rendered electrical 
likewise4 ,amber1 on the contrary1 will 
attract electric glass and other        
substances of the same class1 and will  
repel gum-sack1 copal1 silk thread1 etc4
 ,two silk ribbons rendered electrical  
will repel each other2 two woollen      
threads will do the like2 but a woollen 
thread and a silken thread will mutually
 attract each other4 ,this principle    
very naturally explains why the ends of 
threads of silk or wool recede from each
 other1 in the form of pencil or broom1 
when they have acquired an electric     
quality4 ,from this principle one may   
with the same ease deduce the           
explanation of a great number of other  
phenomena2 and it is probable that this 
truth will lead us to the further       
discovery of many other things4  ,in    
order to know immediately to which of   

the two classes of electrics belongs any
 body whatsoever1 one need only render  
electric a silk thread1 which is known  
to be of the resinuous electricity1 and 
see whether that body1 rendered         
electrical1 attracts or repels it4 ,if  
it attracts it1 it is certainly of the  
kind of electricity which ,i call       
,,vitreous2 if1 on the contrary1 it     
repels it1 it is of the same kind of    
electricity with the silk--that is1 of  
the ,,resinous4 ,i have likewise        
observed that communicated electricity  
retains the same properties2 for if a   
ball of ivory or wood be set on a glass 
stand1 and this ball be rendered        
electric by the tube1 it will repel such
 substances as the tube repels2 but if  
it be rendered electric by applying a   
cylinder of gum-sack near it1 it will   
produce quite contrary effects--namely1 
precisely the same as gum-sack would    
produce4 ,in order to succeed in these  
experiments1 it is requisite that the   
two bodies which are put near each      

other1 to find out the nature of their  
electricity1 be rendered as electrical  
as possible1 for if one of them was not 
at all or but weakly electrical1 it     
would be attracted by the other1 though 
it be of that sort that should naturally
 be repelled by it4 ,but the experiment 
will always succeed perfectly well if   
both bodies are sufficiently            
electrical47#a7  ,as we now know1 ,dufay
 was wrong in supposing that there were 
two different kinds of electricity1     
vitreous and resinous4 ,a little later  
the matter was explained by calling one 
positive electricity and the other      
negative1 and it was believed that      
certain substances produced only the one
 kind peculiar to that particular       
substance4 ,we shall see presently1     
however1 that some twenty years later an
 ,english scientist dispelled this      
illusion by producing both positive 7or 
vitreous7 and negative 7or resinous7    
electricity on the same tube of glass at
 the same time4  ,after the death of    

,dufay his work was continued by his    
fellow-countryman ,dr4 ,joseph          
,desaguliers1 who was the first         
experimenter to electrify running water1
 and who was probably the first to      
suggest that clouds might be electrified
 bodies4 ,but about1 this time--that is1
 just before the middle of the          
eighteenth century--the field of        
greatest experimental activity was      
transferred to ,germany1 although both  
,england and ,france were still active4 
,the two ,german philosophers who       
accomplished most at this time were     
,christian ,august ,hansen and ,george  
,matthias ,bose1 both professors in     
,leipsic4 ,both seem to have conceived  
the idea1 simultaneously and            
independently1 of generating electricity
 by revolving globes run by belt and    
wheel in much the same manner as the    
apparatus of ,hauksbee4  ,with such     
machines it was possible to generate a  
much greater amount of electricity than 
,dufay had been able to do with the     

rubbed tube1 and so equipped1 the two   
,german professors were able to generate
 electric sparks and jets of fire in a  
most startling manner4 ,bose in         
particular had a love for the           
spectacular1 which he turned to account 
with his new electrical machine upon    
many occasions4 ,on one of these        
occasions he prepared an elaborate      
dinner1 to which a large number of      
distinguished guests were invited4      
,before the arrival of the company1     
however1 ,bose insulated the great      
banquet-table on cakes of pitch1 and    
then connected it with a huge electrical
 machine concealed in another room4 ,all
 being ready1 and the guests in their   
places about to be seated1 ,bose gave a 
secret signal for starting this machine1
 when1 to the astonishment of the party1
 flames of fire shot from flowers1      
dishes1 and viands1 giving a most       
startling but beautiful display4  ,to   
add still further to the astonishment of
 his guests1 ,bose then presented a     

beautiful young lady1 to whom each of   
the young men of the party was          
introduced4 ,in some mysterious manner  
she was insulated and connected with the
 concealed electrical machine1 so that  
as each gallant touched her fingertips  
he received an electric shock that made 
him reel4 ,not content with this1 the   
host invited the young men to kiss the  
beautiful maid4 ,but those who were bold
 enough to attempt it received an       
electric shock that nearly knocked their
 teeth out1 as the professor tells it4  
,,ludolff',s ,,experiment ,,with ,,the  
,,electric ,,spark  ,but ,bose was only 
one of several ,german scientists who   
were making elaborate experiments4      
,while ,bose was constructing and       
experimenting with his huge machine1    
another ,german1 ,christian ,friedrich  
,ludolff1 demonstrated that electric    
sparks are actual fire--a fact long     
suspected but hitherto unproved4        
,ludolff's discovery1 as it chanced1 was
 made in the lecture-hall of the        

reorganized ,academy of ,sciences at    
,berlin1 before an audience of          
scientists and great personages1 at the 
opening lecture in #agdd4  ,in the      
course of this lecture on electricity1  
during which some of the well-known     
manifestations of electricity were being
 shown1 it occurred to ,ludolff to      
attempt to ignite some inflammable fluid
 by projecting an electric spark upon   
its surface with a glass rod4 ,this idea
 was suggested to him while performing  
the familiar experiment of producing a  
spark on the surface of a bowl of water 
by touching it with a charged glass rod4
 ,he announced to his audience the      
experiment he was about to attempt1 and 
having warmed a spoonful of sulphuric   
ether1 he touched its surface with the  
glass rod1 causing it to burst into     
flame4 ,this experiment left no room for
 doubt that the electric spark was      
actual fire4  ,as soon as this          
experiment of ,ludolff's was made known 
to ,bose1 he immediately claimed that he

 had previously made similar            
demonstrations on various inflammable   
substances1 both liquid and solid2 and  
it seems highly probable that he had    
done so1 as he was constantly           
experimenting with the sparks1 and must 
almost certainly have set certain       
substances ablaze by accident1 if not by
 intent4 ,at all events1 he carried on a
 series of experiments along this line  
to good purpose1 finally succeeding in  
exploding gun-powder1 and so making the 
first forerunner of the electric fuses  
now so universally used in blasting1    
firing cannon1 and other similar        
purposes4 ,it was ,bose also who1       
observing some of the peculiar          
manifestations in electrified tubes1 and
 noticing their resemblance to northern 
lights1 was one of the first1 if not the
 first1 to suggest that the aurora      
borealis is of electric origin4  ,these 
spectacular demonstrations had the      
effect of calling public attention to   
the fact that electricity is a most     

wonderful and mysterious thing1 to say  
the least1 and kept both scientists and 
laymen agog with expectancy4 ,bose      
himself was aflame with excitement1 and 
so determined in his efforts to produce 
still stronger electric currents1 that  
he sacrificed the tube of his           
twenty-foot telescope for the           
construction of a mammoth electrical    
machine4 ,with this great machine a     
discharge of electricity was generated  
powerful enough to wound the skin when  
it happened to strike it4  ,until this  
time electricity had been little more   
than a plaything of the scientists--or1 
at least1 no practical use had been made
 of it4 ,as it was a practising         
physician1 ,gilbert1 who first laid the 
foundation for experimenting with the   
new substance1 so again it was a medical
 man who first attempted to put it to   
practical use1 and that in the field of 
his profession4 ,gottlieb ,kruger1 a    
professor of medicine at ,halle in      
#agdc1 suggested that electricity might 

be of use in some branches of medicine2 
and the year following ,christian       
,gottlieb ,kratzenstein made a first    
experiment to determine the effects of  
electricity upon the body4 ,he found    
that the action of the heart was        
accelerated1 the circulation increased1 
and that muscles were made to contract  
by the discharge3 and he began at once  
administering electricity in the        
treatment of certain diseases4 ,he found
 that it acted beneficially in rheumatic
 affections1 and that it was            
particularly useful in certain nervous  
diseases1 such as palsies4 ,this was    
over a century ago1 and to-day about the
 most important use made of the         
particular kind of electricity with     
which he experimented 7the static1 or   
frictional7 is for the treatment of     
diseases affecting the nervous system4  
,by the middle of the century a perfect 
mania for making electrical machines had
 spread over ,europe1 and the whirling1 
hand-rubbed globes were gradually       

replaced by great cylinders rubbed by   
woollen cloths or pads1 and generating  
an enormous power of electricity4 ,these
 cylinders were run by belts and        
foot-treadles1 and gave a more powerful1
 constant1 and satisfactory current than
 known heretofore4 ,while making        
experiments with one of these machines1 
,johann ,heinrichs ,winkler attempted to
 measure the speed at which electricity 
travels4 ,to do this he extended a cord 
suspended on silk threads1 with the end 
attached to the machine and the end     
which was to attract the bits of        
gold-leaf near enough together so that  
the operator could watch and measure the
 interval of time that elapsed between  
the starting of the current along the   
cord and its attracting the gold-leaf4  
,the length of the cord used in this    
experiment was only a little over a     
hundred feet1 and this was1 of course1  
entirely inadequate1 the current        
travelling that space apparently        
instantaneously4  ,the improved method  

of generating electricity that had come 
into general use made several of the    
scientists again turn their attention   
more particularly to attempt putting it 
to some practical account4 ,they were   
stimulated to these efforts by the      
constant reproaches that were beginning 
to be heard on all sides that           
electricity was merely a philosopher's  
plaything4 ,one of the first to succeed 
in inventing something that approached a
 practical mechanical contrivance was   
,andrew ,gordon1 a ,scotch ,benedictine 
monk4 ,he invented an electric bell     
which would ring automatically1 and a   
little motor1 if it may be so called4   
,and while neither of these inventions  
were of any practical importance in     
themselves1 they were attempts in the   
right direction1 and were the first     
ancestors of modern electric bells and  
motors1 although the principle upon     
which they worked was entirely different
 from modern electrical machines4 ,the  
motor was simply a wheel with several   

protruding metal points around its rim4 
,these points were arranged to receive  
an electrical discharge from a          
frictional machine1 the discharge       
causing the wheel to rotate4 ,there was 
very little force given to this         
rotation1 however1 not enough1 in fact1 
to make it possible to more than barely 
turn the wheel itself4 ,two more great  
discoveries1 galvanism and              
electro-magnetic induction1 were        
necessary before the practical motor    
became possible4  ,the sober ,gordon had
 a taste for the spectacular almost     
equal to that of ,bose4 ,it was he who  
ignited a bowl of alcohol by turning a  
stream of electrified water upon it1    
thus presenting the seeming paradox of  
fire produced by a stream of water4     
,gordon also demonstrated the power of  
the electrical discharge by killing     
small birds and animals at a distance of
 two hundred ells1 the electricity being
 conveyed that distance through small   
wires4   ,,the ,,leyden ,,jar           

,,discovered  ,as yet no one had        
discovered that electricity could be    
stored1 or generated in any way other   
than by some friction device4 ,but very 
soon two experimenters1 ,dean von       
,kleist1 of ,camin1 ,pomerania1 and     
,pieter van ,musschenbroek1 the famous  
teacher of ,leyden1 apparently          
independently1 made the discovery of    
what has been known ever since as the   
,leyden jar4 ,and although              
,musschenbroek is sometimes credited    
with being the discoverer1 there can be 
no doubt that ,von ,kleist's discovery  
antedated his by a few months at least4 
,von ,kleist found that by a device made
 of a narrow-necked bottle containing   
alcohol or mercury1 into which an iron  
nail was inserted1 he was able to retain
 the charge of electricity1 after       
electrifying this apparatus with the    
frictional machine4 ,he made also a     
similar device1 more closely resembling 
the modern ,leyden jar1 from a          
thermometer tube partly filled with     

water and a wire tipped with a ball of  
lead4 ,with these devices he found that 
he could retain the charge of           
electricity for several hours1 and could
 produce the usual electrical           
manifestations1 even to igniting        
spirits1 quite as well as with the      
frictional machine4 ,these experiments  
were first made in ,october1 #agde1 and 
after a month of further experimenting1 
,von ,kleist sent the following account 
of them to several of the leading       
scientists1 among others1 ,dr4          
,lieberkuhn1 in ,berlin1 and ,dr4       
,kruger1 of ,halle4  ,when a nail1 or a 
piece of thick brass wire1 is put into a
 small apothecary's phial and           
electrified1 remarkable effects follow2 
but the phial must be very dry1 or warm4
 ,i commonly rub it over beforehand with
 a finger on which ,i put some pounded  
chalk4 ,if a little mercury or a few    
drops of spirit of wine be put into it1 
the experiment succeeds better4 ,as soon
 as this phial and nail are removed from

 the electrifying-glass1 or the prime   
conductor1 to which it has been exposed1
 is taken away1 it throws out a pencil  
of flame so long that1 with this burning
 machine in my hand1 ,i have taken above
 sixty steps in walking about my room4  
,when it is electrified strongly1 ,i can
 take it into another room and there    
fire spirits of wine with it4 ,if while 
it is electrifying ,i put my finger1 or 
a piece of gold which ,i hold in my     
hand1 to the nail1 ,i receive a shock   
which stuns my arms and shoulders4  ,a  
tin tube1 or a man1 placed upon         
electrics1 is electrified much stronger 
by this means than in the common way4   
,when ,i present this phial and nail to 
a tin tube1 which ,i have1 fifteen feet 
long1 nothing but experience can make a 
person believe how strongly it is       
electrified4 ,i am persuaded1 he adds1  
that in this manner ,mr4 ,bose would not
 have taken a second electrical kiss4   
,two thin glasses have been broken by   
the shock of it4 ,it appears to me very 

extraordinary1 that when this phial and 
nail are in contact with either         
conducting or non-conducting matter1 the
 strong shock does not follow4 ,i have  
cemented it to wood1 metal1 glass1      
sealing-wax1 etc41 when ,i have         
electrified without any great effect4   
,the human body1 therefore1 must        
contribute something to it4 ,this       
opinion is confirmed by my observing    
that unless ,i hold the phial in my hand
 ,i cannot fire spirits of wine with    
it47#b7  ,but it seems that none of the 
men who saw this account were able to   
repeat the experiment and produce the   
effects claimed by ,von ,kleist1 and    
probably for this reason the discovery  
of the obscure ,pomeranian was for a    
time lost sight of4  ,musschenbroek's   
discovery was made within a short time  
after ,von ,kleist's--in fact1 only a   
matter of about two months later4 ,but  
the difference in the reputations of the
 two discoverers insured a very         
different reception for their           

discoveries4 ,musschenbroek was one of  
the foremost teachers of ,europe1 and so
 widely known that the great            
universities vied with each other1 and  
kings were bidding1 for his services4   
,naturally1 any discovery made by such a
 famous person would soon be heralded   
from one end of ,europe to the other4   
,and so when this professor of ,leyden  
made his discovery1 the apparatus came  
to be called the ,leyden jar1 for want  
of a better name4 ,there can be little  
doubt that ,musschenbroek made his      
discovery entirely independently of any 
knowledge of ,von ,kleist's1 or1 for    
that matter1 without ever having heard  
of the ,pomeranian1 and his actions in  
the matter are entirely honorable4  ,his
 discovery was the result of an         
accident4 ,while experimenting to       
determine the strength of electricity he
 suspended a gun-barrel1 which he       
charged with electricity from a         
revolving glass globe4 ,from the end of 
the gun-barrel opposite the globe was a 

brass wire1 which extended into a glass 
jar partly filled with water4           
,musschenbroek held in one hand this    
jar1 while with the other he attempted  
to draw sparks from the barrel4         
,suddenly he received a shock in the    
hand holding the jar1 that shook him    
like a stroke of lightning1 and for a   
moment made him believe that he was done
 for4 ,continuing his experiments1      
nevertheless1 he found that if the jar  
were placed on a piece of metal on the  
table1 a shock would be received by     
touching this piece of metal with one   
hand and touching the wire with the     
other--that is1 a path was made for the 
electrical discharge through the body4  
,this was practically the same          
experiment as made by ,von ,kleist with 
his bottle and nail1 but carried one    
step farther1 as it showed that the jar 
need not necessarily be held in the     
hand1 as believed by ,von ,kleist4      
,further experiments1 continued by many 
philosophers at the time1 revealed what 

,von ,kleist had already pointed out1   
that the electrified jar remained       
charged for some time4  ,soon after this
 ,daniel ,gralath1 wishing to obtain    
stronger discharges than could be had   
from a single ,leyden jar1 conceived the
 idea of combining several jars1 thus   
for the first time grouping the         
generators in a battery which produced a
 discharge strong enough to kill birds  
and small animals4 ,he also attempted to
 measure the strength of the discharges1
 but soon gave it up in despair1 and the
 solution of this problem was left for  
late nineteenth-century scientists4     
,the advent of the ,leyden jar1 which   
made it possible to produce strong      
electrical discharges from a small and  
comparatively simple device1 was        
followed by more spectacular            
demonstrations of various kinds all over
 ,europe4 ,these exhibitions aroused the
 interest of the kings and noblemen1 so 
that electricity no longer remained a   
plaything of the philosophers alone1 but

 of kings as well4 ,a favorite          
demonstration was that of sending the   
electrical discharge through long lines 
of soldiers linked together by pieces of
 wire1 the discharge causing them to    
spring into the air simultaneously in a 
most astonishing manner4 ,a certain monk
 in ,paris prepared a most elaborate    
series of demonstrations for the        
amusement of the king1 among other      
things linking together an entire       
regiment of nine hundred men1 causing   
them to perform simultaneous springs and
 contortions in a manner most amusing to
 the royal guests4 ,but not all the     
experiments being made were of a purely 
spectacular character1 although most of 
them accomplished little except in a    
negative way4 ,the famous ,abbe ,nollet1
 for example1 combined useful           
experiments with spectacular            
demonstrations1 thus keeping up popular 
interest while aiding the cause of      
scientific electricity4   ,,william     
,,watson  ,naturally1 the new           

discoveries made necessary a new        
nomenclature1 new words and electrical  
terms being constantly employed by the  
various writers of that day4 ,among     
these writers was the ,english scientist
 ,william ,watson1 who was not only a   
most prolific writer but a tireless     
investigator4 ,many of the words coined 
by him are now obsolete1 but one at     
least1 circuit1 still remains in use4   
,in #agdf1 a ,french scientist1 ,louis  
,guillaume le ,monnier1 bad made a      
circuit including metal and water by    
laying a chain half-way around the edge 
of a pond1 a man at either end holding  
it4 ,one of these men dipped his free   
hand in the water1 the other presenting 
a ,leyden jar to a rod suspended on a   
cork float on the water1 both men       
receiving a shock simultaneously4       
,watson1 a year later1 attempted the    
same experiment on a larger scale4 ,he  
laid a wire about twelve hundred feet   
long across ,westminster ,bridge over   
the ,thames1 bringing the ends to the   

water's edge on the opposite banks1 a   
man at one end holding the wire and     
touching the water4 ,a second man on the
 opposite side held the wire and a      
,leyden jar2 and a third touched the jar
 with one hand1 while with the other he 
grasped a wire that extended into the   
river4 ,in this way they not only       
received the shock1 but fired alcohol as
 readily across the stream as could be  
done in the laboratory4 ,in this        
experiment ,watson discovered the       
superiority of wire over chain as a     
conductor1 rightly ascribing this       
superiority to the continuity of the    
metal4  ,watson continued making similar
 experiments over longer watercourses1  
some of them as long as eight thousand  
feet1 and while engaged in making one of
 these he made the discovery so         
essential to later inventions1 that the 
earth could be used as part of the      
circuit in the same manner as bodies of 
water4 ,lengthening his wires he        
continued his experiments until a       

circuit of four miles was made1 and     
still the electricity seemed to traverse
 the course instantaneously1 and with   
apparently undiminished force1 if the   
insulation was perfect4   ,,benjamin    
,,franklin  ,watson's writings now      
carried the field of active discovery   
across the ,atlantic1 and for the first 
time an ,american scientist appeared--a 
scientist who not only rivalled1 but    
excelled1 his ,european contemporaries4 
,benjamin ,franklin1 of ,philadelphia1  
coming into possession of some of       
,watson's books1 became so interested in
 the experiments described in them that 
he began at once experimenting with     
electricity4 ,in ,watson's book were    
given directions for making various     
experiments1 and these assisted         
,franklin in repeating the old          
experiments1 and eventually adding new  
ones4 ,associated with ,franklin1 and   
equally interested and enthusiastic1 if 
not equally successful in making        
discoveries1 were three other men1      

,thomas ,hopkinson1 ,philip ,sing1 and  
,ebenezer ,kinnersley4 ,these men worked
 together constantly1 although it       
appears to have been ,franklin who made 
independently the important discoveries1
 and formulated the famous ,franklinian 
theory4  ,working steadily1 and keeping 
constantly in touch with the progress of
 the ,european investigators1 ,franklin 
soon made some experiments which he     
thought demonstrated some hitherto      
unknown phases of electrical            
manifestation4 ,this was the effect of  
pointed bodies in ,,drawing ,,off and   
,,throwing ,,off the electrical fire4   
,in his description of this phenomenon1 
,franklin writes3  ,place an iron shot  
of three or four inches diameter on the 
mouth of a clean1 dry1 glass bottle4 ,by
 a fine silken thread from the ceiling  
right over the mouth of the bottle1     
suspend a small cork ball1 about the    
bigness of a marble2 the thread of such 
a length that the cork ball may rest    
against the side of the shot4 ,electrify

 the shot1 and the ball will be repelled
 to the distance of four or five inches1
 more or less1 according to the quantity
 of electricity4 ,when in this state1 if
 you present to the shot the point of a 
long1 slender shaft-bodkin1 at six or   
eight inches distance1 the repellency is
 instantly destroyed1 and the cork flies
 to the shot4 ,a blunt body must be     
brought within an inch1 and draw a      
spark1 to produce the same effect4  ,to 
prove that the electrical fire is       
,,drawn ,,off by the point1 if you take 
the blade of the bodkin out of the      
wooden handle and fix it in a stick of  
sealing-wax1 and then present it at the 
distance aforesaid1 or if you bring it  
very near1 no such effect follows2 but  
sliding one finger along the wax till   
you touch the blade1 and the ball flies 
to the shot immediately4 ,if you present
 the point in the dark you will see1    
sometimes at a foot distance1 and more1 
a light gather upon it like that of a   
fire-fly or glow-worm2 the less sharp   

the point1 the nearer you must bring it 
to observe the light2 and at whatever   
distance you see the light1 you may draw
 off the electrical fire and destroy the
 repellency4 ,if a cork ball so         
suspended be repelled by the tube1 and a
 point be presented quick to it1 though 
at a considerable distance1 'tis        
surprising to see how suddenly it flies 
back to the tube4 ,points of wood will  
do as well as those of iron1 provided   
the wood is not dry2 for perfectly dry  
wood will no more conduct electricity   
than sealing-wax4  ,to show that points 
will ,,throw ,,off as well as ,,draw    
,,off the electrical fire1 lay a long1  
sharp needle upon the shot1 and you     
cannot electrify the shot so as to make 
it repel the cork ball4 ,or fix a needle
 to the end of a suspended gun-barrel or
 iron rod1 so as to point beyond it like
 a little bayonet1 and while it remains 
there1 the gun-barrel or rod cannot1 by 
applying the tube to the other end1 be  
electrified so as to give a spark1 the  

fire continually running out silently at
 the point4 ,in the dark you may see it 
make the same appearance as it does in  
the case before mentioned47#c7  ,von    
,guericke1 ,hauksbee1 and ,gray had     
noticed that pointed bodies attracted   
electricity in a peculiar manner1 but   
this demonstration of the drawing off of
 electrical fire was original with      
,franklin4 ,original also was the theory
 that he now suggested1 which had at    
least the merit of being thinkable even 
by non-philosophical minds4 ,it assumes 
that electricity is like a fluid1 that  
will flow along conductors and          
accumulate in proper receptacles1 very  
much as ordinary fluids do4 ,this       
conception is probably entirely         
incorrect1 but nevertheless it is likely
 to remain a popular one1 at least      
outside of scientific circles1 or until 
something equally tangible is           
substituted4   ,,franklin',s ,,theory   
,,of ,,electricity  ,according to       
,franklin's theory1 electricity exists  

in all bodies as a common stock1 and    
tends to seek and remain in a state of  
equilibrium1 just as fluids naturally   
tend to seek a level4 ,but it may1      
nevertheless1 be raised or lowered1 and 
this equilibrium be thus disturbed4 ,if 
a body has more electricity than its    
normal amount it is said to be          
,,positively electrified2 but if it has 
less1 it is ,,negatively electrified4   
,an over-electrified or plus body tends 
to give its surplus stock to a body     
containing the normal amount2 while the 
minus or under-electrified body will    
draw electricity from one containing the
 normal amount4  ,working along lines   
suggested by this theory1 ,franklin     
attempted to show that electricity is   
not created by friction1 but simply     
collected from its diversified state1   
the rubbed glass globe attracting a     
certain quantity of electrical fire1 but
 ever ready to give it up to any body   
that has less4 ,he explained the charged
 ,leyden jar by showing that the inner  

coating of tin-foil received more than  
the ordinary quantity of electricity1   
and in consequence is ,,positively      
electrified1 while the outer coating1   
having the ordinary quantity of         
electricity diminished1 is electrified  
,,negatively4  ,these studies of the    
,leyden jar1 and the studies of pieces  
of glass coated with sheet metal1 led   
,franklin to invent his battery1        
constructed of eleven large glass plates
 coated with sheets of lead4 ,with this 
machine1 after overcoming some defects1 
he was able to produce electrical       
manifestations of great force--a force  
that knew no bounds1 as he declared     
7except in the matter of expense and of 
labor71 and which could be made to      
exceed the greatest know effects of     
common lightning4  ,this reference to   
lightning would seem to show ,franklin's
 belief1 even at that time1 that        
lightning is electricity4 ,many eminent 
observers1 such as ,hauksbee1 ,wall1    
,gray1 and ,nollet1 had noticed the     

resemblance between electric sparks and 
lightning1 but none of these had more   
than surmised that the two might be     
identical4 ,in #agdf1 the surgeon1 ,john
 ,freke1 also asserted his belief in    
this identity4 ,winkler1 shortly after  
this time1 expressed the same belief1   
and1 assuming that they were the same1  
declared that there is no proof that    
they are of different natures2 and still
 he did not prove that they were the    
same nature4   ,,franklin ,,invents     
,,the ,,lightning-,,rod  ,even before   
,franklin proved conclusively the nature
 of lightning1 his experiments in       
drawing off the electric charge with    
points led to some practical suggestions
 which resulted in the invention of the 
lightning-rod4 ,in the letter of ,july1 
#agej1 which he wrote on the subject1 he
 gave careful instructions as to the way
 in which these rods might be           
constructed4 ,in part ,franklin wrote3  
,may not the knowledge of this power of 
points be of use to mankind in          

preserving houses1 churches1 ships1     
etc41 from the stroke of lightning by   
directing us to fix on the highest parts
 of the edifices upright rods of iron   
made sharp as a needle1 and gilt to     
prevent rusting1 and from the foot of   
these rods a wire down the outside of   
the building into the grounds1 or down  
round one of the shrouds of a ship and  
down her side till it reaches the water8
 ,would not these pointed rods probably 
draw the electrical fire silently out of
 a cloud before it came nigh enough to  
strike1 and thereby secure us from that 
most sudden and terrible mischief8  ,to 
determine this question1 whether the    
clouds that contain the lightning are   
electrified or not1 ,i propose an       
experiment to be tried where it may be  
done conveniently4 ,on the top of some  
high tower or steeple1 place a kind of  
sentry-box1 big enough to contain a man 
and an electrical stand4 ,from the      
middle of the stand let an iron rod rise
 and pass1 bending out of the door1 and 

then upright twenty or thirty feet1     
pointed very sharp at the end4 ,if the  
electrical stand be kept clean and dry1 
a man standing on it when such clouds   
are passing low might be electrified and
 afford sparks1 the rod drawing fire to 
him from a cloud4 ,if any danger to the 
man be apprehended 7though ,i think     
there would be none71 let him stand on  
the floor of his box and now and then   
bring near to the rod the loop of a wire
 that has one end fastened to the leads1
 he holding it by a wax handle2 so the  
sparks1 if the rod is electrified1 will 
strike from the rod to the wire and not 
effect him47#d7  ,not satisfied with all
 the evidence that he had collected     
pointing to the identity of lightning   
and electricity1 he adds one more       
striking and very suggestive piece of   
evidence4 ,lightning was known sometimes
 to strike persons blind without killing
 them4 ,in experimenting on pigeons and 
pullets with his electrical machine1    
,franklin found that a fowl1 when not   

killed outright1 was sometimes rendered 
blind4 ,the report of these experiments 
were incorporated in this famous letter 
of the ,philadelphia philosopher4  ,the 
attitude of the ,royal ,society towards 
this clearly stated letter1 with its    
useful suggestions1 must always remain  
as a blot on the record of this usually 
very receptive and liberal-minded body4 
,far from publishing it or receiving it 
at all1 they derided the whole matter as
 too visionary for discussion by the    
society4 ,how was it possible that any  
great scientific discovery could be made
 by a self-educated colonial newspaper  
editor1 who knew nothing of ,european   
science except by hearsay1 when all the 
great scientific minds of ,europe had   
failed to make the discovery8 ,how      
indeed6 ,and yet it would seem that if  
any of the influential members of the   
learned society had taken the trouble to
 read over ,franklin's clearly stated   
letter1 they could hardly have failed to
 see that his suggestions were worthy of

 consideration4 ,but at all events1     
whether they did or did not matters     
little4 ,the fact remains that they     
refused to consider the paper seriously 
at the time2 and later on1 when its true
 value became known1 were obliged to    
acknowledge their error by a tardy      
report on the already well-known        
document4  ,but if ,english scientists  
were cold in their reception of         
,franklin's theory and suggestions1 the 
,french scientists were not4 ,buffon1   
perceiving at once the importance of    
some of ,franklin's experiments1 took   
steps to have the famous letter         
translated into ,french1 and soon not   
only the savants1 but members of the    
court and the king himself were         
intensely interested4 ,two scientists1  
,de ,lor and ,d',alibard1 undertook to  
test the truth of ,franklin's           
suggestions as to pointed rods drawing  
off lightning4 ,in a garden near ,paris1
 the latter erected a pointed iron rod  
fifty feet high and an inch in diameter4

 ,as no thunder-clouds appeared for     
several days1 a guard was stationed1    
armed with an insulated brass wire1 who 
was directed to test the iron rods with 
it in case a storm came on during       
,d',alibard's absence4 ,the storm did   
come on1 and the guard1 not waiting for 
his employer's arrival1 seized the wire 
and touched the rod4 ,instantly there   
was a report4 ,sparks flew and the guard
 received such a shock that he thought  
his time had come4 ,believing from his  
outcry that he was mortally hurt1 his   
friends rushed for a spiritual adviser1 
who came running through rain and hail  
to administer the last rites2 but when  
he found the guard still alive and      
uninjured1 he turned his visit to       
account by testing the rod himself      
several times1 and later writing a      
report of his experiments to ,m4        
d',alibard4 ,this scientist at once     
reported the affair to the ,french      
,academy1 remarking that ,franklin's    
idea was no longer a conjecture1 but a  

reality4   ,,franklin ,,proves ,,that   
,,lightning ,,is ,,electricity  ,europe1
 hitherto somewhat sceptical of         
,franklin's views1 was by this time     
convinced of the identity of lightning  
and electricity4 ,it was now ,franklin's
 turn to be sceptical4 ,to him the fact 
that a rod1 one hundred feet high1      
became electrified during a storm did   
not necessarily prove that the          
storm-clouds were electrified4 ,a rod of
 that length was not really projected   
into the cloud1 for even a very low     
thunder-cloud was more than a hundred   
feet above the ground4 ,irrefutable     
proof could only be had1 as he saw it1  
by extracting the lightning with        
something actually sent up into the     
storm-cloud2 and to accomplish this     
,franklin made his silk kite1 with which
 he finally demonstrated to his own and 
the world's satisfaction that his theory
 was correct4  ,taking his kite out into
 an open common on the approach of a    
thunder-storm1 he flew it well up into  

the threatening clouds1 and then1       
touching1 the suspended key with his    
knuckle1 received the electric spark2   
and a little later he charged a ,leyden 
jar from the electricity drawn from the 
clouds with his kite4  ,in a brief but  
direct letter1 he sent an account of his
 kite and his experiment to ,england3   
,make a small cross of two light strips 
of cedar1 he wrote1 the arms so long as 
to reach to the four corners of a large1
 thin1 silk handkerchief when extended2 
tie the corners of the handkerchief to  
the extremities of the cross so you have
 the body of a kite2 which being        
properly accommodated with a tail1 loop1
 and string1 will rise in the air like  
those made of paper2 but this being of  
silk is fitter to bear the wind and wet 
of a thunder-gust without tearing4 ,to  
the top of the upright stick of the     
cross is to be fixed a very             
sharp-pointed wire1 rising a foot or    
more above the wood4 ,to the end of the 
twine1 next the hand1 is to be tied a   

silk ribbon2 where the silk and twine   
join a key may be fastened4 ,this kite  
is to be raised when a thunder-gust     
appears to be coming on1 and the person 
who holds the string must stand within a
 door or window or under some cover1 so 
that the silk ribbon may not be wet2 and
 care must be taken that the twine does 
not touch the frame of the door or      
window4 ,as soon as any of the          
thunder-clouds come over the kite1 the  
pointed wire will draw the electric fire
 from them1 and the kite1 with all the  
twine1 will be electrified and the loose
 filaments will stand out everywhere and
 be attracted by the approaching finger1
 and when the rain has wet the kite and 
twine so that it can conduct the        
electric fire freely1 you will find it  
stream out plentifully from the key on  
the approach of your knuckle1 and with  
this key the phial may be charged2 and  
from electric fire thus obtained spirits
 may be kindled and all other electric  
experiments performed which are usually 

done by the help of a rubbed glass globe
 or tube1 and thereby the sameness of   
the electric matter with that of        
lightning completely demonstrated47#e7  
,in experimenting with lightning and    
,franklin's pointed rods in ,europe1    
several scientists received severe      
shocks1 in one case with a fatal result4
 ,professor ,richman1 of ,st4           
,petersburg1 while experimenting during 
a thunder-storm1 with an iron rod which 
he had erected on his house1 received a 
shock that killed him instantly4  ,about
 #agcc1 as we have seen1 ,dufay had     
demonstrated that there were two        
apparently different kinds of           
electricity2 one called ,,vitreous      
because produced by rubbing glass1 and  
the other ,,resinous because produced by
 rubbed resinous bodies4 ,dufay supposed
 that these two apparently different    
electricities could only be produced by 
their respective substances2 but twenty 
years later1 ,john ,canton 7#agae-aggb71
 an ,englishman1 demonstrated that under

 certain conditions both might be       
produced by rubbing the same substance4 
,canton's experiment1 made upon a glass 
tube with a roughened surface1 proved   
that if the surface of the tube were    
rubbed with oiled silk1 vitreous or     
positive electricity was produced1 but  
if rubbed with flannel1 resinous        
electricity was produced4 ,he discovered
 still further that both kinds could be 
excited on the same tube simultaneously 
with a single rubber4 ,to demonstrate   
this he used a tube1 one-half of which  
had a roughened the other a glazed      
surface4 ,with a single stroke of the   
rubber he was able to excite both kinds 
of electricity on this tube4 ,he found  
also that certain substances1 such as   
glass and amber1 were electrified       
positively when taken out of mercury1   
and this led to his important discovery 
that an amalgam of mercury and tin1 when
 used on the surface of the rubber1 was 
very effective in exciting glass4       
,,xv4 ,,natural ,,history ,,to ,,the    

,,time ,,of ,,linnaeus  ,modern         
systematic botany and zoology are       
usually held to have their beginnings   
with ,linnaeus4 ,but there were certain 
precursors of the famous ,swedish       
naturalist1 some of them antedating him 
by more than a century1 whose work must 
not be altogether ignored--such men as  
,konrad ,gesner 7#aeaf-aefe71 ,andreas  
,caesalpinus 7#aegi-afjc71 ,francisco   
,redi 7#afah-afgf71 ,giovanni ,alfonso  
,borelli 7#afjh-afgi71 ,john ,ray       
7#afbh-agje71 ,robert ,hooke            
7#afce-agjc71 ,john ,swammerdam         
7#afcg-afhj71 ,marcello ,malpighi       
7#afbh-afid71 ,nehemiah ,grew           
7#afbh-agaa71 ,joseph ,tournefort       
7#afef-agjh71 ,rudolf ,jacob ,camerarius
 7#affe-agba71 and ,stephen ,hales      
7#afgg-agfa74 ,the last named of these  
was1 to be sure1 a contemporary of      
,linnaeus himself1 but ,gesner and      
,caesalpinus belong1 it will be         
observed1 to so remote an epoch as that 
of ,copernicus4  ,reference has been    

made in an earlier chapter to the       
microscopic investigations of ,marcello 
,malpighi1 who1 as there related1 was   
the first observer who actually saw     
blood corpuscles pass through the       
capillaries4 ,another feat of this      
earliest of great microscopists was to  
dissect muscular tissue1 and thus become
 the father of microscopic anatomy4 ,but
 ,malpighi did not confine his          
observations to animal tissues4 ,he     
dissected plants as well1 and he is     
almost as fully entitled to be called   
the father of vegetable anatomy1 though 
here his honors are shared by the       
,englishman ,grew4 ,in #afha1 while     
,malpighi's work1 ,anatomia plantarum1  
was on its way to the ,royal ,society   
for publication1 ,grew's ,anatomy of    
,vegetables was in the hands of the     
publishers1 making its appearance a few 
months earlier than the work of the     
great ,italian4 ,grew's book was        
epoch-marking in pointing out the       
sex-differences in plants4  ,robert     

,hooke developed the microscope1 and    
took the first steps towards studying   
vegetable anatomy1 publishing in #affg1 
among other results1 the discovery of   
the cellular structure of cork4 ,hooke  
applied the name cell for the first time
 in this connection4 ,these discoveries 
of ,hooke1 ,malpighi1 and ,grew1 and the
 discovery of the circulation of the    
blood by ,william ,harvey shortly       
before1 had called attention to the     
similarity of animal and vegetable      
structures4 ,hales made a series of     
investigations upon animals to determine
 the force of the blood pressure2 and   
similarly he made numerous statical     
experiments to determine the pressure of
 the flow of sap in vegetables4 ,his    
,vegetable ,statics1 published in #agbg1
 was the first important work on the    
subject of vegetable physiology1 and for
 this reason ,hales has been called the 
father of this branch of science4  ,in  
botany1 as well as in zoology1 the      
classifications of ,linnaeus of course  

supplanted all preceding                
classifications1 for the obvious reason 
that they were much more satisfactory2  
but his work was a culmination of many  
similar and more or less satisfactory   
attempts of his predecessors4 ,about the
 year #afgj ,dr4 ,robert ,morison       
7#afbj-afhc71 of ,aberdeen1 published a 
classification of plants1 his system    
taking into account the woody or        
herbaceous structure1 as well as the    
flowers and fruit4 ,this classification 
was supplanted twelve years later by the
 classification of ,ray1 who arranged   
all known vegetables into thirty-three  
classes1 the basis of this              
classification being the fruit4 ,a few  
years later ,rivinus1 a professor of    
botany in the ,university of ,leipzig1  
made still another classification1      
determining the distinguishing character
 chiefly from the flower1 and           
,camerarius and ,tournefort also made   
elaborate classifications4 ,on the      
,continent ,tournefort's classification 

was the most popular until the time of  
,linnaeus1 his systematic arrangement   
including about eight thousand species  
of plants1 arranged chiefly according to
 the form of the corolla4  ,most of     
these early workers gave attention to   
both vegetable and animal kingdoms4     
,they were called naturalists1 and the  
field of their investigations was spoken
 of as natural history4 ,the            
specialization of knowledge had not     
reached that later stage in which       
botanist1 zoologist1 and physiologist   
felt their labors to be sharply divided4
 ,such a division was becoming more and 
more necessary as the field of knowledge
 extended2 but it did not become        
imperative until long after the time of 
,linnaeus4 ,that naturalist himself1 as 
we shall see1 was equally distinguished 
as botanist and as zoologist4 ,his great
 task of organizing knowledge was       
applied to the entire range of living   
things4  ,carolus ,linnaeus was born in 
the town of ,rashult1 in ,sweden1 on    

,may #ac1 #agjg4 ,as a child he showed  
great aptitude in learning botanical    
names1 and remembering facts about      
various plants as told him by his       
father4 ,his eagerness for knowledge did
 not extend to the ordinary primary     
studies1 however1 and1 aside from the   
single exception of the study of        
physiology1 he proved himself an        
indifferent pupil4 ,his backwardness was
 a sore trial to his father1 who was    
desirous that his son should enter the  
ministry2 but as the young ,linnaeus    
showed no liking for that calling1 and  
as he had acquitted himself well in his 
study of physiology1 his father at last 
decided to allow him to take up the     
study of medicine4 ,here at last was a  
field more to the liking of the boy1 who
 soon vied with the best of his         
fellow-students for first honors4       
,meanwhile he kept steadily at work in  
his study of natural history1 acquiring 
considerable knowledge of ornithology1  
entomology1 and botany1 and adding      

continually to his collection of        
botanical specimens4 ,in #agbi his      
botanical knowledge was brought to the  
attention of ,olaf ,rudbeck1 professor  
of botany in the ,university of ,upsala1
 by a short paper on the sexes of plants
 which ,linnaeus had prepared4 ,rudbeck 
was so impressed by some of the ideas   
expressed in this paper that he         
appointed the author as his assistant   
the following year4  ,this was the      
beginning of ,linnaes's career as a     
botanist4 ,the academic gardens were    
thus thrown open to him1 and he found   
time at his disposal for pursuing his   
studies between lecture hours and in the
 evenings4 ,it was at this time that he 
began the preparation of his work the   
,systema naturae1 the first of his great
 works1 containing a comprehensive      
sketch of the whole field of natural    
history4 ,when this work was published1 
the clearness of the views expressed and
 the systematic arrangement of the      
various classifications excited great   

astonishment and admiration1 and placed 
,linaeus at once in the foremost rank of
 naturalists4 ,this work was followed   
shortly by other publications1 mostly on
 botanical subjects1 in which1 among    
other things1 he worked out in detail   
his famous system4  ,this system is     
founded on the sexes of plants1 and is  
usually referred to as an artificial    
method of classification because it     
takes into account only a few marked    
characters of plants1 without uniting   
them by more general natural affinities4
 ,at the present time it is considered  
only as a stepping-stone to the natural 
system2 but at the time of its          
promulgation it was epoch-marking in its
 directness and simplicity1 and         
therefore superiority1 over any existing
 systems4  ,one of the great reforms    
effected by ,linnaeus was in the matter 
of scientific terminology4 ,technical   
terms are absolutely necessary to       
scientific progress1 and particularly so
 in botany1 where obscurity1 ambiguity1 

or prolixity in descriptions are fatally
 misleading4 ,linnaeus's work contains  
something like a thousand terms1 whose  
meanings and uses are carefully         
explained4 ,such an array seems at first
 glance arbitrary and unnecessary1 but  
the fact that it has remained in use for
 something like two centuries is        
indisputable evidence of its            
practicality4 ,the descriptive language 
of botany1 as employed by ,linnaeus1    
still stands as a model for all other   
subjects4  ,closely allied to botanical 
terminology is the subject of botanical 
nomenclature4 ,the old method of using a
 number of ,latin words to describe each
 different plant is obviously too       
cumbersome1 and several attempts had    
been made prior to the time of ,linnaeus
 to substitute simpler methods4         
,linnaeus himself made several          
unsatisfactory attempts before he       
finally hit upon his system of trivial  
names1 which was developed in his       
,species plantarum1 and which1 with     

some1 minor alterations1 remains in use 
to this day4 ,the essence of the system 
is the introduction of binomial         
nomenclature--that is to say1 the use of
 two names and no more to designate any 
single species of animal or plant4 ,the 
principle is quite the same as that     
according to which in modern society a  
man has two names1 let us say1 ,john    
,doe1 the one designating his family1   
the other being individual4 ,similarly  
each species of animal or plant1        
according to the ,linnaeean system1     
received a specific or trivial name2    
while various species1 associated       
according to their seeming natural      
affinities into groups called genera1   
were given the same generic name4 ,thus 
the generic name given all members of   
the cat tribe being ,felis1 the name    
,felis leo designates the lion2 ,felis  
pardus1 the leopard2 ,felis domestica1  
the house cat1 and so on4 ,this seems   
perfectly simple and natural now1 but to
 understand how great a reform the      

binomial nomenclature introduced we have
 but to consult the work of ,linnaeus's 
predecessors4 ,a single illustration    
will suffice4 ,there is1 for example1 a 
kind of grass1 in referring to which the
 naturalist anterior to ,linnaeus1 if he
 would be absolutely unambiguous1 was   
obliged to use the following descriptive
 formula3 ,gramen ,xerampelino1         
,miliacea1 praetenuis ramosaque sparsa  
panicula1 sive ,xerampelino congener1   
arvense1 aestivum2 gramen minutissimo   
semine4 ,linnaeus gave to this plant the
 name ,poa bulbosa--a name that         
sufficed1 according to the new system1  
to distinguish this from every other    
species of vegetable4 ,it does not      
require any special knowledge to        
appreciate the advantage of such a      
simplification4  ,while visiting ,paris 
in #agch ,linnaeus met and botanized    
with the two botanists whose natural    
method of classification was later to   
supplant his own artificial system4     
,these were ,bernard and ,antoine       

,laurent de ,jussieu4 ,the efforts of   
these two scientists were directed      
towards obtaining a system which should 
aim at clearness1 simplicity1 and       
precision1 and at the same time be      
governed by the natural affinities of   
plants4 ,the natural system1 as finally 
propounded by them1 is based on the     
number of cotyledons1 the structure of  
the seed1 and the insertion of the      
stamens4 ,succeeding writers on botany  
have made various modifications of this 
system1 but nevertheless it stands as   
the foundation-stone of modern botanical
 classification4     ,,appendix         
,,reference ,,list  ,,chapter ,i        
,,science ,,in ,,the ,,dark ,,age  7#a7 
7p4 #d74 ,james ,harvey ,robinson1 ,an  
,introduction to the ,history of        
,western ,europe1 ,new ,york1 #ahih1 p4 
#ccj4  7#b7 7p4 #f74 ,henry ,smith      
,williams1 ,a ,prefatory                
,characterization of ,the ,history of   
,italy1 in vol4 ,,ix4 of ,the           
,historians' ,history of the ,world1 #be

 vols41 ,london and ,new ,york1 #aijd4  
,,chapter ,,iii  ,,mediaeval ,,science  
,,in ,,the ,,west  7#a7 7p4 #dg74       
,etigene ,muntz1 ,leonardo do ,vinci1   
,artist1 ,thinker1 and ,man of ,science1
 #b vols41 ,new ,york1 #ahib4 ,vol4     
,,ii41 p4 #gc4   ,,chapter ,,iv  ,,the  
,,new ,,cosmology--,,copernicus ,,to    
,,kepler ,,and ,,galileo  7#a7 7p4 #fb74
 ,copernicus1 uber die ,kreisbewegungen 
der ,welfkorper1 trans4 from            
,dannemann's ,geschichle du             
,naturwissenschaften1 #b vols41         
,leipzig1 #ahif4  7#b7 7p4 #ij74        
,galileo1 ,dialogo dei due ,massimi     
,systemi del ,mondo1 trans4 from        
,dannemann1 op4 cit4  ,,chapter ,v      
,,galileo ,,and ,,the ,,new ,,physics   
7#a7 7p4 #aja74 ,rothmann1 ,history of  
,astronomy 7in the ,library of ,useful  
,knowledge71 ,london1 #ahcd4  7#b7 7p4  
#ajb74 ,william ,whewell1 ,history of   
the ,inductive ,sciences1 #c ,vols1     
,london1 #ahdg-,vol4 ,,ii41 p4 #dh4     
7#c7 7p4 #aaa74 ,the ,lives of ,eminent 

,persons1 by ,biot1 ,jardine1 ,bethune1 
etc41 ,london1 #ahcc4  7#d7 7p4 #aac74  
,william ,gilbert1 ,de ,magnete1        
translated by ,p4 ,fleury ,motteley1    
,london1 #ahic4 ,in the biographical    
memoir1 p4 xvi4  7#e7 7p4 #aad74        
,gilbert1 op4 cit41 p4 x#avii4  7#f7 7p4
 #aad74 ,gilbert1 op4 cit41 p4 #bd4     
,,chapter ,,vi  ,,two                   
,,pseudo-,,sciences--,,alchemy ,,and    
,,astrology  7#a7 7p4 #abe74 ,exodus    
xxxii1 #bj4  7#b7 7p4 #abf74 ,charles   
,mackay1 ,popular ,delusions1 #c vols41 
,london1 #ahej4 ,vol4 ,,ii41 p4 #bhj4   
7#c7 7p4 #adj74 ,mackay1 op4 cit41 ,vol4
 #aa41 p4 #bhi4  7#d7 7,p4 #ade74 ,john 
,b4 ,schmalz1 ,astrology ,vindicated1   
,new ,york1 #ahih4  7#e7 7p4 #adf74     
,william ,lilly1 ,the ,starry           
,messenger1 ,london1 #afde1 p4 #fc4     
7#f7 7p4 #adi74 ,lilly1 op4 cit41 p4    
#gj4  7#g7 7p4 #aeb74 ,george ,wharton1 
,an ,astrological judgement upon ,his   
,majesty's ,present ,march begun from   
,oxford1 ,may #g1 #afde1 pp4 #g-aj4     

7#h7 7p4 #aed74 ,c4 ,w4 ,roback1 ,the   
,mysteries of ,astrology1 ,boston1      
#ahed1 p4 #bi4   ,,chapter ,,vii  ,,from
 ,,paracelsus ,,to ,,harvey  7#a7 7p4   
#aei74 ,a4 ,e4 ,waite1 ,the ,hermetic   
and ,alchemical ,writings of            
,paracelsus1 #b vols41 ,london1 #ahid4  
,vol4 ,i41 p4 #ba4  7#b7 7p4 #afg74 ,e4 
,t4 ,withington1 ,medical ,history from 
the ,earliest ,times1 ,london1 #ahid1 p4
 #bgh4  7#c7 7p4 #agc74 ,john ,dalton1  
,doctrines of the ,circulation1         
,philadelphia1 #ahhd1 p4 #agi4  7#d7 7p4
 #agd74 ,william ,harvey1 ,de ,motu     
,cordis et ,sanguinis1 ,london1 #ahjc1  
chap4 ,x4  7#e7 7p4 #agh74 ,the ,works  
of ,william ,harvey1 translated by      
,robert ,willis1 ,london1 #ahdg1 p4 #ef4
   ,,chapter ,,viii  ,,medicine ,,in    
,,the ,,sixteenth ,,and ,,seventeenth   
,,centuries  7#a7 7p4 #ahi74 ,hermann   
,baas1 ,history of ,medicine1 translated
 by ,h4 ,e4 ,henderson1 ,new ,york1     
#ahid1 p4 #ejd4  7#b7 7p4 #ahi74 ,e4 ,t4
 ,withington1 ,medical ,history from the

 ,earliest ,times1 ,london1 #ahid1 p4   
#cbj4   ,,chapter ,,ix                  
,,philosopher-,,scientists ,,and ,,new  
,,institutions ,,of ,,learning  7#a7 7p4
 #aic74 ,george ,l4 ,craik1 ,bacon and  
,his ,writings and ,philosophy1 #b      
vols41 ,london1 #ahdf4 ,vol4 ,,ii41 p4  
#aba4  7#b7 7p4 #aic74 ,from ,huxley's  
address ,on ,descartes's ,discourse     
,touching the ,method of ,using ,one's  
,reason ,rightly and of ,seeking        
,scientific ,truth4  7#c7 7p4 #aie74    
,rene ,descartes1 ,traite de l',homme   
7,cousins's edition4 in ii vols471      
,paris1 #ahbd4 ,vol1 ,,vi41 p4 #cdg4    
,,chapter ,x  ,,the ,,successors ,,of   
,,galileo ,,in ,,physical ,,science     
7#a7 7p4 #bje74 ,see ,the ,phlogiston   
,theory1 ,vol1 ,,iv4  7#b7 7p4 #bje74   
,robert ,boyle1 ,philosophical ,works1  
#c vols41 ,london1 #agch4 ,vol4 ,,iii41 
p4 #da4  7#c7 7p4 #bjf74 ,ibid41 ,vol4  
,,iii41 p4 #dg4  7#d7 7p4 #bjf74 ,ibid41
 ,vol4 ,,ii41 p4 #ib4  7#e7 7p4 #bjg74  
,ibid41 ,vol4 ,,ii41 p4 #b4  7#f7 7p4   

#bji74 ,ibid41 ,vol4 ,i41 p4 #h4  7#g7  
7p4 #bji74 ,ibid41 vol4 ,,iii41 p4 #ejh4
  7#h7 7p4 #baj74 ,ibid41 ,vol4 ,,iii41 
p4 #cfa4  7#i7 7p4 #bac74 ,otto von     
,guericke1 in the ,philosophical        
,transactions of the ,royal ,society of 
,london1 ,no4 #hh1 for #afgb1 p4 #eajc4 
7#aj7 7p4 #bbb74 ,von ,guericke1 ,phil4 
,trans4 for #affi1 ,vol ,i41 pp4 #agc1  
#agd4  ,,chapter ,,xi  ,,newton ,,and   
,,the ,,composition ,,of ,,light  7#a7  
7p4 #bcc74 ,phil4 ,trans4 of ,royal     
,soc4 of ,london1 ,no4 #hj1 #afgb1 pp4  
#cjgf-cjgi4 7#b7 7p #bcd74 ,ibid41 pp4  
#cjhd1 #cjhe4  7#c7 7p4 #bce74          
,voltaire1 ,letters ,concerning the     
,english ,nation1 ,london1 #ahaa4       
,,chapter ,,xii  ,,newton ,,and ,,the   
,,law ,,of ,,gravitation  7#a7 7p4      
#bdb74 ,sir ,isaac ,newton1 ,principia1 
translated by ,andrew ,motte1 ,new      
,york1 #ahdh1 pp4 #cia1 #cib4  7#b7 7p4 
#bej74 ,newton op4 cit41 pp4 #ejf1 #ejg4
  ,,chapter ,,xiv  ,,progress ,,in      
,,electricity ,,from ,,gilbert ,,and    

,,von ,,guericke ,,to ,,franklin  7#a7  
7p4 #bgd74 ,a letter from ,m4 ,dufay1   
,f4,r4,s4 and of the ,royal ,academy of 
,sciences at ,paris1 etc41 in the ,phil4
 ,trans4 of the ,royal ,soc41 vol4      
,,xxxviii41 pp4 #beh-bfe4  7#b7 7p4     
#bhb74 ,dean von ,kleist1 in the        
,danzick ,memoirs1 ,vol4 ,i41 p4 #djg4  
,from ,joseph ,priestley's ,history of  
,electricity1 ,london1 #agge1 pp4 #hc1  
#hd4  7#c7 7p4 #bhh74 ,benjamin         
,franklin1 ,new ,experiments and        
,observations on ,electricity1 ,london1 
#agfj1 pp4 #ajg1 #ajh4  7#d7 7p4 #bia74 
,franklin1 op4 cit41 pp4 #fb1 #fc4  7#e7
 7p4 #bie74 ,franklin1 op4 cit41 pp4    
#ajg1 #ajh4  7,for notes and            
bibliography to vol4 ,,ii4 see vol4 ,v47