,,nature',s ,,miracles1 ,,vol4 ,,iii4   
,electricity                            
& ,magnetism                            
,,by                        ,,eli%a     
,,gray1 ,,ph4,d41 ,,ll4,d4              
,,william ,,briggs                      
#bi-cc ,ri*mond ,/4 ,we/1 ,toronto      
,c4 ,w4 ,,coates1 ,montreal1 ,que4      
,s4 ,f4 ,,hue/is1 ,halifax1 ,n4,s4      
,,cont5ts4     ,,*apt]                  
,,page            ,,introduction        
v        ,i4 ,,! ,,au?or',s ,,design    
#a       ,,ii4 ,,hi/ory ,,( ,,electrical
 ,,sci5ce                #f      ,,iii4 
,,hi/ory ,,( ,,magnetism                
#bj       ,,iv4 ,,!ory ,,& ,,nature ,,( 
,,magnetism              #be        ,v4 
,,!ory ,,( ,,electricity                
#ci       ,,vi4 ,,electrical ,,curr5ts  
#di      ,,vii4 ,,electric ,,g5]ators   
#fb     ,,viii4 ,,atmosph]ic            
,,electricity                     #gg   
,,ix4 ,,electrical ,,measurem5t         
#hc        ,x4 ,,! ,,electric           
,,telegraph                      #hh    

,,xi4 ,,receiv+ ,,messages              
#ajc      ,,xii4 ,,miscellane\s ,,me?ods
                      #ajh     ,,xiii4  
,,multiple ,,transmission               
#aad      ,,xiv4 ,,way ,,duplex ,,sy/em 
#abi       ,,xv4 ,,! ,,telephone        
#acd      ,,xvi4 ,,h[ ,,! ,,telephone   
,,talks                    #ade         
,,xvii4 ,,subm>9e ,,telegraphy          
#aed    ,,xviii4 ,,%ort-,,l9e           
,,telegraphs                      #aei  
,,xix4 ,,! ,,telautograph               
#afe       ,,xx4 ,,"s ,,curiosities     
#aga      ,,xxi4 ,,wireless ,,telegraphy
                        #agf     ,,xxii4
 ,,niag>a ,,falls ,,p[]--,,introduction 
#ahf    ,,xxiii4 ,,niag>a ,,falls       
,,p[]--,,appliances            #aij     
,,xxiv4 ,,niag>a ,,falls                
,,p[]--,,appliances            #aii     
,,xxv4 ,,electrical                     
,,products--,,c>borundum           #bji 
,,xxvi4 ,,electrical                    
,,products--,,blea*+-,,p[d]      #bah   
,,xxvii4 ,,electrical                   

,,products--,,alum9um              #bbc 
,,xxviii4 ,,electrical                  
,,products--,,calcium ,,c>bide          
#bbh     ,,xxix4 ,,! ,,new ,,era        
#bcd     ,,introduction4   ,= ! b5efit (
 ! read]s ( ,vol4 ,,iii1 :o h n read !  
g5]al ,introduction f\nd 9 ,vol4 ,i1 a  
^w z to ! scope & object ( ?is volume w 
n be amiss4  ,x w be pla9 to any "o on  
see+ ! size ( ! little book t x _c be an
 exhau/ive treatise on a subject s l>ge 
z t ( ,electricity4 ,?is volume1 l !    
o!rs1 is int5d$ = popul> read+1 &       
te*nical t]ms are avoid$ z f> z         
possible1 or :5 us$ cle>ly expla9$4 ,!  
subject is treat$ hi/orically1          
!oretically1 & practically4  ,z ! au?or 
has liv$ ?r\gh ! p]iod dur+ :i* ! sci5ce
 ( ,electricity has _h mo/ ( its gr[?1  
he naturally & necess>ily deals some:at 
9 rem9isc5ce4 ,all he hopes to d is to  
plant a few se$-?\ghts 9 ! m9ds ( 8     
read]s t w awak5 an int]e/ 9 ! /udy (   
natural sci5ce2 & especially 9 its mo/  
fasc9at+ bran*--,electricity4  ,if ,vol4

 ,i is at h&1 please read !             
,introduction4 ,x w br+ y into clos]    
sympa?y ) ! au?or & 8 mode ( treatm5t4  
,aga91 if ! read] is especially int]e/$ 
9 ! !ory ( ,electricity x w help him v  
mu* if he fir/ reads ,vols4 ,i & ,,ii1 z
 a prep>ation = a bett] und]/&+ ( ,vol4 
,,iii4 ,all ! natural sci5ces are s     
closely relat$ t x is difficult to get a
 cle> insight into any "o ( !m )\t at   
lea/ a g5]al idea ( all ! o!rs4         
,,nature',s ,,miracles4  ,,electricity  
,,& ,,magnetism4     ,,*apt] ,i4  ,,!   
,,au?or',s ,,design4   ,! writ] has sp5t
 mu* ( 8 "t = ?irty-five ye>s 9 ! /udy (
 electricity & 9 inv5t+ appliances =    
purposes ( transmitt+ intellig5ce       
electrically betwe5 di/ant po9ts1 & is  
p]haps m famili> ) ! ph5om5a (          
electricity ?an ) ^? ( any o!r bran* (  
physics2 yet he f9ds x /ill ! mo/       
difficult ( all ! natural sci5ces to    
expla94 ,to give any satisfactory !ory z
 to its place ) & relation to o!r =ms ( 
en]gy is a p]plex+ problem4  ,x is said 

t ,"l ,kelv9 lately made ! /atem5t t no 
advance _h be5 made 9 expla9+ ! real    
nature ( electricity = fifty ye>s4 ,:ile
 ?is /atem5t--if he really made x--is r 
broad1 x mu/ be ackn[l$g$ t all ! !ories
 s f> advanc$ are little bett] ?an      
guesses4 ,b !re is value 9 guess+1 = "o 
man's guess may lead to ano!r t is      
bett]1 &1 z x is r>ely ! case t ea* "o  
does n give u a little diff]5t view ( ! 
matt]1 x may be t out ( ! multiplicity (
 guesses !re may "s "t be a sugge/ion   
giv5 to "s inve/igator t w solve !      
problem1 or at lea/ c>ry ! !me f>!r back
 & e/abli% its true relation%ip to ! o!r
 =ms ( en]gy4 ,i _c b ?9k t !re is yet a
 simple /atem5t to be made ( ,en]gy 9   
its relation to ,matt] t w e/abli% a    
clos] relation%ip betwe5 ! diff]5t      
bran*es ( physical sci5ce4 ,& ?is1 mo/  
likely1 w be br\ght ab\t by a bett]     
und]/&+ ( ! nature ( ! int]/ell>        
sub/ance call$ ,e!r1 & its relation to  
all =ms & conditions ( s5sible matt] &  
en]gy4  ,9 ! talks t w foll[ x w be !   

endeavor ( ! writ] to give su* a simple 
& popul> exposition ( ! ph5om5a &       
applications ( electricity1 9 a g5]al   
way only1 t ! popul> read] may get1 at  
lea/1 an elem5t>y und]/&+ ( ! subject s 
f> z x is kn[n4 ,z we h said1 !         
descriptions w h to be elem5t>y1 = no?+ 
else c be done )\t su* elaborate        
te*nical draw+s & specifications z w\ld 
be impossible 9 our limit$ space1 & w\ld
 n be cle> to ! ord9>y read] :o kn[s    
no?+ ( ! sci5ce4  ,?\s&s :o are employ$ 
9 v>i\s ways ) ent]prises1 ! f\ndations 
( :i* are electrical1 "k no?+ (         
electricity z a sci5ce4 ,a fri5d ( m9e1 
:o is a pr(essor ( physics 9 "o ( our   
colleges1 0 travel+ a few ye>s ago1 & 9 
8 w&]+s he came across "s sort ( a      
factory :]e an electric motor 0 employ$4
 ,be+ on ! al]t = in=mation1 he /epp$ 9 
& introduc$ himself to ! eng9e]1 & began
 ask+ him que/ions ab\t ! electric motor
 ( :i* he _h *>ge4 ,! pr(essor c\ld talk
 ohm1 amp]es1 & volts smoo?ly1 & he fir$
 "s ( ^! electrote*nical names at !     

eng9e]4 ,! eng9e] look$ at him blankly &
 said3 ,y c't prove x by me4 ,i don't "k
 :at y're talk+ ab\t4 ,all ,i "k is to  
turn on ! juice & let h] buzz4 ,h[ mu*  
juice is wa/$ 9 ?is cut-&-dry _w ( ours 
& h[ mu* c\ld be sav$ if only all 7 ev5 
fairly intellig5t reg>d+ ! laws (       
nature6 ,a great deal ( ! bus9ess ( ?is 
_w is run on ! let h] buzz !ory1 & !    
public pays = ! wa/e4 ,x w cont9ue to be
 s until a high] ord] ( intellig5ce is m
 g5]ally diffus$ among ! p4 ,a f\nta9 c 
rise no high] ?an its s\rce4 ,a bus9ess 
w nev] exce$ ! intellig5ce t is put into
 x1 nor w a gov]nm5t ev] be great] ?an  
its p4  ,let u beg9 ! subject (         
electricity by go+ some:at into its pa/ 
hi/ory4 ,x is always well to "k ! hi/ory
 ( any subject we are /udy+1 = we (t5   
pr(it z mu* by ! mi/akes ( o!rs z by _! 
successes4 ,i %all also give ! !ories   
advanc$ by diff]5t inve/igators1 & if ,i
 %\ld h any ?\ghts ( my own on ! subject
 ,i %all be free to give !m1 = ,i h j z 
good a "r to make a guess z any "o4 ,x  

mu/ be confess$1 h[ev]1 t ! old] ,i gr[ 
! less ,i feel t ,i "k ab\t ! subject ( 
electricity1 or any?+ else1 9 comp>ison 
) :at ,i see !re is yet to be kn[n4 ,i  
once met a "y man :o _h j graduat$ f    
college1 & 9 8 conv]sation he /at$ t he 
_h tak5 a c\rse 9 electricity4 ,i ask$  
him h[ long he _h /udi$ ! subject4 ,he  
said ?ree mon?s4 ,i ask$ him if he      
und]/ood x--& he said t he did4 ,i told 
him t he 0 ! man t ! _w 0 look+ =2 t ,i 
_h /udi$ x = ?irty ye>s & did n und]/& x
 yet4  ,a little le>n+ is a dang]\s     
?+--= x puffs u up1 & we feel t we "k x 
all & h ! _w 9 our grasp2 b aft] we h   
tri$ our little le>n+ on ! _w = a :ile &
 h receiv$ ! _m h>d knocks t are sure to
 come1 we are soon] or lat] br\ght up 9 
front ( ! mirror ( exp]i5ce1 & we see   
ourselves z o!rs see u1 & are n satisfi$
 ) ! view4  ,:atev] ! !ories may be     
reg>d+ electricity1 & h[ev]             
unsatisfactory !y may be1 !re are c]ta9 
well-def9$ facts & ph5om5a t are ( !    
greate/ importance to ! _w4 ,^! we may  

und]/&3 & to ?is end let u especially   
direct our ef=ts4     ,,*apt] ,,ii4     
,,hi/ory ,,( ,,electrical ,,sci5ce4     
,electricity z a well-develop$ sci5ce is
 n old4 ,^? ( u :o h liv$ fifty ye>s h  
se5 ne>ly all its developm5t s f> z x   
has be5 appli$ to useful purposes1 & ^? 
:o h liv$ ov] tw5ty-five ye>s h se5 !   
major portion ( its developm5t4  ,?ales 
( ,miletus1 #fjj ,b4,c41 discov]$1 or at
 lea/ describ$1 ! prop]ties ( amb] :5   
rubb$1 %[+ t x _h ! p[] to attract &    
repel light sub/ances1 su* z /raws1 dry 
leaves1 etc4 ,& f ! ,greek ^w =         
amb]--elektron--came ! "n electricity1  
d5ot+ ?is peculi> prop]ty4 ,!ophra/us & 
,pl9y made ! same obs]vations2 ! =m]    
ab\t #cba ,b4,c41 & ! latt] ab\t #gj    
,a4,d4 ,x is also said t ! anci5ts _h   
obs]v$ ! effects ( animal electricity1  
su* z t ( ! fi% call$ ! torp$o4 ,pl9y & 
,ari/otle bo? speak ( its p[] to p>alyze
 ! feet ( m5 & animals1 & to fir/ b5umb 
! fi% :i* x !n prey$ ^u4 ,x is also     
record$ t a fre$-man ( ,tib]ius 0 cur$ (

 ! g\t by ! %ocks ( ! torp$o4 ,x is     
fur!r record$ t ,wolim]1 ! ,k+ ( !      
,go?s1 0 able to emit sp>ks f 8 body4   
,com+ d[n to m mod]n times--,a4,d4      
#afjj--we f9d ,dr4 ,gilb]t1 an          
,engli%man1 tak+ up ! inve/igation ( !  
electrical prop]ties ( v>i\s sub/ances  
:5 submitt$ to friction1 & =mulat+ !m 9 
! ord] ( _! importance4 ,9 ^! exp]im5ts 
we h ! beg9n+s ( :at has s9ce develop$  
into a great sci5ce4 ,he made ! discov]y
 t :5 ! air 0 dry he c\ld soon electrify
 ! sub/ances rubb$1 b :5 x 0 damp x took
 mu* long] & sometimes he fail$         
altoge!r4 ,9 #agje ,francis ,hawksbee1  
an exp]im5tal philosoph]1 discov]$ t    
m]cury c\ld be r5d]$ lum9\s by agitat+ x
 9 an exhau/$ receiv]4 7,x is a "q :e!r 
?is ph5om5on %\ld n be class$ ) t (     
phosphoresc5ce r ?an electricity47 ,!   
numb] ( inve/igators 0 s great t all (  
!m _c be m5tion$4 ,x (t5 happ5s t ^? :o 
d really mo/ = a sci5ce are nev] kn[n to
 fame4 ,a numb] ( p w make small        
contributions till ! /ructure has by    

degrees assum$ l>ge proportions1 :5     
f9ally "s "o comes along & puts a gild$ 
dome on x & ! :ole /ructure takes 8 "n4 
,?is is em95tly true ( _m ( ! m         
important developm5ts 9 ! sci5ce &      
applications ( electricity dur+ ! la/   
tw5ty-five or ?irty ye>s4  ,foll[+      
,hawksbee may be m5tion$ ,/eph5 ,gray1  
,sir ,isaac ,newton1 ,dr4 ,wall1 ,m4    
,dupay & o!rs4 ,dupay discov]$ ! two    
conditions ( electrical excitation kn[n 
n[ z positive & negative conditions4 ,9 
#agde ! ,leyd5 j> 0 inv5t$4 ,x takes its
 "n f ! city ( ,leyd51 :]e its use 0    
fir/ discov]$4 ,x is a glass j>1 coat$  
inside & out ) t9-foil4 ,! inside coat+ 
is connect$ ) a brass knob at ! top1    
?r\gh :i* x c be *>g$ ) electricity4 ,! 
inn] & out] coat+s mu/ n be cont9u\s b  
insulat$ f ea* o!r4 ,! au?or's "n is n  
kn[n1 b x is said t ?ree diff]5t p]sons 
inv5t$ x indep5d5tly1 to wit1 a monk by 
! "n ( ,klei/1 a man by ! "n ( ,cuneus1 
& ,pr(essor ,mus*5broeck ( ,leyd54 ,?is 
0 an important inv5tion1 z x 0 ! =]unn] 

( our own ,frankl9's discov]ies & a     
necess>y "p ( 8 outfit ) :i* he e/abli%$
 ! id5tity ( lightn+ & electricity4 ,e  
,am]ican s*oolboy has he>d1 f ,f\r? (   
,july orations1 h[ ,frankl9 caught ! =k$
 lightn+ f ! cl\ds & tam$ x & made x    
subs]vi5t to ! w ( man4 ,h[ my boyi% s\l
 us$ to be /irr$ to its dep?s by ?is    
oratorical display ( electrical         
fireworks6  ,frankl9 _h long ent]ta9$ ! 
idea t ! lightn+ ( ! cl\ds 0 id5tical ) 
:at is call$ frictional electricity1 &  
he wait$ long = a *ur* spire to be      
erect$ 9 8 adopt$ home1 ! ,quak] ,city1 
9 ord] t he might make ! te/ & settle ! 
"q4 ,b ! ,quak]s did n believe 9 spires1
 & ,frankl9's pati5ce _h a limit4       
,frankl9 _h ! !ory t mo/ inve/igators _h
 at t "t1 t electricity 0 a fluid & t   
c]ta9 sub/ances _h ! p[] to hold x4 ,!re
 7 two !ories preval5t 9 ^? days--bo?   
fluid !ories4 ,"o !ory 0 t !re 7 two    
fluids1 a positive & a negative4        
,frankl9 held to ! !ory ( a s+le fluid1 
& t ! ph5om5on ( electricity 0 pres5t   

only :5 ! balance or natural am\nt (    
electricity 0 di/urb$4 ,accord+ to ?is  
!ory1 a body *>g$ ) positive electricity
 _h an excessive am\nt1 &1 ( c\rse1 "s  
o!r body some:]e else _h less ?an nature
 _h allott$ to x2 h5ce x 0 *>g$ )       
negative electricity4 ,a ,leyd5 j>1 =   
in/ance1 hav+ "o ( its coat+s 7say !    
inside7 *>g$ ) positive or  electricity1
 ! o!r coat+ w be *>g$ ) negative or -  
electricity4 ,! =m] 0 only a "n = an    
am\nt above normal & ! latt] a "n = a   
%ortage or lack ( ! normal am\nt4  ,z we
 h said1 ,frankl9 believ$ 9 ! id5tity ( 
lightn+ & electricity1 & he wait$ long =
 an opportunity to demon/rate 8 !ory4   
,he _h ! ,leyd5 j>1 & n[ all he ne$$ 0  
to e/abli% "s suitable connection betwe5
 a ?und]-cl\d & ! e>?4  ,previ\s to     
#agej ,frankl9 _h writt5 a pap] 9 :i* he
 %[$ ! lik5ess betwe5 ! lightn+ sp>k & t
 ( frictional electricity4 ,he %[$ t bo?
 sp>ks move 9 crook$ l9es--z we see x 9 
a /orm-cl\d1 t bo? /rike ! highe/ or    
ne>e/ po9ts1 t bo? inflame combu/ibles1 

fuse metals1 r5d] ne$les magnetic &     
de/roy animal life4 ,all ?is did n      
def9itely e/abli% _! id5tity 9 ! m9d (  
,frankl91 & he wait$ long = an          
opportunity1 & f9ally1 f9d+ t no "o     
pres5t$ itself1 he did :at _m m5 h _h to
 d 9 o!r matt]s2 he made "o4  ,9 ! mon? 
( ,june1 #ageb1 tir$ ( wait+ = a /eeple 
to be erect$1 ,frankl9 devis$ a plan t 0
 mu* bett] & probably sav$ ! exp]im5t f 
failure2 = ! /eeple w\ld probably n h   
be5 high en\gh4 ,he con/ruct$ a kite by 
mak+ a cross ( light c$> rods1 fa/5+ !  
f\r ends to ! f\r corn]s ( a l>ge silk  
h&k]*ief4 ,he fix$ a loop to tie ! kite 
/r+ to & balanc$ x ) a tail1 z boys d   
n[adays4 ,he fix$ a po9t$ wire to ! upp]
 end ( "o ( ! cross /icks = a           
lightn+-rod1 & !n wait$ = a ?und]-/orm4 
,:5 x came1 ) ! help ( 8 boy1 he s5t up 
! kite4 ,he ti$ a loop ( silk ribbon on 
! end ( ! /r+ next 8 h&--z silk 0 kn[n  
to be an insulator or non-conductor--&  
hav+ ti$ a key to ! /r+ he wait$ !      
result1 /&+ )9 a door to prev5t ! silk  

loop f gett+ wet & ?us de/roy+ its      
insulat+ qualities4 ,! cl\d _h ne>ly    
pass$ & he fe>$ 8 long wait$ = exp]im5t 
_h fail$1 :5 he notic$ ! loose fib]s ( !
 /r+ /&+ out 9 e direction1 & saw t !y 7
 attract$ by ! approa* ( 8 f+]4 ,! ra9  
n[ wet ! /r+ & made a bett] conductor ( 
x4 ,soon he c\ld draw sp>ks ) 8 knuckle 
f ! key4 ,he *>g$ a ,leyd5 j> ) ?is     
electrical curr5t f ! ?und]-cl\d1 &     
p]=m$ all ! exp]im5ts ) x t he _h done )
 ord9>y electricity1 ?us e/abli%+ !     
id5tity ( ! two & confirm+ beyond a d\bt
 :at he _h long be=e believ$ 0 true4 ,9 
aft] exp]im5ts ,frankl9 f\nd t sometimes
 ! electricity ( ! cl\ds 0 positive & at
 o!r times negative4 ,f ?is exp]im5t    
,frankl9 conceiv$ ! idea ( erect+       
lightn+-rods to protect build+s1 :i* are
 us$ to ?is day4  ,! news spread all ov]
 ,europe1 n ?r\gh ! m$ium ( electricity1
 h[ev]1 b z soon z sail+ vessels &      
/age-coa*es c\ld c>ry x4 ,_m philosoph]s
 repeat$ ! exp]im5ts & at lea/ "o man   
sacrific$ 8 life ?r\gh 8 int]e/ 9 ! new 

discov]y4 ,9 #agec ,pr(essor ,ri*man (  
,/4 ,pet]sburg erect$ on 8 h\se a metal 
rod :i* t]m9at$ 9 a ,leyd5 j> 9 "o ( !  
rooms4 ,on ! #ca/ ( ,may he 0 att5d+ a  
meet+ ( ! ,academy ( ,sci5ces4 ,he he>d 
a roll ( ?und] & hurri$ home to wat* 8  
app>atus4 ,he & "o ( ! assi/ants 7 wat*+
 ! app>atus :5 a /roke ( lightn+ came   
d[n ! rod & leap$ to ! pr(essor's head4 
,he 0 /&+ too ne> x & 0 in/antly kill$4 
,pass+ ov] _m names ( m5 :o foll[$ 9 !  
wake ( ,frankl9 we come to ! next       
era-mak+ discov]y1 namely1 t ( galvanic 
electricity4 ,9 ! ye> #agij an incid5t  
occurr$ 9 ! h\sehold ( "o ,luigi        
,galvani1 an ,italian physician &       
anatomi/1 t l$ to a new & important     
bran* ( electrical sci5ce4 ,galvani's   
wife 0 prep>+ "s frogs = s\p1 & hav+    
sk9n$ !m plac$ !m on a table ne> a newly
 *>g$ electric ma*9e4 ,a scalpel 0 on ! 
table & _h be5 9 contact ) ! ma*9e4 ,%e 
accid5tally t\*$ "o ( ! frogs to ! po9t 
( ! scalpel1 :51 lo6 ! frog kick$1 & !  
kick ( t dead frog *ang$ ! :ole face (  

electrical sci5ce4 ,%e call$ h] husb& & 
he repeat$ ! exp]im5t1 & also           
appropriat$ ! discov]y z well1 & he has 
_h ! cr$it ( x ev] s9ce1 :5 really 8    
wife made ! discov]y4 ,galvani suppos$ x
 to be animal electricity & clung to t  
!ory ! re/ ( 8 life1 mak+ _m exp]im5ts &
 publi%+ _! results2 b ! discov]y l$    
o!rs to solve ! problem4  ,aless&ro     
,volta1 a pr(essor ( natural philosophy 
at ,pavia1 ,italy1 01 x mu/ be said1 !  
f\nd] ( ! sci5ce ( galvanic or voltaic  
electricity4 ,/imulat$ by ! discov]y (  
,galvani he attribut$ ! action ( !      
frog's muscles1 n to animal electricity1
 b to "s *emical action betwe5 ! metals 
t t\*$ x4 ,to prove 8 !ory1 he con/ruct$
 a pile made ( alt]nate lay]s ( z9c1    
copp]1 & a clo? or pa/ebo>d saturat$ 9  
"s sal9e solution4 ,by repeat+ ^!       
trios--copp]1 z9c1 & ! saturat$ clo?--he
 atta9$ a pile t w\ld give a p[]ful     
%ock4 ,x is call$ ! ,voltaic ,pile4  ,i 
h a cle> idea ( ! con/ruction ( ?is =m (
 pile1 f\nd$ on exp]i5ce4 ,x 0 my habit 

:5 a boy to make ev]y?+ t ,i f\nd       
describ$1 if x 7 possible4 ,! bottom (  
my "m's wa%-boil] 0 copp]1 & j ! ?+ to  
make ! squ>e plates ( copp] to mat* !   
z9c ones1 made f ano!r piece ( dome/ic  
furniture us$ "u ! /ove4 ,i %ock$ my "m 
twice--fir/ ) ! voltaic pile t ,i _h    
con/ruct$1 & aga9 :5 %e f\nd out :]e !  
metal plates came f4 ,! sequel to all   
?is 0--b :y dwell ^u a pa9ful subject6  
,galvanism & voltaic electricity are !  
same4 ,volta 0 ! fir/ to con/ruct :at is
 t]m$ ! galvanic batt]y4 ,! unit (      
electrical pressure or electromotive =ce
 is call$ ! volt1 & takes its "n f      
,volta1 ! great f\nd] ( ! sci5ce (      
galvanic or voltaic electricity4 ,f ?is 
pile con/ruct$ by ,volta innum]able =ms 
( batt]ies h be5 devis$4 ,! evolution ( 
! galvanic batt]y 9 all its =ms1 f      
,volta to ! pres5t day1 w\ld fill a l>ge
 volume if all 7 describ$4  ,!          
discov]ies ( ,mi*ael ,f>aday            
7#agia-ahfg71 ! di/+ui%$ ,engli% *emi/ &
 physici/1 l$ to ano!r phase ( ! sci5ce 

t has revolutioniz$ mod]n life4 ,f>aday 
made an exp]im5t t conta9s ! g]m ( all  
=ms ( ! mod]n dynamo1 :i* is a ma*9e (  
comp>atively rec5t developm5t4 ,he f\nd 
t by w9d+ a piece ( insulat$ wire ar\nd 
a piece ( s(t iron & br++ ! two ends 7( 
! wire7 v close toge!r1 & !n plac+ !    
iron across ! poles ( a p]man5t magnet &
 sudd5ly j]k+ x away1 a sp>k w\ld pass  
betwe5 ! two ends ( ! wire t 0 w\nd     
ar\nd ! piece ( s(t iron4 ,"h 0 an      
incipi5t dynamo-electric ma*9e--! g]m ( 
t :i* plays su* an important "p 9 our   
mod]n civilization4  ,hav+ br\ght our   
hi/ory d[n to ! pres5t day1 x w\ld seem 
sc>cely necess>y to recite t :i*        
ev]ybody kn[s4 ,x is well1 h[ev]1 to    
call a halt once 9 a :ile & comp>e our  
pres5t conditions ( civilization ) ^? ( 
! pa/4 ,our _w is fill$ ) croak]s :o are
 always sigh+ = ! good old days4 ,b we c
 easily imag9e t if !y c\ld g back to ^?
 days _! croak+ w\ld be /ill l\d] ?an x 
is4  ,be=e ! adv5t ( electricity _m ?+s 
7 impossible t are easy n[4 ,9 ! old    

days ! _w 0 v1 v l>ge2 n[1 ?anks to     
electricity1 x is knock+ at ! door ( e  
man's h\se4 ,! lumb]+ /age-coa* t 0     
=m]ly our limit$ express--limit$ to     
?irty or =ty miles a day--has be5       
supplant$ by "o t cov]s #ajjj miles 9 ! 
same "t1 & ?is high rate ( spe$ is made 
possible only by ! use ( ! electric     
telegraph4  ,9 ! old days all ,europe   
c\ld be involv$ 9 a great w> & ! news ( 
x w\ld be weeks 9 rea*+ our %ores1 b n[ 
! fir+ ( ! fir/ gun is he>d at e        
fireside ! _w ov]1 almo/ be=e ! smoke   
has cle>$ away4 ,our planet is ?read$ ) 
iron n]ves t run ov] m\nta9s & "u seas1 
^: trembl+ atoms1 ?rill$ ) ! electric   
fire1 speak to u daily & h\rly ( ! great
 ?robb+ life ( ! :ole civiliz$ _w4      
,electricity has giv5 u a voice t c be  
he>d a ?\s& miles1 & n only he>d1 b     
recogniz$4 ,x has giv5 u a p5 t w write 
our autograph 9 ,new ,york1 al?\gh we   
are /ill 9 ,*icago4 ,x has giv5 u ! be/ 
light1 bo? f an optical & a sanit>y     
/&po9t1 t ! _w has ev] se54 ,!          

old-fa%ion$1 jogg+ horse-c> has be5     
supplant$ by ! electric trolley1 & we no
 long] h our feel+s h>r[$ ) pity = !    
poor old /e$s t pull$ ^? lumb]+ coa*es  
?r\gh ! /reets1 ) m5 & wom5 cr[d$ 9 &   
hang+ on to /raps1 :ile ev]ybody trod on
 e o!r body's toes4    ,9 old5 times we 
took a c>   ,drawn by a horse1 if go+   
f>1     ,& felt t we 7 ble/2   ,n[ !    
conductor takes ! f>e   ,& puts a       
broom/ick 9 ! air--     ,& lightn+ does 
! re/4    ,9 o!r days1 along ! /reet1   
,a glimm]+ lant]n l$ ! feet1     ,:5 on 
a midnight /roll2   ,b n[ we cat*1 :5   
night is nigh1   ,a piece ( lightn+ f ! 
sky     ,& /ick x on a pole4    ,"t 0 :5
 "o mu/ hold 8 e>   ,close to a :isp]+  
voice to he>1     ,l deaf m5--nigh &    
nigh]2   ,b n[ f t[n to t[n he talks    
,& puts 8 nose into a box     ,& :isp]s 
?r\gh a wire4  ,s jogs ! old _w along4  
,we sometimes ?9k x is sl[1 b :5 we look
 back a few ye>s & see :at has be5      
accompli%$ x seems to h _h a m>vel\sly  
rapid developm5t4  ,some?+ l fifty ye>s 

ago a pr(essor ( physics 9 "o ( our     
colleges 0 giv+ 8 class a c\rse 9       
electricity4 ,! electric telegraph 0 too
 little kn[n at t "t to cut mu* ( a     
figure 9 ! classroom1 s ! /ock exp]im5ts
 7 ^? made ) ! frictional electric ma*9e
 & ! ,leyd5 j>4 ,"o day ! pr(essor _h1 9
 "o h\r's "t1 tak5 8 class ?r\gh a c\rse
 ( electricity1 & at ! end he said3     
,g5tlem51 y 7 born too late to witness !
 developm5t ( ?is great sci5ce4 ,i (t5  
wond] if ! good pr(essor is ev] all[$ to
 "p ! veil t sep>ates u f ! great beyond
 & to look d[n ^u ?is busy _w ( ours 9  
:i* electricity plays su* an important  
"p 9 our e-day life2 & if s1 :at he ?9ks
 ( t little spee* he made to ! boys     
fifty ye>s or m ago4  ,if we make an    
analysis ( ! hi/ory ( ! sci5ce (        
electricity we %all see t x has         
progress$ 9 successive eras1 %ort5+ z !y
 approa* our "t4 ,= a p]iod ( #bcjj     
ye>s1 f ,?ales to ,frankl91 b little or 
no progress 0 made beyond ! fur!r       
developm5t ( ! ph5om5a ( frictional     

electricity--! mo/ important inv5tion   
be+ t ( ! ,leyd5 j>4 ,f ,frankl9 to     
,volta 0 =ty-eight ye>s1 & f ,volta to  
,f>aday ab\t ?irty-two ye>s4 ,f ?is "t  
on ! developm5t 0 v rapid z comp>$ ) !  
old days4 ,soon aft] ,f>aday1 ,morse1   
,h5ry1 ,:eat/one1 & o!rs began exp]im5ts
 t h gr[n1 dur+ fifty or sixty ye>s1    
into a mo/ colossal sy/em ( electric    
telegraphs1 telephones1 electric lights 
& electric railroads4 ,9 ! latt] days   
m>vel has succe$$ m>vel ) su* rapid     
/rides t ! ink is sc>cely dry f !       
description ( "o be=e ano!r cr[ds itself
 ^u our att5tion4 ,:]e x w all end no "o
 kn[s1 b t x has end$ no "o believes4 ,!
 human m9d has become s accu/om$ to ^!  
p]iodic revelations ( ! m>vel\s t x mu/ 
h ! /imulus once 9 a :ile or x suff]s z 
! top] does :5 depriv$ ( 8 cups4 ,!     
comm]cial in/9ct ( ! news-v5d] is n sl[ 
to see ! situation1 & if ! developm5t is
 too sl[ to suit ! public dem& 8 f]tile 
bra9 supplies ! lack4 ,s t e few days we
 he> ( "s great discov]y made by "s "o x

 may be unkn[n to fame4 ,x has s]v$ its 
purpose4 ,! public m9d has _h its m5tal 
toddy & has be5 sav$ f a fit (          
intellectual delirium trem5s t x 0 9    
dang] ( f lack ( its accu/om$ /imulus4  
,hav+ giv5 y a v limit$ outl9e ( !      
hi/ory ( electricity1 f anci5t times d[n
 to ! pres5t1 we w endeavor n[ to give y
 an elem5t>y notion ( ! sci5ce z x /&s  
to-day4 ,to ! common m9d ! sci5ce is a  
blank page4 ,s little is kn[n ( x by !  
ord9>y read]1 :o is fairly intellig5t 9 
o!r matt]s1 t to acc\nt = any?+ t we d n
 und]/& x is only necess>y to say t x is
 an electrical ph5om5on & he accepts x4 
,electricity is a synonym = all t we _c 
und]/&4 ,inasmu* z magnetism is s       
closely relat$ to electricity 9 its uses
 z relat$ to e-day life1 we w c>ry ! two
 subjects along toge!r1 z ! "o w to a   
l>ge ext5t help to expla9 ! o!r4 ,9 our 
next *apt] we w look at ! hi/ory (      
magnetism4     ,,*apt] ,,iii4  ,,hi/ory 
,,( ,,magnetism4   ,x is said t ! ^w    
magnetism is d]iv$ f ! "n ( a ,greek    

%eph]d1 call$ ,magnes1 :o once obs]v$ on
 ,m\nt ,ida ! attractive prop]ties (    
load/one :5 appli$ to 8 iron %eph]d's   
crook4 ,x is m likely t ! "n came f     
,magnesia1 a c\ntry 9 ,lydia1 :]e x 0   
fir/ discov]$4 ,x 0 also call$ ,lapis   
,h]acleus4 ,h]aclea 0 ! capital (       
,magnesia4 ,load/one is a magnetic ore  
or oxide ( iron f\nd 9 ! natural /ate1 &
 has at "s "t by natural processes be5  
r5d]$ magnetic--t is1 giv5 ! p[] (      
attract+ iron1 &1 :5 susp5d$1 ( po9t+ to
 ! ,nor? & ,s\? ,poles4 ,! p[] ( !      
natural magnet 0 kn[n at a v e>ly age 9 
! hi/ory ( man4 ,x 0 ref]r$ to by ,hom]1
 ,py?agoras1 & ,ari/otle4 ,pl9y also    
speaks ( x1 & ref]s to "o ,d9oc>es1 :o  
recomm5d$ to ,ptolemy ,philadelphus to  
build a temple at ,alex&ria & susp5d 9  
its vault a /atue ( ! que5 by !         
attractive p[] ( load/ones4 ,!re is also
 m5tion ( a /atue be+ susp5d$ 9 l mann] 
9 ! temple ( ,s]apis1 ,alex&ria4  ,x is 
claim$ t ! ,*9ese knew ( & us$ !        
magnetic ne$le 9 ! e>lie/ times & t     

travel]s by l& employ$ ?is ne$le susp5d$
 by a /r+ to guide !m 9 _! j\rneys      
across ! c\ntry a ?\s& ye>s be=e ,*ri/4 
,not)/&+ ! claims ( ! ,*9ese & ,arabians
 to ! discov]y ( ! use ( ! magnetic     
ne$le1 mod]n au?ors "q :e!r ! anci5ts 7 
famili> ) any artificial con/ruction ( a
 magnetic ne$le1 h[ev] mu* !y may h     
/udi$ & us$ ! load/ones4 ,no d\bt !     
load/one 9 its natural /ate 0 us$ by    
m>9]s to /e] _! %ips by1 long be=e its  
artificial c\nt]p>t 0 inv5t$4 ,9 a      
hi/ory ( ! discov]y ( ,icel&1 by ,are   
,frode1 :o 0 born 9 #ajfh1 x is /at$ t a
 m>9] by "n ( ,folke ,gad5hal5 sail$ f  
,norway 9 se>* ( ,icel& 9 ! ye> #hfh1 & 
t he c>ri$ ) him ?ree rav5s z guides1 = 
he says1 9 ^? times seam5 _h no         
load/ones 9 ! nor!rn c\ntries4 ,!       
magnetic ne$le z appli$ to ! m>9]'s     
compass 0 kn[n 9 ! elev5? c5tury1 z     
prov$ by v>i\s au?ors4 ,9 an old ,fr5*  
poem1 ! manuscript ( :i* /ill exi/s1 !  
m>9]'s compass is cle>ly m5tion$4 ,!    
au?or 0 ,guyot1 ( ,prov5ce1 :o 0 alive 9

 #aaha4  ,l electricity1 magnetism has  
_h a long hi/ory1 b little use 0 made ( 
x till mod]n times beyond t ( ! m>9]'s  
compass4 ,x c readily be se5 :at an     
important factor x 0 9 ! sci5ce (       
navigation4 ,long aft] ! discov]y ( !   
compass ne$le !re 7 _m p]plex+ problems 
aris+1 & all sorts ( !ories 7 advanc$ to
 acc\nt = ! v>i\s ph5om5a4 ,! v>iation (
 ! ne$le 0 "o ( ^! problems4 ,x is said 
t ,columbus 0 ! fir/ to discov] !       
v>iation ( ! ne$le1 z well z ,am]ica4   
,?is is disput$1 h[ev]1 z e man's       
pret5sions usually are4 ,h[ev] ?is may  
be1 ,columbus _h to inv5t "s plausible  
!ory to acc\nt = ?is v>iation to prev5t 
a mut9y among 8 crew4 ,!y 7 v sup]/iti\s
 & ?\ght t !y 7 sail+ into a new _w :]e 
! laws ( nature 7 diff]5t f ^? ( ,spa94 
,"o ph5om5on t di/urb$ ,columbus 0 ! dip
 ( ! ne$le4 ,z we move 9 a nor!rly      
direction a magnetic ne$le dips1 & x 0 !
 obs]vation ( ?is ph5om5on 9 diff]5t    
latitudes t f9ally result$ 9 ! inv5tion 
( ! dipp+ ne$le4 ,x is well kn[n t "o   

pole ( a magnetic ne$le po9ts to ! nor? 
& ! o!r to ! s\?4 ,9 o!r words1 :at is  
call$ ! nor? pole ( a ne$le po9ts to "o 
( ! magnetic poles ( ! e>? :i* is 9 !   
direction ( ! nor? pole1 ?\gh n ! same z
 ! geographical pole4 ,a dipp+ ne$le    
revolves on an axis s t x c po9t to any 
decl9ation4 ,if we %\ld con/ruct "o t is
 p]fectly balanc$1 s z to lie 9 a       
p]fectly horizontal direction be=e x is 
magnetiz$1 x w dip--9 ?is               
latitude--d[nw>d t[>d ! nor? aft]       
magnetization4 ,if we keep mov+ nor?w>d 
x w cont9ue to dip d[nw>d till we come  
to ! true magnetic pole1 :5 :at is call$
 ! nor? pole ( ! ne$le w po9t directly  
d[nw>d4 ,if we g back to ! equator !    
ne$le w lie horizontally aga94 ,we call 
! end ( ! ne$le t po9ts to ! nor? ! nor?
 pole4 ,x is really ! s\? pole1 because 
unlike poles attract ea* o!r4 ,if !     
magnetic poles ( ! e>? are at ! nor? &  
s\? geographical poles1 ! s\? pole ( !  
ne$le w po9t nor?4 ,b x is less confus+ 
to call ! end ( ! ne$le t po9ts nor? !  

nor? pole4 ,! nom5clature is purely     
arbitr>y4  ,x 0 n until x 0 le>n$ t     
magnets c\ld be made by electricity t !y
 became comm]cially important outside ( 
_! use 9 navigation4 ,! adv5t (         
electricity has br\ght magnetism to !   
front z "o ( ! great factors 9 our mod]n
 civilization4 ,& we might say ) equal  
=ce t ! discov]y ( magnetism has br\ght 
electricity to ! front4 ,! tru? is t !y 
dep5d ^u ea* o!r4 ,electricity w\ld be  
robb$ ( a l>ge "p ( its importance z a  
factor 9 mod]n life if x 7 n = its      
relation to magnetism4 ,ev5 electric    
light+ w\ld be impossible1 comm]cially1 
if x 7 n = ! "p magnetism plays 9 !     
production ( electricity = ?is purpose4 
,x c\ld n be successfully c>ri$ on ) any
 batt]y b ! /orage-batt]y1 & !          
/orage-batt]y is dep5d5t ^u ! dynamo1 & 
! dynamo is a magneto-electric ma*9e4   
,:5 we come to analyze ! relation betwe5
 magnetism & electricity we _c sep>ate  
!m )\t robb+ ea* ( a l>ge "p ( its      
usefulness4 ,!y are int]dep5d5t =ces4   

,z 9 ! case ( electricity !re h be5 _m  
!ories reg>d+ magnetism4 ,"o philosoph] 
9 ! old days acc\nts = ! v>iation ( !   
compass-ne$le on ! !ory t !re are two   
globes1 "o revolv+ )9 ! o!r1 & t any    
d]angem5t ( _! normal movem5ts 9        
relation to ea* o!r affects ! ne$le4    
,evid5tly !re 7 cranks 9 ^? days z well 
z n[4 ,ano!r !ory ( magnetism 0 t !re 7 
two fluids--a boreal & an au/ral--"o    
develop+ nor? pol>ity & ! o!r s\?       
pol>ity4 ,9 ! next *apt] ! nature (     
magnetism 9 ! light ( mod]n inve/igation
 w be discuss$4     ,,*apt] ,,iv4       
,,!ory ,,& ,,nature ,,( ,,magnetism4    
,iron & /eel h a peculi> prop]ty call$  
magnetism4 ,x is an attraction 9 _m ways
 unlike ! attraction ( cohesion or !    
attraction ( gravitation4 ,x is v c]ta9 
t magnetism is an inh]5t prop]ty ( !    
molecules ( iron & /eel1 &1 to a small  
degree1 o!r =ms ( matt]4 ,t is to say1 !
 molecules are little natural magnets ( 
!mselves4 ,x is z unnecess>y to inquire 
:y !y are magnets z x is to inquire :y !

 molecules ( all ord9>y sub/ances       
possess ! attraction ( cohesion4 ,! "o  
is z easy to expla9 z ! o!r4 ,p ( all   
ages h insi/$ ^u mak+ a great] my/]y (  
all electrical & magnetic ph5om5a ?an !y
 d ( o!r natural =ces4 ,amp]e's !ory is 
t electric curr5ts are fl[+ ar\nd !     
molecules :i* r5d] !m magnetic2 b x is j
 z easy to suppose t magnetism is an    
inh]5t quality ( ! molecule4 7,! ^w     
molecule is "h us$ z ref]r+ to ! smalle/
 p>ticle ( iron47  ,^! little molecul>  
magnets1 s small t #ajj1jjj million     
million million ( !m c be put into a    
cubic in* ( space1 h _! attractions     
satisfi$ by =m+ into little molecul>    
r+s1 ) _! unlike poles toge!r1 s t :5 ! 
iron is 9 a natural or unmagnetiz$      
condition x does n attract o!r iron4 ,if
 ,i %\ld take a r+ ( h>d5$ /eel & cut x 
into two or m pieces & magnetize !m1 ea*
 "o ( ! pieces w\ld be an indep5d5t     
magnet4 ,if n[ ,i put !m toge!r 9 ! =m (
 a r+ !y w cl+ toge!r by _! mutual      
attraction = ea* o!r4 ,be=e ,i put !m   

toge!r into a r+ ea* piece w\ld attract 
& adh]e to o!r pieces ( iron or /eel4 ,b
 z soon z !y are put toge!r 9 ! r+ !y   
are satisfi$ ) _! own mutual attraction1
 & ! r+ z a :ole w n attract o!r pieces 
( iron4  ,suppose ! pieces =m+ ! r+--x  
may be only two1 if y *oose--are z small
 z ! molecules we h describ$1 ! same ?+ 
w\ld be true ( !m4 ,ea* molecul> r+ w\ld
 h its magnetic attractions satisfi$ &  
w\ld n attract o!r molecules outside (  
its own little circle4 ,:5 ! iron is 9 !
 neutral /ate x w n z a mass attract    
ano!r piece ( iron1 because ! millions (
 little natural magnets ( :i* x is made 
up h _! attractive =ce all turn$ 9 ^u   
!mselves4  ,n[1 if we make a helix1 or  
coil1 ( insulat$ wire & put a piece (   
iron into x1 & pass a curr5t (          
electricity ?r\gh ! helix1 ! iron       
becomes a magnet4 ,:y8 ,because !       
electric curr5t has ! p[] to break up ^!
 molecul> magnetic r+s & turn all _! l  
poles 9 "o direction1 s t _! attractions
 are no long] satisfi$ among !mselves1 &

 ) a comb9$ ef=t !y rea* outside &      
attract any piece ( iron t is )9 rea*4  
,9 ?is /ate we say x is magnetiz$4 ,mo/ 
p ?9k t we h put some?+ into ! iron1 b  
we h n2 we h only develop$ & made active
 its inh]5t p[]4 ,x mu/ be kept 9 m9d t 
x takes p[] to develop ?is magnetic p[] 
f its /ate ( neutrality & t some?+ is   
nev] made f no?+4 ,:5 ?is p[] is        
develop$ x w d "w 9 fall+ back to its   
natural /ate4 ,! p[] is natural to !    
molecules ( ! metal4 ,x is only be+     
ex]t$ 9 a new direction4 ,! millions (  
little natural magnets h be5 =c$ to     
comb9e _! attractions into "o :ole &    
ex]t x on some?+ outside ( !mselves4 ,!y
 are "u a /ra9 9 ?is condition1 l a b5t 
b[1 & !re is a t5d5cy to fly back to !  
natural position1 & if x is s(t iron & n
 /eel1 !y w fly back z soon z ! p[] t   
wr5*$ !m ap>t & is hold+ !m ap>t is tak5
 away4 ,?is p[] is ! electric curr5t4   
,n[ break ! curr5t1 & ! little natural  
magnets1 t h be5 s ru?lessly torn f _!  
home circle atta*m5ts1 fly back to !m   

aga9 ) ! spe$ ( lightn+1 & ! iron rod z 
a :ole is no long] a magnet4 ,! p[] to  
become s "u ! electrical /ra9 is 9 x    
/ill--only lat5t4  ,! k9d ( magnet t we 
h be5 describ+ is call$ an              
electromagnet4 ,x is a magnet only s    
long z ! electric curr5t is pass+ ar\nd 
x4 ,!re is ano!r k9d ( magnet call$ a   
p]man5t magnet t w rema9 a magnet aft] !
 curr5t is tak5 away4 ,! p]man5t magnet 
is made ( /eel & h>d5$2 !n its poles are
 plac$1 to ! poles ( a p[]ful magnet1   
ei!r electro or p]man5t1 :5 its molecul>
 r+s are wr5*$ ap>t & arrang$ 9 a       
pol>iz$ position z h]et(ore describ$4   
,n[ take x away f ! magnet & x w be f\nd
 to reta9 its magnetism4 ,! molecules   
t5d to fly back ! same z ^? ( ! s(t     
iron1 b !y _c because h>d5$ /eel is s   
mu* f9] gra9$ ?an s(t iron1 & !         
molecules are s close toge!r t !y are   
held 9 position by a friction t is call$
 its co]cive =ce4 ,! s(t iron is        
comp>atively free f ?is co]cive =ce1    
because its molecules are free to move  

on ea* o!r1 s t :5 !y are wr5*$ out ( _!
 natural position !y fly back by _! own 
attractions z soon z ! =ce hold+ !m ap>t
 is tak5 away4 ,! molecules ( h>d5$ /eel
 are unable to fly back1 al?\gh !y t5d  
to d x j z mu* z 9 ! iron1 & s x is     
call$ a p]man5t magnet4 ,its molecules  
also are "u a /ra91 l a b5t b[4 7,! =m (
 su* a magnet is usually t ( a          
horse-%oe1 or ,u47  ,let u use a homely 
illu/ration t may help u to und]/&4 ,let
 t5 boys repres5t ! molecules 9 a piece 
( iron4 ,let !m pair (f into five pairs 
& ea* "o clasp 8 mate 9 8 arms2 ea* "o1 
say1 is ex]t+ a =ce ( t5 p\nds1 & x w\ld
 require a =ce ( tw5ty p\nds to pull any
 "o ( ! pairs ap>t4 ,! five pairs are   
ex]t+ a =ce ( "o hundr$ p\nds1 b ?is =ce
 is n felt outside ( !mselves4 ,n[ let  
!m unclasp !mselves & take hold ( a rope
 t is ti$ to a po/1 & all pull ) ! same 
=ce t !y 7 us+1 to wit1 t5 p\nds ea*1 & 
all pull 9 ! same direction1 & !y w\ld  
put a /ra9 ( "o hundr$ p\nds ^u ! po/1 !
 same p[] t !y 7 ex]t+ ^u !mselves be=e 

!y comb9$ _! ef=ts on some?+ outside (  
!mselves4 ,s ) ! magnet4 ,s long z ! =ce
 ( ea* molecule is :olly sp5t ^u its    
neighbor !re is no?+ left = ext]ior use4
 ,b z soon z !y all l9e up & pull       
conjo9tly 9 ! same direction _! comb9$  
=ce is felt outside4 ,! analogy may n be
 p]fect1 b x w help y to get a m5tal    
picture ( :at takes place 9 iron :5 x is
 magnetiz$4  ,we h n[ describ$ ! magnet 
& ! inh]5t p[] resid+ 9 ! molecul>      
/ructure ( iron4 ,x is ?is magic p[]    
slumb]+ 9 its molecules & ! ability ( ! 
electric curr5t to ar\se !m to action at
 w & to hold !m 9 action & at w let !m  
fly back to _! normal position1 t gives 
to electricity & magnetism--tw9 si/]s 9 
nature's h\sehold--_! great value z !   
s]vants ( man4 ,!re w\ld be no virtue 9 
w9d+ up a weight if x c\ld n run d[n & d
 "w 9 its fall4 ,simply b5d+ a b[ w\ld  
nev] s5d ! arr[ fly+ ov] its c\rse2 x   
mu/ be releas$ z well4 ,! magnet c\ld n 
accompli% ! great "w x does if we c\ld  
only *>ge x & n h ! ability to dis*>ge  

x4 ,)\t ?is ability ! electric motor    
w\ld n revolve1 ! electric light w\ld n 
burn1 ! click ( ! telegraph w\ld n be   
he>d1 ! telephone w\ld n talk1 nor w\ld 
! telautograph write4  ,i h said t !    
p]man5t magnet w\ld hold its *>ge aft]  
once hav+ be5 magnetiz$4 ,?is is true   
only 9 a s5se & "u favorable conditions4
 ,if made ( ! be/ ( /eel = ! purpose &  
h>d5$ & temp]$ 9 j ! "r way1 x w hold   
its *>ge if x is giv5 some?+ to d4 ,if a
 piece ( iron is plac$ across its poles 
x also becomes a magnet & its molecules 
turn & "w 9 h>mony ) ^? ( ! "m magnet4  
,^! magnetic l9es ( =ce rea* ar\nd 9 a  
circuit4 ,ev5 be=e ! iron1 or keep]1 z x
 is call$1 is put across its poles !re  
are l9es ( =ce rea*+ ar\nd ?r\gh ! air  
or e!r f "o pole to ano!r4 7,= a        
description ( ,e!r see ,*ap4 ,v47 ,?is  
is call$ ! field ( ! magnet1 & :5 ! iron
 is plac$ 9 ?is field ! l9es ( =ce pass 
?r\gh x 9 a clos$ circuit1 & if ! keep] 
is l>ge en\gh to take c>e ( all ! l9es (
 =ce 9 ! field ! magnet w n attract o!r 

bodies1 because its attraction is       
satisfi$1 l its prototype 9 ! molecul>  
r+ describ$ above4  ,we speak ( l9es (  
=ce1 n t =ce is necess>ily ex]t$ 9 a    
bundle ( l9es b z a conv5i5t way ( tell+
 ! /r5g? ( a magnetic field4 ,!         
practical limit ( ! magnetization ( s(t 
iron 7call$ saturation7 is #ah1jjj l9es 
to ! squ>e c5timet]4 ,z long z we give  
our magnet some?+ to d1 up to ! measure 
( its capacity1 x w keep up its p[]4 ,we
 may make o!r magnets ) x1 ?\s&s1 yea1  
millions ( !m1 & x n only does n lose   
its p[] b may be ev5 /rong] = hav+ done 
?is "w4 ,if1 h[ev]1 we hang x up )\t its
 keep]1 & give x no?+ to d1 x gradually 
returns to its natural condition 9 !    
home circle ( molecul> r+s4 ,little by  
little ! co]cive =ce is ov]come by !    
con/ant t5d5cy ( ! molecule to g back to
 its natural position among its fell[s4 
,! magnet furni%es _m beautiful lessons1
 z inde$ d all ! natural ph5om5a4 ,e man
 has )9 him a lat5t p[] t ne$s only to  
be ar\s$ & direct$ 9 ! "r way to make 8 

influ5ce felt ^u 8 fell[s4 ,l ! magnet1 
! man :o uses 8 p[] to help 8 fell[s up 
to ! measure ( 8 limitations n only has 
be5 a b5efactor to 8 race1 b is himself 
a /rong] & bett] man = hav+ done s4 ,b1 
aga91 l ! magnet1 if he all[s ^!        
,god-giv5 p[]s to lie /ill & ru/ = want 
( legitimate use he gradually loses !   
p[] he _h & becomes simply a mov+ ?+ )\t
 influ5ce or use 9 a _w 9 :i* he        
vegetates4 ,b let u leave philosophy & g
 back to sci5ce4  ,"o ( ! /rik+         
exhibitions ( magnetism is f\nd 9 ! e>?4
 ,! e>? itself is a great magnet2 & !re 
is good reason = believ+ t x is an      
electromagnet ( great p[]4 ,! magnetic  
poles ( ! e>? are n exactly co9cid5t ) !
 geographical poles1 & !y are n con/ant4
 ,!re is a gradual deviation go+ on1 b z
 x foll[s a c]ta9 law m>9]s are able to 
tell j :at ! deviation %\ld be at a     
c]ta9 "t4 ,! magnetic pole revolves     
ar\nd ! pol> axis ( ! e>? once 9 ab\t   
#cbj ye>s4 ,a !rmal curr5t 7"o produc$  
by heat7 ( electricity seems to fl[     

ar\nd ! e>? caus$ by ! irregul>ities (  
temp]ature at ! e>?'s surface1 z ! sun  
makes 8 daily r\nd4 ,^! e>? curr5ts v>y 
at times1 & o!r ph5om5a are ! occasion4 
,?is w be discuss$ :5 we come to        
electric /orms4  ,! value ( ! e>?'s     
magnetism is se5 mo/ 9 ! sci5ce (       
navigation4 ,a magnetic ne$le is only a 
sl5d] p]man5t magnet susp5d$ v          
delicately1 & :5 n "u local influ5ce x  
po9ts nor? & s\? on ! magnetic axis4 ,! 
law ( its action may be expla9$ z       
foll[s3 ,take a /raight b> magnet (     
fairly good p[] & susp5d a magnetic     
ne$le ov] x4 ,! ne$le w arrange itself  
p>allel to ! b> magnet4 ,! nor? pole ( !
 ne$le w po9t t[>d ! s\? pole ( ! b>    
magnet4 ,9 ! pres5ce ( ! magnet ! ne$le 
is n affect$ by ! e>?1 b yields to a    
sup]ior =ce4 ,if1 h[ev]1 ! b> magnet is 
tak5 out ( ! way ( ! ne$le x w          
imm$iately arrange itself nor? & s\?4 ,(
 c\rse if ! e>?'s magnetic axis *anges !
 ne$le w v>y ) x4 ,?is v>iation is uni=m
 & 9 navigation is r$uc$ to a sci5ce1 s 

t ! m>9] kn[s h[ mu* to all[ = !        
v>iation4 ,columbus1 z h]et(ore m5tion$1
 0 suppos$ to h fir/ notic$ ?is v>iation
 & x made him tr\ble4 ,he did n "k h[ to
 acc\nt = x1 & z 8 crew ?\ght ! laws (  
nature 7 *ang+ because !y 7 s f> f home 
he saw ! necessity = "s sort (          
explanation4 ,s1 l ! brave man t he 01  
he hat*$ up a !ory t satisfi$ ! crew1 & 
al?\gh 9 ! light ( ! clos+ ye>s ( !     
n9ete5? c5tury x 0 a que/ionable "o1 x  
work$ well en\gh 9 practice to s]ve 8   
purpose4  ,we h already /at$ t ! e>? 0 a
 great magnet1 & t probably x 0 an      
electromagnet1 caus$ by e>? curr5ts     
circulat+ ar\nd ! globe4 ,y want to "k  
h[ ! e>? c be a magnet unless x has an  
iron core l an electromagnet4 ,magnetism
 or magnetic l9es ( =ce may be develop$ 
)\t ! pres5ce ( iron4 ,:5 we pass a     
curr5t ( electricity ?r\gh a wire1      
magnetic l9es ( =ce are ?r[n out at "r  
angles ) ! direction ( ! curr5t4 ,?is w 
be fully expla9$ fur!r on4 ,if we w9d ! 
wire into a coil1 or helix1 ^! magnetic 

l9es are conc5trat$4 ,if n[ we susp5d   
?is helix1 or1 bett]1 float x on wat] s 
t x c move freely1 & pass a curr5t (    
electricity ?r\gh x1 ! helix w arrange  
itself nor? & s\? ! same z a magnetic   
ne$le4 ,its attractive prop]ties are    
feeble 9 comp>ison ) t ( ! iron1 b x    
obeys ! laws ( a magnet4 ,! e>? is      
probably a magnet ( ?is k9d1 consi/+    
mo/ly ( l9es ( =ce4  ,h[ev]1 ! iron 9 ! 
e>? is affect$ magnetically1 z we h     
evid5ce 9 ! load/one4 ,! e>? has ! p[]  
also to magnetize iron ?r\gh ! m$ium (  
its magnetic field1 t rea*es out 9 l9es 
( =ce f pole to pole l ^? ( ! artificial
 magnet4 ,if we hold a b> ( iron 9 l9e )
 ! magnetic axis ( ! e>? & dip x 9 l9e )
 ! dipp+ ne$le & !n /rike x a few bl[s  
on ! end1 x w be f\nd to be feebly      
magnetic4 ,! bl[s h p>tly loos5$ !      
molecules & dur+ ! mom5t t !y unclasp$  
!mselves ! e>?'s magnetism has ?r\gh its
 l9es ( =ce caught !m = a "t & held !m a
 little out ( _! natural position--z !y 
are 9 a /ate ( re/4 ,! peculi> *ang+    

light t we sometimes see 9 ! nor!rn sky1
 t is call$ ! ,aurora ,borealis 7,nor!rn
 ,light71 is indirectly due to int5se   
magnetic l9es ( =ce t radiate f ! nor?  
magnetic pole ( ! e>?4 ,^? l9es ( =ce   
are able to cause ! r>ifi$ air molecules
 to become feebly inc&esc5t1 giv+ !m !  
appe>ance t we see 9 a tube t is a      
p>tial vacuum :5 electricity is pass$   
?r\gh x4 ,:ile ^! auroral displays may  
be se5 almo/ any night 9 ! f> nor?1 !y  
v>y greatly 9 _! int5sity1 s x is only  
once 9 a :ile t !y are visible 9 !      
temp]ate latitudes4  ,:at are call$     
magnetic /orms occur occasionally1 & at 
su* times ! telegraph s]vice w sometimes
 be p>alyz$ on all ! ea/ & we/ l9es = _m
 h\rs4 ,/rong e>?-curr5ts w fl[ ea/ &   
we/1 & be s p[]ful & s erratic t x is   
sometimes impossible to use ! telegraph4
 ,x sometimes happ5s t ! op]ators c ?r[ 
(f _! batt]ies & "w on ! e>?-curr5t     
alone4 ,sometimes x is necess>y to make 
a complete metallic circuit to get away 
f ! influ5ce ( ! e>? 9 ord] to use !    

telegraph4 ,curr5ts equal to ! =ce (    
#b1jjj cells ( ord9>y batt]y h be5      
develop$ sometimes 9 telegraph wires4   
,?is ( c\rse is a m]e fraction ( :at is 
pass+ ?r\gh ! e>? "u ! wire ?r\gh :i* ! 
curr5t fl[$4 ,on ! #ag? & #ah? (        
,novemb]1 #ahhb1 a magnetic /orm occurr$
 t ext5d$ ar\nd ! globe1 z x 0 felt     
:]ev] !re 7 telegraph wires4 ,^!        
magnetic /orms are att5d$ by brilliant  
displays ( ! aurora1 & ?is fact /r5g!ns 
! !ory t ! e>? is a great electromagnet2
 = ! /rong] ! electrical curr5t ! m     
p[]ful we %\ld expect ! magnetism to be1
 & ?is is %[n by ! action ( ! magnetic  
ne$le at su* times4 ,! /rong] ! magnet !
 m int5se w be ! l9es ( =ce1 & naturally
 ! m int5se ! light1 if inde$ ^! l9es ( 
=ce are ! cause ( ! light4 ,!re is      
evid5tly "s close relation betwe5 ! two4
  ,ano!r co9cid5ce is t at ! times ( ^! 
/orms !re is an unusual display (       
sun-spots4 ,^! sun-spots seem to be     
great holes t h be5 bl[n ?r\gh !        
photosph]e ( ! sun4 ,! photosph]e is a  

great lum9\s body ( gase\s matt] t is   
believ$ to envelop ! sun1 s t we d n see
 ! core ( ! sun unless x is :5 we look  
into "o ( ^! spots4 ,9 "s way1 evid5tly1
 ! sun affects ! e>? by radiat+ magnetic
 l9es ( =ce :i* are cut by ! e>?'s      
revolution1 & s creat+ curr5ts (        
electricity4 ,! sun is ! field-magnet1 &
 ! e>? is ! revolv+ armature ( nature's 
great dynamo-electric ma*9e4 ,x w\ld    
seem t ! radiant en]gy t comes out ?r\gh
 ^! spots or ^! holes 9 ! sun's         
envelope1 are m pot5t to develop        
e>?-curr5ts ?an ! ord9>y rays2 & s1 :5 =
 a brief :ile 9 ! revolution ( ! e>?    
ab\t ! sun1 ^! extra pot5t rays /rike ! 
e>?1 an unusual en]gy is develop$1 & ^! 
unusual ph5om5a are ! consequ5ce4 ,^!   
ph5om5a seem to occur p]iodically2 "s   
ye>s 7ab\t elev57 int]v5+4  ,all ! =ces 
& ph5om5a ( nature are ?us se5 to be 9 a
 /ate ( unre/4 ,& x is to ?is unre/1 :i*
 does n /op ) visible ?+s1 b p]vades ev5
 ! atoms ( matt] ?r\gh\t ! univ]se1 t we
 are indebt$ = ! ability to c>ry on all 

! activities ( life1 & = life itself4 ,=
 univ]sal quiet w\ld mean univ]sal dea?4
 ,! cyclone & tornado t deva/ate & /rike
 t]ror to a :ole region are only        
ecc5tricities ( nature :5 %e is sett+ h]
 h\se to rights4 ,! play ( natural =ces 
has di/urb$ h] equilibrium1 & %e is b   
mak+ an ef=t to re/ore x4     ,,*apt]   
,v4  ,,!ory ,,( ,,electricity4   ,9 !   
s]ies ( *apt]s on ,heat 7,vol4 ,,ii7 & 9
 ! *apt] on ,magnetism ! ^w molecule 0  
frequ5tly us$ synonym\sly ) atom4 ,9    
*emi/ry a di/9ction is made1 & z we c   
bett] expla9 ! !ory1 at lea/1 (         
electricity by keep+ ?is di/9ction 9 m9d
 we w ref] to x "h4  ,x has be5 /at$ t  
!re are betwe5 sixty & sev5ty elem5t>y  
sub/ances4 ,an elem5t>y sub/ance _c be  
de/roy$ z su*4 ,x c be unit$ ) o!r      
elem5ts & =m *emical comp\nds ( almo/   
endless v>iety4 ,! smalle/ p>ticle ( an 
elem5t>y sub/ance is call$ 9 *emi/ry an 
atom4 ,! smalle/ p>ticle ( a comp\nd    
sub/ance is call$ a molecule4 ,! atom is
 ! unit ( ! elem5t1 & ! molecule is !   

unit ( ! comp\nd z su*4 ,x foll[s1 !n1 t
 !re are z _m diff]5t k9ds ( atoms z !re
 are elem5ts1 & z _m diff]5t k9ds (     
molecules z !re are comp\nds4 ,if !     
elem5ts h a molecul> ,/ructure !n two or
 m atoms ( ! same k9d mu/ comb9e to make
 a molecule ( an elem5t>y sub/ance4 ,two
 atoms ( hydrog5 comb9e ) "o ( oxyg5 to 
=m "o molecule ( wat]4 ,x _c exi/ z wat]
 9 any small] quantity4 ,if we subdivide
 x1 x no long] exi/s z wat]1 b z !      
orig9al gases f :i* x 0 comp\nd$4  ,we h
 %[n 9 ! s]ies on ,s\nd1 ,heat & ,light 
t !y are all modes ( motion4 ,s\nd is   
transmitt$ 9 longitud9al waves ?r\gh air
 & o!r mat]ial sub/ance z vibration4    
,heat is a motion ( ! ultimate p>ticles 
or atoms ( matt]1 & ,light is a motion (
 ! lum9if]\s e!r transmitt$ 9 waves t   
are transv]se4 ,electricity is also     
und\bt$ly a mode ( motion relat$ 9 a    
peculi> way to ! atoms ( ! conductor4   
,notice t !re is a diff]5ce betwe5      
conduction & radiation4 ,! =m] transmits
 en]gy by a transf]5ce ( motion f atom  

to atom or molecule to molecule )9 !    
body1 :ile ! latt] does x by a vibration
 ( ! e!r outside--z light1 radiant heat1
 & electromagnetic l9es ( =ce4  ,= !    
b5efit ( ^? p]sons :o h n read ,vol4    
,,ii1 :]e ! nature ( e!r is discuss$    
some:at1 let u ref] to x "h1 z x plays  
an important "p 9 ! explanation (       
electrical ph5om5a4 ,e!r is a t5u\s &   
highly ela/ic sub/ance t fills all      
int]/ell> & int]atomic space4 ,x has few
 ( ! qualities ( ord9>y matt]4 ,x is    
cont9u\s & has no molecul> /ructure4 ,x 
(f]s no p]ceptible resi/ance1 & !       
close/-gra9$ sub/ances ( ord9>y matt]   
are m op5 to ! e!r ?an a co>se sieve is 
to ! f9e/ fl\r4 ,x fills all space1 &1 l
 et]nity1 x has no limits4 ,"s physici/s
 suppose--& !re is mu* plausibility 9 ! 
supposition--t ! e!r is ! "o sub/ance   
out ( :i* all =ms ( matt] come4 ,t !    
atoms ( matt] are vortices or little    
:irlpools 9 ! e!r2 & t rigidity & o!r   
qualities ( matt] all arise 9 ! e!r f   
diff]5t degrees or k9ds ( motion4       

,electricity is n a fluid1 or any =m (  
mat]ial sub/ance1 b a =m ( en]gy4 ,en]gy
 is express$ 9 diff]5t ways1 &1 :ile z  
en]gy x is "o & ! same1 we call x by    
diff]5t names--z heat en]gy1 *emical    
en]gy1 electrical en]gy1 & s on4 ,!y w  
all d "w1 & 9 t respect are alike4 ,"o  
difficulty 9 expla9+ electrical ph5om5a 
is ! nom5clature t ! sci5ce is load$ d[n
 )4 ,all ! old names 7 adopt$ :5        
electricity 0 reg>d$ z a fluid1 h5ce !  
^w curr5t4 ,x is spok5 ( z fl[+ :5 x    
does n fl[ any m ?an light fl[s4  ,if a 
man wants to write a treatise on        
electricity--outside ( ! m]e ph5om5a &  
applications--& wants to make a l>ge    
book ( x1 he w\ld bett] tell :at he does
 n "k ab\t x1 = 9 t way he c make a     
volume ( almo/ any size4 ,b if he wants 
to tell :at x really is1 & :at he really
 kn[s x is1 a prim] w be l>ge en\gh4    
,?is mu* we "k--t x is "o ( _m          
expressions ( en]gy4  ,*emi/ry tea*es t 
heat is directly relat$ to ! atoms (    
matt]4 ,atoms ( diff]5t sub/ances diff] 

greatly 9 weight4 ,= in/ance1 ! hydrog5 
atom is ! unit ( atomic weight1 because 
x is ! lighte/ ( all ( !m4 ,tak+ !      
hydrog5 atom z ! unit1 9 r\nd numb]s !  
iron atom weighs z mu* z #ef atoms (    
hydrog51 copp] a little ov] #fc1 silv]  
#ajh1 gold #aig4 ,heat acts ^u matt]    
accord+ to ! numb] ( atoms 9 a giv5     
space1 & n z its weight4 ,kn[+ !        
relative weights ( ! atoms ( ! diff]5t  
metals nam$1 x w\ld be possible to      
det]m9e by weight ! dim5sions ( diff]5t 
pieces ( metal s t !y w conta9 an equal 
numb] ( atoms4 ,if we take pieces (     
iron1 copp]1 silv] & gold1 ea* ( su*    
weight z t all ! pieces w conta9 ! same 
numb] ( atoms1 & subject !m to heat till
 all are rais$ to ! same temp]ature1 x w
 be f\nd t !y h all absorb$ practically 
! same quantity ( heat )\t reg>d to !   
diff]5t weights ( matt]4 ,x w be obs]v$ 
t ! piece ( silv]1 = in/ance1 w h to    
weigh ne>ly twice z mu* z ! iron 9 ord] 
to conta9 ! same numb] ( atoms1 b x w   
absorb ! same am\nt ( heat z ! piece (  

iron conta9+ ! same numb] ( atoms1 if   
bo? are rais$ to ! same temp]ature4 ,9  
view ( ! above fact x seems t heat acts 
especially ^u ! atoms ( matt] & is a    
peculi> =m ( atomic motion4 ,heat is "o 
k9d ( motion ( ! atoms1 :ile electricity
 may be ano!r =m ( motion ( ! same4 ,!  
two motions may be c>ri$ on toge!r4 ,!  
e>? has a comp\nd motion4 ,x revolves ^u
 its axis once 9 tw5ty-f\r h\rs1 & x    
also revolves ar\nd ! sun once ea* ye>4 
,s y see t !re are diff]5t k9ds ( motion
 t may be communicat$ to ! same         
body--all produc+ diff]5t results4  ,!  
motion ( ! individual atom z heat may   
be1 & is1 z rapid z light itself :5 !   
temp]ature is suffici5tly high1 b x does
 n travel along a conductor rapidly z ! 
electro-atomic motion w4 ,if we apply   
heat to ! end ( a metal rod x w travel  
sl[ly along ! rod4 ,b if we make ! rod a
 conductor ( electricity x travels f    
atom to atom ) a spe$ ne>] t ( ! light  
ray ?r\gh ! e!r4 ,"s mod]n writ]s h     
attempt$ to expla9 all ! ph5om5a (      

electricity z hav+ _! orig9 9 a c]ta9   
play ( =ces ^u ! e!r1 & !re is no d\bt b
 t ! e!r plays an important "p 9 all    
electrical ph5om5a z a m$ium ?r\gh :i*  
en]gy is transf]r$2 b e!r-waves t are   
set 9 motion by ! electrical excitation 
( ord9>y matt] are no m electricity ?an 
! e!r-waves set up by ! sun 9 ! cold    
regions ( space are heat4 ,!y become    
heat only :5 !y /rike matt]4 ,heat1 z   
su*1 beg9s & ends 9 matt]2--s 7,i       
believe7 does electricity4  ,d n be     
disc\rag$ ) ^! feeble attempts to expla9
 ! !ory ( electricity4 ,all ,i ev5 hope 
to d is to e/abli% 9 y\r m9ds ?is       
fundam5tal ?\ght1 to wit1 t !re is      
really b "o ,en]gy1 & t x is always     
express$ by "s =m ( motion or ! ability 
to create motion4 ,motions diff]1 & h5ce
 are call$ by diff]5t names4  ,if ,i    
%\ld set an em]y-:eel to revolv+ & hold 
a piece ( /eel aga9/ x ! piece ( /eel   
w\ld become heat$ & inc&esc5t p>ticles  
w\ld fly (f1 mak+ a brilliant display ( 
fireworks4 ,! heat t has be5 develop$ is

 ! measure ( ! me*anical en]gy t ,i h   
us$ aga9/ ! em]y-:eel4 ,n[1 let u       
sub/itute = ! em]y-:eel ano!r :eel ( !  
same size made ( vulcaniz$ rubb]1 glass 
or res94 ,i set x to revolv+ at ! same  
spe$1 & in/ead ( ! piece ( /eel1 ,i n[  
hold a silk h&k]*ief or a catsk9 aga9/ !
 :eel ) ! same =ce t ,i did ! /eel4 ,if 
n[ ,i provide a ,leyd5 j> & "s po9ts to 
ga!r up ! electricity t w be produc$    
7in/ead ( ! heat g5]at$ 9 ! o!r case71 x
 w\ld be f\nd t ! en]gy develop$ 9 ! "o 
case w\ld exactly balance t ( ! o!r1 if 
x 7 all ga!r$ up & put into "w4 ,!      
electricity /or$ 9 ! j> is 9 a /ate (   
/ra91 l a b5t b[1 & w recoil1 :5 x has a
 *ance1 ) a p[] comm5surate ) ! "t x has
 be5 /or+ & ! am\nt ( en]gy us$ 9 press+
 aga9/ ! :eel4  ,if n[ ,i connect my two
 h&s1 "o ) ! inside & ! o!r ) ! outside 
( ! j>1 ?is /or$ en]gy w /rike me ) a   
=ce equal to all ! en]gy ,i h previ\sly 
exp5d$ 9 press+ aga9/ ! :eel1 m9us !    
loss 9 heat4 ,if ,i did x = a long en\gh
 "t ?is electrical spr+ w\ld be w\nd up 

to su* a t5sion t ! recoil w\ld de/roy  
life if "o put himself 9 ! pa? ( its    
dis*>ge4 ,if all ! heat 9 ! fir/ case 7 
ga!r$ up & made to b5d a /iff spr+1 & "o
 %\ld put himself 9 its way :5 releas$1 
?is me*anical spr+ w\ld /rike ) ! same  
p[] t ! electrical spr+ did :5 ! ,leyd5 
j> 0 dis*>g$4 ,?is /atem5t assumes t all
 ! en]gy 9 ! second exp]im5t 0 /or$ z   
electricity 9 ! j>4 ,y w be able to see 
f ! above illu/ration t heat1 electrical
 en]gy1 & me*anical en]gy are really !  
same4 ,!n y ask1 h[ d !y diff]8 ,simply 
9 _! ph5om5a--_! outw>d manife/ations4  
,:ile !re is mu* t we _c "k ab\t any ( !
 ph5om5a ( nature1 x is a great /ep 9   
advance if we c e/abli% a close         
relation%ip betwe5 !m4 ,x helps to free 
electricity f _m vag>ies t exi/ 9 ! m9ds
 ( mo/ p reg>d+ x2 vag>ies t 9 ignorant 
m9ds am\nt to sup]/ition4 ,:ile x       
possesses wond]ful p[]s1 !y give x      
attributes t x does n possess4 ,n long  
ago a favorite headl9e ( ! m$ical       
electrician's adv]tisem5t 0 ,electricity

 ,is ,life1 & x 0 a common ?+ to see    
/reet-v5d]s deal+ out ?is life 9 %ock+  
quantities to ! innoc5t multitudes--t5  
c5ts' wor? 9 z _m seconds4  ,sci5ce     
divides electricity into two k9ds--/atic
 & dynamic4 ,/atic comes f a ,greek ^w1 
mean+ to /&1 & ref]s to electricity z a 
/ation>y *>ge4 ,dynamic is f ! ,greek ^w
 mean+ p[]1 & ref]s to electricity 9    
motion4 ,:5 ,frankl9 made 8 celebrat$   
kite exp]im5t1 ! electricity came d[n ! 
/r+1 & f ! key on ! end ( ! /r+ he /or$ 
x 9 a ,leyd5 j>4 ,:ile ! electricity 0  
mov+ d[n ! /r+ x 0 dynamic1 b z soon z x
 0 /or$ 9 ! ,leyd5 j> x became /atic4   
,curr5t electricity is dynamic4 ,a clos$
 telegraphic circuit is *>g$            
dynamically1 :ile ! prime conductor ( a 
frictional electric ma*9e is *>g$       
/atically4 ,! di/9ction is arbitr>y & 9 
a s5se a misnom]4 ,:5 we rub a piece (  
h>d rubb] ) a catsk9 x is /atically *>g$
 because ! sub/ances are :at are call$  
non-conductors1 & ! *>ge _c be conduct$ 
readily away4 ,all sub/ances are divid$ 

into two classes1 to wit1 conductors or 
non-electrics1 & non-conductors or      
electrics1 m commonly call$ dielectrics4
 ,^!1 h[ev]1 are relative t]ms1 z no    
sub/ance is ei!r a p]fect conductor or a
 p]fect non-conductor4  ,! metals1      
beg9n+ ) silv] z ! be/1 are conductors4 
,ebonite1 p>aff9e1 %ellac1 etc41 are    
insulators1 or v poor conductors4 ,! be/
 conductors (f] "s resi/ance to !       
passage ( ! curr5t & ! be/ insulators   
conduct to "s ext5t4 ,if we make a      
comp>ison ( electric conductors we f9d t
 ! metals t conduct heat be/ also       
conduct electricity be/4 ,?is1 x seems  
to me1 is a confirmation ( ! atomic !ory
 ( electricity s f> z x means any?+4 ,if
 a good conductor1 z silv]1 is subject$ 
to int5se cold by putt+ x into liquid   
air1 its conductivity is greatly        
increas$4 ,x is well kn[n t heat+ a     
conductor ord9>ily dim9i%es its p[] to  
conduct electricity4 ,?is %[s t1 9 ord] 
t electrical motion ( ! atom may h free 
play1 ! heat motion mu/ be suppress$4   

,,*apt] ,,vi4  ,,electric ,,curr5ts4    
,! simple/ =m ( an electric ma*9e is "o 
9 :i* ! op]ator is a prom95t "p ( !     
op]ation4 ,electricity1 l magnetism1    
op]ates 9 a clos$ circuit1 ev5 :5 x is  
/atic--s-call$4 ,take a /ick (          
seal+-wax1 say1 9 y\r left h&1 & rub x )
 a piece ( fur or silk ) y\r "r h&1 & y 
h ! simple/ =m ( electric ma*9e--! "o t 
0 kn[n to ! anci5ts1 & ! "o f :i* !     
sci5ce1 great z x is to-day1 _h its     
beg9n+s4 ,! /ick ( seal+-wax is "o      
elem5t ( ! batt]y1 & ! piece ( fur or   
silk is ! o!r1 :ile y\r h&s1 arm & body 
=m ! conductor t connects ! two poles1 &
 ! friction is ! excit+ ag5t & may be   
said to take ! place ( ! fluid ( a      
batt]y4 ,! electrical conditions are n  
:olly /atic1 z a sl[ curr5t is pass+    
ar\nd ?r\gh y\r arms & body f "o pole to
 ! o!r4 ,ev5 if ! conditions 7 :olly    
/atic !re w\ld be pol>iz$ l9es ( =ce1 9 
a /ate ( /ra91 rea*+ ar\nd 9 a clos$    
circuit4  ,if we rub ! wax ) ! fur & !n 
take x away ! wax has a *>ge (          

electricity & w attract light objects4  
,if we _h rubb$ a piece ( metal or "s   
good conductor x w\ld h be5 w>m$ in/ead 
( electrifi$4 ,9 bo? cases ! p>ticles ( 
! sub/ances h be5 affect$1 & if ! atomic
 !ory is correct--& x seems plausible--9
 ! =m] case ! atoms are p>tly put into  
electrical motion & p>tly into a /ate ( 
electrical /ra9 t we call /atic 7/&+7   
electricity2 :ile 9 ! latt] case ! atoms
 are put into ! peculi> motion t belongs
 to heat4 ,! =m] we call electricity1 & 
! latt] we call heat4 ,! electro-atomic 
motion "u "s circum/ances readily turns 
to heat1 :i* seems to be ! t5d5cy ( all 
=ms ( en]gy4 ,! electric light is a     
result ( ?is t5d5cy4 ,all               
non-conductors1 or electrics1 h a       
complex molecul> /ructure1 &1 :ile _!   
atoms :5 subject$ to friction are put   
into a /ate ( electro/atic /ra91 !y are 
n able readily to respond z a conductor 
( dynamic electricity4 ,! electric-light
 filam5t 9 ! inc&esc5t lamp is a mu*    
poor] conductor ?an ! copp] wire t leads

 up to x4 ,! copp] wire is readily      
responsive to ! electrical influ5ce1 b !
 c>bon filam5t is n4 ,s electrical      
action t freely passes along ! wire1 is 
resi/$ & becomes heat action 9 !        
filam5t1 & light is ! att5dant ( int5se 
heat4 ,b1 to g back to ! s\rces (       
electricity4  ,frictional electric      
ma*9es h be5 con/ruct$ 9 great v>iety4  
,all1 h[ev]1 embrace ! ess5tials set =? 
9 ! seal+-wax exp]im5t1 & w\ld be       
difficult to describe )\t cuts4 ,let u1 
!re=e1 consid] ano!r s\rce (            
electricity1 :i* 0 ! outgr[? ( !        
discov]y ( ,galvani 7or r 8 wife71 &    
r$uc$ to concrete =m by ,volta4 ,we ref]
 to ! galvanic or voltaic batt]y4 ,if we
 put a b> ( z9c into a glass vessel &   
p\r sulphuric acid & wat] into x1 !re w 
be a boil+1 & an evolution ( hydrog5    
gas1 & en]gy is releas$ 9 ! =m ( heat1 s
 t ! fluid & ! glass vessel become      
heat$4 ,n[ let u put a b> ( copp] or a  
/ick ( c>bon into ! glass1 b n 9 contact
 ) ! z9c2 connect ! ends 7t are n       

imm]s$7 ( ! two elem5ts--copp] & z9c--) 
a metal wire or any conductor1 & a new  
condition is set up4 ,heat is no long]  
evolv$ to ! same ext5t1 b mo/ ( ! en]gy 
becomes electrical 9 "*1 & an electrical
 *a9 ( action takes place 9 ! circuit t 
has n[ be5 =m$4 ,tak+ ! z9c z ! />t+    
po9t1 ! s-call$ curr5t fl[s f ! z9c     
?r\gh ! fluid to ! copp] & f ! copp]    
?r\gh ! wire to ! z9c4  ,a *a9 ( pol>iz$
 atomic activity is e/abli%$ 9 !        
circuit1 simil> to ! clos$ circuit (    
magnetic l9es ( =ce1 only ! latt] is    
/atic1 :ile ! =m] is dynamic4  ,y ask   
:at is ! diff]5ce8 ,well1 x is mu* easi]
 to ask a "q ?an x is to answ] x4 ,y w  
rememb] t 9 ! *apt] on magnetism x 0    
/at$ t ! molecules ( a magnet 7 little  
natural magnets1 & t _! attractions 7   
satisfi$ )9 !mselves2 t :5 _! local     
atta*m5ts 7 brok5 up & all _! l poles   
turn$ 9 "o direction !y c\ld act ^u o!r 
pieces ( iron outside ( ! magnet4       
,outside & betwe5 ! poles !re are       
magnetic l9es ( =ce rea*+ out f "o pole 

to ! o!r4 ,if we put a piece ( iron     
across ! poles ^! l9es ( =ce are ga!r$  
up & pass ?r\gh ! iron4 ,?is is purely a
 /atic condition4 ,let u g back to !    
cell ( batt]y4 ,:5 ! elem5ts are 9      
position 7! copp]1 ! acidulat$ wat] & ! 
z9c71 & ! two wires atta*$ to ! two     
metals :i* are ! two poles ( ! batt]y n 
yet connect$1 !re is a condition induc$ 
9 ^! two wires t did n exi/ be=e !      
acidulat$ wat] 0 p\r$ 91 al?\gh !       
circuit is n yet e/abli%$4 ,if we te/ ! 
two wires we f9d a diff]5ce (           
pot5tial--a /ate ( /ra91 s to speak--t  
did n exi/ be=e ! acid act$ on ! z9c &  
lib]at$ :at 0 /or$ en]gy4 ,x is 9 a     
/atic condition1 l ! magnet1 &          
electrical l9es ( =ce are rea*+ out f   
bo? wires s t ! e!r is 9 a /ate ( /ra9  
betwe5 ! two poles4 ,! air molecules may
 p>take ( x1 b we h to br+ 9 ! e!r z a  
sub/ance1 because ! same conditions w\ld
 practically exi/ if ! two wires 7 9 a  
vacuum4 ,if n[ we connect ! two wires1  
we h e/abli%$ a metallic circuit betwe5 

! two poles ( ! batt]y1 ! /atic         
conditions are reliev$1 ! l9es ( =ce are
 ga!r$ up into ! wire1 & ! ph5om5on t we
 call a curr5t is e/abli%$ & we h       
dynamic or mov+ electricity4  ,hav+     
e/abli%$ ! s-call$ electric curr5t we w 
n[ try to %[ y t !re really is no       
curr5t4 ,! idea ( a curr5t involves !   
idea ( a fluid sub/ance fl[+ f "o po9t  
to ano!r4 ,:5 y 7 a boy did y nev] set  
up a r[ ( bricks on _! ends1 j f> en\gh 
ap>t s t if y pu%$ "o ov] !y all fell "o
 aft] ano!r8 ,n[1 imag9e r[s ( molecules
 or atoms1 & 9 y\r imag9ation !y may be 
arrang$ l ! bricks1 s t !y are affect$  
"o by ! o!r successively ) a rapidity t 
is ak9 to t ( light-waves1 & y c        
conceive h[ a motion may be communicat$ 
f end to end ( a wire hundr$s ( miles 9 
l5g? 9 a small fraction ( a second1 & no
 mat]ial sub/ance has be5 c>ri$ ?r\gh ! 
wire--only en]gy4 ,we d n mean to say t 
! r[ ( bricks illu/rates ! exact mode ( 
molecul> or atomic motion t takes place 
9 a conductor4 ,:at we mean is1 t 9 "s  

way motion is pass$ along f atom to     
atom4  ,to give y a bett] conception (  
an electric curr5t1 let u g back ( !    
galvanic cell to ! electric ma*9e4 ,if  
bo? poles ( ! ma*9e are atta*$ to rods  
t]m9at+ 9 r\nd knobs we c set ! ma*9e 9 
action & keep up a /eady /ream (        
disruptive dis*>ges t w1 if _! frequ5cy 
is great en\gh1 p]=m ! function ( a     
curr5t1 & we h dynamic electricity f a  
/atical ma*9e2 :5 ! acid ( ! galvanic   
batt]y breaks d[n a molecule ( z9c1     
en]gy is set free1 & 9 ! batt]y we h :at
 corresponds to a disruptive dis*>ge (  
inf9itesimal proportions4 ,?is dis*>ge  
w\ld h be5 imm$iately conv]t$ into heat 
en]gy if ! copp] elem5t _h be5 left out 
( ! batt]y1 b z x is1 x impresses itself
 on ! atomic brick next to x1 :i*       
e/abli%es a *a9 ( atomic movem5t ?r\gh\t
 ! circuit4 ,?is may con/itute1 if y    
please1 a l9e ( electrical =ce4 ,b z    
?\s&s ( ^! disruptive dis*>ges are tak+ 
place simultane\sly z _m diff]5t l9es ( 
=ce are e/abli%$4 ,y mu/ n conceive ( ^!

 *a9s ( atoms z simply ?r[n d[n l !     
bricks & left ly+ !re1 b t ! atom is    
active2 t x has ! p[] to pick itself up 
aga9 9 an inf9itesimally %ort "t & is   
aga9 knock$ d[n 7foll[+ ! illu/ration ( 
! bricks7 by ! next dis*>ge along its   
l9e or *a9 ( atoms4  ,if y c\ld get a   
m5tal picture ( ?is action y w\ld see t 
! :ole conductor is 9 a mo/ viol5t /ate 
( atomic motion ( a peculi> k9d4 ,at !  
same "t a "p ( ?is electrical motion is 
be+ conv]t$ into a heat motion ( !      
atoms1 & f9ally x all returns to heat   
unless "s ( x is /or$ up some:]e z      
pot5tial en]gy4 ,if ! curr5t has driv5 a
 motor t has w\nd up a weight1 a "p is  
/or$ up 9 ! weight1 :i* has ! ability to
 d "w if x is all[$ to run d[n4 ,if x   
drives ma*9]y z x runs d[n1 ! me*anical 
motion is ! expression ( ! /or$ en]gy4  
,:5 ! weight has run d[n ! en]gy w be   
repres5t$ by ! heat creat$ by friction (
 ! j\rnals ( ! :eels & pulleys & ! heat+
 ( ! air4 ,if ! weight is all[$ to fall 
sudd5ly x w heat ! air to "s ext5t1 b   

mo/ly ! e>? & ! weight itself w be      
heat$4 ,if ! s\rce ( en]gy 7! batt]y7 is
 great & ! pressure high & ! conductor  
is too small to c>ry ! en]gy develop$ 9 
! batt]y z electricity1 heat is         
develop$1 & if ! heat is suffici5tly    
int5se1 light also4  ,we h se5 7,vol4   
,,ii7 t heat motion :5 x rea*es a       
suffici5tly high rate ?r[s ! e!r into a 
vibratory motion t we call light4       
,h[ev]1 ?is vibratory motion ( ! e!r is 
set up long be=e x rea*es ! lum9\s /age2
 9 o!r words1 !re are d>k rays ( ! e!r4 
,we f9d t ! electro-atomic motions ( a  
conductor h ! p[] to impress !mselves ^u
 ! e!r4      ,illu/ration3 ,fig4 #a4    
,a is ! prim>y l9e2 a1 ! batt]y3 b1 !   
key4 ,b is !     second>y l9e 9 :i* is  
plac$ ! galvanomet] c4  ,let u try ano!r
 exp]im5t to %[ t ?is is ! case1 n only1
 b t ! impress$ e!r c transf] ^!        
impressions to /ill ano!r conductor4    
,suppose we /ret* two p>allel wires =1  
say1 half a mile1 or any di/ance1 only a
 few feet ap>t1 & make ( ea* a complete 

circuit by r\nd+ ! end ( ! c\rse &      
return+ ! wire to ! />t+ po9t 7z %[n 9  
,fig4 #a74 ,put 9 "o ( ^! circuits a    
batt]y1 & a circuit-break] 7a common    
telegraph-key71 & 9 ! o!r circuit a     
galvanomet] 7an in/rum5t = detect+ !    
pres5ce & measur+ ! int5sity ( a        
galvanic curr5t1 by means ( a dial & a  
deflect+ ne$le or po9t]74 ,n[ if we t\* 
! key & close ! circuit 9 ,a1 ! ne$le ( 
! galvanomet] 9 ,b w sw+ 9 "o direction 
f z]o on ! dial2 & if we release ! key1 
break+ ! circuit 9 ,a1 ! ne$le w sw+    
back 9 ! opposite direction4 ,9 nei!r   
case w ! ne$le /ay deflect$1 b w at once
 return to z]o4  ,?is %[s t :5 ! batt]y 
curr5t 0 all[$ to complete its circuit  
?r\gh wire ,a by clos+ its key1 an      
electrical action 0 in/antly felt 9 wire
 ,b1 al?\gh !re 0 no mat]ial connection 
betwe5 !m o!r ?an ! air1 :i* is a       
non-conductor4  ,! curr5t 9 ! second    
circuit is call$ an induc$ curr5t4 ,:y  
?is curr5t8 ,accord+ to "o !ory1 :5 we  
close ! prim>y circuit ! surr\nd+ e!r is

 ?r[n into a peculi> /ate ( /ra9 t we w 
call magnetic or electrical l9es ( =ce4 
,:5 ! e!r wave /rikes ! second wire !re 
is a molecul> movem5t f a /ate ( re/ to 
a /ate ( /atic /ra94 ,dur+ ! "t t !     
molecules are mov+ f ! normal to ! /ra9$
 position 9 sympa?y ) ! e!r we h !      
condition ( a dynamic curr5t1 :i* la/s  
only a mom5t4 ,?is /ate ( /ra9 cont9ues 
till ! circuit is op5$ 7break+ !        
wire-l9e71 :5 all ! electrical l9es (   
=ce vani% & ! molecul> /ra9 ( ! second  
wire is reliev$1 & we aga9 h !          
conditions1 mom5t>ily1 = a curr5t ( !   
opposite pol>ity1 & ! ne$le w sw+ 9 !   
opposite direction because ! molecules  
or atoms h1 9 _! recoil to ! natural    
/ate1 mov$ 9 an opposite direction4     
,go+ back to ,fig4 #a1 let u fur!r /udy 
! ph5om5a "u o!r conditions4 ,9 our fir/
 circuit 7,a7 !re is a batt]y & a       
circuit-break]1 :i* is a common         
telegraph-key4 ,n[ close ! key s t a    
curr5t w be e/abli%$4 7,rememb] t curr5t
 is only a "n = a condition ( dynamic   

*>ge47 ,place a piece ( s(t iron across 
! wire at "r angles ) ! direction ( !   
wire1 :5 ( c\rse x w be at "r angles ) !
 direction ( ! curr5t1 & y w f9d n[ t ! 
iron is m or less magnetic1 dep5d+ ^u ! 
am\nt ( curr5t pass+ ?r\gh ! wire4 ,if  
we w9d a numb] ( turns ( insulat$ wire  
?r\gh :i* ! curr5t is pass+ ar\nd ! iron
 ! magnetism w be increas$4 ,9 practice 
!re are a c]ta9 numb] ( turns & a c]ta9 
siz$ wire t w give ! be/ results ) a    
giv5 numb] ( cells ( batt]y 7or a giv5  
voltage or pressure71 op]at+ 9 a clos$  
circuit ( a giv5 resi/ance4 ,all ^!     
que/ions are work$ out ma!matically 9 _m
 /&>d books on ! subject4 ,x is n !     
int5tion 9 ^! talks to develop ! sci5ce 
ma!matically b to set out ! fundam5tal  
physical facts & applications (         
electricity4  ,"u ! conditions above    
nam$ magnetism is develop$ 9 ! s(t iron 
b>4 ,if we op5 ! key ! curr5t w cease & 
! magnetism w vani%--t is to say1 !     
molecules w turn back to _! neutral     
position by _! own attractions1 z has   

be5 describ$ 9 a previ\s *apt]4         
,magnetism develop$ 9 ?is way is call$  
electromagnetism4 7,see ,*ap4 ,,iv47 ,if
 we use a piece ( h>d5$ /eel in/ead ( ! 
s(t iron x w become magnetic & rema9 s  
:5 ! circuit is op5$1 because ! natural 
t5d5cy ( ! molecules to turn back to !  
neutral position is n great en\gh to    
ov]come ! co]cive =ce1 or molecul>      
friction1 ( h>d5$ /eel1 z has be5 also  
describ$ 9 a previ\s *apt]4 ,to make !  
be/ electromagnet we ne$ qualities (    
iron j ! opposite f ^? ( ! p]man5t      
magnet4 ,= ! =m] we ne$ ! pure/ ( s(t   
iron1 well anneal$ 7heat$ to r$ness &   
sl[ly cool$1 mak+ x less brittle71 s t  
its molecules are free to turn2 :ile = !
 latt] we ne$ h>d5$ /eel1 s t :5 !      
molecules are once wr5*$ into ! magnetic
 condition !y _c1 ( !mselves1 turn back 
to ! neutral /ate4 ,! great value ( !   
electromagnet lies 9 its ability to     
readily dis*>ge1 or g back to ! neutral 
/ate1 :5 ! curr5t is brok54  ,let u n[ g
 back to ! beg9n+ ( our exp]im5t4 ,:5 we

 clos$ ! key & e/abli%$ ! curr5t ?r\gh !
 wire we f\nd t a piece ( iron held at  
"r angles to ! wire1 al?\gh n t\*+ x1   
became magnetic4 ,we h already said t :5
 ! circuit 0 op51 ! batt]y be+ 9        
circuit1 !re 7 electrical l9es ( =ce    
e/abli%$ 9 ! e!r1 betwe5 ! two poles ( !
 batt]y1 & t !y 7 ga!r$ up into !       
conduct+ wire :5 ! circuit 0 clos$4 ,we 
n[ f9d t !re are o!r l9es ( =ce ( a     
diff]5t nature e/abli%$ 9 ! e!r :5 !    
circuit is clos$4 ,^! we call magnetic  
l9es ( =ce1 or ! magnetic field ( ! *>g$
 wire1 & !y are e/abli%$ at "r angles to
 ! direction ( ! curr5t4 ,^! magnetic   
l9es ( =ce act+ ?r\gh ! e!r f an        
electrically *>g$ conductor are able to 
break up ! natural molecul> magnetic    
r+s1 ref]r$ to 9 ,*apt] ,,iv1 & turn all
 _! l poles 9 ! same direction--?us mak+
 "o comp\nd magnet ( ! iron :i* 9 !     
neutral /ate consi/$ ( millions ( little
 natural magnets ^: attractions 7       
satisfi$ by a jo9+ ( _! unlike poles4   
,mo/ writ]s acc\nt = all ( ! ph5om5a (  

induc$ curr5ts 9 a second wire z com+   
directly f ^! magnetic l9es ( =ce       
develop$ ^u clos+ ! circuit4  ,s mu* =  
!ory bas$ ^u a set ( facts t make ! !ory
 seem probable4 ,if y don't l x give u a
 bett] "o4 ,if x is correct ! writ]     
claims no cr$it2 x is m]ely a           
compilation ( sugge/ions f _m s\rces1   
includ+ 8 own exp]i5ce4 ,we are simply  
seek+ aft] tru?4 ,! man :o is an e>ne/  
seek] aft] sci5tific tru? _c af=d to    
pursue 8 inve/igations ) any prejudice 9
 favor ( "o !ory m ?an ano!r1 unless !  
facts su/a9 him1 & !n he is n act+ f    
prejudice1 b is l$ by ! facts4 ,_m p    
make pets ( _! !ories2 & !y become      
atta*$ to !m z !y d _! *ildr52 & !y look
 ^u a man :o de/roys !m by a pres5tation
 ( ! facts z an enemy4 ,i once knew a   
lady :o became s atta*$ to h] family    
doctor t1 %e said1 %e w\ld r die "u 8   
treatm5t1 if necess>y1 ?an to be cur$ by
 any o!r doctor4 ,!re are _m p :o are   
imbu$ ) ?is k9d ( _s n only 9 matt]s    
sci5tific1 b 9 matt]s religi\s z well4  

,su* p are n ! k9d :o contribute to !   
_w's progress1 b are ! h9drances t h to 
be ov]come4     ,,*apt] ,,vii4          
,,electric ,,g5]ators4   ,( ! s\rces (  
electricity we h m5tion$ two3 ,friction1
 & ,galvanism or *emical action4 ,!re   
are hundr$s ( =ms ( ! latt] species (   
app>atus = g5]at+ electrical en]gy1 s we
 w m5tion only a few ( ! m prom95t ones4
 ,x is n our int5tion to g into !       
*emi/ry ( batt]ies4 ,!re are too _m     
exhau/ive works on ?is subject ly+ on ! 
%elves ( libr>ies t are accessible to   
all4 ,all galvanic batt]ies act on "o   
g5]al pr9ciple--! g5]ation ( electricity
 by ! *emical action ( acid on metal    
plates2 b ! *emi/ry ( _! action is v    
diff]5t4 ,9 all batt]ies ! pot5tial     
en]gy ( "o elem5t is great] ?an ! o!r4  
,! acid ( ! batt]y dissolves ! elem5t ( 
great] pot5tiality1 & its en]gy is fre$ 
& "u "r conditions takes on ! =m (      
electricity4 ,! pot5tial ( z9c1 =       
in/ance1 is great] ?an t ( copp]1 & !   
measure ( ! diff]5ce is call$ !         

electromotive =ce1 ! unit ( :i* is !    
volt4 ,electromotive =ce is ano!r "n =  
pressure2 ! symbol = :i* is ,e4,m4,f4   
,if we 7 to put two z9c plates 9 !      
batt]y fluid & connect !m 9 ! ord9>y way
 !re w\ld be no electricity evolv$      
7assum+ t !y 7 p]fectly homog5e\s71     
because !y are bo? ( ! same pot5tial1 or
 h ! same possible am\nt ( /or$         
electrical en]gy measur$ by its work+   
p[]4 ,if "o ( ! z9c plates 7 s(t] ?an ! 
o!r1 a feeble curr5t w\ld be develop$1 =
 "o w\ld be m readily act$ ^u by ! acids
 ?an ! o!r4 ,! batt]y t has be5 mo/ us$ 
9 ,am]ica = telegraphic purposes is     
call$ ! gravity-batt]y4 ,x is con/ruct$ 
by putt+ a copp] plate 9 "s =m at !     
bottom ( a j>1 usually ( glass1 & fill+ 
x p>tly full ( ! cry/als ( sulphate (   
copp]1 commonly call$ blue/one4 ,z9c1   
usually ca/ 9 "s op5 =m1 s z to expose a
 l>ge surface to ! solution1 is susp5d$ 
9 ! upp] "p ( ! j>1 :i* is !n fill$ )   
wat] till x cov]s ! z9c4 ,! z9c is !    
positive metal1 b x is call$ ! negative 

pole4 ,! en]gy develop$ by ! z9c passes 
f z9c to copp] & out on ! circuit f !   
copp] pole4 ,h5ce ! copp] came to be    
call$ ! positive pole1 al?\gh 9 relation
 to z9c x is negative4 ,copp] w\ld1     
h[ev]1 be positive to "s o!r metal ^:   
pot5tial 0 less4 ,s y see t metals are  
relative1 n absolute1 9 _! "* z positive
 & negative elem5ts4  ,! galvanic batt]y
 has be5 almo/ entirely sup]s$$ 9 ?is   
c\ntry = telegraphic purposes by !      
dynamo1 a ma*9e develop+ electrical     
curr5ts by me*anical p[]4 ,ano!r =m (   
batt]y t is ext5sively us$ = "s k9ds (  
heavy curr5t "w is call$ !              
/orage-batt]y4 ,! man :o did ! mo/1     
p]haps1 to br+ ! /orage-batt]y to its   
pres5t /ate ( p]fection 0 ,plante1 a    
,fr5*man1 :o di$ only a %ort "t ago4    
,al?\gh v _m types ( batt]y h be5       
develop$1 x is f\nd t1 aft] all1 ! l9es 
on :i* he develop$ x make ! mo/ effici5t
 batt]y4 ,!re is a common notion t      
electricity is /or$ 9 ! /orage-batt]y4  
,en]gy is /or$1 t w produce electricity 

:5 x is set free1 j ! same z en]gy is   
/or$ 9 z9c4 ,! /orage-batt]y1 :5 ready =
 action1 is "o =m ( acid or prim>y      
batt]y4 ,x has be5 made by pass+ a      
curr5t ( electricity ?r\gh x until !    
*emical relations ( ! two lead plates h 
be5 *ang$ s t ! pot5tial ( "o is great] 
?an t ( ! o!r4 ,a simple /orage-batt]y  
elem5t is made up ( two plates ( lead   
held out ( contact ) ea* o!r by "s      
insulat+ sub/ance ! same z ! elem5ts (  
an ord9>y batt]y4 ,! cell is fill$ )    
dilute sulphuric acid1 & !re w be no    
electrical action till ! cell has be5   
*>g$ by runn+ a curr5t ( electricity    
?r\gh x & =m+ a lead oxide on "o plate4 
,n[1 take (f ! *>g+ batt]y & connect !  
two poles1 & electricity w fl[ until !  
oxide has p>tly *ang$ back into spongy  
metallic lead1 :5 x mu/ be r5ew$ by     
re*>g+4  ,i rememb] p]fectly well ! fir/
 galvanic batt]y ,i ev] saw1 = x 0 ( my 
own con/ruction4 ,x is n[ ne>ly fifty   
ye>s ago1 & yet x seems b ye/]day--su*  
is ! flight ( "t4 ,i relat$ to y 9 ano!r

 *apt] h[ ,i made a voltaic batt]y--or  
pile1 z x 0 call$--by cutt+ up my "m's  
boil] & h] /ove-z9c1 & ! dome/ic incid5t
 t foll[$4 ,well1 a little lat] ,i made 
a real galvanic batt]y z foll[s3 ,i liv$
 9 ! c\ntry & f> f t[n or city1 & my    
facilities 7 extremely limit$1 s t ,i   
pursu$ my sci5tific inve/igations "u    
great difficulties4 ,my only text-book 0
 an old ,com/ock's ,philosophy4 ,9 !    
book 0 a crude cut ( a ,morse regi/] & a
 %ort description ( its con/ruction1    
includ+ ! batt]y4 ,i det]m9$ to make a  
regi/]1 & ,i did4 ,x 0 all con/ruct$ (  
wood except ! magnet & its armature & ! 
emboss+-po9t1 :i* latt] 0 made ( ! end (
 a nail4 ,! ?+ t seem$ out ( rea* 0 !   
electromagnet4 ,i _h no money2 & !re 0  
no "o t believ$ ,i c\ld d x1 & if ,i    
c\ld :at good w\ld come ( x8 ,i made    
fri5ds ) a blacksmi? by keep+ flies (f a
 horse :ile he nail$ ! %oes on1 & bl[+ !
 bell[s & occasionally us+ ! sl$ge =    
him4 ,:5 ,i ?\ght ! obligation _h       
accumulat$ a suffici5t voltage 7to      

express x electrically7 ,i communicat$  
to ! blacksmi? ! situation & :at ,i     
want$4  ,! good-natur$ old fell[ 0 n    
long 9 b5d+ up a ,u magnet ( s(t iron & 
=g+ out an armature4 ,! next /ep 0 to   
w9d ! ,u ) insulat$ wire4 ,! only ?+ t  
,i _h ev] se5 ( ! k9d 0 an iron wire    
call$ bonnet wire t 0 wrapp$ ) cotton   
?read4 ,?is1 h[ev]1 0 n available1 s ,i 
captur$ a piece ( brass bell-wire & w\nd
 /rips ( cotton clo? ar\nd x =          
insulation--& 9 t way complet$ ! magnet4
  ,n[ ev]y?+ 0 ready b ! batt]y4 ,i w5t 
at its con/ruction ) a feel+ almo/ ak9  
to awe1 = ,i c\ld n believe t x w\ld d z
 describ$ 9 ! book4 ,i procur$ a c&y-j> 
f ! groc] & f\nd "s pieces ( %eet z9c & 
copp]4 ,^! ,i roll$ toge!r into loose   
spirals & plac$ "o inside ! o!r s t !y  
w\ld n t\*1 :5 ,i 0 ready = ! solution4 
,! druggi/ tru/$ me = a half p\nd ( blue
 vitriol1 & ,i put x into my batt]y &   
fill$ x ) wat]4 ,i wait$ a:ile = x to   
dissolve1 & !n connect$ my magnet 9     
circuit1 :5--to my a/oni%m5t &          

delight--x w\ld lift a p\nd or m4 ,x 0 a
 great triumph4 ,i nev] h _h "o s9ce t  
gave me ! same satisfaction4 ,b ,i _h my
 triumph all to myself4 ,i 0 /ill ! same
 t9k] 7a "n ,i _h long c>ri$71 & a      
nuisance to be endur$ b n enc\rag$4  ,! 
dynamo is ! =m ( g5]ator n[ 9 g5]al use 
:]e heavy curr5ts ( electricity are     
ne$$4 ,x is aptly describ$ by a writ] 9 
,mod]n ,ma*9]y1 ,mr4 ,john ,a4 ,gri]1 z 
a ?+ t :5 at re/ is a lifeless piece (  
me*anism2 9 action x has a liv+ _s z    
full ( my/]y z ! s\l ( man4 ,?is is a   
poetic way ( describ+ x t conveys to !  
m9d a s5se ( ! p[] & beauty ( natural   
law 9 action1 t w\ld n come f a m]e     
recital ( ! cold sci5tific facts4 ,!    
facts1 h[ev]1 are necess>y3 b let u draw
 f !m all ! poetry & all ! practical    
lessons t we c z we g along2 = x is ?is 
bl5d+ ( ! poetic ) ! practical t l5ds a 
*>m to our e-day gr9d1 & light5s ! load 
( _m a we>y h\r4  ,! dynamo is a ma*9e t
 conv]ts me*anical into electrical      
en]gy1 & ! great practical value ( en]gy

 9 ?is =m is t x c be di/ribut$ ?r\gh a 
conductor economically = _m miles4 ,we c
 transmit me*anical p[] by means ( a    
rope or cable = a limit$ di/ance1 b at  
trem5d\s loss ?r\gh friction4 ,we c     
transmit p[] ?r\gh pipes by compress$   
air or /eam1 b !re is a great loss1     
especially 9 ! case ( /eam1 by          
cond5sation f cold4 ,none ( ^! me?ods   
are available = long di/ances4 ,ano!r   
advantage electricity has ov] o!r =ms ( 
en]gy is ! spe$ ) :i* x c be transmitt$ 
f "o place to ano!r4 ,9 ?is respect x   
has no rival except light4 ,b we h n be5
 able to h>ness light & make x available
 to c>ry ei!r freight or news1 except 9 
! latt] case = a %ort di/ance by fla%+ x
 9 agre$ signals4  ,! helio/at c be us$ 
:5 ! sun %9es to transmit news by fla%es
 ( sunlight *opp$ up into ! ,morse code 
& ?r[n f po9t to po9t by a mov+ mirror4 
,b ?is is limit$ z to di/ance2 besides1 
! sun does n always %9e4 ,x has !       
disadvantage 9 t respect t ! old        
semaphore-telegraph did t 0 9 use 9     

,well+ton's day4 ,^! semaphores 7       
con/ruct$ 9 v>i\s ways1 b a common =m 0 
t ( mov+ arms t c\ld be se5 f hill to   
hill or po9t to po9t4 ,by a code ( mov+ 
signals news 0 repeat$ f po9t to po9t & 
x c be easily imag9$ t _m mi/akes       
occurr$1 to say no?+ ( ! "t x requir$ = 
repetition4 ,:5 ! battle ( ,wat]loo 0   
f\ght--s ! /ory goes--news 0 s5t to     
,engl& by means ( ! semaphore-telegraph4
 ,! dispat* read1 ,well+ton defeat$--   
,at t po9t 9 ! message a ?ick fog came  
up & la/$ = ?ree days1 s t no fur!r news
 c\ld be s5t or receiv$4 ,9 !           
telegraphic p>lance ( to-day ! l9e 0    
bu/$4 ,= ?ree long days all ,london 0 9 
deep m\rn+1 :5 f9ally ! fog lift$1 :i*  
repair$ ! telegraphic l9e1 & ! balance (
 ! dispat* 0 receiv$--! ,fr5* at        
,wat]loo4 ,m\rn+ *ang$ to rejoic+ & !   
,engli% h rejoic$ ev] s9ce :5 !y ?9k (  
ei!r ,well+ton or ,wat]loo4  ,b to      
return to ! dynamo4 ,! "n dynamo is an  
abbreviation = dynamo-electric ma*9e4 ,a
 ma*9e = produc+ dynamic electricity4   

,!re are _m =ms ( ! dynamo1 j z !re are 
9 ! evolution ( e important ma*9e1 & !re
 w be _m m4 ,b ! fundam5tal1 und]ly+    
pr9ciple ( !m all is conta9$ 9 an       
exp]im5t made by ,f>aday4 ,f>aday took !
 s(t iron keep] ( a p]man5t magnet &    
w\nd insulat$ wire ar\nd x & br\ght !   
two ends ( ! wire close toge!r4 ,he n[  
plac$ ! keep]1 ) ! wire w\nd ar\nd x1   
across ! poles ( ! p]man5t magnet1 &    
wr5*$ x away sudd5ly1 :5 he obs]v$ a    
sp>k pass betwe5 ! ends ( ! wires4 ,?is 
w\ld occur :5 he approa*$ ! poles z well
 z :5 he took x away4 ,he discov]$ t !  
curr5ts 7 mom5t>y & occurr$ at ! mom5t (
 approa* or recession1 & t ! curr5ts    
develop$ by ! approa* 7 ( opposite      
pol>ity to ^? occurr+ at ! recession4   
,:5 ! keep] 0 put on ! poles ( ! magnet 
x 0 magnetiz$ by hav+ its molecul> r+s  
brok5 up & ! poles ( ! little natural   
magnets all turn$ 9 "o direction4 ,dur+ 
! "t t ! molecules ( ! keep] are *ang+  
!y are 9 a dynamic or mov+ condition4   
,by "s my/]i\s action ( ! e!r betwe5 !  

iron & ! wire wrapp$ ar\nd x !re is a   
correspond+ molecul> action 9 ! wire t  
is dynamic = a mom5t only1 & dur+ t     
mom5t we h ! ph5om5on ( an electric     
curr5t4 ,:5 ! magnet & s(t iron are     
sep>at$ ?is molecul> /ate ( /ra9 is     
reliev$ & ! molecules ( bo? ! iron & !  
wire w\nd ab\t x return to normal1 & 9 !
 act ( return+ we h a dynamic or mov+   
condition1 result+ 9 a curr5t1 only 9 ! 
opposite direction4 7,see ,*ap4 ,,vi47  
,n[ m\nt ! p]man5t magnet 9 a frame &   
m\nt ! s(t iron ) ! wire on x 7:i* 9 ?is
 %ape is an electromagnet7 on a revolv+ 
arm & s set x on ! arm t its ends w come
 close to1 b n t\*1 ! poles ( ! p]man5t 
magnet4 ,n[ revolve ! arm1 & e "t !     
electromagnet or keep] approa*es !      
p]man5t magnet a curr5t ( "o pol>ity w  
be mom5t>ily develop$ 9 ! wire ( !      
electromagnet1 :i* is mov+4 ,:5 x is    
opposite ! poles1 x has rea*$ ! maximum 
*>ge &1 n[1 z x passes on x dis*>ges & a
 curr5t ( ! opposite pol>ity is develop$
 9 ! wire4 ,! m rapidly we revolve ! arm

 ! m voltage 7electrical pressure7 !    
curr5t x develops w h4  ,x w be pla9 to 
all t we might make ! electromagnet     
/ation>y & revolve ! p]man5t magnet &   
get ! same result4 ,if ! p]man5t magnet 
7 /rong en\gh & ! electromagnet ! "r    
size z to iron1 w9d+s1 etc41 & we       
revolve ! arm ) suffici5t rapidity1 we  
c\ld get an alt]nat+ curr5t (           
electricity t w\ld produce an electric  
light4 ,i h n & _c "h give y !          
con/ruction ( a mod]n alt]nat+-curr5t   
dynamo4 ,i h simply describ$ ! simple/  
=m ( dynamo1 & all ( !m op]ate ^u !     
fundam5tal pr9ciple ( a p]man5t magnetic
 field & an electromagnet1 mov+ 9 a     
c]ta9 relation to ea* o!r4 ,! field may 
revolve or ! electromagnet may revolve1 
:i*ev] is ! mo/ conv5i5t to con/ruct4 ,!
 field-magnet may be a p]man5t magnet or
 an electromagnet1 made p]man5t dur+ !  
op]ation ( ! dynamo by a "p ( ! curr5t  
g5]at$ by ! ma*9e be+ direct$ ?r\gh a   
coil surr\nd+ s(t iron2 or !            
field-curr5t may come f an outside      

s\rce4 ,?is is ! k9d ( field-magnet     
univ]sally us$ = dynamo "w1 z a mu*     
/rong] magnetism is develop$ 9 ?is way  
?an x is possible to obta9 f any sy/em (
 p]man5t /eel magnets4  ,! usual        
con/ruction is to h a /ation>y          
field-magnet & !n a s]ies (             
electromagnets m\nt$ & revolv+ ^u a %aft
 9 ! c5t] ( ! magnetic field4 ,! rotat+ 
"p is call$ ! armature1 & is s w\nd )   
insulat$ wire t successive induc$       
curr5ts are creat$ 9 ! armature w9d+s & 
dis*>g$ ?r\gh bru%es :i* re/ on revolv+ 
segm5ts t connect ) ! armature w9d+s4   
,^! induc$ curr5ts succe$ ea* o!r ) su* 
rapidity z to am\nt 9 practice to a     
/eady curr5t4 ,h[ev]1 ! sep>ate         
pulsations are easily he>d 9 any        
telephone :5 ! circuit is ne> to t ( a  
dynamo circuit4 ,! dynamo curr5t is n   
ne>ly s /eady z ! batt]y curr5t1 al?\gh 
bo? are probably made up ( sep>ate      
dis*>ges4 ,9 ! dynamo !re is a dis*>ge e
 "t ! electromagnet ( ! armature cuts   
?r\gh ! l9es ( =ce ( ! magnetic field1 &

 9 ! galvanic batt]y e "t a molecule is 
brok5 up & its little measure ( en]gy is
 set free4 ,9 ! dynamo ! pulsations are 
s f> ap>t z to make a musical tone ( n v
 high pit*1 b 9 ! galvanic batt]y ! pit*
 ( ! tone1 if !re is "o1 w\ld require a 
special e> to he> x--"o tun$1 x may be1 
up ne> ! rate ( light vibration4  ,!re  
are two types ( dynamo1 "o g5]at+ a     
direct & ! o!r an alt]nat+ curr5t4 7,by 
alt]nat+ we mean fir/ a positive & !n a 
negative curr5t impulse47 ,we _c ent]   
into a te*nical description ( ! dynamo 9
 a popul> treatise su* z ?is4  ,! dynamo
 has evolv$ f ! g]m discov]$ by ,f>aday1
 till to-day x is a ma*9e1 ! con/ruction
 ( :i* requires ! highe/ class ( eng9e]+
 skill4 ,:5 9 action x seems l a great  
liv+ pres5ce1 scatt]+ its en]gy 9 e     
direction 9 a way t is at once a m>vel &
 a bless+ to mank9d4 ,b we mu/ n give   
all ! cr$it to ! dynamo4 ,z ! moon %9es 
) a reflect$ light1 s ! dynamo gives (f 
en]gy by a p[] delegat$ to x by !       
/eam-eng9e t rotates x1 & ! /eam-eng9e  

owes its life to ! burn+ coal1 & ! burn+
 coal is only giv+ up an en]gy t 0 /or$ 
ages ago by ! magic ( ! sunbeam2 & !    
sun--8 ,well1 we are gett+ close on to !
 bord]s ( !ology1 & be+ only sci5ti/s we
 _h bett] /op ) ! sun4  ,!re is /ill    
ano!r way ( g5]at+ electricity besides  
^? t we h nam$2 :i* are friction1       
*emical action1 & ! magneto-electric    
mode ( g5]at+ a curr5t4 ,electricity may
 be g5]at$ by heat4 ,if we connect      
antimony & bismu? b>s toge!r & apply    
heat at ! junction ( ! metals & !n      
connect ! free ends ( ! two b>s to a    
galvanomet]1 x w indicate a curr5t4 ,^! 
pairs c be multipli$1 & 9 ?is way       
increase ! voltage or pressure1 &1 (    
c\rse1 increase ! curr5t1 if we assume t
 !re is resi/ance 9 ! circuit to be     
ov]come4 ,if !re 7 absolutely no        
resi/ance 9 ! circuit--a condition we   
nev] f9d--!re w\ld be no advantage 9    
add+ on elem5ts 9 s]ies4  ,sub/ances    
diff] 9 _! resi/ance to ! passage (     
electricity--! less ! resi/ance ! bett] 

! conductor4 ,! ,g]man electrician1 ,g4 
,s4 ,ohm 7#aghi-ahed71 inve/igat$ ?is & 
prop\nd$ a law ^u :i* ! unit =          
resi/ances is bas$1 & ?is unit takes 8  
"n & is call$ ! ohm4  ,any two metals   
hav+ a diff]5ce ( pot5tial w give !     
ph5om5a ( !rmo-electricity4 ,antimony & 
bismu? hav+ a great diff]5ce ( pot5tial 
are commonly us$4 ,! use made ( !rmal   
curr5ts is *iefly = det]m9+ slight      
diff]5ces ( temp]ature4 ,an app>atus    
call$ ! !rmo-electric pile has be5      
con/ruct$ out ( a great numb] ( pairs ( 
antimony & bismu? b>s4 ,?is in/rum5t 9  
connection ) a galvanomet] makes a mo/  
delicate means ( det]m9+ slight *anges (
 temp]ature4 ,if "o face ( a !rmopile is
 expos$ to a temp]ature great] ?an its  
own1 ! ne$le w move 9 "o direction2 if  
to a temp]ature l[] ?an its own1 ! ne$le
 w be deflect$ 9 ! opposite direction4  
,if bo? faces ( ! pile are expos$ to !  
same *anges ( temp]ature simultane\sly1 
( c\rse no electrical manife/ations w   
occur4  ,! e>? is und\bt$ly a great     

!rmal batt]y t is kept 9 action by !    
con/ant *anges ( temp]ature go+ on at ! 
e>?'s surface1 caus$ by its rotation e  
tw5ty-f\r h\rs on its axis4 ,! sun1 (   
c\rse1 is at "s po9t heat+ ! e>?1 :i* at
 o!r po9ts is cool+1 mak+ a con/ant     
*ange ( pot5tial betwe5 diff]5t po9ts4  
,if we heat a metal r+ at "o po9t a     
curr5t ( electricity w fl[ ar\nd        
x--especially if x is made ( two        
dissimil> metals--until ! heat is       
equally di/ribut$ ?r\gh\t ! r+4  ,"s    
ye>s ago1 :5 ! ,po/al ,telegraph        
,company fir/ began op]ations betwe5    
,new ,york & ,*icago1 ! writ] made      
obs]vations twice a day = "s "t ( !     
temp]ature & direction ( ! e>?-curr5t4  
,! fir/ two wires con/ruct$ gave only   
two ohms resi/ance to ! mile1 :i*       
facilitat$ ! exp]im5ts4 ,i f\nd t 9     
almo/ e in/ance ! curr5t fl[$ f ! po9t (
 high] temp]ature to ! l[]4 ,if !       
temp]ature 9 ,new ,york 7 high] at ! "t 
( obs]vations ?an 9 ,*icago ! curr5t    
w\ld fl[ we/w>d1 & if ! conditions 7    

rev]s$ ! curr5t w\ld be rev]s$ also4    
,,*apt] ,,viii4  ,,atmosph]ic           
,,electricity4   ,nature has ano!r mode 
( g5]at+ electricity1 call$ atmosph]ic4 
,! normal conditions ( pot5tial betwe5 !
 e>? & ! upp] atmosph]e seem to be t !  
atmosph]e is positively electrifi$ & !  
e>? negatively4 ,^! conditions *ange1   
app>5tly f local causes1 = %ort p]iods  
dur+ /orms4 ,9 "s way ! sun's rays h !  
p[] directly or indirectly to give !    
globules ( moi/ure 9 ! air a pot5tial   
diff]5t f t ( ! e>?4  ,9 cle> wea!r we  
f9d ! air ne> to ! e>? 9 a neutral      
condition1 b gradually assum+ !         
condition ( a positive *>ge z we asc5d2 
s t ! upp] air & ! e>? are oppositely   
*>g$ l ! two sides ( a ,leyd5 j> or two 
leaves ( a cond5s]4 ,?is condition is   
int5sifi$ & localiz$ :5 a ?und]-cl\d    
passes ov] ! e>?4 ,! moi/ure globules h 
be5 *>g$ ) pot5tial en]gy by ! p[] ( !  
sun's rays :5 evaporation took place2 b 
9 ?is /ate ! en]gy is nei!r heat nor    
electricity1 b a /ate ( /ra9 l a b5t b[ 

or a w\nd-up spr+4 ,:5 ^! moi/ure       
globules cond5se into drops ( wat] !    
pot5tial en]gy is set free & becomes    
active ei!r z heat or electricity4 ,!   
cl\d ga!rs up ! en]gy into a cond5s$ =m1
 & :5 ! t5sion gets too great a dis*>ge 
takes place betwe5 ! cl\d & ! e>? or f  
"o cl\d to ano!r1 :i* to an ext5t       
equalizes ! en]gy4  ,9 mo/ cases ( ?und]
 & lightn+ x is only a dis*>ge f cl\d to
 cl\d unequally *>g$4 ,?is does n       
relieve ! t5sion betwe5 ! e>? & ! cl\d1 
b di/ributes x ov] a l>g] area4 ,!      
reason = ?is con/ant electrical diff]5ce
 betwe5 ! e>? & ! upp] regions (        
atmosph]e is n well und]/ood1 except t  
prim>ily x is an effect ( ! sun's rays4 
,evaporation may & probably does play a 
"p1 & ! same causes t give rise to !    
auroral display may contribute 9 "s way 
to ! same result4 ,evaporation does n   
always take place at ! e>?'s surface4   
,cl\d =mations may be evaporat$ 9 ! upp]
 air into invisible moi/ure sph]ules1 & 
*>g$ at ! "t ) pot5tial en]gy4 ,if we g 

up into a high m\nta9 :5 ! conditions   
are "r1 we c witness ! effect ( ?is     
condition ( electrical *>ge or /ra9     
betwe5 ! upp] regions ( ! atmosph]e & ! 
e>?1 & ! t5d5cy to equalize ! pot5tials 
betwe5 ! cl\ds & ! e>?4 ,(t5 "o's hair w
 /& on end1 n f fright1 b f electricity 
pass+ d[n f ! upp] regions to ! e>?4 ,:5
 ! t5sion is v great a l\d hiss+ s\nd z 
( _m musical tones ( n v good quality   
may be he>d1 & a bru% or f9e-po9t$      
radiation ( electricity may be se5 f e  
po9t1 ev5 f y\r f+]-ends4 ,! ?und] is n 
usually s l\d on high m\nta9s = two     
reasons--"o because ! air is r>e1 b !   
*ief reason is t ! m\nta9 acts z a great
 lightn+-rod & gradually dis*>ges ! cl\d
 or atmosph]e1 = (t5 ! ph5om5a may occur
 :5 ! sky is cle>4  ,i rememb] be+ on   
top ( :at is call$ ! ,mosquito ,range1  
betwe5 ,alma & ,leadville 9 ,colorado1  
dur+ ! passage ( a ?und] %[]4 ,!re 0 no 
heavy ?und]1 b a con/ant fusillade (    
snapp+ s\nds1 accompani$ by fla%es n v  
int5se4 ,i c\ld feel ! %ocks1 b n       

pa9fully4 ,a "p ( ! "t ,i 0 9 ! cl\d &  
became = ! "t be+ a v]itable            
lightn+-rod4 ,aft] ! cl\d pass$ x crawl$
 d[n ! m\nta9side z if cl++ to x1 all ! 
"t bomb>d+ x ) little electric missiles4
 ,aft] ! cl\d left ! m\nta9 & pass$ ov] 
! valley ,i c\ld he> l\d ?und]1 because 
! *>ge w\ld h to accumulate q a         
quantity1 s to speak1 be=e x c\ld       
dis*>ge4 ,^! heavy dis*>ges :5 ! cl\d is
 "s di/ance f ! e>? w\ld be dang]\s to  
life1 :ile ! light ones1 :5 ! cl\d is 9 
contact ) ! e>?1 are n4  ,_m wond]ful & 
de/ructive effects come f ^! lightn+    
dis*>ges & _m lives are lo/ e ye> f ?is 
cause4 ,i d n suppose x is possible to  
be on "o's gu>d cont9ually1 b _m lives  
are ne$lessly lo/ ei!r f ignorance or   
c>elessness4 ,al?\gh !re is a j         
prejudice aga9/ lightn+-rods z ord9>ily 
con/ruct$1 x is /ill j z possible to    
protect y\r h\se & its inmates f !      
de/roy+ effects ( lightn+ z f ra94 ,if1 
= in/ance1 we liv$ 9 metal h\ses t _h   
p]fect contact all r\nd !m ) moi/ e>?1  

or bett]1 ) a wat]-pipe t has a l>ge    
surface contact ) ! e>?1 ! lightn+ w\ld 
nev] hurt ! h\se or ! inmates4 ,9 su* a 
case y simply c>ry ! surface ( ! e>? to 
! top ( y\r h\se1 electrically speak+1 &
 neutralization takes place !re 9 case !
 lightn+ /rikes ! h\se4 ,a h\se t is    
heat$ ) hot wat] c easily be made       
lightn+-pro( by a little "w at ! top &  
bottom ( ! heat+ sy/em4 ,all ! heavy    
metal ( ! h\se %\ld be a "p ( !         
lightn+-rod4 ,po9ts %\ld be erect$ at ! 
*imneys1 & if !re is a metal ro( !y %\ld
 be connect$ ) x4 ,!n connect ! ro( )   
rods f sev]al po9ts ) ! gr\nd4 ,"h is   
:]e mo/ rods fail4 ,! gr\nd connection  
is n suffici5t4 ,! e>? is a poor        
conductor1 & we h to make up by hav+ a  
l>ge metal surface 9 contact ) x4 ,x is 
be/ to h ! rod connect$ ) ! wat] pipe1  
if !re is "o1 & h x connect$ ) metal    
runn+ all ar\nd ! h\se z l[ d[n z !     
bottom ( ! cell>1 = sometimes !re is an 
upw>d /roke1 & y nev] c tell :]e x is   
com+ up4 ,if y h a heat+ sy/em x %\ld be

 ?or\ghly gr\nd$ & ! top pipe connect$ )
 ! rods at ! *imneys4 ,^! rods ne$ n be 
insulat$ z is ! usual practice4  ,if y  
are outdoors dur+ a ?und]-/orm nev] get 
"u a tree1 b if y are tw5ty or ?irty    
feet away x may save y\r life1 because1 
if x comes ne> en\gh to /rike y1 x w    
probably take ! tree 9 pref]5ce4 ,x     
seeks ! e>? by ! easie/ passage4 ,an    
oil-tank & a b>n are dang]\s places1 if 
! "o has oil 9 x & ! o!r is fill$ ) hay 
& gra94 ,a column ( gas is ris+ t acts z
 a conductor = lightn+4 ,( c\rse if !   
b>n is prop]ly protect$ ) rods x w be   
safe4 ,sometimes a cl\d is s heavily    
*>g$ t ! lightn+ comes d[n l an         
avalan*e1 & 9 su* a case ! rods mu/ h   
great capacity & be close toge!r to     
fully protect a build+4  ,!re is a      
popul> notion t rods draw ! lightn+ &   
increase ! damage r ?an o!rwise4 ,?is is
 a mi/ake4 ,po9ts w draw (f electricity 
f a *>g$ body sil5tly4 ,x w\ld be       
possible to s protect a di/rict ( any   
size 9 su* a way t ?und] w\ld nev] be   

he>d )9 its b\nd>ies if we %\ld erect   
rods en\gh & run !m high en\gh into !   
upp] air4 ,! po9ts--if !y 7 close en\gh 
toge!r--w\ld sil5tly draw (f !          
electricity f a cl\d z fa/ z x =m$1 &   
?us effectually prev5t any disruptive   
dis*>ge f tak+ place4     ,,*apt] ,,ix4 
,,electrical ,,measurem5t4   ,hav+ giv5 
a %ort acc\nt ( "s ( ! s\rces (         
electricity1 let u n[ proce$ to describe
 "s ( ! practical uses to :i* x is put1 
& at ! same "t describe ! op]ation ( !  
appliances us$4 ,be=e proce$+ fur!r1    
h[ev]1 we ought to tell h[ electricity  
is measur$4 ,we h p\nds = weight1 feet &
 in*es = l9eal measure1 & p9ts1 qu>ts1  
gallons1 pecks & bu%els = liquid & dry  
measure1 & we also h ohms1 volts1 amp]es
 & amp]e-h\rs = electricity4  ,:5 a     
curr5t ( electricity fl[s ?r\gh a       
conductor ! conductor resi/s its fl[ m  
or less accord+ to ! quality & size ( ! 
conductor4 ,silv] & copp] are good      
conductors4 ,silv] is bett] ?an copp]4  
,call+ silv] #ajj1 copp] w be only #gc4 

,if we h a mile ( silv] wire & a mile ( 
iron wire & want ! iron wire to c>ry z  
mu* electricity z ! silv] & h ! same    
batt]y = bo?1 we w h to make ! iron wire
 ov] sev5 times z l>ge4 ,t is1 ! area ( 
a cross-section ( ! iron wire mu/ be ov]
 sev5 times t ( ! silv] wire4 ,b if we  
want to keep bo? wires ! same size &    
/ill =ce ! same am\nt ( curr5t ?r\gh ea*
 we mu/ increase ! pressure ( ! batt]y  
connect$ ) ! iron wire4 ,we measure ?is 
pressure by a unit call$ ! volt1 nam$ = 
,volta1 ! inv5tor or discov]] ( !       
voltaic batt]y4 ,! volt is ! unit (     
pressure or electromotive =ce4 7,9 all  
^! cases a unit is a c]ta9 am\nt or     
quantity--z ( resi/ance1 electromotive  
=ce1 etc4--fix$ ^u z a /&>d = measur+   
o!r am\nts ( ! same k9d47  ,! iron wire 
(f]s a resi/ance t is ab\t sev5 times   
great] ?an silv] to ! passage ( !       
curr5t4 ,to illu/rate by wat] pressure3 
,if we %\ld h two columns ( wat]1 & a   
hole at ! bottom ( ea* column1 "o ( !m  
sev5 times l>g] ?an ! o!r1 ! wat] w\ld  

run out mu* fa/] f ! l>g] hole if !     
columns 7 ! same height4 ,n[1 if we keep
 ! column ) ! l>g] hole at a fix$ height
 a c]ta9 am\nt ( wat] w fl[ ?r\gh p]    
second4 ,if we raise ! height ( ! column
 hav+ ! small hole we %all rea* a po9t  
aft] a "t :5 !re w be z mu* wat] fl[    
?r\gh ! small hole p] second z !re is   
fl[+ ?r\gh ! l>ge hole4 ,?is result has 
be5 accompli%$ by increas+ ! pressure4  
,s1 we c accompli% a simil> result 9    
pass+ electricity ?r\gh an iron wire at 
! same rate x fl[s ?r\gh a silv] wire ( 
! same size1 by increas+ ! pressure1 or 
electromotive p[]2 & ?is is call$       
increas+ ! voltage4  ,! quality ( ! iron
 wire t prev5ts ! same am\nt ( curr5t f 
fl[+ ?r\gh x z ! silv] is call$ its     
resi/ance4 ,! unit ( resi/ance1 z       
m5tion$ 9 ! la/ *apt]1 is call$ ! ohm1 &
 ! m ohms !re are 9 a wire z comp>$ )   
ano!r1 ! m volts we h to put into !     
batt]y to get ! same curr5t4  ,! unit = 
measur+ ! curr5t is call$ ! amp]e1 nam$ 
aft] ! ,fr5* electrician1 ,a4 ,m4 ,amp]e

 7#aghi-ahcf74  ,n[1 to make practical  
application ( ^! units4 ,! volt is !    
pot5tial or pressure ( "o cell ( batt]y 
call$ a /&>d cell1 made 9 a c]ta9 way4  
,! electromotive =ce ( "o cell ( a      
,daniell batt]y is ab\t "o volt4 ,"o ohm
 is ! resi/ance (f]$ to ! passage ( a   
curr5t hav+ "o volt pressure by a column
 ( m]cury "o millimet] 9 cross-section &
 #ajf4c c5timet]s 9 l5g?4 ,ord9>y iron  
telegraph-wire measures ab\t ?irte5 ohms
 to ! mile4 ,n[ connect our /&>d        
cell--"o volt--?r\gh "o ohm resi/ance & 
we h a curr5t ( "o amp]e4 ,unit         
electromotive =ce 7volt7 ?r\gh unit     
resi/ance 7ohm7 gives unit ( curr5t     
7amp]e74 ,x is n ! int5tion to treat !  
subject ma!matically1 b ,i w give y a   
simple =mula = f9d+ ! am\nt ( curr5t if 
y "k ! resi/ance & ! voltage4 ,!        
electromotive =ce divid$ by ! resi/ance 
gives ! curr5t4 ,c  ,e_/,r or curr5t    
7amp]es7 equals electromotive =ce       
7volts7 divid$ by ! resi/ance 7ohms74   
,b /ill fur!r3 ,"o amp]e ( curr5t hav+  

"o volt pressure w develop "o watt (    
p[]1 :i* is equal to #a_/gdf ( a        
horse-p[]4 7,! watt is nam$ 9 honor (   
,james ,watt1 ! ,scotti% inv5tor ( !    
/eam-eng9e--#aghf-ahac74 ,9 o!r words1  
#gdf watts equal "o horse-p[]4 ,by      
multiply+ volts & amp]es toge!r we get  
watts4  ,if we want to c>ry only a small
 curr5t = a long di/ance we d n ne$ to  
use l>ge cells1 b _m ( !m4 ,we increase 
! pressure or voltage by increas+ !     
numb] ( cells set up 9 s]ies4 ,if we h a
 wire ( giv5 l5g? & resi/ance & f9d we  
ne$ #ajj volts to =ce ! "r am\nt or     
/r5g? ( curr5t ?r\gh x1 & !             
electromotive =ce ( ! cells we are us+  
is "o volt ea*1 x w require #ajj cells4 
,if we h a batt]y t has an ,e4 ,m4 ,f4 (
 two volts to ! cell1 z ! /orage-batt]y 
has1 fifty cells w\ld answ]4 ,if we want
 a v /rong curr5t ( great volume1 s to  
speak1 = electric light or p[]1 & use a 
galvanic batt]y1 we %\ld h to h cells ( 
l>ge surface & l[] resi/ance bo? inside 
& outside ! cells4  ,:5 dynamos are us$ 

!y are s con/ruct$ t a giv5 numb] (     
revolutions p] m9ute w give ! "r        
voltage4 ,9 fact1 ! dynamo has to be    
built = ! am\nt ( curr5t t mu/ be       
deliv]$ ?r\gh a giv5 resi/ance4 ,! same 
holds good = a dynamo z = a galvanic    
batt]y4 ,if any "o factor is fix$1 we   
mu/ adapt ! o!rs to t "o 9 ord] to get !
 result we want4 ,!re are _m o!r units1 
b to introduce !m "h w\ld only confuse !
 read]4 ,! advanc$ /ud5t is ref]r$ to ! 
text-books4  ,) ?is mu* z a prelim9>y we
 are prep>$ to take up ! applications ( 
electricity1 :i* to mo/ p w be m int]e/+
 ?an :at has gone be=e4     ,,*apt] ,x4 
,,! ,,electric ,,telegraph4   ,9 ! ye>  
#afag ,/rada1 an ,italian ,jesuit1      
propos$ to telegraph news )\t wires by  
means ( two sympa!tic ne$les made (     
load/one s balanc$ t :5 "o 0 turn$ ! o!r
 w\ld turn ) x4 ,ea* ne$le 0 to h a dial
 ) ! lett]s on x4 ,?is w\ld h be5 v nice
 if x _h only work$1 b x 0 n bas$ on any
 kn[n law ( nature4  ,_m attempts at    
telegraph+ ) electricity 7 made by      

diff]5t p dur+ ! eighte5? c5tury4 ,ab\t 
#agdh ,frankl9 succe$$ 9 fir+ spirits by
 means ( a wire across ! ,s*uylkill     
,riv]1 us+1 z all ! o!r exp]im5t]s _h   
done1 frictional electricity4 ,9 #agec  
an anonym\s lett] 0 writt5 to ,scott's  
,magaz9e describ+ a me?od by :i* x 0    
possible to communicate at a di/ance by 
electricity4 ,! writ] propos$ ! use ( a 
wire = ea* lett] ( ! alphabet1 t %\ld   
t]m9ate 9 pi? balls at ! receiv+ end1 & 
"u ! balls 7 to be /rips ( pap]         
correspond+ to ! lett]s ( ! alphabet4 ,!
 message 0 to be s5t by dis*>g+ /atic   
electricity ?r\gh ! wire correspond+ to 
! fir/ lett] ( a ^w :5 ! pap] w\ld be   
attract$ to ! pi? ball & read by !      
obs]v]4 ,!n ! wire correspond+ to !     
second lett] ( ! ^w 0 to be *>g$ 9 l    
mann]1 & s on till ! :ole message 0     
spell$ out4 ,?is 0 ! fir/ practical     
7i4e41 possible7 sugge/ion = a          
telegraph4 ,! writ] also propos$ to h ! 
wires /rung on insulators1 :i* 0 a great
 advance ov] ! o!r attempts4  ,!        

communication 0 anonym\s1 z no d\bt1 l  
_m o!rs1 ! au?or fe>$ ! ridicule ( 8    
neighbors4 ,x requires a va/ am\nt (    
moral c\rage to /& up be=e ! _w & op5ly 
advocate "s new !ory t has nev] come )9 
! exp]i5ce ( any "o be=e4 ,x requires   
mu* n[1 b x requir$ m !n2 = a man 9 ^?  
days w\ld h be5 roa/$ = :at 9 ^! days he
 w\ld be toa/$4 ,! rank & file (        
humanity h be5 oppos$ to innovations 9  
all ages1 b no progress c\ld h be5 made 
)\t innovations4 ,!re always has to be a
 fir/ "t4 ,galileo is said to h be5 =c$ 
to retract1 on 8 knees1 "s !ory he      
advanc$ ab\t ! motion ( ! e>?1 & its    
relation to ! sun & o!r heav5ly bodies4 
,not)/&+ ?is retraction ! se$-?\ght s[n 
by ,galileo took root 9 o!r m9ds1 :i* l$
 to ! triumph ( sci5tific tru? ov]      
religi\s fanaticism4  ,! writ] 9        
,scott's ,magaz9e did n h ! opportunity 
to put 8 ideas into practice1 s ! glory 
( ! inv5tion fell to o!rs4 ,su* m5 z ?is
 unkn[n writ] are made ( f9] /uff1 & !y 
/& alone on ! fronti] ( progress4 ,!y d 

n fe> ! bullets ( an enemy half s mu* z 
! gibes ( a fri5d4 ,mu* ( _! "w is done 
quietly & )\t notice1 & :5 some?+ ( real
 importance is work$ out !oretically &  
exp]im5tally1 "s "o seizes ^u x &       
proclaims x f ! h\setops & atta*es to x 
8 "n2 b p]haps ye>s aft] ! real inv5tor 
7! man :o taught ! s-call$ inv5tor h[ to
 d x7 is dead1 "s "o writes a book t    
reveals ! tru?1 & !n ! h]o-lov+ p erect 
a monum5t to 8 memory4  ,su* a man 0 our
 own ,pr(essor ,joseph ,h5ry1 s long !  
presid+ g5ius at ! ,smi?sonian          
,in/itution at ,wa%+ton4 ,he work$ out  
all ! problems ( ! pres5t ,am]ican      
telegraphic sy/em & demon/rat$ x        
practically4 ,ev]y?+ t made ! s-call$   
,morse telegraph a success _h long be=e 
be5 describ$ & demon/rat$ by ,h5ry4 ,yet
 ) ! mode/ grace t 0 +ra9$ 9 ! man he   
yield$ all to ! "o :o 0 in/rum5tal 9    
con/ruct+ ! fir/ telegraph l9e betwe5   
,baltimore & ,wa%+ton4 ,great cr$it is  
due to su* m5 z ,morse & ,cyrus ,w4     
,field--nei!r ( !m inv5tors1 b promot]s 

( great sy/ems ( communication t are (  
unspeakable b5efit to mank9d4 ,h5ry     
po9t$ out ! way1 & ,morse c>ri$ x into  
effect4 ,morse has _h no m cr$it ?an 0  
due him1 b has ,h5ry _h z mu* z is due  
him8 ,no great inv5tion 0 ev] yet ! "w1 
:olly1 ( "o man4 ,we ,am]icans are too  
apt to =get ?is4  ,i %all always rememb]
 ,h5ry z a mo/ unassum+1 k9dly1 g5ial   
man1 & ,i %all nev] =get 8 k9dness to   
me4 ,9 #ahgd ,i began my rese>*es 9     
telephony1 hav+ appli$ = a pat5t = an   
app>atus = transmitt+ musical tones     
telegraphically4 ,?is consi/$ ( a means 
( transmitt+ musical tones ?r\gh a wire 
& reproduc+ !m on a metal plate 7/ret*$ 
on ! body ( a viol9 to give x resonance7
 by rubb+ ! plate ) ! h&--! latt] be+ a 
"p ( ! circuit4 ,! exam9] refus$ !      
application at fir/ on ! gr\nd t !      
inv5tor or op]ator c\ld n be a "p ( 8   
ma*9e4 ,i took my app>atus & w5t to     
,wa%+ton1 fir/ call+ ^u ,pr(essor ,h5ry1
 nev] hav+ met him be=e4 ,he receiv$ me 
mo/ k9dly1 & all[$ me to /r+ wires f    

room to room 9 ! in/itute1 & :5 he _h   
witness$ ! exp]im5ts he seem$ z delight$
 z a *ild4 ,i n[ br\ght ! pat5t (fice   
(ficial ov] to ! ,smi?sonian & soon     
conv9c$ him t ! inv5tor c\ld be a "p ( 8
 own ma*9e4  ,! same ye> ,i w5t abroad1 
& ,h5ry gave me a lett] to ,tyndall4 ,x 
0 v =tunate = me t he did1 = ,tyndall 0 
v %y at fir/1 & x 0 only ,h5ry's lett] t
 gave me a he>+ = a mom5t4 ,! hi/ory ( !
 few days t foll[$ ?is fir/ int]view )  
,tyndall at ! ,royal ,in/itution w\ld   
make v int]e/+ read+1 if ,i felt at     
lib]ty to publi% x4 ,suffice x to say t 
he 0 conv9c$ 9 a few m9utes aft] he _h  
rea*$ ! exp]im5tal /age t n all my "w _h
 be5 anticipat$ by ,:eat/one1 z he      
ass]t$ be=e see+ ! exp]im5ts4 ,:eat/one 
_h transmitt$ ! tones ( a piano1        
me*anically1 f "o room to ano!r by a    
wood5 rod plac$ ^u ! s\nd-bo>d & t]m9at+
 9 ano!r room 9 contact ) ano!r         
s\nd-bo>d4 ,b ?is 0 v diff]5t f         
transmitt+ musical tones & melodies f "o
 city to ano!r ?r\gh a wire1 z ,i c\ld d

 ) my electrotelephonic app>atus4  ,x is
 a curi\s fact t ! _w is divid$ into two
 great classes1 lead]s & foll[]s4 ,or we
 might say1 orig9ators & copyi/s2 ! =m] 
division be+ v small1 :ile ! latt] is v 
l>ge4 ,z late z #ahbj ! ,european       
philosoph]s 7 try+ to con/ruct a        
telegraphic sy/em bas$ ^u two ideas1    
ann\nc$ a long "t be=e1 to wit1 ! use ( 
/atic or frictional electricity1 & a    
wire = e lett]4 ,x does n seem to h     
occurr$ to any "o to devise a code      
consi/+ ( motions diff]5tly relat$ z to 
"t1 & to use simply "o wire4  ,9 #ahai  
,o]/$ discov]$ ! effect ( a galvanic    
curr5t on a magnetic ne$le1 & publi%$ a 
pamphlet conc]n+ 8 discov]y4 ,?is       
/imulat$ o!rs1 & ,amp]e appli$ x to !   
galvanomet] ! same ye>4 ,arago appli$ x 
to s(t iron1 & "h 0 ! g]m ( !           
electromagnet4 ,we see t z f> back z    
#ahbj we _h ! galvanic batt]y & !       
electromagnet1 ! two great ess5tials ( !
 mod]n telegraph4  ,h[ev]1 !re rema9$   
ano!r great discov]y to be made be=e ^! 

elem5ts c\ld be utiliz$ = telegraphic   
purposes4 ,"o cell ( batt]y 0 us$1 & !  
magnet 0 made by w9d+ "o lay] ( wire    
spirally ar\nd ! iron1 s t ea* spiral 0 
out ( t\* ) its neighbor4 ,b>l[ (       
,engl&1 a ,fell[ ( ! ,royal ,society1   
tri$ ! effect ( a curr5t ?r\gh a wire   
#bjj feet long1 & f\nd t ! p[] 0 s      
dim9i%$ t he 0 disc\rag$1 & 9 a pap]    
gave x z 8 op9ion t galvanism 0 ( no use
 = telegraph+ at a di/ance4 ,?is pap]   
/imulat$ o!rs1 & x 0 res]v$ = our own   
,joseph ,h5ry1 already ref]r$ to1 to %[ 
n only h[ to con/ruct a magnet =        
long-di/ance telegraphy1 b also h[ to   
adapt ! batt]y to ! di/ance4 ,he %[$ u t
 by insulat+ ! wire & us+ sev]al lay]s (
 :irls1 in/ead ( "o1 & by us+ en\gh     
cells ( batt]y c\pl$ up 9 s]ies to get m
 voltage1 z we n[ express x1 x 0        
possible to transmit signals to a       
di/ance4 ,he n only set =? ! !ory1 b he 
con/ruct$ a l9e ( bell-wire #ajfj feet  
long & work$ 8 magnet by mak+ ! armature
 /rike a bell = ! signals1 :i* is !     

basis ( ! mod]n s\nd]4  ,no?+ 0 ne$$ b  
to con/ruct a l9e & devise a code to be 
read by s\nd1 to h practically our mod]n
 ,morse telegraph4 ,?is l9e 0 con/ruct$ 
9 #ahca4 ,9 #ahce ,h5ry1 :o 0 !n at     
,pr9ceton1 con/ruct$ a l9e & work$ x z x
 is to-day work$1 ) a relay & local     
circuit1 s t at t p]iod all ! problems  
_h be5 work$ out4 ,b1 l !               
speak+-telephone 9 its e>ly inception1  
no "o appreciat$ its real importance4   
,h5ry himself did n ?9k x wor? :ile to  
take out a pat5t4 ,two ye>s lat] !      
,secret>y ( ! ,treasury s5t out a       
circul> lett] ( inquiry to "k if "s     
sy/em ( telegraphic communication c\ld n
 be devis$4 ,! le>n$ heads ( ! ,frankl9 
,in/itute ( ,philadelphia1 ! olde/      
sci5tific society 9 ,am]ica1 advis$ t a 
semaphore sy/em be e/abli%$ betwe5 ,new 
,york & ,wa%+ton1 consi/+ ( =ty t[]s )  
sw++ arms1 ! same z us$ 9 ! days (      
,well+ton4 ,among o!r replies to !      
circul> lett] ( ! secret>y 0 "o f       
,samuel ,f4 ,b4 ,morse4 ,morse 0 n a    

sci5ti/ or ev5 an inv5tor1 at lea/ n at 
t "t4 ,he 0 an arti/ ( "s note4 ,9      
#ahcb1 :ile cross+ ! ocean1 ,morse1 9   
connection ) "o ,dr4 ,jackson ( ,bo/on1 
devis$ a code ( telegraphic signs int5d$
 to be us$ 9 a *emical telegraph sy/em4 
,"s ye>s lat] ,morse adapt$ ,h5ry's     
signal-in/rum5t to a record]1 call$ !   
,morse regi/]1 & ?is 0 ! in/rum5t us$ 9 
! e>ly days ( ! ,morse telegraph4  ,:at 
,morse seems to h really inv5t$ 0 !     
regi/]1 :i* made emboss$ m>ks on a /rip 
( pap]1 & ! code ( dots & da%es         
repres5t+ lett]s1 n[ kn[n z ! ,morse    
alphabet1 al?\gh ?is latt] is que/ion$4 
,morse took 8 app>atus to ,wa%+ton &    
exhibit$ x to ! memb]s ( ,congress 9 !  
ye> #ahch1 b x 0 f\r ye>s be=e a bill 0 
pass$ t enabl$ him to try ! exp]im5t    
betwe5 ,baltimore & ,wa%+ton4 ,we w let 
him describe 9 8 own words ! clos+ day (
 ,congress4 ,he says3  ,my bill _h inde$
 pass$ ! ,h\se ( ,repres5tatives & x 0  
on ! cal5d> ( ! ,s5ate1 b ! ev5+ ( ! la/
 day _h comm5c$ ) m ?an #ajj bills to be

 consid]$ & pass$ ^u be=e m9e c\ld be   
rea*$4 ,we>i$ out ) ! anxiety ( susp5se1
 ,i consult$ "o ( my s5atorial fri5ds4  
,he ?\ght ! *ance ( rea*+ x to be s     
small t he advis$ me to consid] x z lo/4
 ,9 a /ate ( m9d :i* ,i mu/ leave y to  
imag9e1 ,i return$ to my lodg+s to make 
prep>ations = return+ home ! next day4  
,my funds 7 r$uc$ to ! fraction ( a     
doll>4 ,9 ! morn+1 z ,i 0 ab\t to sit   
d[n to breakfa/1 ! s]vant ann\nc$ t a "y
 lady desir$ to see me 9 ! p>lor4 ,x 0 !
 daught] ( my excell5t fri5d & college  
classmate1 ! commission] ( pat5ts1 ,h5ry
 ,l4 ,ellswor?4 ,%e _h call$1 %e said1  
by h] fa!r's p]mission1 & 9 ! exub]ance 
( h] own joy1 to ann\nce to me ! passage
 ( my telegraph bill at midnight1 b a   
mom5t be=e ! ,s5ate adj\rn$4 ,?is 0 !   
turn+-po9t ( ! telegraph inv5tion 9     
,am]ica4 ,z an appropriate ackn[l$gm5t (
 ! "y lady's sympa?y & k9dness--a       
sympa?y :i* only a woman c feel &       
express--,i promis$ t ! fir/ dispat* by 
! fir/ l9e ( telegraph f ,wa%+ton to    

,baltimore %\ld be indit$ by h]2 to :i* 
%e repli$3 ',rememb]1 n[1 ,i %all hold y
 to y\r ^w4' ,ab\t a ye> f t "t ! l9e 0 
complet$1 &1 ev]y?+ be+ prep>$1 ,i      
appris$ my "y fri5d ( ! fact4 ,a note f 
h] inclos$ ?is dispat*3 ',:at ha? ,god  
wr\ght8' ,^! 7 ! fir/ words t pass$ on !
 fir/ complet$ l9e 9 ,am]ica4  ,! fir/  
telegraph-l9e 9 ,am]ica 0 put into      
op]ation 9 ! spr+ ( #ahdd at ! beg9n+ ( 
,polk's adm9i/ration4 ,i rememb] z a boy
 hav+ ! two cities1 ,baltimore &        
,wa%+ton1 po9t$ out to me on ! map1 & h[
 ! /ory ( ! telegraph impress$ me4      
,congress appropriat$ #cj1jjj = !       
con/ruction ( ! l9e1 & #hjjj to keep x  
runn+ ! fir/ ye>4 ,x 0 plac$ "u !       
control ( ! po/ma/]-g5]al1 & ! l9e 0    
?r[n op5 to ! public4 ,! t>iff 0 fix$ at
 "o c5t = e f\r words4 ,x 0 op5 =       
bus9ess on ,april #a1 #ahdd1 & = ! fir/ 
few days ! rev5ue 0 exce$+ly small4 ,on 
! morn+ ( ! fir/ day a g5tleman came 9 &
 want$ to see x "w4 ,! op]ator told him 
t he w\ld be glad to %[ x at ! regul>   

t>iff ( "o c5t = f\r words4 ,! g5tleman 
grew angry & said t he 0 influ5tial ) ! 
adm9i/ration1 & t if he did n %[ him !  
work+ free ( *>ge he w\ld see to x t he 
lo/ 8 job4 ,8 bluff did n succe$4 ,!    
op]ator ref]r$ him to ! po/ma/]-g5]al1 &
 ?us ! /ormy int]view end$4 ,no patrons 
came 9 = ! next ?ree days1 b a great    
numb] /ood ar\nd hop+ to see ! in/rum5t 
/>t up1 b no "o 0 will+ to inve/ a      
c5t--probably f fe> ( be+ laugh$ at4    
,on ! f\r? day ! same g5tleman :o _h    
?reat5$ ! "y man ) dismissal came back &
 inve/$ a c5t1 & ?is 0 ! fir/ & only    
rev5ue = f\r days4 ,! message t 0 s5t   
only came to "o-half c5t1 b z ! op]ator 
c\ld n make *ange ! /rang] laid d[n !   
c5t & dep>t$4 ,8 "n ought to be kn[n to 
fame z ! fir/ man patron ( ! telegraph4 
,illu/ration3 ,fig4 #b4      ,a gives a 
diagram view ( a ,morse telegraph-l9e ) 
?ree     /ations4 ,b is ! batt]y2 ,c ,c 
,c1 ! transmitt+ keys 9 !     ?ree      
(fices2 ,d ,d ,d1 ! relay magnets2 ,e ,e
 ,e1 ! armatures     t are actuat$ by ! 

magnets4  ,! op]ation ( ! ,morse        
telegraph is v simple if we grant all t 
has gone be=e4 ,all t is ne$$ is ! wire1
 ! batt]y1 & ! key1 z %[n 9 ,fig4 #b    
7page #ii71 & a relay--an extra         
electromagnet :i* receives ! electric   
curr5t & by its means puts into or out (
 action a small local batt]y on a %ort  
circuit 9 :i* is plac$ ! receiv+ or     
record+ app>atus4 ,?us we h a wire />t+ 
f ! e>? 9 ,new ,york & pass+ ?r\gh a    
batt]y1 a key & a relay1 & !nce to      
,bo/on on poles1 ) insulators on :i* !  
wire is /rung1 & ?r\gh ano!r in/rum5t1  
key & batt]y 9 ,bo/on1 ! same z at !    
,new ,york end1 & into ! gr\nd1 leav+ ! 
e>? to complete "o-half ( ! circuit4 ,:5
 ! keys at bo? ends are clos$ ! batt]ies
 are active & ! armatures or keep]s are 
attract$ s t ! armature lev]s re/ on !  
=w>d /ops4 7,see diagram ,fig4 #b47 ,if 
ei!r "o ( ! keys is op5$ ! curr5t /ops  
fl[+ & ! magnetism vani%es f all !      
electromagnets on ! l9e1 & a spr+ or    
retractile ( "s k9d pulls ! armatures   

away f ! magnets & ! lev]s re/ on _!    
back /ops4 ,9 ?is way all ! lev]s ( all 
! magnets are made to foll[ ! motions ( 
any key4 ,if !re are m ?an two magnets 9
 circuit 7& !re may be tw5ty or m7 !y   
all respond 9 unison to ! work+ ( "o    
key1 s t :5 any "o /ation is s5d+ a     
dispat* all ! o!r /ations get x4  ,b !re
 is a call = ea* (fice1 s t ! op]ator   
only he$s ! in/rum5t :5 he he>s 8 own   
call4 ,op]ators become s exp]t 9 read+  
by s\nd t !y may lie d[n & sleep 9 !    
room1 &1 al?\gh ! in/rum5t is rattl+    
away all ! "t1 he does n he> x till 8   
own call is made1 :5 he imm$iately      
awakes4  ,9 ! old days messages 7       
receiv$ on slips ( pap] by ! ,morse     
regi/] by means ( dots & da%es4         
,gradually ! op]ator le>n$ to read by   
s\nd1 till n[ ?is mode ( receiv+ is     
almo/ univ]sal ! _w ov]4 ,read+ by s\nd 
0 ( ,am]ican orig94 ,x is a spok5       
language1 & :5 "o becomes accu/om$ to x 
x is l any o!r language4 ,?is code      
language has "s advantages ov]          

articulate spee*1 z well z _m           
disadvantages4 ,a g5tleman :o 0 connect$
 ) a ,l\isville telegraph (fice told me 
t "o ( ! be/ op]ators he ev] knew 0 z   
deaf z a po/4 ,he w\ld receive ! message
 by hold+ 8 knee aga9/ ! leg ( ! table  
^u :i* ! s\nd] 0 m\nt$1 & ?r\gh ! s5se (
 feel+ receive ! long & %ort vibrations 
( ! table1 & by ?is means read z well or
 bett] ?an ?r\gh ! e>1 because he 0 n   
di/ract$ by o!r s\nds4  ,a /ory is told 
( ! late ,g5]al ,/ag] t at "o "t he 0 on
 a tra9 t 0 wreck$ at "s di/ance f any  
/ation4 ,he climb$ a telegraph pole1 cut
 ! wire & by alt]nately jo9+ & sep>at+ !
 ends s5t a message1 detail+ ! /ory ( ! 
wreck1 to headqu>t]s1 & ask$ =          
assi/ance4 ,he !n held ! two ends ( !   
wire on ea* side ( 8 tongue & ta/$ out !
 reply--t help 0 com+4 ,any "o :o has   
ev] ta/$ a curr5t kn[s t x is v         
pron\nc$4  ,a /ory simil> to ?is is told
 ( ! e>ly days :5 ! ,ba9 *emical sy/em 0
 us$ betwe5 ,wa%+ton ,city & "s o!r     
po9t4 ,?is sy/em made m>ks on           

*emically-prep>$ pap]2 z ! curr5t pass$ 
?r\gh x left m>ks on ! pap] f !         
decomposition ( ! *emicals4 ,"s ( !     
prep>ations emitt$ an odor dur+ ! "t t !
 curr5t pass$4 ,! occurr5ce to :i* we   
ref] took place at presid5tial election 
"t4 ,at "s /ation out ( ,wa%+ton an     
op]ator 0 employ$ :o _h a bl9d si/]1 &  
?is si/] knew ! ,morse alphabet well    
be=e %e became bl9d4 ,"o ev5+ a signal  
came to get ready = a message conta9+ ! 
returns f ! election4 ,9 ! hurry1 & j z 
! message _h />t$1 ! lamp 0 upset & !y 7
 9 total d>kness--at lea/1 ! bro!r 04 ,!
 si/]1 poor girl1 _h be5 9 d>kness a    
long "t4 ,! bl9d si/] lean$ ov] ! /ylus 
?r\gh :i* ! curr5t fl[$ to ! pap] &     
smell$ out z well z spell$ out !        
message1 & repeat$ x to h] a/oni%$      
bro!r4  ,by ! old semaphore sy/em !     
motions 7 s5s$ ?r\gh ! eye z well z !   
e>ly me?od ( cable signal+4 ,x w be se5 
f ! above t ! ,morse code may be        
communicat$ ?r\gh any "o ( ! five s5ses4
     ,,*apt] ,,xi4  ,,receiv+           

,,messages4   ,) b few exceptions !     
,morse code is ! "o almo/ univ]sally us$
 ! _w ov]4 ,z x is us$ 9 ,europe1 x is  
slightly *ang$ f our ,am]ican code1 b !y
 all dep5d ^u dots1 da%es1 & spaces1    
relat$ 9 diff]5t comb9ations1 = !       
diff]5t lett]s4 ,not)/&+ its univ]sal   
use x is n free f s]i\s difficulties 9  
transmission unless x is repeat$ back to
 ! s5d] = correction2 & !n 9 "s cases x 
is impossible to be sure1 ow+ to        
difficulties ( punctuation & capitaliz+1
 & ! fur!r difficulty ( runn+ ! signals 
toge!r1 caus$1 x may be1 by faulty      
transmission1 induc$ curr5ts f o!r      
wires1 sw++ crosses or atmosph]ic       
electricity4 ,sometimes x is a          
psy*ological difficulty 9 ! m9d ( !     
receiv+-op]ator4 ,! telegraph companies 
h to suff] damages f all ^! & _m o!r    
un=ese5 causes4  ,prescott tells "s     
curi\s ?+s t happ5$ 9 ! e>ly days1 gr[+ 
out ( ! peculi>ities ( !                
receiv+-op]ator4 ,at "o "t he 0 report+ 
by telegraph "o ( ,web/]'s spee*es made 

at ,albany 9 #aheb 9 :i* !re 7 _m pi?y  
int]rogative s5t5ces1 & he 0 desir\s (  
hav+ ! int]rogation-po9ts appe>4 ,s to  
make sure1 :5ev] he wi%$ an             
int]rogation-po9t he said "q at ! end ( 
almo/ e s5t5ce4 ,next day he 0 horrifi$ 
on read+ ! spee* to see ! ends ( !      
s5t5ces bri/l+ ) ! ^w "q4  ,"s "t back 9
 ! fifties a g5tleman 9 ,bo/on          
telegraph$ to a h\se 9 ,new ,york to    
=w>d sample =ks by express4 ,! message  
:5 receiv$ by ! ,new ,york m]*ant read3 
,=w>d sample = ,k4 ,s4 by express4 ,!   
,new ,york m]*ant did n "k :o ,k4 ,s4 01
 nor did he ga!r f ! dispat* :at k9d (  
sample he want$4 ,s he w5t to !         
telegraph (fice to h ! matt] cle>$ up4  
,! ,bo/on op]ator repeat$ ! message1    
say+ sample =ks4 ,t's ! way ,i receiv$ x
 & s deliv]$ x--sample = ,k4 ,s41 said  
,new ,york4 ,b1 says ,bo/on1 ,i did n   
say = ,k4 ,s42 ,i said f-o-r-k-s4 ,new  
,york _h read x wrong 9 ! />t & c\ld n  
get x any o!r way4 ,:at a fool t ,bo/on 
fell[ is4 ,he says he did n say = ,k4   

,s41 b = ,k4 ,s4 ,bo/on _h to resort to 
! ,unit$ ,/ates mail be=e ! my/]y 0     
solv$4  ,curi\sly en\gh1 ! old me?od (  
record+ ! dots & da%es on ! pap] /rip 0 
n s reliable z ! pres5t mode ( read+ by 
s\nd4 ,a man c put 8 individuality to "s
 ext5t into a s\nd]1 & :5 "o becomes us$
 to 8 /yle x is mu* easi] to read him   
accurately by s\nd ?an by ! pap]        
impressions4 ,"s p nev] c\ld le>n to    
read ei!r by pap] or s\nd4 ,an in/ance (
 ?is k9d is giv5 ( a middle-ag$ man :o 0
 employ$ by a railroad company z depot  
ma/] & telegraph op]ator1 9 ! old days (
 ! pap] /rip4 ,"o day he ru%$ out &     
hail$ ! conductor ( a tra9 t _h j pull$ 
into ! /ation1 & told him t ---- tra9 _h
 brok5 bo? driv+-:eels & 0 badly sma%$  
up4 ,! conductor c\ld read ! my/ic      
symbols1 s he took ! tape & deciph]$ !  
dispat* z foll[s3 ,ask ! conductor ( !  
,bo/on tra9 to exam9e c>efully !        
connect+-rods ( bo? driv+-:eels1 & if n 
9 good condition to await ord]s4 ,x is  
fur!r relat$ ( ?is same op]ator t :5 he 

got into real difficulty ) 8 tape he us$
 to run ov] to ! regul> comm]cial (fice 
to h 8 messages translat$4 ,"o day he   
ru%$ into 8 neighbor's (fice trail+ !   
tape beh9d him & say+3 ,i am sure an    
awful accid5t has happ5$ by ! way !     
message 0 rattl$ (f4 ,a playful dog _h  
torn (f a l>ge "p ( ! /rip z x trail$   
along1 s only a "p 0 left4 ,x read1     
,good morn+1 ,uncle ,b54 ,:5 are y----  
,! dog _h swall[$ ! balance ( ! dispat*4
  ,sometimes ! ,morse code is n only    
funny b disa/r\s4 ,a g5tleman want$ to  
borr[ money ( "s capitali/s :o1 n kn[+ 8
 f9ancial /&+1 telegraph$ to a bank] :o 
!y knew c\ld po/ !m4 ,!y receiv$ an     
answ]1 ,note good = l>ge am\nt4 ,!      
g5tleman borr[$ a l>ge am\nt1 b aft]w>d 
:5 x came to be inve/igat$ x 0 f\nd t ! 
dispat* 0 orig9ally writt5 n1 in/ead (  
note1 :i* made all ! diff]5ce 9 ! _w4   
,x has be5 /at$ t any "o ( ! five s5ses 
may be call$ into s]vice to int]pret !  
,morse code into words & ideas4 ,a /ory 
is told by ,mr4 ,prescott t he says is  

true1 z he knew ! p>ty4 ,a fri5d ( 81 by
 "n ,lang5zunge1 :o knew ! ,morse code1 
_h s]v$ "u ,g5]al ,taylor 7:o at ?is "t 
0 ,presid5t7 at ,palo ,alto1 9 ,mexico4 
,! g5]al _h j promis$ him an (fice2 soon
 aft] he left ,wa%+ton = ! we/ ov] !    
,baltimore & ,ohio on a freight tra92 ! 
,presid5t 0 tak5 s]i\sly ill1 & 8 fri5d 
he>+ ( x 0 tr\bl$ n only because he lov$
 ! old g5]al1 b on acc\nt ( ! *ange 9 8 
own prospects4 ,! tra9 /opp$ some:]e on 
! ,potomac at midnight & rema9$ !re =   
f\r h\rs4 ,uneasy & sad1 he w&]$ d[n !  
track & climb$ a pole1 cut ! wire &     
plac$ ! ends ea* side ( 8 tongue & ta/$ 
out ! fatal message--,di$ at half-pa/   
t54 ,! %ock 7n ! electric7 0 s great t  
he almo/ fell f ! pole4  ,:at a         
situation6 ,a man climbs a pole at      
midnight miles f ! sick fri5d he loves1 
puts 8 tongue to inanimate wire1 & is   
told 9 concrete language--?r\gh ! s5se (
 ta/e--t 8 fri5d is dead4 ,?is is only  
"o ( ! _m1 _m wond]ful episodes ( !     
telegraph4     ,,*apt] ,,xii4           

,,miscellane\s ,,me?ods4   ,x nev] ra9s 
b x p\rs4 ,almo/ simultane\sly ) !      
demon/ration ( ! ,morse telegraph o!r   
types 7 devis$4 ,!re 7 ! ne$le sy/ems ( 
,cooke & ,:eat/one1 ! *emical telegraph 
( ,alex&] ,ba91 & soon ! pr9t+ telegraph
 ( ,h\se1 & lat] t ( ,hughes4 ,! latt]  
is 9 use on ! cont95t ( ,europe1 & a    
modification ( x has a v limit$ use on  
"s ,am]ican l9es4 ,! ,ba9 telegraph us$ 
a key & batt]y ! same z ! ,morse sy/em1 
b x did n dep5d ^u electromagnetism z ! 
,morse sy/em does4 ,:5 9 op]ation a /rip
 ( pap] 0 made to move "u an iron /ylus 
at ! receiv+-end ( ! l9e4 ,! pap] 0     
saturat$ ) "s *emical t w\ld discolor by
 ! electrolytic action ( ! curr5t4 ,:5 a
 message 0 s5t ! pap] 0 set to mov+ by a
 clock me*anism or o!rwise1 "u ! /ylus t
 0 press+ on ! pap] z x pass$ ov] a     
metal roll] or b$-plate4 ,!             
transmitt+-op]ator work$ 8 key precisely
 z 9 s5d+ an ord9>y message by ! ,morse 
sy/em4 ,! effect 0 to s5d curr5ts ?r\gh 
! receiv+-/ylus *opp$ into long or %ort 

m>ks1 or ! dots & da%es ( ! ,morse code1
 & record$ on ! tape 9 m>ks t 7 blue or 
br[n1 accord+ to ! *emical us$4 ,a few  
l9es 7 e/abli%$ 9 ?is c\ntry on ! ,ba9  
sy/em1 b x nev] came into g5]al use4  ,a
 numb] ( sy/ems1 call$ automatic1 grew  
out ( ! ,ba9 sy/em4 ,ba9 himself devis$1
 p]haps1 ! fir/ automatic telegraph4 ,! 
fundam5tal pr9ciple ( all automatic     
telegraphs dep5ds ^u ! prep>ation ( !   
message be=e s5d+1 & is usually pun*$ 9 
a /rip ( pap] & !n run ?r\gh betwe5     
roll]s t all[ ! /ylus to ride on ! pap] 
& drop ?r\gh ! holes t repres5t ! dots &
 l9es ( ! ,morse alphabet4 ,e "t ! /ylus
 drops ?r\gh a hole 9 ! pap] x makes    
electrical contact & s5ds a curr5t1 long
 or %ort1 accord+ to ! l5g? ( ! hole4 ,!
 object ( ! automatic sy/em 0 to s5d a  
l>ge am\nt ( bus9ess ?r\gh a s+le wire 9
 a %ort "t4 ,x does n save op]ators1 z !
 messages h to be prep>$ = transmission1
 & !n translat$ at ! receiv+-end & put  
into ord9>y writ+ = deliv]y4  ,!        
automatic sy/em is n us$ except =       

special purposes1 & ! "o t seems to be !
 mo/ favor$ is t ( ,:eat/one4 ,! sy/em  
is 9 use 9 ,engl& & 9 ,am]ica to a      
limit$ degree4  ,e>ly 9 ! hi/ory ( !    
telegraph a pr9t+ sy/em 0 devis$4       
,:eat/one & o!rs _h propos$ sy/ems (    
pr9t+ telegraphs 9 ,europe1 b ^! nev]   
pass$ ! exp]im5tal /age4 ,! fir/ pr9t+  
telegraph introduc$ 9 ,am]ica 0 inv5t$  
by ,royal ,e4 ,h\se ( ,v]mont1 & fir/   
introduc$ 9 #ahdg on a l9e betwe5       
,c9c9nati & ,jeff]sonville1 a di/ance ( 
#aej miles4 ,9 #ahdi a l9e = comm]cial  
use 0 e/abli%$ betwe5 ,new ,york &      
,philadelphia1 & = "s ye>s foll[+ _m    
l9es 7 equipp$ ) ! ,h\se pr9t+ telegraph
 in/rum5t4 ,! late ,g5]al ,anson ,/ag] 0
 a ,h\se op]ator at "o "t4 ,all pr9t+   
telegraph in/rum5ts1 :ile diff]+ greatly
 9 detail1 h c]ta9 ?+s 9 common1 to wit3
 a means = br++ ! type into position1 an
 ink+ device1 a pr9t+ me*anism1 a pap]  
fe$1 & a means = br++ ! type-:eels into 
unison4 ,!re are two g5]al types ( pr9t+
 in/rum5ts1 ! /ep-by-/ep1 & !           

syn*ron\sly mov+ type-:eels4 ,! ,h\se   
pr9t] 0 a /ep-by-/ep in/rum5t & consi/$ 
( two p>ts1 a transmitt] & a receiv]4 ,!
 transmitt] consi/s ( a keybo>d l a     
piano1 ) tw5ty-eight keys4 ,^! keys are 
held 9 position by spr+s4 ,"u ! keys is 
a cyl9d] hav+ tw5ty-eight p9s on x      
correspond+ to ! tw5ty-six lett]s ( !   
alphabet & a dot & a space4 ,?is cyl9d] 
0 driv5 by "s p[]4 ,9 ^? days x 0 by    
man-p[]4 ,x 0 c>ri$ by a friction1 s t x
 c\ld be easily /opp$ by ! depression ( 
any "o ( ! keys t int]f]$ ) "o ( ! p9s4 
,"o revolution ( ! cyl9d] w\ld break &  
close ! curr5t tw5ty-eight times1 mak+  
tw5ty-eight /eps4  ,! receiv+-in/rum5t  
consi/$ ( a type-:eel & means = driv+ x4
 ,x 0 some:at complicat$1 & c only be   
describ$ 9 a g5]al way4 ,if ! cyl9d] ( !
 transmitt] 0 set to rotat+ x w\ld break
 & close tw5ty-eight times ea*          
revolution4 7,!re 7 f\rte5 closes &     
f\rte5 breaks1 ea* break & ea* close ( !
 curr5t repres5t+ a /ep47 ,! type-:eel (
 ! receiv] 0 divid$ into tw5ty-eight    

p>ts1 hav+ tw5ty-six lett]s & a dot &   
space1 ea* break mov$ x "o /ep & ea*    
close a /ep2 s t if ! cyl9d]1 ) its     
tw5ty-eight p9s1 />t$ 9 unison ) !      
type-:eel1 ) its tw5ty-eight lett]s &   
spaces1 !y w\ld revolve 9 unison4 ,!    
keys 7 lett]$1 & if any "o 0 depress$ ! 
p9 correspond+ to x on ! cyl9d] w\ld    
/rike x & /op ! rotation ( ! cyl9d]1 :i*
 /opp$ ! break+ & clos+ ( ! circuit1 :i*
 9 turn /opp$ ! rotation ( !            
type-:eel--& n only /opp$ x1 b also put 
x 9 a position s t ! lett] on !         
type-:eel correspond+ to ! lett] on !   
key t 0 depress$ 0 opposite ! pr9t+     
me*anism4 ,! pr9t+ 0 done on a /rip (   
pap]1 :i* 0 c>ri$ =w>d "o space ea* "t x
 pr9t$4 ,! pr9t+ me*anism 0 s arrang$ t 
s long z ! :eel cont9u$ to rotate x 0   
held f pr9t+1 b ! mom5t ! type-:eel     
/opp$ x pr9t$ automatically4  ,!        
messages 7 deliv]$ on /rips ( pap] z !y 
came f ! ma*9e4  ,9 #ahee ,david ,e4    
,hughes ( ,k5tucky pat5t$ a type-pr9t+  
telegraph t employ$ a diff]5t pr9ciple =

 rotat+ ! type-:eel4 ,! electric curr5t 
0 us$ = pr9t+ ! lett]s & unify+ !       
type-:eels ) ! transmitt+-app>atus4 ,!  
transmitt]1 cyl9d]1 & ! type-:eel       
revolv$ syn*ron\sly1 or z ne>ly s z     
possible1 & ! pr9t+ 0 done )\t /opp+ !  
type-:eel4 ,:5ev] a lett] 0 pr9t$ !     
type-:eel 0 correct$ if !re 0 any lack (
 unison4  ,?is type ( ma*9e 9 a greatly 
improv$ =m is /ill us$ on "s ( ! ,we/]n 
,union l9es1 especially betwe5 ,new     
,york1 ,bo/on1 ,philadelphia1 &         
,wa%+ton4 ,x is also 9 use 9 "o ( its   
=ms 9 mo/ ( ! ,european c\ntries4       
,,*apt] ,,xiii4  ,,multiple             
,,transmission4   ,al?\gh ! pr9t+ &     
automatic sy/ems ( telegraph+ are us$ 9 
,am]ica to "s ext5t1 ! l>g] "p is done  
by ! ,morse sy/em ( s\nd-read+ & copy+ f
 x1 ei!r by p5 or ! typewrit]4 ,9 ! e>ly
 days only "o message c\ld be s5t ov] "o
 wire at ! same "t1 b n[ f f\r to six or
 ev5 m messages may be s5t ov] ! same   
wire simultane\sly )\t "o message       
int]f]+ ) ! o!r4 ,l mo/ o!r inv5tions1  

_m inv5tors h contribut$ to ! developm5t
 ( multiple transmission1 till f9ally "s
 "o did ! la/ ?+ ne$$ to make x a       
success4 ,! fir/ attempts 7 9 ! l9e (   
d\ble transmission1 & _m inv5tors abroad
 h work$ on ?is problem4  ,moses ,g4    
,f>m] ( ,salem1 ,mass41 propos$ x z e>ly
 z #aheb1 & pat5t$ x 9 #aheh4 ,g9tl1    
,preece1 ,siem5s & ,halske & o!rs abroad
 _h f "t to "t propos$ diff]5t me?ods ( 
d\ble transmission1 b no "o ( !m 0 a    
p]fect success4 ,:5 ! l9e 0 v long !re 0
 a difficulty t seem$ insurm\ntable4 ,9 
! common p>lance ( telegraphy1 !re 0 a  
kick 9 ! in/rum5t t came 9 & mutilat$ ! 
signals4 ,ab\t #ahgb ,joseph ,b4 ,/e>ns 
( ,bo/on made a c]ta9 application ( :at 
is call$ a cond5s] to duplex telegraphy 
t cur$ ! kick1 & f t "t to ?is x has be5
 a success4 ,f>!r along ,i w tell y :at 
occasion$ ?is kick & h[ x 0 cur$4 ,if   
?is or "s o!r me?od c\ld be appli$ z    
successfully to cure ! _m *ronic kick]s 
9 ! _w x w\ld be a great bless+ to      
mank9d4  ,x has always be5 a my/]y to ! 

un9itiat$ h[ two messages c\ld g 9      
opposite directions & n run into "o     
ano!r & get wreck$ by ! way4 ,if y w    
foll[ me closely = a few m9utes ,i w try
 to tell y4  ,we h already /at$ t an    
electromagnet is made by w9d+ an        
insulat$ wire ar\nd a s(t iron core4 ,if
 we pass a curr5t ( electricity ?r\gh   
?is wire ! core becomes magnetic1 &     
rema9s s z long z ! curr5t passes ar\nd 
x4 ,9 duplex telegraphy we use :at is   
call$ a diff]5tial magnet4 ,a diff]5tial
 electromagnet is w\nd ) two insulat$   
wires & s connect$ to ! batt]y t !      
curr5t divides & passes ar\nd ! iron    
core 9 opposite directions4 ,n[ if an   
equal curr5t is simultane\sly pass$     
?r\gh ea* ( ! wires ( ! coil 9 opposite 
directions ! effect on ! iron w be no?+1
 because "o curr5t is try+ to develop a 
c]ta9 k9d ( pol>ity at ea* pole ( !     
magnet1 :ile ! curr5t 9 ! o!r wire is   
try+ to develop an opposite k9d 9 ea*   
pole4 ,!re is an equal /ruggle betwe5 ! 
two oppos+ =ces1 & ! result is no       

magnetism4 ,?is assumes t ! two curr5ts 
are exactly ! same /r5g?4  ,if we break 
! curr5t 9 "o ( ! coils we imm$iately h 
magnetism 9 ! iron2 or if we de/roy !   
balance ( ! two curr5ts by mak+ "o      
/rong] ?an ! o!r we %all h magnetism ( a
 /r5g? t measures ! diff]5ce betwe5 !   
two4  ,)\t specifically describ+ "h !   
entire me*anism--s9ce ?is is n a        
text-book or a treatise--we may say t a 
duplex telegraph-l9e is fitt$ ) ^!      
diff]5tially w\nd electromagnets at e   
/ation4 ,:5 ,/ation ,a 7,fig4 #c7 is    
connect$ to ! l9e by ! positive pole (  
its batt]y1 ,/ation ,b w h its negative 
pole to l9e & its positive to e>?4 ,:5  
,a depresses 8 key to s5d a message1    
half ! curr5t passes by "o set ( coils  
ar\nd 8 diff]5tial magnet ?r\gh a %ort  
resi/ance-coil to ! e>?1 & ! o!r half by
 ! contr>y coil ar\nd ! magnet to ! l9e1
 & s to ,/ation ,b4 ,! divid$ curr5t    
does n affect ,a's own /ation1 be+      
neutraliz$ by ! diff]5tial magnet1 b x  
does affect ,b1 ^: in/rum5t responds &  

gives him ! message4  ,n[ ,b may at !   
same "t s5d a message to ,a by half ( 8 
own divid$ curr5t f 8 own end ( ! l9e4  
,illu/ration3 ,fig4 #c4      ,repres5ts 
a duplex #ejj-mile telegraph-l9e4 ,a &  
,b are ! two     t]m9al /ations2 ,b ,b'1
 ! batt]ies2 ,k ,k'1 ! keys2 ,d ,d'1    
! small resi/ance-coils1 equal to !     
batt]y-resi/ance :5     ! latt] is n 9  
circuit2 ,r ,r'1 resi/ances ea* equal to
     ! #ejj-mile l9e2 & ,c ,c'1 cond5s]s
 giv+ ! artificial     l9es ,r ,r' !    
same capacity z ! #ejj-mile l9e4  ,!    
puzzle to mo/ p is3 ,h[ c ! signals pass
 ea* o!r 9 diff]5t directions on ! same 
wire8 ,b ! signals d n h to pass ea*    
o!r4 ,9 effect1 !y pass2 b 9 fact1 x is 
l go+ r\nd a circle--! e>? =m+ half4 ,a 
s5ds 8 message ov] ! l9e to ,b4 ,b s5ds 
8 message to ,a ?r\gh ! e>? & up ,a's   
gr\nd-wire4 ,! op]ative :o is s5d+ )    
positive pole to l9e pu%es 8 curr5t     
?r\gh--s to speak--:ile ! op]ative :o is
 s5d+ ) ! negative pole to l9e pulls m  
curr5t 9 ! same direction ?r\gh ! l9e   

:5ev] he closes 8 key4  ,?is may n be a 
/rictly sci5tific /atem5t2 b1 z long z  
we speak ( a curr5t fl[+ f positive to  
negative poles 7:i* is ! inv>iable c\rse
 electricity takes71 x is ! way to look 
at ! matt] und]/&+ly4  ,! %ort          
resi/ance-coil at ea* end1 =tifi$ by a  
cond5s] made ( _m leaves ( isolat$      
t9-foil1 to give x capacity1 (f]s       
precisely ! same resi/ance to ! curr5t z
 ! #ejj miles ( wire l9e2 s t ! tw9     
curr5ts t run ar\nd ! diff]5tial magnet 
exactly neutralize ea* o!r & make no    
effect 9 ! (fice ! message />ts f2 :ile 
"o ( !m takes to ! e>?1 & ! o!r to ! l9e
 to c>ry ! message4  ,?is cond5s] is    
necess>y1 because ! %ort resi/ance-coil 
affects ! curr5t imm$iately1 :ile ! long
 l9e ) its great] am\nt ( metal does n  
give ! same am\nt ( resi/ance till x is 
fill$ f end to end1 :i* requires a      
fraction ( a second4 ,dur+ ?is "t1      
h[ev]1 m curr5t is pass+ ?r\gh !        
diff]5tial coil connect$ ) ! l9e ?an    
?r\gh ! %ort resi/ance-coil2 & ! unequal

 fl[ causes ! relay armature to jump1 or
 kick4 ,! cond5s]1 ) ! _m leaves (      
t9-foil1 supplies ! great] metal surface
 to be trav]s$ by ! %ort l9e curr5t1    
causes ! fl[ to be equal 9 bo? circuits 
at all times1 & ?us cures ! kick4 ,x is 
?is quality ( a cond5s] t enables u to  
give to an artificial l9e ( any         
resi/ance all ! qualities1 includ+      
capacity1 & exhibit all ! ph5om5a ( a   
real l9e ( any l5g?1 & x 0 ?is quality t
 enabl$ ,mr4 ,/e>ns to take ! kick out (
 duplex transmission & ?us *ange ! :ole 
sy/em1 :i* creat$ a new era 9           
telegraphy4  ,we h j spok5 ( ! capacity 
( a circuit1 & /at$ t x 0 det]m9$ by !  
mass ( metal us$4 ,?is capacity is      
measur$ by a /&>d ( capacity t is       
arbitr>y & consi/s ( a cond5s]1         
con/ruct$ s t a giv5 am\nt ( surface (  
t9-foil may be plugg$ 9 or out4 ,!      
practical unit ( capacity is call$ !    
micro-f>ad1 ! real unit is ! f>ad1 &    
takes its "n f ,f>aday4  ,b let u g back
 to multiple sy/ems ( transmission4 ,!re

 are _m o!r sy/ems ( simultane\s        
transmission aside f ! duplex1 & all (  
!m are class$ "u ! g5]al head ( multiple
 telegraphy4 ,fir/ !re is ! quadruplex1 
t s5ds two messages ea* way             
simultane\sly1 mak+ "o wire d ! "w ( f\r
 s+le wires--z !y 7 us$ at fir/4 ,!     
quadruplex is v ext5sively us$ by !     
,we/]n ,union ,telegraph ,company &     
o!rs4 ,x w\ld be difficult to expla9 x 9
 a popul> article1 s we w n attempt x4  
,!re is ano!r =m ( multiple telegraph t 
0 us$ on ! ,po/al ,telegraph l9e :5 x   
fir/ />t$--:i* 0 inv5t$ & p]fect$ by !  
writ]--t c be m easily expla9$4  ,9     
#ahgd ,i discov]$ a me?od ( transmitt+  
musical tones telegraphically1 & ! ?+ t 
set my m9d 9 t direction 0 a dome/ic    
incid5t4 ,x is a curi\s fact t mo/      
inv5tions h _! beg9n+s 9 "s incid5t or  
obs]vation t comes )9 ! exp]i5ce ( "s "o
 :o is able to see & int]pret ! mean+ ( 
su* incid5ts or obs]vations4 ,i d n mean
 to say t inv5tions are usually ! result
 ( a happy ?\ght1 or accid5t2 ! g]m may 

be1 b ! g]m has to h ! "r k9d ( soil to 
take root 9 & ! "r k9d ( culture        
aft]w>d4 ,x is a r>e ?+ t an inv5tion1  
ei!r ( comm]cial or sci5tific           
importance1 ev] comes to p]fection )\t  
h>d "w--midnight oil & daylight toil2 & 
x is r>ely1 if ev]1 t a discov]y or an  
inv5tion bas$ ^u a discov]y does n h1   
soon] or lat]1 a practical use1 al?\gh  
we sometimes h to wait c5turies to f9d x
 put4 ,we _h to wait =ty-f\r ye>s aft] !
 galvanic batt]y 0 discov]$ be=e x      
became a useful s]vant ( man4 ,x 0 fifty
 ye>s or m aft] ! discov]y by ,f>aday ( 
magneto-electricity be=e x f\nd a useful
 application beyond t ( a m]e toy1 b n[ 
x is "o ( ! mo/ useful s]vants we h1 z  
%[n 9 its wond]ful developm5t 9 electric
 light+ & electric railroads1 to say    
no?+ ( its heat+ qualities & ! useful   
purpose x s]ves 9 driv+ ma*9]y4 ,!      
int]e/+ discov]ies ( ,pr(essor ,crookes 
9 pass+ a curr5t ( electricity ?r\gh    
tubes ( high vacua wait$ _m ye>s be=e !y
 f\nd a practical use 9 ! ,x-ray1 t     

promises to be ( great s]vice 9 m$ic9e &
 surg]y4  ,! transmission ( musical     
h>monies telegraphically1 :ile 9 itself 
( great sci5tific int]e/1 0 ( no        
practical use1 b x l$ to o!r inv5tions1 
( :i* x is ! base1 t are transc5d5tly   
useful 9 e-day life4 ,! transmission (  
h>monic s\nds by electricity und]lies ! 
pr9ciple ( ! telephone4 ,!re is a va/   
diff]5ce1 9 pr9ciple1 betwe5 !          
transmission ( simple melody1 :i* is a  
comb9ation ( musical tones transmitt$   
successively--"o tone foll[+ ano!r--& ! 
transmission ( h>mony1 :i* involves !   
transmission ( two or m tones           
simultane\sly4 ,! =m] c be transmitt$ by
 a make-&-break curr5t4 ,9 ! latt] case 
"o tone has to be sup]pos$ ^u ano!r &   
mu/ be transmitt$ ) a v>y+ b a          
cont9u\sly clos$ curr5t4 ,i make a      
di/9ction betwe5 a clos$ circuit & a    
clos$ curr5t4 ,9 ! case ( ! arc-light ! 
circuit is op5 7t is1 brok571 te*nically
 speak+1 b ! curr5t is /ill fl[+4 ,!    
reason :y ! ,reiss & o!r metallic       

contact telephone transmitt]s _c        
successfully be us$ = telephone purposes
 is t metal po9ts w n all[ ( suffici5t  
sep>ation ( ! transmitt+ po9ts )\t      
break+ ! curr5t z well z ! circuit4     
,c>bon contacts admit ( a mu* wid]      
sep>ation )\t actually /opp+ ! fl[ ( !  
curr5t1 :i* latt] is a necessity =      
p]fect telephonic transmission1 & x 0 ! 
use ( c>bon t made t =m ( transmitt] a  
success4  ,!re are o!r =ms1 or at lea/  
"o o!r =m t does n dep5d ^u ! l5g? ( !  
voltaic arc =m$ :5 ! electrodes are     
sep>at$4 ,( ?is we w speak ano!r "t4 ,n[
 let u g back to ! dome/ic incid5t      
ref]r$ to above4  ,"o ev5+ 9 ! w9t] (   
#ahgc-d ,i came home f my laboratory "w 
& w5t into ! ba?room to make my toilet =
 d9n]4 ,i f\nd my nephew1 ,mr4 ,*>les   
,s4 ,%epp>d1 toge!r ) "s ( 8 playmates1 
tak+ electrical %ocks f a little m$ical 
induction-coil t ,i he>d humm+ 9 !      
closet4 ,he _h "o t]m9al ( ! coil       
connect$ to ! z9c l9+ ( ! ba?tub--:i* 0 
dry at t "t--:ile he held ! o!r 9 8 left

 h&1 & ) 8 "r 0 tak+ %ocks f ! l9+ ( !  
tub by rubb+ 8 h& aga9/ ! z9c4 ,i notic$
 t ea* "t he made contact ) ! tub1 z he 
rubb$ x = a %ort di/ance1 a peculi> s\nd
 0 emitt$ f "u 8 h&1 n unlike ! s\nd    
made by ! electrotome t 0 vibrat+ 9 !   
closet4 ,my int]e/ 0 imm$iately ar\s$1 &
 ,i took ! electrode out ( 8 h& & = "s  
"t exp]im5t$ ) x1 go+ to ! cupbo>d f "t 
to "t to *ange ! rate ( vibration ( !   
electrotome1 & ?us *ange ! quality ( !  
s\nd4 ,i notic$ t ! s\nd or tone "u my  
h&1 if x c\ld be s call$1 *ang$ ) ea*   
*ange ( ! rate ( vibration4 ,! ?+ t mo/ 
int]e/$ me 0 t ! peculi> *>act]i/ics ( !
 noise 7 reproduc$4 ,9 ^? few m9utes ,i 
laid out "w en\gh = ye>s ( exp]im5t1 & z
 a result ,i 0 late to d9n]4  ,?is      
discov]y op5$ up to my m9d ! possibility
 ( ?ree ?+s--! transmission ( music & ( 
spee* or articulate words ?r\gh a       
telegraph-wire1 & ! transmission ( a    
numb] ( messages ov] a s+le wire4 ,i    
con/ruct$ a keybo>d consi/+ ( "o octave 
& made a set ( re$s tun$ to ! notes ( ! 

scale1 & !n :5 "s "o w\ld play a melody 
,i c\ld reproduce x 9 two ways3 ,"o by  
plac+ my body 9 ! circuit & rubb+ a     
metal plate--x might be ! bottom ( a t9 
pan1 a jo9t ( /ovepipe or o!rwise--any?+
 t 0 metal & w\ld vibrate w\ld give !   
effect4 ,ano!r way 0 to connect an      
electromagnet 7hav+ a diaphragm or re$  
across its poles7 9 ! circuit at !      
receiv+-end & m\nt x on "s k9d ( a      
s\ndbo>d4 ,i made a great numb] (       
diff]5t k9ds ( receiv]s t 7 capable (   
receiv+ ei!r musical or articulate      
s\nds1 z has _m times be5 prov5 by      
exp]im5t4 ,i c>ri$ two sets ( exp]im5ts 
along toge!r2 ! "o look+ t[>d a sy/em ( 
multiple telegraphy & ! o!r !           
transmission ( articulate spee*4 ,let u 
fir/ look into ! multiple telegraph &   
take ! o!r up "u ! head ( ! telephone4  
,:5 ! electrical keybo>d 0 complet$ ,i  
f\nd t ,i c\ld transmit n only a melody 
b a h>mony2 t m ?an "o tone c\ld be     
transmitt$ simultane\sly4 ,?is discov]y 
op5$ up a long s]ies ( exp]im5ts ) !    

view ( s5d+ a numb] ( messages          
simultane\sly by means ( musical tones  
diff]+ 9 pit*4 ,i _h already demon/rat$ 
t sev]al tones c\ld be transmitt$ at    
once1 b !y w\ld speak all alike 7) !    
same l\dness7 on ! receiv+-in/rum5t4 ,i 
n[ w5t to "w on an in/rum5t t respond$ =
 "o note only & succe$$ beyond my       
expectations4 ,i made ?ree diff]5t k9ds 
( receiv+-in/rum5ts4 ,! fir/ 0 a /eel   
/rap ab\t eight in*es long by           
?ree-eigh?s wide4 ,?is /rap 0 m\nt$ 9 an
 iron frame 9 front ( an electromagnet4 
,a ?umbscrew enabl$ me to /ret* ! /rap  
till x w\ld vibrate at ! requir$ pit*4  
,if1 = in/ance1 ! s5d+-re$ vibrat$ at ! 
rate ( #ajj times p] second & ! /rap ( !
 receiv] 0 /ret*$ to a t5sion t w\ld    
give #ajj vibrations p] second :5       
pluck$1 x w\ld !n respond to !          
vibrations ( ! s5d+-re$ b n to ^? (     
ano!r re$ ( a diff]5t rate ( vibration4 
,if we take m\nt$ tun+-=ks tun$ 9 pairs 
( diff]5t pit*es1 say f\r pairs1 s t ea*
 =k has a mate t is 9 exact accord ) x1 

& place !m all 9 ! same room1 & s\nd "o 
( !m = a few seconds & !n /op x1 ^u     
exam9+ ! o!r =ks y w f9d all ( !m quiet 
except ! mate ( ! "o t 0 s\nd$4 ,?is "o 
w be s\nd+4 ,if we n[ s\nd f\r ( ! =ks &
 !n /op !m ! o!r f\r w be s\nd+ f       
sympa?y because ! mate ( ea* "o ( !m has
 be5 s\nd$4 ,if only two =ks diff]+ 9   
pit* are s\nd$ only two ( ! o!rs w s\nd 
9 sympa?y4 ,9 ! fir/ case only "o set ( 
s\nd-waves 7 set up 9 ! air1 & ! =k t   
f\nd itself 9 accord ) ?is set respond$4
 ,:5 f\r =ks diff]+ 9 pit* 7 s\nd$ !re 7
 f\r sets ( tone-waves sup]pos$ ^u ea*  
o!r exi/+ 9 ! air1 s t ea* ( ! rema9+   
=ks f\nd a set ( waves 9 sympa?y ) its  
own natural rate ( vibration & s        
respond$4  ,n[ apply ?is pr9ciple to !  
h>monic telegraph & y c und]/& its      
op]ation4 ,at ! transmitt+-end ( a l9e (
 wire !re are a c]ta9 numb] ( =ks or    
re$s kept vibrat+ cont9u\sly4 ,^! re$s  
ea* h a fix$ rate ( vibration & be> a   
h>monic relation to ea* o!r s z n to h  
s\nd-int]f]5ce or beats4 ,at !          

receiv+-end ( ! l9e !re are z _m        
electromagnets z !re are                
transmitt+-re$s1 & ea* magnet has a re$ 
or /rap 9 front ( x tun$ to "s "o ( !   
transmitt+-re$s1 s t ea* transmitt+-re$ 
has a mate 9 exact h>mony ) x at !      
receiv+-end ( ! l9e4 ,keys are s arrang$
 at ! transmitt+-end z to ?r[ ! tones   
correspond+ to !m to l9e :5 depress$4 ,9
 o!r words1 :5 ! key belong+ to batt]y  
,b & vibrator #a is depress$ 7see ,fig4 
#d7 ! effect is to s5d electrical       
pulsations ?r\gh ! l9e correspond+ 9    
rate p] second to t ( ! vibrator4 ,!    
same is true ( batt]y ,b' & vibrator #b4
 ,dur+ ! "t any key is depress$--we w   
say ( tone ,no4 #a--?is tone w be       
transmitt$ ?r\gh ! l9e & be reproduc$ by
 its mate--! "o tun$ 9 accord ) x--at ! 
receiv+-/ation4 ,by a succession ( long 
& %ort tones repres5t+ ! ,morse code a  
message c be s5t4 ,numb]s two1 ?ree &   
f\r might be s5d+ at ! same "t1 b !y    
w\ld n int]f]e ) numb] "o or ) ea* o!r4 
,9 #ahgf-g ! writ] succe$$ 9 s5d+ eight 

simultane\s messages betwe5 ,new ,york &
 ,philadelphia by ! h>monic me?od4      
,illu/ration3 ,fig4 #d4      ,9 ?is     
diagram1 #a & #b are tun$ re$s2 #a;,a   
#b;,a are receiv]s     tun$ to ! re$s #a
 & #b respectively2 #a & #a;,a are 9    
unison1     also #b & #b;,a1 b ! two    
gr\ps 7! #as & ! #bs7 diff]     f ea*   
o!r 9 pit*4  ,!re 7 two ways ( read+ by 
! h>monic me?od4 ,"o 0 by ! long & %ort 
tone-s\nds & ! o!r by ! ord9>y s\nd]4   
,! vibration ( ! receiv+-re$ 0 made to  
op5 & close a local circuit l a common  
,morse relay & ?us op]ate ! s\nd]4 ,x is
 useless to try to s5d a message if !   
s5d] & receiv] are out ( tune ) ea* o!r 
9 ?is sy/em4  ,:at is true 9 sci5ce is  
true 9 life4 ,if we are out ( tune ) our
 surr\nd+s we only beat ! air1 & our    
ef=ts are 9 va94 ,we get no sympa!tic   
response4     ,,*apt] ,,xiv4  ,,way     
,,duplex ,,sy/em4   ,a novel =m ( d\ble 
transmission 0 inv5t$ by ! writ] soon   
aft] ! completion ( ! h>monic sy/em1 & 0
 an outgr[? ( x4 ,x is /ill 9 use on "s 

( ! railroad-l9es4 ,an ord9>y railroad  
telegraph-l9e has an in/rum5t 9 circuit 
9 e (fice along ! road1 *iefly =        
purposes ( tra9-dispat*+4 ,z we h       
h]et(ore expla9$1 :5ev] any "o (fice is 
s5d+1 ! dispat* is he>d 9 all ( !       
(fices4 ,! ,way duplex sy/em p]mits ( ! 
use ( ! l9e = ?r\gh bus9ess             
simultane\sly ) ! op]ation ( ! local    
(fices4 ,t is to say1 any /ation along !
 l9e may be telegraph+ ) any o!r /ation 
by ! ord9>y ,morse me?od1 & at ! same "t
 messages may be pass+ back & =? betwe5 
! two end (fices4  ,?is is accompli%$ by
 ! foll[+ me?od3 ,at ea* end ( ! l9e !re
 is a tun$ re$1 su* z we h describ$ 9   
our la/ *apt]1 t is kept con/antly 9    
vibration by a local batt]y dur+ work+  
h\rs4 ,?is vibrator is s arrang$ 9      
relation to ! batt]y t :5ev] ! key      
belong+ to x is depress$ ! curr5t all   
?r\gh ! l9e is r5d]$ vibratory4 ,!re is 
also 9 circuit at ea* end ( ! l9e a     
h>monic relay1 t is tun$ 9 accord ) !   
vibrat+ re$ ( ! s5d]4 ,if ei!r key      

belong+ to ?is "p ( ! sy/em is op5$1 z 9
 ! act ( s5d+ a message1 ^! h>monic     
relays1 be+ tun$ 9 sympa?y ) !          
s5d+-vibrator1 w respond1 ?us s5d+      
,morse *>act]s made up ( a tone brok5   
into dots & da%es4 ,?is tone c be read  
directly f ! relay1 or1 z is usually !  
case1 x causes ! s\nd] to op]ate 9 !    
common way4  ,y w at once inquire :y !  
ord9>y ,morse in/rum5ts 9 ! local (fices
 are n affect$ by ^! vibratory signals1 
& also :y ! h>monic in/rum5ts at ! end  
(fice are n affect$ by ! work+ ( ! local
 (fices4 ,! local (fice does n op5 !    
circuit entirely1 b simply cuts out a   
resi/ance by ! op]ation ( ! special     
h>monic key4 ,:5 a resi/ance is ?r[n    
into an electric circuit x weak5s !     
curr5t 9 proportion to ! am\nt (        
resi/ance int]pos$4 ,y w see t !re is "s
 curr5t /ill left 9 ! l9e :5 ! key is   
op51 b ! spr+ ( ! relay at ! local (fice
 is s adju/$ z to pull ! armatures away 
f ! magnets :5ev] ! curr5t is weak5$ by 
?r[+ 9 ! resi/ance1 s t by ?is means an 

ord9>y ,morse telegraphic relay may be  
work$ )\t ev] entirely op5+ ! circuit4  
,9 ! ,way duplex sy/em !re is a         
resi/ance at ea* /ation t is cut 9 & out
 by ! op]ation ( its key1 :i* causes all
 ! in/rum5ts 9 ! l9e to "w simultane\sly
 except ! two h>monic relays locat$ "o  
at ea* end ( ! l9e4 ,^! w n respond to  
any?+ b ! vibratory signal4  ,9 ord] to 
prev5t ! ,morse relays at ! local (fices
 f respond+ to ! vibratory curr5t a     
cond5s] is connect$ ar\nd !m4 ,?is      
cond5s] s]ves two purposes3 ,x enables !
 %ort impulses ( ! vibrat+ curr5t to    
pass ar\nd ! relays )\t hav+ to be      
resi/$ by ! coils ( ! magnets1 & betwe5 
! pulsations ea* cond5s] w dis*>ge ?r\gh
 ! relay at ! local (fices1 & ?us fill 9
 ! gap betwe5 ! pulsations1 produc+ !   
effect on ! relay ( a /eady curr5t4 ,:5 
a l9e is ?us equipp$ x may be treat$ 9 e
 respect z two sep>ate wires1 "o ( !m   
do+ way bus9ess & ! o!r ?r\gh bus9ess4  
,x is a curi\s bl5d+ ( sci5ce &         
me*anism4  ,ano!r int]e/+ application 0 

made ( ! sy/em ( transmission by musical
 tones--by ,edison1 "s ye>s ago4 ,we    
ref] to ! transmission ( messages to & f
 a mov+ railroad-tra9 ) ! head (fice at 
! end ( ! l9e4 ,9 ?is case ! message 0  
transmitt$ a "p ( ! di/ance ?r\gh !     
air2--ano!r in/ance ( wireless          
telegraphy4 ,! op]ation 0 z foll[s3 ,"o 
( ! wires /rung on ! poles ne>e/ to !   
track 0 fitt$ up ) a vibrator & key at !
 end ( ! l9e simil> to t ( ! ,way duplex
 j describ$4 ,9 "o ( ! c>s 0 ano!r      
batt]y1 key & vibrator1 & z only "o tone
 0 us$1 no tone-select+ device or       
h>monic relay 0 ne$$1 b in/ead an ord9>y
 receiv+-telephone 0 us$ to read ! long 
& %ort s\nds s5t ov] ! l9es4 ,"o end ( !
 batt]y 9 ! c> 0 connect$ ?r\gh ! :eels 
to ! e>?1 :ile ! o!r end 0 connect$ to !
 metal ro( ( ! c>4 ,be+ ?us equipp$1 we 
w suppose our tra9 to be out on ! road  
=ty or fifty miles f ei!r end ( ! l9e1  
mov+ at ! rate ( =ty miles an h\r4 ,!   
op]ator at ,*icago1 say1 wi%es to s5d a 
message to ! mov+ tra92 he op]ates 8 key

 9 ! ord9>y mann]1 :i* makes ! curr5t on
 ! l9e vibratory dur+ ! "t ! key is     
depress$4 ,^! electrical vibrations     
cause magnetic vibrations1 or e!r-waves1
 to radiate 9 e direction f ! wire1 at  
"r angles to ! direction ( ! curr5t1 l  
rays ( light4 ,:5 !y /rike ! ro( ( ! c> 
!y create electrical impulses 9 ! metal 
by induction 7describ$ 9 ,*ap4 ,,vi74   
,^! impulses pass ?r\gh a telephone     
locat$ 9 ! c> to ! gr\nd4 ,a ,morse     
op]ator li/5+1 ) ! telephone to 8 e>1 w 
he> ! message ?r\gh ! m$ium ( a musical 
tone *opp$ up into ! ,morse code4 ,9 l  
mann] ! op]ator 9 ! c> may transmit a   
message to ! ro( ( ! c> & !nce ?r\gh !  
air to ! wire1 :i* w be he>d1 by any "o 
li/5+1 9 a telephone :i* is connect$ 9 t
 circuit1--&1 z a matt] ( fact1 x w be  
he>d f any wire t may be /rung on any ( 
! poles on ei!r side ( ! road4  ,"s ye>s
 ago an exp]im5t ( ?is k9d 0 made on "o 
( ! roads betwe5 ,milwaukee & ,*icago4  
,:at wond]ful ?+s c be done )           
electricity6 ,z a s]vant ( man x is     

reliable & accurate--seem+ almo/ to h ! 
qualities ( docility--:5 "u intellig5t  
direction1 t is 9 accord ) ! laws (     
nature2 b "u o!r conditions x *anges f !
 will+ s]vant to a h>d ma/]1 hesitat+ n 
to de/roy life or prop]ty )\t reg>d to  
p]sons or ?+s4     ,,*apt] ,,xv4        
,,telephony4   ,9 ! =ego+ *apt]s ,i h   
describ$ ! me?od ( transmitt+ musical   
tones telegraphically & its applications
 to multiple telegraphy1 z well z to a  
mode ( communicat+ ) a mov+             
railroad-tra94 ,z ,i /at$ 9 a =m] *apt]1
 aft] discov]+ a me?od ( transmitt+     
h>mony z well z melody1 ,i _h 9 m9d two 
l9es ( developm5t1 "o 9 ! direction (   
multiple telegraphy1 & ! o!r t ( !      
transmission ( articulate spee*4 ,i w n 
attempt to give ! names ( all ! p :o h  
contribut$ to ! developm5t ( ! telephone
 7z ?is alone w\ld fill a volume7 b only
 describe my own %>e 9 ! "w--leav+      
hi/ory to give ea* "o due cr$it = 8 "p4 
,:ile ,i d n int5d1 "h1 to ent] into any
 controv]sy reg>d+ ! priority ( !       

inv5tion ( ! telephone1 ,i wi% to say t 
f ! "t ,i began my rese>*es1 9 ! w9t] ( 
#ahgc-d1 until "s "t aft] ,i _h fil$ my 
specification = a speak+ or articulat+  
telephone1 9 ! w9t] ( #ahge-gf1 ,i _h no
 idea t any "o else _h done or 0 do+    
any?+ 9 ?is direction4 ,i wi% to say    
fur!r t if ,i _h fil$ my description ( a
 telephone z an application = a pat5t   
in/ead ( z a caveat1 & _h prosecut$ x to
 a pat5t1 )\t *ang+ a ^w 9 !            
specification z x /&s to-day1 ,i %\ld h 
be5 aw>d$ ! priority ( inv5tion by !    
c\rts4 ,i am borne out 9 ?is ass]tion by
 ! highe/ legal au?ority4 ,9 law1 a     
caveat 7,lat9 ^w1 mean+ ,let him bew>e7 
is a w>n+ to o!r inv5tors1 to protect an
 incomplete inv5tion2 :]eas 9 fact !    
inv5tion to be protect$ may be complete4
 ,an application = a pat5t is presum$ by
 ! law to be = a complet$ inv5tion2 b x 
may be1 & v (t5 is1 incomplete4 ,x w\ld 
(t5 make a v great diff]5ce if decisions
 7 r5d]$ accord+ to ! facts 9 ! case r  
?an accord+ to rules ( law & practice1 t

 sometimes "w great inju/ice to         
individuals4  ,z has be5 said 9 ano!r   
*apt]1 9 ! summ] ( #ahgd ,i w5t to      
,europe 9 ! int]e/ ( ! telephone1 tak+  
my app>atus1 z !n develop$1 ) me4 ,i    
came home e>ly 9 ! fall & resum$ my     
exp]im5tal "w4 ,_m int]e/+ z well z     
amus+ ?+s occurr$ dur+ ^! exp]im5ts4  ,i
 rememb] t 9 ! fall or e>ly w9t] ( #ahgd
 ,i 0 9 ,milwaukee ) my app>atus c>ry+  
on "s exp]im5ts on a wire betwe5        
,milwaukee & ,*icago4 ,i _h my musical  
transmitt] along1 & "o ev5+1 = !        
ent]ta9m5t ( "s fri5ds at ! ,ne:all     
,h\se1 a wire 0 /ret*$ across ! /reet f 
! telegraph (fice into "o ( ! rooms ( ! 
hotel4 ,a great numb] ( tunes 7 play$ at
 ! telegraph-(fice by ,mr4 ,goodridge1  
:o 0 my assi/ant at t "t1 :i* 7         
transmitt$ across ! /reet1 z be=e /at$4 
,9 ^? days x 0 a common practice 9      
telegraphy to use "o batt]y = a great   
numb] ( l9es4 ,= in/ance1 />t+ ) "o     
gr\nd-wire :i* connect$ )1 say1 !       
negative pole ( ! batt]y1 f ! positive  

pole two1 ?ree or a half-doz5 l9es might
 be connect$1 runn+ 9 v>i\s directions1 
connect+ ) ! gr\nd at ! fur!r end1 ?us  
complet+ _! circuits4 ,= use 9          
transmitt+ tones across ! /reet t ev5+  
we connect$ our l9e-wire on to !        
telegraph company's batt]y1 :i* consi/$ 
( #ajj or m cells1 & :i* _h f\r or five 
m l9es radiat+ f ! end ( ! batt]y to    
diff]5t p>ts ( ,wiscons94 ,our l9e 0    
tapp$ on to ! batt]y 7)\t *ang+ any (   
its connections7 tw5ty cells f !        
gr\nd-wire4 ,9 transmitt+1 ea* vibration
 w\ld mom5t>ily %ut (f ^! tw5ty cells f 
! l9es t 7 connect$ ) ! :ole batt]y4 ,! 
effect ( ?is 7an effect t we did n      
anticipate at ! "t7 0 to s5d a vibratory
 curr5t out on all ! l9es t 7 connect$ )
 t s+le batt]y z well z across ! /reet4 
,a great _m famili> tunes 7 play$ dur+ !
 c\rse ( an h\r or two :i*1 unconsci\sly
 = u1 7 creat+ great con/]nation ?r\gh\t
 ! ,/ate ( ,wiscons91 9 _m ( ! (fices   
?r\gh :i* ^! v>i\s l9es pass$4  ,next   
morn+ reports & inquiries began to come 

9 f v>i\s t[ns & cities we/1 nor?we/ &  
nor?1 giv+ details ( ! ph5om5a t 7      
notic$ on ! in/rum5ts locat$ 9 ! v>i\s  
(fices along ! l9es4 ,!y report$ _!     
relays z s++ tunes2 "o p>ty said he     
?\ght ! in/rum5ts 7 hold+ a pray]-meet+ 
f ! fact t !y seem$ to be s++ hymn-tunes
 = q a :ile1 b ?is notion 0 f9ally      
dissipat$1 because !y grew hil>i\s &    
sang ,yankee ,doodle4  ,"o op]ator1 up 9
 ! p9e woods ( nor!rn ,wiscons91 did n  
seem to take ! *e]ful view ( x t "s ( ! 
o!rs did4 ,he 0 sitt+ alone 9 !         
telegraph-(fice t ev5+ :5 he ?\ght he   
he>d ! notes ( a bugle 9 ! di/ance2 he  
got up & w5t to ! door to li/51 b c\ld  
he> no?+2 b on com+ back into ! room he 
he>d ! same bugle notes v fa9tly4 ,he 0 
incl9$ to be some:at sup]/iti\s & grew v
 n]v\s2 f9ally1 on look+ ar\nd1 he      
locat$ ! s\nd 9 8 relay1 b ?is did n    
help matt]s ) him4 ,) sup]/iti\s awe he 
li/5$ to ! in/rum5t = a few mom5ts1 :ile
 x gave out ! solemn tones ( ,old       
,hundr$1 !n x sudd5ly jump$ into a      

hil>i\s r5d]+ ( ,yankee ,doodle4 ,?is 0 
too mu* = our n]v\s fri5d1 & ha/ily     
putt+ on 8 ov]coat1 he left ! (fice = ! 
night4  ,on ano!r occasion1 :5 ,i 0 giv+
 a lecture 9 "o ( ! cities outside (    
,*icago1 :]e exhibitions ( music        
transmitt$ f ,*icago 7 giv51 "o ( !     
op]ators along ! l9e 0 v mu* a/oni%$ by 
8 swit*bo>d sudd5ly becom+ musical4     
,ord]s _h be5 giv5 = ! in/rum5ts 9 all !
 local (fices to be cut out ( ! p>ticul>
 l9e t ,i 0 us+4 ,h5ce ! in/rum5t 9 ?is 
p>ticul> (fice 0 n 9 ! circuit ?r\gh :i*
 ! tunes 7 be+ transmitt$4 ,! wire1     
h[ev]1 ran ?r\gh 8 swit*bo>d1 & ow+     
probably to a loose connection1 or an   
induc$ effect1 !re 0 a sp>k t leap$     
across a %ort space at ea* electrical   
pulsation t pass$ ?r\gh ! l9e1 ?us      
reproduc+ ! notes ( ! v>i\s tunes play$4
  ,y w rememb] 9 "o ( ! *apt]s on s\nd  
7,volume ,,ii471 x is /at$ t a musical  
tone is made up ( a succession ( s\nds  
repeat$ at equal int]vals1 & t ! pit* ( 
! tone is det]m9$ by ! numb] (          

s\nd-impulses p] second4 ,apply+ ?is law
 to ! sp>ks1 y w be able to see h[ !    
swit*bo>d play$ tunes = ! op]ator4  ,9 !
 =ego+ exp]im5ts 9 transmitt+ musical   
tones telegraphically1 ,i us$ a great _m
 diff]5t v>ieties ( receiv]s4 ,"s ( !m 7
 design$ ) metal diaphragms m\nt$ ov]   
s+le electromagnets1 n unlike ! receiv] 
( an ord9>y telephone4 ,^! in/rum5ts    
w\ld bo? transmit & receive articulate  
spee* :5 plac$ 9 circuit ) ! "r am\nt ( 
batt]y to furni% ! necess>y magnetism4  
,h[ev]1 !y 7 n us$ 9 t way at ! "t !y 7 
fir/ made--9 #ahgd4 ,^! ,i call$ common 
receiv]s1 z !y 7 design$ to reproduce   
all tones equally well4 ,i design$ &    
con/ruct$ ano!r =m ( receiv]1 bas$      
some:at ^u ! !ory ( ! h>monic telegraph4
  ,?is consi/$ ( an electromagnet (     
consid]able size1 m\nt$ ^u a wood5 rod  
ab\t t5 feet long4 ,m\nt$ ^u ?is rod 7  
also resonat+ boxes or tubes made ( wood
 ( ! "r size to h _! air-cavities       
correspond ) ! v>i\s pit*es ( !         
transmitt+-re$s1 s t ea* tone w\ld be   

re-en=c$ by "s "o ( ^! air-cavities1 ?us
 giv+ a l\d] & m resonant effect to !   
musical notes4  ,"h 7 two types (       
receiv]1 "o t w\ld receive "o s\nd z    
well z ano!r1 b none ( !m s l\d1 :ile ! 
o!r 0 con/ruct$ on ! pr9ciple (         
selection & re-en=cem5t1 s t a p>ticul> 
note w\ld be s\nd$ by ! box hav+ a      
cavity correspond+ to ! pit* ( ! tone1 &
 0 mu* l\d] & ( mu* bett] quality ?an ,i
 c\ld get f ! diaphragm receiv]4 ,"o (  
^! receiv]s po9t$ to ! h>monic telegraph
 & ! o!r to ! speak+ telephone4 ,i knew 
t ,i _h a receiv] t w\ld reproduce      
articulate spee* or any?+ else t c\ld be
 transmitt$4  ,my fir/ conceptions ( an 
articulate spee*-transmitt] 7 some:at   
complicat$4 ,i conceiv$ ( a funnel made 
( ?9 metal hav+ a great numb] ( little  
rid]s1 insulat$ f ! funnel at "o end &  
re/+ lightly 9 contact ) ! funnel at !  
o!r end4 ,^! rid]s 7 to be made ( all   
sizes & weights s z to be responsive to 
all rates ( vibration4 ,9 ! light ( !   
pres5t day we "k t su* an arrangem5t    

w\ld h transmitt$ articulate spee*1 b   
p]haps n s well z a s+le po9t w\ld d :5 
prop]ly adju/$4 ,my m9d clung to ?is    
idea till 9 ! fall ( #ahge1 :5 an       
obs]vation ,i made ^u ! /reet *ang$ !   
:ole c\rse ( my ?9k+ & solv$ ! problem4 
,! incid5t ,i ref] to took place 9      
,milwaukee1 :]e ,i 0 !n exp]im5t+4 ,"o  
day :ile out on an err& ,i notic$ two   
boys ) fruit-cans 9 _! h&s hav+ a ?read 
atta*$ to ! c5t] ( ! bottom ( ea* c &   
/ret*$ across ! /reet1 p]haps #ajj feet 
ap>t4 ,!y 7 talk+ to ea* o!r1 ! "o hold+
 8 m\? to 8 c & ! o!r 8 e>4 ,at t "t ,i 
_h n he>d ( ?is lov]s' telegraph1 al?\gh
 x 0 old4 ,x is said to h be5 us$ 9 ,*9a
 #bjjj ye>s ago4  ,! two boys seem$ to  
be conv]s+ 9 a l[ tone ) ea* o!r & my   
int]e/ 0 imm$iately ar\s$4 ,i took ! c  
out ( "o ( ! boy's h&s 7r rudely z ,i   
rememb] x n[71 & putt+ my e> to ! m\? ( 
x ,i c\ld he> ! voice ( ! boy across !  
/reet4 ,i conv]s$ ) him a mom5t1 !n     
notic$ h[ ! cord 0 connect$ at ! bottom 
( ! two cans1 :51 sudd5ly1 ! problem (  

electrical spee*-transmission 0 solv$ 9 
my m9d4 ,i did n h an opportunity       
imm$iately to con/ruct an in/rum5t1 z ,i
 _h a p>tn] :o 0 furni%+ money = !      
developm5t ( ! h>monic telegraph & w\ld 
n li/5 to any collat]al exp]im5ts4 ,i   
rememb] sitt+ d[n by ?is p>tn] "o day & 
tell+ him :at ,i c\ld d 9 ! way (       
transmitt+ spee* ?r\gh a wire4 ,i told  
him ,i ?\ght x w\ld be v valuable if    
work$ out4 ,he gave me a look t ,i %all 
nev] =get1 b he did n say a ^w4 ,! look 
convey$ m mean+ ?an all ! words he c\ld 
h said1 & ,i did n d>e broa* ! subject  
aga94  ,h[ev]1 z soon z ,i f\nd         
opportunity1 )\t say+ a ^w to anybody   
except my pat5t lawy]1 ,i fil$ a        
description1 accompani$ by draw+s1 ( a  
speak+ telephone :i* /&s 9 hi/ory to-day
 z ! fir/ complete description on record
 ( ! op]ation ( ! speak+ telephone4 ,x  
describ$ an app>atus :i*1 :5 con/ruct$1 
work$ z describ$1 & x is a matt] (      
hi/ory t ! fir/ articulate spee*        
electrically transmitt$ 9 ?is c\ntry 0  

by a transmitt] con/ruct$ on ! pr9ciple 
describ$1 & almo/ id5tically aft] !     
draw+s 9 my caveat4 ,:ile ! transmitt]  
describ$ 9 ?is caveat 0 n ! be/ =m1 x   
w\ld transmit spee*1 & x conta9$ !      
f\ndation pr9ciple ( all ! telephone    
transmitt]s 9 use to-day4  ,!re are two 
me?ods ( transmitt+ spee*4 ,"o is kn[n z
 ! magneto me?od & ! o!r t ( v>y+ !     
resi/ance ( ! circuit4 ,my fir/         
transmitt] 0 devis$ on ! latt] pr9ciple4
  ,i app5d to ?is extracts f my         
specification fil$ ,feb4 #ad1 #ahgf3    
,to ,all ,:om ,x ,may ,conc]n3--,be x   
kn[n t ,i1 ,eli%a ,gray      ( ,*icago1 
9 ! ,c\nty ( ,cook & ,/ate ( ,ill9ois1 h
      inv5t$ a new art ( transmitt+     
vocal s\nds      telegraphically1 ( :i* 
! foll[+ is a specification3 ,x      is 
! object ( my inv5tion to transmit !    
tones ( !      human voice ?r\gh a      
telegraphic circuit1 & reproduce !m     
at ! receiv+-end ( ! l9e1 s t actual    
conv]sations      c be c>ri$ on by      
p]sons at long di/ances ap>t4 ,i h      

inv5t$ & pat5t$ me?ods ( transmitt+     
musical      impressions or s\nds       
telegraphically1 & my pres5t inv5tion   
is bas$ ^u a modification ( ! pr9ciple (
 said      inv5tion1 :i* is set =? &    
describ$ 9 lett]s pat5t      ( ! ,unit$ 
,/ates1 grant$ to me ,july #bg1 #ahge1  
respectively      numb]$ #aff1jie &     
#aff1jif1 & also 9 an application =     
lett]s pat5t ( ! ,unit$ ,/ates1 fil$ by 
me1 ,feb4 #bc1      #ahge4 99 99 99 ,my 
pres5t belief is t ! mo/ effective me?od
      ( provid+ an app>atus capable (   
respond+ to ! v>i\s      tones ( ! human
 voice is a tympanum1 drum1 or          
diaphragm1      /ret*$ across "o end ( !
 *amb]1 c>ry+ an app>atus      = produc+
 fluctuations 9 ! pot5tial ( ! electric 
circuit & consequ5tly v>y+ 9 its p[]4 99
 99 99 ,!      vibrations ?us imp>t$ are
 transmitt$ ?r\gh an electric           
circuit to ! receiv+-/ation1 9 :i*      
circuit is includ$      an electromagnet
 ( ord9>y con/ruction1 act+ ^u a        
diaphragm to :i* is atta*$ a piece ( s(t

 iron1 & :i*      diaphragm is /ret*$   
across a receiv+ vocaliz+ *amb]      ,c1
 some:at simil> to ! correspond+        
vocaliz+ *amb]      ,a4       ,!        
diaphragm at ! receiv+-end ( ! l9e is   
?us ?r[n      into vibrations           
correspond+ ) ^? at !                   
transmitt+-end1 & audible s\nds or words
 are produc$4       ,! obvi\s practical 
application ( my improvem5t w be to     
enable p]sons at a di/ance to conv]se ) 
ea* o!r      ?r\gh a telegraphic        
circuit1 j z !y n[ d 9 ea*      o!r's   
pres5ce1 or ?r\gh a speak+-tube4        
,i claim z my inv5tion ! art (          
transmitt+ vocal s\nds or               
conv]sations telegraphically ?r\gh an   
electric circuit4  ,?is specification 0 
accompani$ by cuts ( ! transmitt] &     
receiv] connect$ by a l9e-wire & %[+ "o 
p]son talk+ to ! transmitt] & ano!r     
li/5+ at ! receiv]4 ,^! cuts may be se5 
9 v>i\s books on ! subject ( telephony4 
,,*apt] ,,xvi4  ,,h[ ,,! ,,telephone    
,,talks4   ,ev]ybody kn[s :at !         

telephone is because x is 9 almo/ e     
man's h\se4 ,b :ile ev]ybody kn[s :at x 
is1 !re are v few 7comp>atively speak+7 
t "k h[ x works4 ,if y rememb] :at has  
be5 said ab\t s\nd & electromagnetism x 
w n be h>d to und]/&4  ,:5 any "o utt]s 
a spok5 ^w ! air is ?r[n into %iv]s or  
vibrations ( a peculi> =m1 & e diff]5t  
s\nd has a diff]5t =m4 ,!re=e1 e        
articulate ^w diff]s f e o!r ^w1 n only 
z a %ape 9 ! air1 b z a s5sation 9 !    
bra91 :]e ! air-vibrations h be5        
conduct$ ?r\gh ! organ ( he>+2 o!rwise  
we c\ld n di/+ui% betwe5 "o ^w & ano!r4 
,e diff]5t ^w produces a diff]5t        
s5sation because !re is a physical      
diff]5ce1 z a %ape or motion1 9 ! air   
:]e x is utt]$4 ,if "o ^w conta9s #ajjj 
simultane\s air-motions & ano!r #aejj y 
c see t !re is a physical or me*anical  
diff]5ce 9 ! air4  ,! con/ruction ( !   
simple/ =m ( telephone is z foll[s3     
,take a piece ( iron rod "o-half or     
?ree-qu>t]s ( an in* long & "o-qu>t] in*
 ?ick1 & aft] putt+ a spool-head on ea* 

end to hold ! wire 9 place w9d x full ( 
f9e insulat$ copp] wire2 fa/5 ! end (   
?is spool to ! end ( a /raight-b>       
p]man5t magnet4 ,!n put ! :ole into a   
suitable frame1 & m\nt a ?9 circul>     
diaphragm 7membrane or plate7 ( iron or 
/eel1 held by its edges1 s t ! free end 
( ! spool w come ne> to b n t\* ! c5t] (
 ! diaphragm4 ,?is diaphragm mu/ be held
 rigidly at ! edges4  ,n[ if ! two ends 
( ! insulat$ copp] wires are br\ght out 
to suitable b9d+-screws ! in/rum5t is   
done4  ,! p]man5t /eel magnet s]ves a   
d\ble purpose4 ,:5 ! telephone 0 fir/   
us$ comm]cially1 ! in/rum5t n[ us$ z a  
receiv] 0 also us$ z a transmitt]4 ,z a 
transmitt] x is a dynamo-electric ma*9e4
 ,e "t ! iron diaphragm is mov$ 9 !     
magnetic field ( ! pole ( ! p]man5t     
magnet1 :i* 9 ?is case is ! free end ( !
 spool 7! iron ( ! spool be+ magnetic by
 contact ) ! p]man5t magnet71 !re is a  
curr5t set up 9 ! wire w\nd on ! spool2 
a %ort impulse1 la/+ only z long z !    
movem5t la/s4 ,! int5sity ( ! impulse w 

dep5d ^u ! amplitude & quickness ( !    
movem5t ( ! diaphragm4 ,if !re is a long
 movem5t !re w be a /rong curr5t & vice 
v]sa4 ,if a s\nd is utt]$1 & ev5 if !   
multitude ( s\nds t are requir$ to =m a 
^w1 be spok5 to ! diaphragm1 ! latt]    
p>takes 9 k9d ( ! air-motions t /rike x4
 ,x sw+s or vibrates 9 ! air1 & if x is 
a p]fect diaphragm x moves exactly z !  
air does1 bo? z to amplitude &          
complexity ( movem5t4 ,y w rememb] t 9 !
 *apt] on s\nd-quality 7,vol4 ,,ii7 x 0 
said t !re 7 hundr$s & sometimes ?\s&s (
 sup]pos$ motions 9 ! tones ( "s voices 
t gave !m ! elem5t we call quality4     
,all ^! complex motions are communicat$ 
by ! air to ! diaphragm1 & ! diaphragm  
sets up electric curr5ts 9 ! wire w\nd  
on ! spool1 correspond+ exactly 9 numb] 
& =m1 s t ! curr5t is mold$ exactly z ! 
air-waves are4 ,n[1 if we connect ano!r 
telephone 9 ! circuit1 & talk to "o (   
!m1 ! diaphragm ( ! o!r w be vibrat$ by 
! electric curr5t s5t1 & caus$ to move 9
 sympa?y ) x & make exactly ! same      

motions relatively1 bo? z to numb] &    
amplitude4  ,x w be pla9 t if ! receiv+ 
diaphragm is mak+ ! same motions z !    
transmitt+ diaphragm1 x w put ! air 9 ! 
same k9d ( motion t ! air is 9 at !     
transmitt+ end1 & w produce ! same      
s5sation :5 s5s$ by ! bra9 ?r\gh ! e>4  
,if ! air-motion is t ( any spok5 ^w x w
 be ! same at bo? ends ( ! l9e1 except t
 x w n be s int5se at ! receiv+-end2 x  
is ! same relatively4 ,& ?is is h[ !    
telephone talks4  ,i h said t ! p]man5t 
magnet _h two functions4 ,9 ! case ( !  
transmitt] x is ! m$ium ?r\gh :i*       
me*anical is conv]t$ into electrical    
en]gy4 ,x corresponds to ! field-magnet 
( ! dynamo1 :ile ! diaphragm corresponds
 to ! revolv+ armature1 & ! voice is !  
/eam-eng9e t drives x4 ,9 ! second      
place1 x puts a t5sion on ! diaphragm & 
also puts ! molecules ( ! iron core ( ! 
magnet 9 a /ate ( t5sion or magnetic    
/ra91 & 9 t condition bo? ! molecules & 
! diaphragm are mu* m s5sitive to !     
electric impulses s5t ov] ! wire f !    

transmitt]4 ,?is fact 0 exp]im5t$ ^u by 
! writ] z f> back z #ahgi & publi%$ 9 ! 
,j\rnal ( ! ,am]ican ,electrical        
,society4 ,at ! pres5t day ?is =m (     
telephone is us$ only z a receiv]4      
,transmitt]s h be5 made 9 a v>iety (    
=ms1 b !re are only two g5]ic me?ods (  
transmission4 ,"o is ! magneto me?od--! 
"o we h describ$--& ! o!r is effect$ by 
v>y+ ! resi/ance ( a batt]y curr5t4 ,!  
=m] w "w )\t a batt]y1 z ! voice act+ on
 ! wire ar\nd ! magnet ?r\gh ! diaphragm
 creates ! curr5t2 9 ! latt] ! curr5t is
 creat$ by ! batt]y b mold$ by ! voice4 
,9 ! latt] me?od ! curr5t passes ?r\gh  
c>bon contacts t are mov$ by !          
diaphragm4 ,c>bon is ! be/ sub/ance1    
because x w be> a wid] sep>ation (      
contact )\t actually break+ ! curr5t4   
,:5 c>bon po9ts are sep>at$ t h an      
electric curr5t pass+ ?r\gh !m1 !re is  
an arc =m$ on ! same pr9ciple z !       
electric arc-light4  ,great improvem5ts 
9 details h be5 made 9 ! telephone s9ce 
its fir/ use1 b no new pr9ciples h be5  

discov]$ z appli$ to transmission4  ,we 
h spok5 9 ano!r place reg>d+ ! v>i\s    
claimants to ! inv5tion ( ! telephone1 b
 "h is "o t has be5 ov]look$4 ,a "y man 
f ! c\ntry 0 9 a telegraph-(fice at "o  
"t & 0 left alone :ile ! op]ator w5t to 
d9n]4 ,sudd5ly ! s\nd] />t$ up & rattl$ 
away at su* a rate t ! c\ntryman ?\ght  
some?+ %\ld be done4 ,he lean$ d[n close
 to ! in/rum5t & %\t$ z l\dly z possible
 ^! words3 ,! op]ator has gone to d9n]4 
,f :at we "k n[ ( ! op]ation ( !        
telephone ,i h no d\bt b t he transmitt$
 8 voice to "s ext5t ov] ! wire4 ,?is "y
 man's claims h nev] be5 put =w>d be=e1 
& we are do+ him t>dy ju/ice4 ,b 8 claim
 is q z good z _m o!rs set =? by p :o   
?9k !y inv5t1 :5ev] x occurs to !m t    
some?+ new might possibly be done1 if   
only somebody w\ld d x4 ,& :5 t somebody
 does d x !y lay claim to x4  ,9 ! e>ly 
days ( ! telephone x 0 n suppos$ t a    
vocal message c\ld be transmitt$ to a v 
great di/ance4 ,h[ev]1 z "t w5t on &    
exp]im5ts 7 multipli$ ! di/ance to :i*  

"o c\ld conv]se ) ano!r ?r\gh a wire    
kept on increas+4  ,9 ^! days1 z e "o   
kn[s1 x is a daily occurr5ce t bus9ess  
m5 conv]se ) ea* o!r1 telephonically1 = 
a di/ance ( #ajjj miles or m2 9 fact1 x 
is possible to transmit ! voice ?r\gh a 
s+le circuit ab\t z great a di/ance z x 
is possible to practically telegraph4   
,?is leads u to speak ( ano!r           
telegraphic app>atus :i* we h n h]et(ore
 m5tion$1 & t is ! telegraphic repeat]4 
,x is a common notion t messages are s5t
 ?r\gh a s+le circuit across ! cont95t1 
b ?is is n ! case1 al?\gh ! circuits are
 v mu* long] ?an !y 7 "s ye>s ago4 ,!   
repeat] is an in/rum5t t repeats a      
message automatically f "o circuit to   
ano!r4 ,= in/ance1 if ,*icago is s5d+ a 
message to ,new ,york ?r\gh two         
circuits1 ! division be+ 9 ,buffalo1 !  
repeat] w be locat$ at ,buffalo & "u !  
control ( bo? ! op]ator at ,*icago & !  
op]ator 9 ,new ,york4 ,:5 ,*icago is    
s5d+1 "o "p ( ! repeat] works 9 unison )
 ! ,*icago key & is ! key to ! ,new     

,york circuit1 :i* beg9s at ,buffalo4   
,:5 ,new ,york is s5d+ ! o!r "p ( !     
repeat] op]ates1 :i* becomes a key :i*  
repeats ! message to ! ,*icago l9e4 ,9  
?is way ! practical result is ! same z  
?\gh ! circuit 7 complete f ,new ,york  
to ,*icago4 ,at ! pres5t day "s ( !     
copp] wires & p]haps "s ( ! l>g] iron   
wires are us$ direct f ,*icago to ,new  
,york )\t repetition1 b all messages    
betwe5 ,new ,york & ,san ,francisco are 
automatically repeat$ at lea/ twice & "u
 c]ta9 conditions ( wea!r (t5]4 ,i c    
rememb] t 9 wet wea!r 9 ! old days1 )   
su* wires z !y _h !n 7be+ ,no4 #i iron )
 bad jo9ts1 :i* gave ! circuit a high   
resi/ance7 t ^! repeat]s w\ld be ins]t$ 
at ,tol$o1 ,clevel&1 ,buffalo & ,albany 
9 ord] to "w f ,*icago to ,new ,york4   
,"u su* conditions ! transmission w\ld  
necess>ily be sl[1 because an armature  
"t w be lo/ at ea* repeat]4 ,reg>d+ ea* 
repeat] z a key1 :5 ,*icago depresses 8 
key ! armature ( ! next repeat] mu/ act1
 & !n ! next successively1 & all ( ?is  

takes "t1 al?\gh only a small fraction (
 a second4  ,! repeat] 0 a v delicate   
in/rum5t & _h to be h&l$ by a skill$    
op]ator4 ,e wire mu/ be 9 its place or !
 in/rum5t w\ld fail to op]ate4 ,i       
rememb] on "o occasion 9 ,clevel& t     
along 9 ! middle ( ! night ! repeat]    
fail$ to "w4 ,! op]ator knew no?+ ( !   
pr9ciple ( its op]ation1 s t :5 x fail$ 
he _h to appeal to "s ( 8 sup]iors4  ,at
 ?is "t !re 0 no "o 9 ! (fice :o knew h[
 to adju/ x1 s !y _h to s5d up to ! h\se
 ( ! sup]9t5d5t & ar\se him f 8 sleep & 
br+ him d[n to ! (fice4 ,he look$ "u !  
table & f\nd t "o ( ! wires _h loos5$ f 
its b9d+-po/ & 0 hang+ d[n4 ,he said    
imm$iately1 ,"h's ! tr\ble2 ,i %\ld ?9k 
y c\ld h se5 x y\rself4 ,! op]ator      
repli$1 ,i did see t1 b ,i didn't ?9k "o
 wire w\ld make any diff]5ce4 ,he le>n$ 
! lesson t all electricians h _h to     
le>n--t ev5 "o wire makes all ! diff]5ce
 9 ! _w4 ,b ?is op]ator 0 no worse 9 t  
respect ?an "s ( 8 sup]iors4 ,"o ( !    
heads ( ! ,clevel& (fice at "o "t 9 !   

e>ly days want$ to give "s directions to
 ! (fice at ,buffalo4 ,he told ! op]ator
 at ! key to tell ,buffalo s & s1 :5 !  
op]ator repli$3 ,i c't d x2 ,buffalo has
 8 key op54 ,! (ficial imm$iately said )
 sev]ity3 ,tell him to close x4 ,he =got
 t x w\ld be z difficult = him to tell  
him to close x1 z x w\ld h be5 to h s5t 
! orig9al message4  ,b let u g back to !
 telephone4 ,:ile x is possible to s5d a
 message f ,new ,york to ,san ,francisco
 by telegraph1 x is n possible to       
telephone t di/ance1 because z yet no "o
 has be5 able to devise a repeat] t w   
transf] spok5 words f "o l9e to ano!r   
satisfactorily4 ,b unless ! pr9t] &     
publi%] be/ir !mselves "s "o may        
accompli% ! feat be=e ?is little book   
rea*es ! read]4 ,if ?is proves to be    
true1 let ! writ] be ! fir/ to          
congratulate ! successful inv5tor4      
,,*apt] ,,xvii4  ,,subm>9e ,,cables4    
,! fir/ attempts at transmitt+ messages 
?r\gh wires laid 9 wat] 7 made ab\t     
#ahci4 ,^! e>ly exp]im5ts 7 n v         

successful1 because ! art (             
wire-insulation _h n atta9$ any degree (
 p]fection at t "t4 ,x 0 n until        
gutta-p]*a began to be us$ z an         
insulator = subm>9e l9es t any          
sub/antial progress 0 made4  ,! fir/    
l9e1 s hi/ory /ates1 t 0 successfully   
laid & op]at$ 0 across ! ,hudson ,riv] 9
 #ahdh4 ,?is l9e 0 con/ruct$ = ! use ( !
 ,magnetic ,telegraph ,company4  ,9 !   
foll[+ ye> exp]im5ts ) gutta-p]*a       
insulation 7 successfully made1 & ab\t  
#ahej a cable 0 laid across ! ,engli%   
,*annel betwe5 ,dov] & ,calais          
7tw5ty-sev5 miles71 consi/+ ( a s+le /r&
 ( wire hav+ a cov]+ ( gutta-p]*a4 ,!   
insulation 0 de/roy$ 9 a day or two1 :i*
 demon/rat$ ! fact t all subm>9e cables 
mu/ be protect$ by "s k9d ( armor4 ,9   
#ahea ano!r cable 0 laid betwe5 ^! two  
po9ts1 conta9+ f\r conductors insulat$ )
 gutta-p]*a1 & ov] all 0 an armor ( iron
 wire4 ,tw5ty-"o ye>s lat] ?is cable 0  
/ill work+1 & = all we "k is work+ n[4  
,aft] ?is successful demon/ration o!r   

cables 7 laid = long] di/ances4  ,^!    
%ort-l9e cables s]v$ to demon/rate !    
relative value ( diff]5t mat]ial =      
insulat+ purposes "u wat]1 & x has be5  
f\nd t gutta-p]*a possesses qualities   
sup]ior to almo/ e o!r mat]ial z an     
insulator = subm>9e cables1 al?\gh !re  
are _m bett] mat]ials = air-l9e         
insulation4 ,gutta-p]*a :5 expos$ to air
 becomes h>d5$ & w crack1 b "u wat] x   
seems to be practically inde/ructible4  
,ocean telegraphy really dates f ! lay+ 
( ! fir/ successful ,atlantic cable4    
,!re 7 _m problems t _h to be solv$1 :i*
 c\ld be done only by ! v exp5sive      
exp]im5t ( lay+ a cable across !        
,atlantic ,ocean4 ,9 ! fir/ place a     
survey _h to be made ( ! bottom ( !     
ocean betwe5 ! %ores ( ,am]ica & ,great 
,brita94 ,! mo/ available r\te 0        
discov]$ by ,lieut5ant ,maury ( ! ,unit$
 ,/ates ,navy1 :o made a s]ies (        
deep-sea s\nd+s1 & discov]$ t1 f        
,newf\ndl& to ! we/ coa/ ( ,irel& !     
bottom ( ! ocean 0 comp>atively ev51 b  

gradually deep5+ t[>d ! coa/ ( ,irel&   
until x rea*$ a dep? ( #bjjj fa?oms4 ,x 
0 n s deep b t ! cable c\ld be laid on !
 bottom1 nor s %all[ z to be 9 dang] ( !
 waves1 iceb]gs or l>ge sea-animals4  ,!
 wat] bel[ a c]ta9 dep? is always /ill &
 n affect$ by w9ds or ocean curr5ts4 ,at
 _m o!r po9ts 9 cross+ ! ocean1 high    
m\nta9s & deep valleys are enc\nt]$1    
possess+ all ! topographical features ( 
dry l&--z ! ocean b$ is only a great    
subm]g$ cont95t4  ,! beg9n+ ( ! lay+ ( !
 fir/ ,atlantic cable 0 on ,aug4 #g1    
#aheg4 ,on ! morn+ ( ,aug4 #g1 #aheh1 a 
ye> lat]1 aft] a s]ies ( mi%aps & adv]se
 circum/ances t w\ld h disc\rag$ mo/ m51
 ! c\ntry 0 electrifi$ by a dispat* f   
,cyrus ,w4 ,field ( ,new ,york 7to :om !
 f9al success ( ! ,atlantic cable is    
ma9ly due71 t ! cable _h be5            
successfully laid & work$4 ,b ?is cable 
work$ only f ! #aj? ( ,augu/ to ! #a/ ( 
,septemb]1 hav+ s5t 9 t "t #bga         
messages4 ,! insulation became impair$  
at "s po9t1 :5 an attempt to =ce !      

curr5t ?r\gh by means ( a l>ge batt]y   
only increas$ ! difficulty4  ,! failure 
( ?is fir/ cable s]v$ to tea*           
manufactur]s & eng9e]s h[ to con/ruct   
cables ) ref]5ce to ! conditions "u :i* 
!y are to be us$4 ,x 0 f\nd t 9 ! deep  
sea a mu* small] & less exp5sive cable  
c\ld be us$ ?an w\ld answ] at ! %ore    
ends1 :]e ! wat] is %all[4 ,! %ore ends 
( an ocean cable are made v l>ge1 z     
comp>$ to ! deep-sea portions1 s z to   
resi/ ! effect ( ! waves & o!r int]f]+  
ob/acles4 ,x 0 fur!r le>n$ t ! mo/      
successful mode ( transmitt+ signals    
?r\gh ! cable 0 ) a small batt]y ( l[   
voltage1 & by ! use ( v delicate        
in/rum5ts = receiv+ ! messages4 ,x is n 
possible to employ su* in/rum5ts on     
cables z are us$ on l&-l9es1 :ile x w\ld
 n be a difficult feat to transmit ev5  
twice ! di/ance ov] l&-l9es /rung on    
poles1 us+ ! ord9>y ,morse telegraph4   
,! wat] ( ! ocean is a conductor1 z well
 z ! heavy armor t surr\nds ! insulation
 ( ! cable4 ,:5 a curr5t is transmitt$  

?r\gh ! conduct+ wires1 9 ! c5t] ( !    
cable1 !y set up a c\nt]*>ge 9 ! armor &
 ! wat] above x1 some:at z an electrifi$
 cl\d w induce a *>ge 9 ! e>? "u x1 ( an
 opposite nature4 ,?is c\nt]*>ge1 be+ s 
close to ! conduct+ wire1 has a ret>d+  
effect ^u ! curr5t transmitt$ ?r\gh x4  
,an ord9>y l&-l9e t is /rung on poles t 
are high up f ! gr\nd has ?is effect    
r$uc$ to a m9imum1 b ! great] ! numb] ( 
wires clu/]$ toge!r on ! same poles ! m 
difficult x becomes to s5d rapid signals
 ?r\gh any "o ( !m4  ,! in/rum5t us$ =  
receiv+ cable messages 0 devis$ by ,sir 
,william ,?ompson1 n[ ,"l ,kelv94 ,"o =m
 consi/s ( a v %ort & delicate          
galvanomet]-ne$le c>ry+ a t9y mirror4   
,?is mirror is s relat$ to a beam (     
light ?r[n ^u x t x reflects x ^u a     
graduat$ scre5 at "s di/ance away1 s t  
its motions are magnifi$ _m hundr$ times
 z x appe>s ^u ! scre54 ,an op]ator sits
 9 a d>k room ) 8 eye on ! scre5 & 8 h& 
^u ! key ( an ord9>y ,morse in/rum5t4   
,he reads ! signal at sight1 & ) 8 key  

transmits x to a s\nd]1 :i* may be 9    
ano!r room1 :]e x is read & copi$ by    
ano!r op]ator4 ,ano!r =m (              
receiv+-in/rum5t c>ries1 in/ead ( !     
mirror1 a delicate capill>y glass tube t
 fe$s ink f a res]voir1 & by ?is means !
 movem5ts ( ! ne$le are record$ on a    
mov+ /rip ( pap]4 ,! symbols 7repres5t+ 
lett]s7 are =m$ by comb9ations ( zigzag 
l9es4 ,?is in/rum5t is ! syphon-record]4
     ,,*apt] ,,xviii4  ,,%ort-,,l9e     
,,telegraphs4   ,e>ly 9 ! hi/ory ( !    
telegraph %ort l9es began to be us$ =   
private purposes1 & z ! ,morse code 0   
famili> only to ^? :o _h /udi$ x & 7    
exp]t op]ators on comm]cial l9es1 "s    
sy/em _h to be devis$ t any "o ) an     
ord9>y ,engli% education c\ld use2 z !  
exp5se ( employ+ two ,morse op]ators    
w\ld be too great = all ord9>y bus9ess  
ent]prises4 ,^! %ort l9es are call$     
private l9es1 & ! in/rum5ts us$ ^u !m 7 
call$ private-l9e telegraph-in/rum5ts4  
,( c\rse !y are n[ ne>ly all sup]s$$ by 
! telephone1 b !y are a "p ( hi/ory4    

,"o ( ! e>lie/ =ms ( %ort-l9e in/rum5ts 
0 call$ ! dial-telegraph4 ,"o ( ! fir/  
inv5tors1 if n ! fir/1 ( ?is =m (       
in/rum5t 0 ,pr(essor ,:eat/one ( ,engl&1
 :o p]fect$ a dial-telegraph-in/rum5t   
ab\t ! ye> #ahci4 ,! receiv+-end ( ?is  
in/rum5t consi/$ ( a lett]$ dial-face1  
"u :i* 0 clockwork me*anism & an        
escape-:eel controll$ by an             
electromagnet4 ,ea* "t ! circuit 0 op5$ 
or clos$ ! :eel w\ld move =w>d "o /ep1 &
 ea* /ep repres5t$ "o ( ! lett]s ( !    
alphabet1 s t ! :eel1 l ! type-:eel ( a 
pr9t+ telegraph1 _h f\rte5 tee?1 ea*    
too? repres5t+ two /eps4 ,z !           
reciprocat+ movem5t ( ! escapem5t _h a  
pallet or *eck-piece on ea* side ( !    
:eel1 its movem5t 0 arre/$ tw5ty-eight  
times 9 ea* revolution4 ,^! tw5ty-eight 
/eps correspond to ! tw5ty-six lett]s ( 
! alphabet1 a dot & a space4 ,on ! %aft 
( ! escape-:eel is fa/5$ a h& or po9t]1 
:i* revolves ov] a dial-face hav+ !     
tw5ty-six lett]s ( ! alphabet1 also a   
dot & space4 ,! po9t] 0 s adju/$ t :5 ! 

escape-:eel 0 arre/$ by "o ( ! pallets x
 w\ld /op ov] a lett]1 %[+ ?us1 lett] by
 lett]1 ! message :i* ! s5d] 0 spell+   
out4  ,! transmitt] consi/$ ( a crank ) 
a knob & a po9t] on x1 :i* 0 m\nt$ ov] a
 dial t 0 lett]$ 9 ! same way z ! face (
 ! receiv+-in/rum5t4 ,a revolution ( ?is
 crank w\ld break & close ! circuit     
tw5ty-eight times2 t is to say1 !re 7   
f\rte5 breaks & f\rte5 closes ( !       
circuit4 ,if n[ ! transmitt+-po9t] & !  
receiv+-po9t] are unifi$ s t !y bo? />t 
f ! same po9t on ! dial1 & !            
transmitt+-crank is rotat$ f left to "r1
 ! receiv+-po9t] w foll[ x up to ! limit
 ( its spe$4 ,9 transmitt+ a message !  
s5d] w\ld turn 8 crank1 or po9t]1 to !  
fir/ lett] ( ! ^w he wi%$ to transmit1  
mak+ a %ort pause1 & !n move on to !    
next lett]1 & s on to ! end ( ! message1
 mak+ a %ort pause on ea* lett]4 ,! end 
( a ^w 0 indicat$ by turn+ ! po9t] to ! 
space-m>k on ! dial4 ,! receiv+-op]ator 
w\ld read by ! pauses ( ! ne$le on !    
v>i\s lett]s4 ,?is 0 a sy/em ( read+ by 

sight4  ,!re h be5 _m =ms ( ?is         
dial-telegraph work$ out by diff]5t     
inv5tors at diff]5t times1 & q a numb] (
 !m 7 us$ 9 ! old days4 ,x 0 a sl[      
process ( telegraph+1 b x 0 suit$ to !  
age 9 :i* x fl\ri%$4 ,"o ( !            
difficulties ( a dial-telegraph consi/$ 
9 ! read9ess ) :i* ! transmitt] &       
receiv] w\ld get out ( unison ) ea* o!r2
 & :5 ?is happ5$ ( c\rse a message is   
un9telligible1 & y h to /op & unify     
aga94  ,ab\t #ahfi ! writ] inv5t$ a     
dial-telegraph to obviate ?is           
difficulty4 ,9 ?is sy/em a transmitt] & 
receiv] 7 comb9$ 9 "o in/rum5t1 & in/ead
 ( a crank !re 7 buttons arrang$ ar\nd !
 dial 9 a circle1 "o opposite ea* lett]4
 ,:5 n 9 op]ation ! po9t]s ( bo?        
in/rum5ts at bo? /ations /ood at z]o4 ,9
 ! act ( transmitt+ ! op]ator w\ld      
depress ! button opposite ! lett] he    
wi%$ to indicate1 :5 imm$iately ! po9t]s
 ( bo? in/rum5ts w\ld />t up & move     
automatically1 /ep by /ep1 until ! po9t]
 came 9 contact ) ! /em ( ! depress$    

button1 :5 x w\ld be arre/$1 & at ! same
 "t cut out ! automatic                 
transmitt+-me*anism & cause bo? ne$les  
to rema9 /ation>y dur+ ! "t ! button 0  
depress$4 ,^u releas+ ! button ! po9t]s 
bo? fall back to z]o at "o leap4  ,!    
fir/ private l9e equipp$ by ?is in/rum5t
 0 = ,rockefell]1 ,&rews  ,flagl]1 :i* 0
 ! firm "n ( ! p>ties :o aft]w>d        
organiz$ ! ,/&>d ,oil ,company4 ,?is l9e
 0 built betwe5 _! (fice on ! public    
squ>e 9 ,clevel& & _! works ov] on !    
,cuyahoga flats4  ,x seem$1 h[ev]1 to be
 ! fate ( ! writ] to make new inv5tions 
t w\ld sup]s$e ! old ones be=e !y 7     
fairly br\ght into use4 ,v soon aft] !  
dial-telegraph began to be us$1 pr9t+   
telegraph in/rum5ts = private-l9e       
purposes sup]s$$ !m4 ,ab\t #ahfg a pr9t+
 in/rum5t 0 devis$ = /ock report+1 :i* 9
 "o ( its =ms is /ill 9 use4 ,soon aft] 
! inv5tion ( ?is =m ( pr9t] a company 0 
organiz$ to op]ate n only ^!            
/ock-report+ l9es1 b %ort l9es = all    
sorts ( private purposes4 ,foll[+ !     

inv5tion ( ! /ock-report+ in/rum5t !re 7
 sev]al adaptations made ( ! pr9t+      
telegraph = private-l9e purposes4 ,among
 o!rs ! writ] inv5t$ "o kn[n z ,gray's  
automatic pr9t]1 a cut & a description (
 :i* may be f\nd on page #fhd 9         
,electricity & ,electric ,telegraph1 by 
,george ,b4 ,prescott1 publi%$ 9 #ahgg4 
,?is in/rum5t 0 adopt$ by ! ,gold &     
,/ock ,telegraph ,company z _! /&>d     
private-l9e pr9t]4 ,x 0 fir/ introduc$ 9
 ! ye> #ahga1 & at ! "t ! telephone     
began to be us$ !re 7 l>ge numb]s ( ^!  
pr9t]s 9 op]ation 9 all ( ! lead+ cities
 & t[ns 9 ! ,unit$ ,/ates4 ,:ile ?is has
 be5 sup]s$$ to a l>ge ext5t by !       
telephone1 !re are /ill a few isolat$   
cases :]e x is us$4  ,%ort l9es h       
multipli$ = all sorts ( purposes1 until 
to-day ! money inve/$ 9 !m l>gely exce$s
 ! am\nt inve/$ 9 ! regul> comm]cial    
telegraphic ent]prises4  ,! inv5tion ( !
 telephone creat$ su* a dem& = %ort-l9e 
s]vice t "s s*eme _h to be devis$ n only
 to make room = ! necess>y wires1 b to s

 *eap5 ! in/rum5ts z to br+ !m )9 rea* (
 ! ability ( ! ord9>y man ( bus9ess4    
,?is problem has be5 solv$ 7b n )\t _m  
difficulties7 by ! inauguration ( :at is
 kn[n z ! c5tral /ation4 ,by ?is sy/em  
"o p>ty simply controls a s+le wire f 8 
(fice or resid5ce to ! c5tral /ation2 "h
 he c h 8 l9e connect$ ) any o!r wire   
runn+ into ?is same /ation1 by call+ !  
c5tral op]ator & ask+ = ! requir$ numb]4
 ,x is useless to tell ! public t v (t5 
?is numb] is busy1 & "h is ! great      
drawback to ! c5tral-/ation sy/em4 ,?is 
is especially true 9 l>ge cities1 :]e   
!re are a great numb] ( l9es4 ,!        
swit*bo>ds 9 l>ge cities are necess>ily 
v complicat$ affairs1 & x requires a    
numb] ( op]ators to answ] ! _m calls t  
are con/antly com+ 94 ,ea* c5tral-/ation
 op]ator presides ov] a c]ta9 section ( 
! bo>d1 & z ?is section has to be relat$
 9 a c]ta9 way to e o!r section1 x is   
easy to see :]e9 arises ! complication4 
,9 l>ge cities ! c5tral /ations !mselves
 h to be divid$ & locat$ 9 diff]5t      

di/ricts1 be+ connect$ by a sy/em (     
trunk l9es4     ,,*apt] ,,xix4  ,,!     
,,telautograph4   ,s f> we h describ$   
sev]al me?ods ( electrical communication
 at a di/ance1 includ+ ! read+ ( lett]s 
& symbols at sight 7z by !              
dial-telegraph & ! ,morse code emboss$  
on a /rip ( pap]72 pr9t$ messages &     
messages receiv$ by means ( arbitr>y    
s\nds1 & culm9at+ 9 ! mo/ wond]ful (    
all1 ! electrical transmission (        
articulate spee*4  ,none ( ^! sy/ems1   
h[ev]1 are able to transmit a message t 
completely id5tifies ! s5d] )\t         
confirmation 9 ! =m ( an autograph lett]
 by mail4  ,9 #ahic !re 0 exhibit$ 9 !  
electrical build+ at ! ,_w's ,fair an   
in/rum5t inv5t$ by ! writ] call$ !      
,telautograph4 ,z ! ^w implies1 x is a  
sy/em by :i* a man's own h&writ+ may be 
transmitt$ to a di/ance ?r\gh a wire &  
reproduc$ 9 facsimile at ! receiv+-end4 
,?is in/rum5t has be5 s (t5 describ$ 9 !
 public pr9ts t we w n attempt to d x   
"h1 = ! reason t x w\ld be impossible   

)\t elaborate draw+s & specifications4  
,x is unnecess>y to /ate t x diff]s 9 a 
fundam5tal way f o!r facsimile sy/ems ( 
telegraphy4 ,suffice x to say t z "o    
writes 8 message 9 "o city ano!r p5 9   
ano!r city foll[s ! transmitt+-p5 )     
p]fect syn*ronism2 x is z ?\gh a man 7  
writ+ ) a p5 ) two po9ts widely sep>at$1
 bo? mov+ at ! same "t & bo? mak+       
exactly ! same motions4 ,by ?is sy/em a 
man may transact bus9ess ) ! same       
accuracy z by ! ,unit$ ,/ates mail1 & ) 
! same cel]ity z by ! electric          
telegraph4  ,a brok] may buy or sell ) 8
 own signature atta*$ to ! ord]1 & d x z
 quickly z he c\ld by any o!r me?od (   
telegraph+1 & ) absolute accuracy1      
secrecy & p]fect id5tification4  ,9     
#ahic1 :5 ?is app>atus 0 fir/ publicly  
exhibit$1 x op]at$ by means ( f\r wires 
betwe5 /ations1 & :ile ! "w x did 0     
faultless1 ! use ( f\r wires made x too 
exp5sive & too cumb]some = comm]cial    
purposes2 s dur+ all ! ye>s s9ce !n !   
endeavor has be5 to r$uce ! numb] (     

wires to two1 :5 x w\ld /& on an        
equality ) ! telephone 9 ?is respect4 ,x
 is only lately t ?is improvem5t has be5
 satisfactorily accompli%$1 &1 = reasons
 above /at$1 no s]i\s attempt has be5   
made to introduce x z yet2 b x has be5  
us$ = a long en\gh "t to demon/rate its 
practicability & comm]cial value4       
,companies h be5 organiz$ bo? 9 ,europe 
& ,am]ica = ! purpose ( putt+ !         
telautograph into comm]cial use4  ,by   
means ( a swit* locat$ 9 ea* subscrib]'s
 (fice ! wires may be swit*$ f a        
telephone to a telautograph1 or vice    
v]sa1 9 a mom5t ( "t4 ,by ?is arrangem5t
 a man may d all ! prelim9>y "w ( a     
bus9ess transaction ?r\gh ! telephone1 &
 :5 he is ready to put x into black &   
:ite swit* 9 ! telautograph & write x   
d[n4 ,= ord9>y ex*ange "w ?is is        
und\bt$ly ! true way to use !           
telautograph1 because "o sy/em ( wires &
 "o c5tral-/ation sy/em w answ] = bo?   
modes ( communication1 & 9 ?is way an   
enorm\s sav+ c be made to ! public4 ,!re

 is no "q 9 ! m9d ( any "o :o is famili>
 ) ! op]ation ( bo? ! telephone &       
telautograph b t "s day !y w bo? be us$1
 ei!r 9 ! same or sep>ate sy/ems1 z !y  
ea* h di/9ctly sep>ate fields (         
usefulness1--! telephone = desultory    
conv]sation1 ! telautograph = accurate  
bus9ess transactions4 ,! "q may arise 9 
! m9ds ( exp]ts h[ ! two sy/ems c be    
work$ 9 ! same set ( cables1 & ?is leads
 u to discuss ! ph5om5a ( induction4  ,e
 "o :o has li/5$ at a telephone has he>d
 a jumble ( noises m or less pron\nc$1  
:i* is ! effect ( ! work+ ( o!r wires 9 
proximity to ^? ( ! telephone4 ,if1 :5 a
 ,morse telegraph in/rum5t is 9 op]ation
 on "o ( a numb] ( wires /rung on ! same
 poles1 we %\ld ins]t a telephone 9 any 
"o ( ! wires t 7 /rung on ! same poles  
or on ano!r set ( poles ev5 across !    
/reet1 we c\ld he> ! work+ ( ?is ,morse 
wire 9 ! telephone1 m or less pron\nc$1 
accord+ to ! di/ance ! wire is f !      
,morse circuit4 ,?is ph5om5on is !      
result ( induction1 caus$ by magnetic   

e!r-waves t are set up :5ev] a circuit  
is brok5 & clos$1 z expla9$ 9 ,*apt]    
,,vi4  ,! telephone is p]haps ! mo/     
s5sitive ( all in/rum5ts1 & w detect    
electrical di/urbances t are too feeble 
to be felt on almo/ any o!r in/rum5t1   
h5ce ! telephone is prey$ ^u by e o!r   
sy/em ( electrical transmission1 & = ?is
 reason has to adopt means (            
self-protection4 ,x has be5 f\nd t !    
sure/ way to prev5t int]f]5ce 9 !       
telephone f neighbor+ wires is to use   
:at is call$ a metallic circuit--t is to
 say1 in/ead ( runn+ a s+le wire f po9t 
to po9t & gr\nd+ at ea* end1 z 9 ord9>y 
telegraph sy/ems1 ! telephone circuit is
 complet$ by us+ a second wire in/ead ( 
! e>?4  ,z a complete def5se aga9/ !    
effects ( induc$ curr5ts ! wires %\ld be
 exactly alike z to cross-section 7or   
size7 & resi/ance4 ,!y %\ld be insulat$ 
& laid toge!r ) a slight twi/4 ,?is     
latt] is to cause ! two wires s twi/$ to
 av]age always ! same di/ance f any     
contigu\s wire4  ,"o factor 9 det]m9+ ! 

int5sity ( an induc$ curr5t is ! di/ance
 ! wire 9 :i* x fl[s is f ! s\rce (     
induction4 ,a telephone put 9 circuit at
 ! end ( ! two wires t are ?us laid     
toge!r w be practically free f ! effects
 ( induc$ curr5ts t are set up by !     
work+ ( contigu\s wires--= ?is reason3  
,:5ev] a curr5t is induc$ 9 "o ( !      
slack-twi/$ wires x is induc$ 9 bo?     
alike2 ! two impulses be+ ( ! same      
pol>ity meet 9 ! telephone1 :]e !y kill 
ea* o!r4 ,9 ord] to h a p]fect result we
 mu/ h p]fect conditions1 :i* are nev]  
atta9$ absolutely1 b ne>ly en\gh = all  
practical purposes4  ,9 ! e>ly days (   
telephony great difficulty 0 exp]i5c$ 9 
us+ a s+le wire gr\nd$ at ea* end 9 !   
ord9>y way1 if x ran ne> o!r wires t 7 9
 active use4 ,z "t pass$ on & ! electric
 light & electric railroad came into    
op]ation ^! difficulties 7 imm5sely     
increas$1 till n[ 9 l>ge cities !       
telephone companies are fa/ be+ driv5 to
 ! d\ble-wire sy/em1 :i* w soon become  
univ]sal = telephonic purposes ! _w ov]1

 except p]haps 9 a few c\ntry places :]e
 !re is fre$om f o!r sy/ems ( electrical
 transmission4 ,to successfully "w !    
telephone & telautograph ?r\gh ! same   
cables1 ^! protective devices aga9/     
induction mu/ be v c>efully provid$ &   
ma9ta9$4     ,,*apt] ,,xx4  ,,"s        
,,curiosities4   ,until )9 rec5t ye>s x 
0 nev] suppos$ t a sunbeam w\ld ev]     
laugh except 9 poetry4 ,b ! mod]n       
sci5ti/ has tak5 x out ( ! realm (      
poetry & put x into ! prosy play ( e-day
 life4 ,! ,radiophone1 inv5t$ by ,a4 ,g4
 ,bell1 is an in/rum5t by :i* articulate
 or o!r s\nds are transmitt$ ?r\gh !    
m$ium ( a ray ( light4 ,x has z yet no  
practical application & has nev] gone   
beyond ! exp]im5tal /age1 b z a bit (   
sci5tific in=mation x is v int]e/+4  ,if
 we introduce into an electric circuit a
 piece ( sel5ium1 prep>$ 9 a c]ta9 way1 
its resi/ance z an electric conductor   
und]goes a radical *ange :5 a beam (    
sunlight is ?r[n ^u x4 ,= in/ance1 a    
sel5ium cell1 s call$1 t 9 ! d>k w\ld   

measure #cjj ohms resi/ance1 w\ld h only
 ab\t #aej ohms :5 expos$ to sunlight4  
,?is am\nt ( v>iation 9 a %ort circuit (
 l[ resi/ance w\ld produce a consid]able
 *ange 9 ! /r5g? ( a curr5t pass+ ?r\gh 
x f a batt]y ( a giv5 voltage4  ,if n[  
we connect a sel5ium cell to "o pole ( a
 batt]y1 & !nce ?r\gh a telephone & back
 to ! o!r pole1 we h complet$ an        
electric circuit1 ( :i* ! sel5ium cell  
is a "p1 & any v>iation ( resi/ance 9   
?is cell1 if made sudd5ly1 w be he>d 9 !
 telephone4 ,let ! diaphragm ( a        
telephone transmitt] h a v light1 ?9    
mirror on "o side ( x1 & a beam (       
sunlight be ?r[n ^u x & reflect$ f t on 
to ! sel5ium cell1 :i* may be "s di/ance
 away4 ,!n1 if ! diaphragm is ?r[n into 
vibration by an articulate ^w or o!r    
s\nd1 ! light-ray is also ?r[n into     
vibration1 :i* causes a vibratory *ange 
( resi/ance 9 ! sel5ium cell 9 sympa?y )
 ! light-vibrations2 & ?is 9 turn ?r[s !
 electric curr5t into a sympa!tic       
vibratory /ate :i* is he>d 9 !          

telephone4 ,s t if a p]son laughs or    
talks or s+s to ! diaphragm1 ! sunbeam  
laughs1 talks & s+s & tells its /ory to 
! electric curr5t1 :i* impresses itself 
^u ! telephone z audible                
s\nds--articulate or o!rwise4 ,in/ead ( 
! telephone1 batt]y & sel5ium cell1 a   
block ( vulcanite or c]ta9 o!r sub/ances
 may be us$ z a receiv]2 z a light-ray  
?r[n into vibration has ! p[] to produce
 s\nd or sympa!tic vibration 9 c]ta9    
sub/ances4  ,ano!r curi\s application ( 
! sel5ium cell has be5 attempt$1 b has  
sc>cely gone beyond ! doma9 ( !ory4 ,?is
 app>atus1 if p]fect$1 might be call$ a 
,telephote4 ,x is an app>atus by :i* an 
illum9at$ picture at "o end ( a l9e ( _m
 wires is reproduc$ ^u a scre5 at ! o!r 
end4 ,! light is n actually transmitt$1 
b only its effects4 ,suppose a picture  
is laid (f into small squ>es & !re is a 
sel5ium cell correspond+ to ea* squ>e & 
= ea* sel5ium cell !re is a wire t runs 
to a di/ant /ation 9 :i* circuit !re is 
a batt]y4 ,at ! di/ant /ation !re are   

little %utt]s1 "o = ea* wire1 t are     
controll$ by ! electric curr5t & s      
adju/$ t :5 ! cell at ! transmitt+-end  
is 9 ! d>k ! %utt] w be clos$4 ,n[ if a 
/rong light be ?r[n ^u ! picture at !   
transmitt+-end1 & ea* squ>e ( ! picture 
reflects ! light ^u its correspond+     
sel5ium cell1 ! high lights ( ! picture 
w reflect /rong] light ?an ! %ad[s1 &   
!re=e ! wires correspond+ to !          
high-light squ>es w h a /rong] curr5t ( 
electricity fl[+ ?r\gh !m1 because !    
resi/ance ( ! circuit is less ?an ! ones
 connect$ ) ! d>k] %ad[s4 ,s t ! degree 
( curr5t-/r5g? 9 ! v>i\s wires w        
correspond to ! int5sity ( light        
reflect$ by ! diff]5t sections ( !      
picture4 ,! %utt]s are s adju/$ t !     
am\nt ( op5+ dep5ds ^u ! /r5g? ( curr5t4
 ,! %utt]s correspond+ to ! high lights 
( ! picture w op5 ! wide/ & ?r[ !       
/ronge/ light ^u ! scre51 f a s\rce (   
light t is plac$ beh9d ! %utt]s4 ,!     
%utt]s t op5 ! lea/ w be ^? t are op]at$
 ^u by ! %ad[s ( ! picture4 ,inasmu* z a

 picture ?r[n on a scre5 f a s\rce (    
light is :olly made up ( lights & %ad[s1
 ! !ory is t ?is app>atus p]fectly      
con/ruct$ w\ld transmit any picture to a
 di/ance1 ?r\gh telegraph-wires4 ,x mu/ 
n be und]/ood t ! rays ( light are      
transmitt$ ?r\gh ! wires z              
s\nd-vibrations are4 ,light1 p] se1 c be
 transmitt$ only ?r\gh ! lum9if]\s e!r1 
z we h se5 9 ! *apt] on light 9 ,volume 
,,ii4  ,:ile we are talk+ ab\t ^! curi\s
 me?ods ( telegraphic transmission1 ,i  
wi% to ref] to an app>atus con/ruct$ by 
! writ] 9 #ahgd-e1 = ! purpose ( receiv+
 musical tones or compositions          
transmitt$ f a di/ance ?r\gh a wire by  
electricity4 7,a cut ( ?is app>atus is  
%[n on page #hge ( ,electricity &       
,electric ,telegraph1 by ,prescott1     
issu$ 9 #ahgg47 ,x consi/s ( a disk (   
metal rotat$ by a crank m\nt$ on a      
suitable /&4 ,! electric circuit passes 
?r\gh ! disk to ! h& ( ! op]ator 9      
contact ) x1 !nce runn+ ?r\gh ! l9e-wire
 to ! di/ant /ation4 ,n[1 if a tune is  

play$ at t /ation1 ^u an electrical     
key-bo>d1 z describ$ 9 a previ\s *apt]1 
& ! disk rotat$ ) ! f+]s 9 contact ) x1 
! tune or o!r s\nds w be reproduc$ at ! 
ends ( ! f+]s4 ,aft] ! telephone 0      
inv5t$ & put into use ,i us$ ?is revolv+
 disk z a receiv] = spee* z well z      
music1 & by ?is means p]sons may c>ry on
 an oral conv]sation ?r\gh ! ends ( _!  
f+]s4 ,?is app>atus has be5 conf\nd$ 9 !
 m9ds ( "s p ) ,edison's                
electromotograph4 ,! ph5om5a ( !        
electromotograph 7 produc$ by *emical   
effects1 :ile t ( ! app>atus j describ$ 
is electro/atic 9 its action4 ,!        
electro/atic disk 0 made 9 ! w9t] (     
#ahgc-d1 :ile ,edison's electro*emical  
discov]y 0 made "s "t lat]4     ,,*apt] 
,,xxi4  ,,wireless ,,telegraphy4        
,broadly speak+1 ,wireless ,telegraphy  
is any me?od ( transmitt+ intelligible  
signals to a di/ance )\t wires2 & ?is   
includes ! old ,semaphore sy/ems (      
visual signals1 su* z flags & long arms 
( wood by day1 & lights by night2 also !

 ,heliograph 7an app>atus = fla%+       
sunlight71 & ,s\nd ,signals1 made ei!r  
?r\gh ! air or wat]4 ,electrical        
conduction1 ei!r ?r\gh r>efi$ air or !  
e>?1 also comes "u ?is head+4  ,! "n    
,wireless ,telegraphy1 h[ev]1 is        
specifically appli$ to a sy/em ( signal+
 by means ( e!r-waves induc$ by         
electrical dis*>ges ( v high voltage4   
,e!r-waves ( a great] or less degree are
 always set up :5ev] !re are sudd5      
electrical di/urbances1 h[ev] slight4   
,e!r-waves1 electrically induc$1 are    
probably z old z ! univ]se4 ,:5 !re 7   
?und]s & lightn+s f ! cl\d t hov]$ ov]  
,m\nt ,s9ai 9 ! "t ( ,moses1 e!r-waves (
 great p[] 7 s5t out ?r\gh ! camp (     
,israel4 ,b ! p ( ^? days _h no coh]] or
 telephone or any o!r means ( conv]t+ ^!
 waves into visual or audible signals4  
,?\s&s ( ye>s _h to elapse be=e !       
intellect ( man c\ld grasp ! mean+ ( ^! 
natural ph5om5a suffici5tly to h>ness !m
 & make !m subs]vi5t to 8 w4  ,_m p h   
be5 p[]fully %ock$--"s ev5 kill$--by !  

impact ( e!r-waves set up by p[]ful     
dis*>ges ( lightn+ betwe5 ! cl\ds & !   
e>?--:5 !y 7 n 9 ! direct pa? ( !       
lightn+-/roke4  ,! hi/ory (             
,electro-,wireless ,telegraphy1 l t (   
all inv5tions1 is "o ( successive /ages1
 & all ! "w 0 n done by "o man4 ,! "o :o
 gets ! mo/ cr$it is usually ! "o :o    
puts on ! f9i%+ t\*es & br+s x out be=e 
! public4 ,he may h done mu* t[>d its   
developm5t or he may h done b little4   
,9 ! ye> #ahdb ,morse transmitt$ a      
batt]y curr5t ?r\gh ! wat] ( a canal    
eighty feet wide s z to affect a        
galvanomet] on ! opposite side f !      
batt]y4 ,?is 0 wireless telegraphy by   
conduction ?r\gh wat]4  ,9 #ahce ,joseph
 ,h5ry produc$ an effect on a           
galvanomet] by e!r-waves ?r\gh a di/ance
 ( tw5ty feet by an arrangem5t (        
batt]ies & circuits l t %[n 9 ,fig4 #a1 
,*apt] ,,vi4 ,?is 0 call$ induction1 &  
is /ill s call$ :5 electrical effects   
are produc$ f "o wire to ano!r ?r\gh !  
e!r = %ort di/ances4 ,all               

induction-coils & trans=m]s 7see ,*apt] 
,,xxiv7 are op]at$ by effects produc$   
?r\gh ! e!r f ! prim>y to ! second>y    
coil--b ?r\gh v %ort di/ances4  ,9 #ahhj
 ,pr(essor ,tr[bridge transmitt$ an     
electrical curr5t ?r\gh ! e>? = "o mile 
s z to produce signals 9 a telephone4 ,9
 #ahha-b ,pr(essor ,dolbe> us$ = a %ort 
di/ance 7fifty feet7 sub/antially ! same
 arrangem5t z ,m>coni n[ uses1 except t 
! =m] us$ a telephone z a receiv]4 ,he  
us$ an induction-coil hav+ "o end ( !   
second>y wire connect$ ) ! e>?1 :ile !  
o!r 0 atta*$ to a wire runn+ up into !  
air4 ,at ! receiv+-end a wire />t+ f !  
e>? ext5d$ into ! air1 pass+ ?r\gh a    
telephone1 :i* act$ z a receiv]4 ,9     
#ahhf he us$ a kite to elevate ! wire1  
?r\gh :i* electrical dis*>ges ( high    
voltage 7 made into ! air to produce    
e!r-waves--! receiv] be+ #bjjj feet     
away4 ,dolbe>'s exp]im5ts 7 public      
f\rte5 ye>s ago1 b at t "t !re 0 no     
int]e/ 9 su* matt]s1 s t 8 "w receiv$   
little or no att5tion4 ,9 #ahhg ,dr4    

,h]tz ( ,g]many made "s exp]im5ts 9     
produc+ & detect+ e!r-waves1 & he did a 
great deal to awak5 an int]e/ 9 !       
subject1 s t o!rs began inve/igations t 
h l$ to its pres5t use z a means (      
telegraph+ to a di/ance ( _m miles4  ,9 
#ahia ,pr(essor ,branly ( ,p>is inv5t$ !
 coh]]4 ,9 #ahid x 0 improv$ by ,lodge &
 by him us$ z a detector ( e!r-waves4 ,9
 #ahif1 t5 ye>s aft] ,dolbe> _h us$ x ) 
! kite at ! transmitt+-end & telephone  
at ! receiv+-end1 ,m>coni1 an ,italian1 
sub/itut$ ! coh]] ( ,branly = !         
telephone ( ,dolbe>4 ,?is coh]] is      
con/ruct$ & op]at$ z foll[s3  ,x consi/s
 ( a glass tube1 ( comp>atively small   
diamet]1 loosely fill$ ) metal fil+s ( a
 c]ta9 grade4 ,?is body ( metal-du/ is  
made a "p ( a local batt]y circuit 9 :i*
 is plac$ an ord9>y electric bell or    
telegraphic s\nd]4 ,! resi/ance ( ?is   
body ( fil+s is s great t curr5t en\gh w
 n pass ?r\gh x to r+ ! bell or actuate 
! s\nd] until an e!r-wave /rikes x & !  
wire atta*$ to x1 :5 ! metal p>ticles   

are made to coh]e to su* an ext5t t !   
conductivity ( ! mass is greatly        
increas$2 s t a curr5t ( suffici5t      
volume w n[ pass ?r\gh ! bell-magnet to 
r+ x4 ,be=e ! next signal comes ! fil+s 
mu/ be made to de-coh]e2 & to accompli% 
?is a little tapp]1 t works             
automatically betwe5 ! signals1 /rikes !
 glass tube ) a succession ( light bl[s4
  ,briefly /at$1 ! wireless sy/em (     
,m>coni1 9 its ess5tials1 consi/s ( a   
p[]ful induction-coil ) "o end ( !      
second>y wire connect$ ) ! e>?1 :ile !  
o!r ext5ds into ! air a great] or less  
di/ance accord+ to ! di/ance x is desir$
 to s5d signals4 ,! great] ! di/ance !  
high] ! wire %\ld ext5d into ! air4 ,at 
! receiv+-end a wire ( correspond+      
height is erect$1 also connect$ ) ! e>?4
 ,9 ?is wire--z a "p ( its circuit--is  
plac$ ! coh]]4 ,9 a local circuit t is  
connect$ to ! upright wire 9 p>allel ) !
 coh]] is plac$ a batt]y1 a s\nd]1 or a 
bell1 t is rung :5 ! fil+s coh]e4  ,:5  
an e!r-wave is set up by a dis*>ge (    

electricity into ! air x /rikes !       
p]p5dicul> wire ( ! receiv]1 & t portion
 ( ! wave t /rikes is conv]t$ into      
electricity1 :i* is call$ an induc$     
curr5t4 ,x is ?is curr5t1 z x dis*>ges  
?r\gh ! coh]] to ! e>?1 t causes ! fil+s
 to unite s z to close ! local circuit &
 op]ate ! s\nd]4 ,to s5d a message x is 
only necess>y to make ! dis*>ges into ! 
air1 at ! s5d+-end1 correspond to !     
,morse alphabet4  ,:ile ,m>coni has done
 m ?an any o!r man to improve &         
popul>ize wireless telegraphy1 hi/ory   
%[s t he inv5t$ none ( ! ess5tial       
elem5ts s f> z ! sy/em has be5 made     
public4  ,:at he seems to h really done 
0 to sub/itute ! coh]] ( ,branly &      
,lodge1 ) its adjuncts1 = ! telephone ( 
,dolbe>4 ,!re is no d\bt b t ,m>coni has
 done mu* to improve & enl>ge ! capacity
 ( ! app>atus & to demon/rate to ! _w "s
 ( its possibilities4 ,he has be5 an    
indefatigable work] & des]ves great     
cr$it2 b )\t ! "w ( ^? :o prec$$ him he 
c\ld n h succe$$3 ! honors %\ld be      

divid$4  ,?is sy/em has be5 us$ at v>i\s
 times = report+ ya*t-races1 & betwe5   
%ips4 ,x is said also to h be5 us$ to "s
 ext5t 9 ! ,s\? ,african ,w>4 ,!re is   
mu* to be done yet1 h[ev]1 be=e x c be  
made entirely reliable = def5sive "w 9  
"t ( w>4 ,z x is n[1 all an enemy w\ld h
 to d to de/roy its usefulness w\ld be  
to set an e!r-wave-produc] to "w        
automatically any:]e )9 ! sph]e (       
influ5ce ( ! sy/em--to speak            
diplomatically--:5 x w\ld r5d]          
un9telligible any message t %\ld be s5t4
 ,to make ! sy/em ( ! greate/ value "s  
sort ( selective receiv] mu/ be inv5t$ t
 w select signals s5t f a transmitt] t  
is design$ to "w ) x4  ,!re is no d\bt b
 t wireless telegraphy w "s "t play an  
important "p 9 _m sph]es ( usefulness4  
,!re is ano!r mode 7already ref]r$ to7 =
 transmitt+ signals electrically )\t    
wires ?r\gh ! e>? in/ead ( ?r\gh ! air1 
b 9 ?is case x is n ?r\gh ! m$ium (     
induction1 b conduction4 ,x has be5     
expla9$ 9 =m] *apt]s t e>?-curr5ts are  

con/antly fl[+ f "o po9t to ano!r :]e ! 
pot5tials are unequal4 ,sometimes ^!    
inequalities ( pot5tial are caus$ by    
heat & sometimes by electricity1 z 9 !  
case ( a ?und]-/orm4 ,if a cl\d is      
heavily *>g$ ) positive electricity1    
say1 ! e>? und]nea? w h an equal *>ge ( 
negative electricity4 ,let u illu/rate x
 by ! tides4 ,z ! moon passes ov] !     
ocean x attracts ! wat] t[>d x & t5ds to
 pile up1 z x 71 at ! ne>e/ po9t betwe5 
! e>? & ! moon4 ,suppose t 7:ile ! wat] 
is ?us pil$ up at a po9t "u ! moon7 we  
c\ld sudd5ly susp5d ! attraction betwe5 
! e>? & ! moon--! wat] w\ld beg9        
imm$iately to fl[ (f by ! =ce (         
gravitation until x _h f\nd a common    
level4 ,suppose 9 ! place ( ! moon we h 
a cl\d conta9+ a /atic *>ge ( positive  
electricity--x attracts a negative *>ge 
to a po9t on ! e>? ne>e/ ! cl\d4 ,if n[ 
a dis*>ge takes place betwe5 ! e>? &    
cl\d ! pot5tial betwe5 ! two w sudd5ly  
become equaliz$ & ! /atic *>ge t 0      
accumulat$ 9 ! e>? is releas$ & x       

dissipates 9 e direction1 seek+ an      
equilibrium1 foll[+ ! analogy ( ! wat]2 
! diff]5ce be+ t 9 "o case ! movem5t is 
v sl[1 :ile 9 ! o!r x is z quick z      
lightn+4  ,ab\t eighte5 ye>s ago ,i _h a
 %ort telephone-l9e betwe5 my h\se & t (
 "o ( my neighbors4 ,?is l9e 0 equipp$ )
 :at 0 kn[n 9 ^? days z                 
magneto-transmitt]s1 su* z we h describ$
 9 a previ\s *apt] on ! subject (       
telephony4 ,:5 a l9e is equipp$ 9 ?is   
way no batt]ies are ne$$1 z ! voice     
g5]ates ! curr5t1 on ! pr9ciple employ$ 
9 ! dynamo-electric ma*9e4 ,(t5 on summ]
 ev5+s1 :5 ! sky appe>s to be cl\dless1 
we c see fa9t fla%es ( lightn+ on !     
horizon1 an appe>ance :i* is commonly   
call$ heat-lightn+4 ,z a matt] ( fact1  
,i d n suppose !re is any su* ?+ z      
heat-lightn+1 b :at we see is ! effect (
 v di/ant /orm-cl\ds4 ,(t5 at su* times 
,i h held ! telephone receiv] to my e> &
 c\ld he> simultane\sly ) ea* fla% a    
slight s\nd 9 ! telephone4 ,?is effect  
c\ld be produc$ 9 ! e>? by a simple     

dis*>ge betwe5 two or m cl\ds1 :i* w\ld 
di/ribute ! electrical dis*>ge ov] a    
great] area4 ,& because my l9e _h       
connection ) ! e>? x c\ld h be5 di/urb$ 
electrically by conduction in/ead (     
induction2 or x may h be5 ! effect (    
e!r-waves set up by ! lightn+ dis*>ges4 
,!re is no d\bt 9 my m9d b t bo? ( ^!   
effects 7e!r-waves & conduction ?r\gh   
e>?7 may be felt :5 a dis*>ge takes     
place betwe5 a cl\d & ! e>?4  ,if we    
c\ld1 by op]at+ an ord9>y telegraphic   
key1 cause ! lightn+ to dis*>ge f cl\d  
to e>?1 & "s "o 0 li/5+ at a telephone 9
 a circuit t 0 gr\nd$ at bo? ends #ajj  
miles or m di/ant f ! cl\d1 ! man :o    
controll$ ! dis*>ges by ! key c\ld      
transmit ! ,morse code ?r\gh ! e>? to ! 
man :o 0 li/5+ at ! telephone4 ,?\s&s ( 
p might be li/5+ at telephones 9 e      
direction f ! transmitt+-/ation1 & !y   
w\ld all get ! same message4 ,if !      
receiv+-/ation is ne> to ! po9t :]e !re 
is a heavy dis*>ge f ! cl\ds to ! e>? ! 
e>?-curr5t is v /rong--fl[+ out 9 e     

direction4 ,= "s ye>s ,i _h an und]gr\nd
 l9e betwe5 my h\se & laboratory1 & no  
"p ( ! l9e betwe5 ! two /ations 0 above 
gr\nd4 ,_m & _m times dur+ ! preval5ce (
 a ?und]-/orm h ! telephone-bells be5   
made to r+ at bo? ends ( ! l9e by a     
dis*>ge f ! cl\d to ! e>?1 & 9 "s cases 
! dis*>ge 0 sev]al miles away4 ,! wires 
c\ld n h be5 affect$ s p[]fully 9 any   
o!r way ?an ?r\gh ! e>?4  ,x w be se5 by
 ! =ego+ /atem5ts t x is possible to    
transmit messages ?r\gh ! e>? = long    
di/ances1 b ! difficulty 9 ! way ( its  
becom+ a g5]al sy/em is tw(old4 ,fir/1  
we _c always h a ?und]-cl\d at h& f :i* 
to transmit our signals1 &1 secondly1 ! 
signals w\ld be receiv$ alike at e      
/ation simultane\sly4     ,,*apt]       
,,xxii4  ,,niag>a ,,falls               
,,p[]--,,introduction4   ,z our read]s  
"k1 ,niag>a ,falls is situat$ ^u !      
,niag>a ,riv]1 :i* is ! connect+-l9k    
betwe5 ,lake ,erie & ,lake ,ont>io4 ,!  
surface ( ,lake ,erie lies #ccj feet    
above t ( ,lake ,ont>io4 ,! high level  

^u :i* ,lake ,erie is situat$ abruptly  
t]m9ates at ,que5/[n1 :i* is ne> ! po9t 
:]e ! ,niag>a ,riv] empties into ,lake  
,ont>io4 ,f ,lake ,erie to ! falls !    
level ( ! riv] is gradually l[]$ a      
little less ?an #ajj feet1 & mo/ ( ?is  
7mak+ ! rapids7 occurs 9 ! la/ mile     
above ! po9t :]e x takes a p]p5dicul>   
plunge ( #afe feet into a n>r[ gorge    
ext5d+ = sev5 miles1 ?r\gh :i* ! riv]   
runs1 gradually fall+ also #ajj feet 9 t
 di/ance4 ,! riv] above ! falls is      
broad1 v>y+ f "o to ?ree miles 9 wid?1 b
 bel[ t po9t x is sudd5ly n>r[$ up to a 
di/ance ( f #bjj to #djj y>ds4  ,x is   
suppos$ t at "o "t ! fall 0 situat$ at !
 bluff ov]look+ ,que5/[n1 ne> ,lake     
,ont>io1 & at t "t 0 v mu* high] ?an x  
is at pres5t4 ,?r\gh long ages ( "t !   
wat] has gradually eat5 away ! rock1 ?us
 =m+ ! gorge4 ,x is e/imat$ by diff]5t  
geologi/s t ! "t requir$ to we> away !  
rock back to ! pres5t position ( ! fall 
has requir$ f #ae1jjj to #ce1jjj ye>s4  
,"s au?orities place ! rate ( we> at    

?ree feet p] annum & o!rs n m ?an "o4 ,x
 is well kn[n1 h[ev]1 t ?is erosion is  
con/antly go+ on1 & if no?+ is done to  
*eck x ! "t w come :5 ! gorge w ext5d up
 to ,lake ,erie & dra9 x1 practically1  
to ! bottom4 ,?is is a matt]1 h[ev]1 t !
 p ( ?is & ^? ( sev]al succe$+ g5]ations
 ne$ n worry ab\t4  ,9 ! e>ly days1 be=e
 ! c\ntry 0 settl$ & ! banks ( ! riv] 7 
l9$ ) trees1 & no h\ses1 hotels or      
horse-c>s 7 to be se52 :5 ! puff+ ( !   
locomotive 0 n he>d e*o+ f %ore to %ore2
 :5 no bridges spann$ ! riv] to m> its  
beauty1 & :5 nature 0 ! only ar*itect & 
beautifi]1 ,niag>a ,falls mu/ h be5 "o (
 ! mo/ attractive spots on ! e>?2 at    
lea/ x is ! place ( all places :]e !    
mighty en]gies ( nature are ga!r$ toge!r
 9 "o gr& exhibition ( sublime p[]4 ,"h 
= ages ?is same gr& exhibition _h be5   
go+ on1 & al?\gh !re 0 no human eye to  
see x1 ^? ( u :o believe t nature is n a
 ?+ ( *ance1 b t x 0 plann$ by an       
intellig5ce inf9itely sup]ior to t ( any
 man1 c easily imag9e t ! ,great        

,ar*itect & beautifi] ( ?is same nature1
 n only plans b enjoys ! "w ( ,8 own h&4
 ,:y n8 ,= ages ! same sun1 9 8 daily   
r\nd1 has reflect$ t beautifully color$ 
ra9b[1 "h ! product ( sun%9e & mi/4 ,!  
same wat]1 ?r\gh ^! successive ages1 has
 be5 lift$ to ! cl\ds by ! p[] ( ! sun's
 rays1 & has be5 c>ri$ back to !        
f\nta9-heads on ! w+s ( ! w9d1 & !re has
 be5 cond5s$ into ra9drops1 t h fall5 on
 l&1 lake & riv]1 & 9 turn has be5 c>ri$
 ov] ?is same wat]fall 9 its onw>d c\rse
 t[>d ! sea1 only aga9 to be caught up  
into ! cl\ds2 & ?us ?r\gh an et]nal r\nd
 x has be5 kept mov+ by t mighty eng9e (
 nature1 ! sun4 ,x is said t ! mill w   
nev] gr9d ) ! wat] t has pass$4 ,?is is 
true only 9 poetry4 ,z a matt] ( fact1 !
 wat] t has pass$ may (t5 return to help
 ! mill to gr9d aga94  ,wat]-p[]s h be5 
utiliz$ 9 a small way = _m ye>s = !     
purpose ( g5]at+ electricity ?r\gh !    
m$ium ( ! dynamo1 b n[h]e 9 ! _w has !  
application ( ! =ce be5 made = ?is      
purpose on su* a gr& scale z at ,niag>a 

,falls4 ,:5 "o /&s on ! bank ( ! riv] & 
sees ! great wat]fall z x plunges ov] ! 
precipice1 ex]t+ a =ce ( f five to t5   
million horse-p[]1 "o is ov]:elm$ 9     
contemplation ( its possibilities z a   
s\rce ( en]gy t may be conv]t$ into "w1 
me*anical & *emical1 ?r\gh ! m$ium (    
electricity4  ,! g5ius ( man has devis$ 
a way by :i* "s ( ?is con/antly wa/+    
en]gy may be conv]t$ into electricity & 
di/ribut$ to diff]5t po9ts to p]=m v>i\s
 k9ds ( "w4 ,b ! am\nt utiliz$ z yet is 
sc>cely a drop :5 comp>$ ) t :i* might  
be if ! :ole torr5t c\ld be set to "w 9 
! same mann] z a v small portion ( x n[ 
is4     ,,*apt] ,,xxiii4  ,,niag>a      
,,falls ,,p[]--,,appliances4   ,"s ye>s 
ago a company 0 =m$ = ! purpose (       
utiliz+1 to "s ext5t1 ?is greate/ ( all 
wat]-p[]s4 ,a tunnel ( l>ge capacity 0  
run f a po9t a %ort di/ance bel[ ! falls
 on a level a little above ! riv] at t  
po9t4 ,! g5]al direction ( ?is tunnel is
 up ! riv]2 x is ab\t a mile & "o-half 9
 l5g?1 t]m9at+ at a po9t ne> ! bank ( ! 

riv] a mile or m above ! falls4 ,above !
 end ( ?is tunnel an upright pit comes  
to ! surface1 :]e a p[]-h\se ( l>ge     
dim5sions has be5 con/ruct$ ( solid     
masonry4 ,x is long en\gh at pres5t to  
conta9 t5 dynamos ( mammo? size4 ,along 
! side ( ?is p[]-h\se a deep broad canal
 is cut1 :i* communicates ) ! riv] at t 
po9t1 & ?r\gh :i* fl[s ! wat] t is to   
furni% ! p[]4 ,( c\rse ! wat] level (   
?is canal is ! same z t ( ! riv]4  ,!   
f\ndations ( ! p[]-h\se ext5d to !      
bottom ( ! tunnel1 :i* at t po9t is #ahj
 feet bel[ ! surface ( ! gr\nd4 ,to put 
x 9 o!r words1 ! cell> or pit "u !      
p[]-h\se is #ahj feet deep &            
communicates ) ! great tunnel1 :i* has  
its outlet bel[ ! falls4  ,ea* ( ! t5   
dynamos is driv5 by a turb9e wat]-:eel  
situat$ ne> ! bottom ( ! pit h]et(ore   
describ$4 ,! turb9e-:eel is on ! l[] end
 ( a cont9u\s %aft1 :i* rea*es f a po9t 
ne> ! bottom ( ! tunnel to a po9t t5 or 
fifte5 feet above ! floor ( ! p[]-h\se  
7:i* is ab\t on a level ) ! surface ( ! 

gr\nd74  ,?is %aft is incas$ 9 a        
wat]-tight cyl9d] ( su* diamet] z w     
admit a suffici5t am\nt ( wat]1 &       
connects ) ! turb9e :eel at ! bottom 9 !
 ord9>y way4 ,! wat] is admitt$ into !  
top ( ?is cyl9d] f ! canal1 s t ! :eel  
is "u ! pressure ( a fall+ column ( wat]
 ov] #adj feet high4 ,! wat]1 =c+ its   
way out at ! bottom ?r\gh ! turb9e1     
revolves x & its long1 upw>d-rea*+ %aft 
) great p[]1 & enables x to "w ! dynamos
 9 ! p[]-h\se above1 z w be describ$4 ,!
 wat] dis*>ges ?r\gh ! :eel 9 su* a     
mann] z to lift ! :ole %aft1 ?us tak+   
away ! trem5d\s end-?ru/ d[nw>d t w\ld  
o!rwise int]f]e greatly ) ! runn+ ( !   
ma*9e ?r\gh friction4 ,aft] ! wat] has  
done its "w x fl[s (f ?r\gh ! tunnel    
into ! riv] bel[ ! falls4  ,to ! upp]   
end ( ! p[]-%aft is atta*$ a great      
revolv+ umbrella-%ap$ hood2 to ! p]iph]y
 7circumf]5ce7 ( ?is hood is atta*$ a   
=g$ /eel r+1 #e in*es 9 ?ickness1 ab\t  
#ab feet 9 diamet] & f #d to #e feet 9  
wid?4 ,! :ole ( ! revolv+               

portion--includ+ ! r+ ^u :i* are m\nt$ !
 field-magnets1 ! hood1 & ! %aft runn+  
to ! bottom ( ! pit1 :]e ! turb9e :eel  
is atta*$--weighs ab\t ?irty-five tons4 
,! dynamos belong to ! alt]nat+ type1 & 
are comp>atively simple 9 con/ruction4  
,9 a previ\s *apt] ^u ! dynamo x 0 /at$ 
t ! fundam5tal feature 0 ! relation t ! 
field-magnet & ! armature su/a9$ to ea* 
o!r1 & t 9 "s cases ! field-magnet      
revolves :ile ! "p t is te*nically call$
 ! armature rema9s /ation>y4 ,9 o!r     
cases ! armature revolves & !           
field-magnets are /ation>y4 ,9 ! latt]  
case bru%es & commutators are us$1 to   
cat* & transf] ! g5]at$ electricity1    
:ile 9 ! =m] ^! are n ne$$1 :i*         
simplifies ! con/ruction ( ! ma*9e4  ,z 
we h /at$1 ! dynamos us$ at ,niag>a are 
con/ruct$ ) revolv+ field-magnets t are 
bolt$ on to ! inn] surface ( ! /eel r+ t
 is c>ri$ by ! hood1 s t !re are no     
bru%es connect$ ) ! ma*9e except ! small
 ones us$ to c>ry ! curr5t to !         
field-magnets4  ,! curr5t = p[] purposes

 is g5]at$ 9 a l>ge /ation>y armature   
ab\t t5 feet 9 diamet] & ( ! same dep? z
 ! revolv+ r+4 ,! revolutions ( ! r+ s5d
 out curr5ts ( alt]nat+ pol>ity1 & ea* (
 ! t5 ma*9es w furni% electrical en]gy  
equal to #ejjj horse-p[]1 s t :5 ! "w t 
is n[ "u way is complet$ #ej1jjj        
horse-p[] c be furni%$ 9 ! =m (         
electricity4 ,ab\t #ce1jjj horse-p[] is 
n[ actually deliv]$ to ! v>i\s indu/rial
 ent]prises4 ,! dynamos are set         
horizontally1 s9ce ! %aft :i* connects  
!m ) ! turb9e :eel /&s 9 a p]p5dicul>   
position4  ,n all ( ! en]gy t is        
develop$ by ! wat]-:eel is conv]t$ into 
electricity1 b "s ( x appe>s z heat4 ,9 
ord] to prev5t ! heat f becom+ s great z
 to be dang]\s to ! ma*9e x mu/ be      
con/ruct$ 9 su* a way z to admit (      
suffici5t v5tilation = cool+ purposes4  
,! armature is s con/ruct$ t !re are    
air-passages runn+ all ?r\gh x1 & on top
 ( ! revolv+ hood are two bonnet-%ap$   
air-tubes set 9 su* a way z to =ce ! air
 d[n ?r\gh ! armature1 :i* c>ries (f !  

heat & w>ms ! p[]-h\se1 on ! pr9ciple ( 
a hot-air furnace4 ,?is great           
ma*9e--:i*1 9 a way1 is s simple 9 its  
con/ruction--:5 9 action conveys to !   
m9d ( ! behold] a s5se ( wond]ful p[]4  
,x is only :5 we /& 9 ! pres5ce ( su*   
exhibitions z may be se5 9 ?is p[]-h\se1
 devis$ & execut$ by ! g5ius ( man1 & 9 
t great] pres5ce1 ! mighty ,falls (     
,niag>a1 t we get some?+ ( a conception 
( ! p[] ( ! sil5t yet pot5t en]gy ( !   
great k+ ( daylight1 ! sun4  ,!re are v 
_m int]e/+ details t "w 9 connection )  
?is great p[]-plant1 "s ( :i* we w      
describe1 9 a g5]al way4  ,/&+ )9 a few 
feet ( ea* "o ( ! great dynamos is a v  
beautifully con/ruct$ piece ( ma*9]y    
call$ ! gov]nor4 ,! gov]nor regulates ! 
spe$ ( ! dynamos by p>tially op5+ &     
clos+ ! wat]-gates t regulate ! fl[ (   
wat] into ! turb9es4 ,! "q may be ask$1 
:y is !re any regulation ne$$1 if !re is
 always an ev5 head ( wat]8 ,!re are two
 reasons--"o because ! load on ! dynamo 
is con/antly *ang+1 & ano!r t ! head (  

wat] *anges1 al?\gh ?is latt]           
fluctuation is 9 long p]iods4 ,if !     
circuit lead+ out f ! dynamo is brok51 !
 rotat+ "p ( ! dynamo w move ) great    
ease & little p[]1 z comp>$ ) :at is    
requir$ :5 ! circuit is clos$1 & !      
curr5t is go+ out & do+ "w4 ,! increas$ 
am\nt ( en]gy t w be requir$ to keep !  
dynamo mov+ at a c]ta9 rate ( spe$ :5 ! 
load is on--9 o!r words1 :5 ! circuit is
 clos$--w dep5d ^u ! am\nt ( curr5t t is
 go+ out f ! dynamo to p]=m "w at o!r   
po9ts4 ,z ! am\nt ( curr5t us$ outside =
 ! v>i\s purposes is con/antly *ang+1 x 
foll[s t ! load on ! dynamo is con/antly
 *ang+ also4 ,z ! load *anges1 ! spe$ w 
*ange1 unless ! am\nt ( wat] t is fl[+  
into ! turb9e is *ang$ 9 a l proportion2
 h5ce ! necessity = a gov]nor t w p]=m  
?is "w4 ,y c easily imag9e t x w require
 a great am\nt ( p[] to move ! gate up  
or d[n ) su* a pressure ( wat] beh9d x4 
,x is n possible "h to expla9 ! op]ation
 ( ! gov]nor 9 detail1 z t c\ld n be    
done )\t elaborate draw+s2 suffice x to 

say t ! :ole ?+ is controll$ by a small 
ball gov]nor su* z we see us$ 9 ord9>y  
/eam-eng9es = regulat+ /eam-pressure4   
,! ris+ or fall+ ( ! balls ( ?is gov]nor
 to only a v slight ext5t w br+ into    
action a p[] t is driv5 by ! turb9e     
itself1 :i* is able to move ! wat]-gate 
9 ei!r direction accord+ z ! balls rise 
or fall4 ,= in/ance1 if ! balls rise    
beyond _! normal position1 x %[s t !    
dynamo is increas+ 9 spe$1 & imm$iately 
ma*9]y is br\ght into action t %uts !   
wat] (f 9 a small degree1 j en\gh to br+
 ! spe$ back to normal4 ,if ! balls drop
 to any ext5t1 x %[s t ! load is too    
great = ! am\nt ( wat]1 & t ! dynamo is 
decreas+ 9 spe$2 imm$iately ! p[] is    
br\ght into action1 n[ 9 ! opposite     
direction1 & ! wat]-gate is op5$ wid]4  
,^! slight v>iations ( spe$ are         
con/antly go+ on1 & ! con/ant op5+ &    
clos+ ( ! gate foll[s ) !m4 ,x is a     
beautiful piece ( ma*9]y1 & is          
beautifully adapt$ to ! "w x has to     
p]=m4 ,x is cont9ually /&+ gu>d ov] ?is 

great] piece ( ma*9]y t is ex]t+ an     
en]gy ( #ejjj horse-p[] & prev5ts x f   
go+ wrong1 bo? 9 do+ t :i* x %\ld n d & 
leav+ undone t :i* x %\ld d4 ,x is a    
ma*9e t1 :5 9 action1 po9ts a moral to e
 ?9k+ p]son :o beholds x4 ,e man has su*
 a gov]nor if he only has ! incl9ation  
to use x4  ,i h said fur!r back t !     
wat]-head v>ies1 b usually at long      
p]iods4 ,?is v>iation is *iefly caus$ by
 *anges ( w9d1 & x is v mu* great] ?an  
"o w\ld suppose )\t /udy+ ! causes4     
,lake ,erie lies 9 an ea/]ly & we/]ly   
direction1 & :5 ! w9d bl[s con/antly = a
 "t f ! we/1 ) consid]able =ce1 ! wat]  
piles up at ! ea/]n end ( ! lake1 :i*   
causes ! level ( ! ,niag>a ,riv] to rise
 to a v s5sible ext5t4 ,x is n s        
noticeable above ! falls z bel[1 because
 ( ! great diff]5ce 9 ! wid? ( ! riv] at
 ^! two po9ts4 ,sometimes ! riv] bel[ ! 
falls1 z x fl[s ?r\gh ! n>r[ gorge1 w   
v>y 9 height f tw5ty to =ty feet4 ,:5 ! 
w9d /ops bl[+ f ! we/ & sudd5ly *anges &
 bl[s f ! ea/1 x c>ries ! wat] ( ! lake 

away f ! ea/ t[>d ! we/ end1 :i* w      
produce a correspond+ depression 9 !    
,niag>a ,riv]4 ,no d\bt !re is an effect
 produc$ by ! diff]5ce ( annual ra9fall1
 b ! effect f ?is cause is n s m>k$ z t 
f ! *ang+ w9ds4  ,ano!r appliance us$ 9 
! p[]-h\se1 *iefly = h&l+ heavy loads & 
transf]r+ !m f "o po9t to ano!r1 is     
call$ ! electric crane4 ,x is m\nt$ ^u  
tracks locat$ on ea* side ( ! p[]-h\se4 
,! crane spans ! :ole di/ance1 & runs on
 ?is track by means ( trucks f "o end ( 
! p[]-h\se to ! o!r4 ,runn+ across ?is  
crane is ano!r track :i* c>ries !       
lift+-ma*9]y1 consi/+ ( block & tackle1 
able to su/a9 a weight ( fifty tons4    
,situat$ at "o end ( ! crane are "o or m
 electric motors1 :i* are able1 "u !    
control ( ! eng9e]1 to produce a motion 
9 any direction1 :i* is ! resultant ( a 
comp\nd motion ( ! two c>s act+         
crosswise to ea* o!r toge!r ) !         
p]p5dicul> motion ( ! lift+-rope        
connect$ ) ! block & tackle4 ,x seems l 
a ?+ end[$ ) human reason1 :5 we see x  

move (f to a di/ant "p ( ! build+1 rea* 
d[n & pick up a piece ( metal weigh+    
sev]al tons1 c>ry x to "s o!r portion ( 
! build+ & l[] x into place1 to !       
fraction ( an in*4 ,:ile ! ma*9e itself 
does n reason1 !re is a reason+ be+ at !
 helm1 :o controls x & makes x subs]vi5t
 to 8 w4 ,! ma*9e is to ! eng9e] :o     
manipulates x :at a man's bra9 is to !  
man himself4 ,! bra9 is ! in/rum5t ?r\gh
 :i* ! unse5 man expresses 8 w &        
impresses 8 "w ^u m5 & ?+s 9 ! visible  
_w4     ,,*apt] ,,xxiv4  ,,niag>a       
,,falls ,,p[]--,,appliances4   ,9 ! la/ 
*apt] ,i describ$ "s ( ! appliances us$ 
9 connection ) ! p[]-h\se4 ,!re are _m  
?+s t are commonplace z electrical      
appliances :5 us$ ) curr5ts ( l[ voltage
 & small quantity1 t become extremely   
int]e/+ :5 con/ruct$ = ! purpose ( h&l+ 
su* curr5ts z are develop$ by ! dynamos 
us$ at ,niag>a4 ,= in/ance1 x is a v    
commonplace & simple ?+ to break & close
 a circuit c>ry+ su* a curr5t z is us$ =
 ord9>y telegraphic purposes1 b x       

requires q a complicat$ & sci5tifically 
con/ruct$ device to h&le curr5ts ( l>ge 
volume & great pressure4 ,if su* a      
curr5t z is g5]at$ by a dynamo giv+ out 
#ejjj horse-p[] "u a pressure ( #bbjj   
volts %\ld be brok5 at a s+le po9t 9 a  
conductor1 !re w\ld be a fla% & a       
report1 att5d$ ) su* a degree ( heat &  
su* p[] = dis9tegration t x w\ld de/roy 
! in/rum5t4  ,! circuit-break]s us$ at  
,niag>a are con/ruct$ ) a v l>ge numb] (
 contacts made ( metal sleeves1 or      
tubes1 say "o in* 9 diamet]1 s con/ruct$
 t "o w slide )9 ! o!r2 ! sleeves be+   
slott$ s z to give !m a little spr+ t   
secures a firm contact4 ,^! are all     
connect$ toge!r electrically1 on ea*    
half ( ! swit*1 z "o conductor1 s t :5 !
 swit* is clos$ ! curr5t is divid$ into 
z _m p>ts z !re are po9ts ( contact 9 ! 
swit*4 ,suppose !re are #ajj ( ^!       
contact-po9ts1 a "o-hundr$? "p ( !      
curr5t w\ld be fl[+ ?r\gh ea* "o ( !m4  
,if1 n[1 ^! po9ts are s arrang$ t !y c  
be all simultane\sly sep>at$1 ! sp>k t w

 occur at ea* break w be v small z      
comp>$ ) :at x w\ld be if ! :ole curr5t 
7 fl[+ ?r\gh a s+le po9t1 & x w\ld be s 
small t !re w\ld be no dang] att5d+ !   
op5+ ( ! swit*4 ,^! swit*es are c>efully
 gu>d$1 be+ box$ 9 & "u ! control ( a   
s+le individual4  ,!re is ano!r app>atus
 t is a necess>y "p ( e manufactur+ or  
o!r k9d ( plant t uses electricity f ?is
 p[]-h\se1 & ?is is call$ ! trans=m]4   
,_m ( y are famili> ) ! box-%ap$        
app>atus t is us$ 9 connection )        
electric light+ :5 ! alt]nat+ curr5t is 
us$4 ,:]e simply heat+ effects are      
requir$1 su* z 9 electric light+1 =     
in/ance1 ! alt]nat+ curr5t c be us$ to  
great] advantage ?an ! direct curr5t :5 
x has to be c>ri$ to "s di/ance1 ow+ to 
! fact t x may be a curr5t ( high       
voltage4 ,a great] am\nt c be c>ri$     
?r\gh a small conductor2 ?us greatly    
r$uc+ ! co/ ( an electrical plant t     
di/ributes p[] to a di/ance4 ,a trans=m]
 is an app>atus t *anges ! curr5t f "o  
voltage to ano!r4  ,9 ! ord9>y          

electric-light plant1 su* z is us$ 9 a  
small t[n or village1 ! curr5t t is s5t 
out f ! p[]-/ation has a pressure ( f   
#ajjj to #aejj volts1 accord+ to !      
di/ance to :i* x is s5t4 ,x w\ld n d1   
h[ev]1 = ! curr5t to ent] a dwell+ at   
?is high pressure1 because x is dang]\s 
to h&le1 & ! liability to fires orig9at+
 f ! curr5t w\ld be greatly increas$4   
,at "s po9t1 !re=e1 outside ( ! build+1 
& n a great di/ance f x1 a trans=m] is  
ins]t$ :i* *anges ! voltage1 say1 f     
#ajjj d[n to #ej or #ajj1 accord+ to !  
k9d ( lamps us$4 ,"s lamps are con/ruct$
 to be us$ ) a curr5t ( fifty volts &   
o!rs = #ajj or m4 ,! lamp mu/ always be 
adapt$ to ! curr5t or ! curr5t to !     
lamp1 z y *oose4 ,! human body may be   
plac$ 9 a circuit :]e su* l[ voltage is 
us$ )\t dang]1 b x w\ld be exce$+ly     
dang]\s to be put 9 contact ) a pressure
 ( #ajjj or m volts1 su* z is us$ =     
light+ purposes4  ,9 pr9ciple ! trans=m]
 is no?+ m or less ?an an induction-coil
 on a v l>ge scale4 ,! ord9>y           

induction-coil1 su* z is us$ = m$ical   
purposes1 is ord9>ily con/ruct$ by w9d+ 
a co>se wire ar\nd an iron core4 ,?is   
core is usually made ( a bundle ( s(t   
iron wires1 because ! wires m readily   
magnetize & demagnetize ?an a solid iron
 core w\ld4 ,ar\nd ?is coil ( co>se     
wire1 :i* we call ! prim>y coil1 is w\nd
 a second>y coil ( f9] wire4 ,if n[ a   
batt]y is connect$ ) ! prim>y coil1 :i* 
is made ( ! co>se wire1 & ! circuit is  
int]rupt$ by "s sort ( me*anical        
circuit-break]1 ea* "t ! prim>y or      
batt]y circuit is op5$ !re w be a       
mom5t>y impulse 9 ! second>y circuit ( a
 mu* high] voltage2 & at ! mom5t !      
prim>y circuit is clos$ !re w be ano!r  
impulse 9 ?is second>y circuit 9 !      
opposite direction4 ,! latt] impulse is 
call$ ! initial & ! =m] ! t]m9al        
impulse4 ,a curr5t creat$ 9 ?is mann] is
 call$ an induc$ curr5t4 ,! initial     
curr5t is n s /rong z ! t]m9al 9 ?is    
p>ticul> arrangem5t4  ,if we %\ld take  
hold ( ! two wires connect$ ) ! two     

poles ( ! batt]y & br+ !m toge!r s z to 
close ! circuit1 & !n sep>ate !m s z to 
break x we %\ld sc>cely feel any        
s5sation--if !re 7 only "o or two cells1
 su* z are ord9>ily us$ ) su* coils4 ,b 
if we connect ^! wires to ! coils ( !   
induction app>atus & !n take hold ( !   
two ends ( ! second>y coil & break &    
close ! prim>y circuit we %\ld feel a   
pa9ful %ock at ea* break & close1 al?\gh
 ! actual am\nt ( curr5t fl[+ ?r\gh !   
second>y wire is n z great z t :i* fl[s 
?r\gh ! prim>y2 b ! voltage 7or         
electromotive =ce7 is high]1 & ?us is   
able to drive :at curr5t !re is ?r\gh a 
conductor ( high] resi/ance1 su* z !    
human body4 ,= ?is reason !re is m      
curr5t =c$ ?r\gh ! body1 :i* is a poor  
conductor1 ?an c be by a direct batt]y  
curr5t :i* has a l[] voltage4 ,if n[ we 
%\ld take a batt]y ( a numb] ( cells1 s 
z to get a voltage equal to t giv5 (f by
 ! second>y coil1 & connect x ) !       
f9e-wire coil in/ead ( ! co>se-wire     
coil--?us mak+ :at 0 be=e ! second>y    

coil ! prim>y--by break+ & clos+ !      
batt]y circuit z be=e we %all get a     
second>y or induc$ curr5t 9 ! co>se-wire
 coil1 b x w be a curr5t ( l[ voltage1 &
 w n produce ! pa9ful s5sation t !      
second>y coil did4  ,we h n[ describ$ ! 
pr9ciple ( a trans=m] z x is work$ out 9
 an ord9>y induction-coil4 ,z has be5   
/at$1 at ,niag>a ,falls ! curr5t comes f
 ! dynamos ) an electromotive =ce or    
pressure ( #bbjj volts4 ,= "s purposes  
?is voltage is n high en\gh1 & = o!r    
purposes x is too high2 !re=e x has to  
be trans=m$ be=e x is us$6 ,= "s        
purposes ?is trans=mation takes place 9 
! p[]-h\se1 & = o!rs x takes place at ! 
e/abli%m5t :]e x is us$4 ,= in/ance1    
take ! curr5t t is s5t to ,buffalo1 a   
di/ance ( f tw5ty to ?irty miles4 ,!    
curr5t fir/ runs to a trans=m] connect$ 
) ! p[]-h\se1 :]e x is /epp$-up 7to use 
! p>lance ( ! craft7 f a voltage ( #bbjj
 to #aj1jjj4 ,x is c>ri$ to ,buffalo    
?r\gh wire conductors t are /rung on    
poles1 & is !re /epp$-d[n aga9 ?r\gh    

ano!r trans=m] to ! voltage requir$ =   
use at t place4 ,! object ( rais+ !     
voltage f #bbjj to #aj1jjj 9 ?is case is
 to save money 9 ! con/ruction ( ! l9e (
 conductors betwe5 ! two po9ts4 ,if !   
voltage 7 left at #bbjj--! conductors   
rema9+ ! same z !y are n[--! loss 9     
transmission w\ld be v great1 ow+ to !  
resi/ance :i* ^! wires w\ld (f] to a    
curr5t ( su* comp>atively l[ voltage z  
#bbjj4 ,to ov]come ?is difficulty--if ! 
voltage is n increas$--x w\ld be        
necess>y to use conductors t are v mu*  
l>g] 9 cross-section 7?ick]7 ?an !      
pres5t ones are4 ,& z ^! conductors are 
made ( copp] ! exp5se w\ld be too great 
to admit ( any pr(it to ! company4  ,if 
we g back to an illu/ration we us$ 9 "o 
( ! e>ly *apt]s on electricity we c     
bett] expla9 :at takes place by increas+
 ! voltage4 ,if we h a column ( wat]    
kept at a level say ( t5 feet above a   
hole :]e x dis*>ges1 t is "o in* 9      
diamet]1 a c]ta9 def9ite am\nt ( wat] w 
dis*>ge !re ea* m9ute4 ,if n[ we        

sub/itute = ! hole t is "o in* 9 diamet]
 "o t is only "o-half in* 9 diamet] a v 
mu* small] am\nt ( wat] w dis*>ge ea*   
m9ute1 if ! head is kept at ! same      
po9t--namely1 t5 feet4 ,b if n[ we raise
 ! column ( wat] we %all 9 "t rea* a    
height :i* w produce a pressure t w     
cause z mu* wat] to dis*>ge p] m9ute    
?r\gh ! "o-half-in* hole z be=e dis*>g$ 
?r\gh ! "o-in* hole ) only ! pressure ( 
a t5-foot column4 ,?is is exactly :at   
takes place :5 ! voltage is /epp$-up1   
:i* is equival5t to an increase (       
pressure4  ,x w be se5 f ! =ego+ t ^!   
trans=m]s h to be made ) ref]5ce to !   
use ! curr5t is to be put to4 ,9 g5]al  
%ape !y are alike 9 appe>ance1 !        
diff]5ce be+ *iefly 9 ! relation !      
prim>y su/a9s to ! second>y coils4 ,!re 
is ano!r k9d ( trans=m] t is us$ :5 x is
 necess>y to h ! curr5t always runn+ 9 !
 same direction4 ,?is trans=m]1 z       
h]et(ore expla9$1 does n *ange ! voltage
 ( ! curr5t1 b simply trans=ms :at 0 an 
alt]nat+ into a direct curr5t4 ,by      

alt]nat+ curr5t we mean "o t is made up 
( impulses ( alt]nat+ pol>ity--fir/ a   
positive & !n a negative4 ,! direct     
curr5t is "o ^: impulses are all ( "o   
pol>ity4 ,! direct curr5t is requir$ =  
all purposes :]e electrolysis 7*emical  
decomposition by electricity1 z ( silv] 
= silv]-plat+1 etc47 is a "p ( !        
process4 ,! alt]nat+ curr5t may be us$  
)\t trans=mation 9 all processes :]e    
heat is ! *ief factor4 ,= motive p[]    
ei!r curr5t may be us$1 only !          
electromotors h to be con/ruct$ )       
ref]5ce to ! k9d ( curr5t t is us$4  ,! 
rot>y trans=m]1 :i* may be driv5 by any 
p[]1 consi/s ( a :eel c>ry+ a rotat+    
commutator s arrang$ ) ref]5ce to bru%es
 t deliv] ! curr5t to ! commutator &    
c>ry x away f ! same1 t ! bru%es lead+  
out f ! trans=m] w always h impulses ( !
 same pol>ity deliv]$ to !m4 ,9 !       
p>lance ( ! craft1 ! trans=m]s t are us$
 to *ange ! voltage f high to l[1 or    
vice v]sa1 are call$ /atic trans=m]s1   
simply because !y are /ation>y1 we      

suppose4 ,! o!rs are call$ rot>y1 or    
mov+ trans=m]s1 to di/+ui% !m f ! o!r   
=ms4 ,! op]ation ( ! latt] is purely    
me*anical1 :ile ! =m] is electrical4 ,9 
"s in/ances :]e ! /atic trans=m]s are v 
l>ge !y develop a great am\nt ( heat1 s 
mu* t x is necess>y to devise means =   
dissipat+ x z fa/ z creat$4 ,9 "s       
in/ances ?is is done by air-curr5ts =c$ 
?r\gh !m1 b 9 o!rs1 :]e !y are v l>ge1  
oil is kept circulat+ ?r\gh ! trans=m] f
 a tank t is elevat$ above x1 ! oil be+ 
pump$ back by a rot>y pump into ! tank  
:]e x is cool$ by a coil ( pipe locat$ 9
 ! oil1 ?r\gh :i* cold wat] is          
cont9ually circulat+4 ,by ?is means cold
 oil is con/antly fl[+ d[n ?r\gh !      
trans=m]1 :]e x absorbs ! heat1 :i* 9   
turn is pump$ back into ! tank1 :]e x is
 cool$4  ,hav+ n[ trac$ ! en]gy f !     
wat]-:eel ?r\gh ! v>i\s trans=mations & 
hav+ describ$ 9 a v g5]al way ! app>atus
 bo? = g5]at+ electricity & = trans=m+ x
 to ! "r voltage necess>y = ! v>i\s uses
 to :i* x is put1 we w proce$ 9 our next

 *apt] to foll[ x out to ! po9ts :]e x  
is deliv]$1 & trace x ?r\gh its         
processes1 & ! "p x plays 9 creat+ !    
products ( ^! v>i\s comm]cial           
e/abli%m5ts4     ,,*apt] ,,xxv4         
,,electrical ,,products--,,c>borundum4  
,! production ( electricity 9 su*       
enorm\s quantities z are g5]at$ at      
,niag>a ,falls has l$ to _m discov]ies &
 w lead to _m m4 ,products t at "o "t   
exi/$ only 9 ! *emical laboratory =     
exp]im5tal purposes1 h be5 s *eap5$ by  
utiliz+ electrical en]gy 9 _!           
manufacture1 z to br+ !m into ! play (  
e-day life4 ,/ill o!r products h only   
be5 discov]$ s9ce ! adv5t ( heavy       
electrical curr5ts4 ,a sub/ance call$   
c>borundum1 :i* 0 discov]$ z late z     
#ahia1 has n[ become ! basis ( an       
indu/ry ( no small importance4 ,x is a  
sub/ance n unlike a diamond 9 h>dness1 &
 n v unlike x 9 its composition4 ,! *ief
 use to :i* x is put is = gr9d+ metals &
 all sorts ( abrasive "w4 ,x is         
manufactur$ into :eels1 9 /ructure l !  

em]y-:eel1 & s]ves ! same purpose4 ,x is
 mu* m exp5sive ?an ! em]y-:eel1 b x is 
claim$ t x w d en\gh m & bett] "w to    
make x fully z economical4  ,x 0 my     
pleasure & privilege to visit ! factory 
at ,niag>a ,falls1 & ?r\gh ! c\rtesy (  
,mr4 ,fitzg]ald1 ! *emi/ 9 *>ge ( !     
works1 ,i le>n$ mu* ( ! manufacture &   
use ( c>borundum4 ,! crude mat]ials us$ 
9 ! manufacture ( c>borundum are1 s&1   
coke1 sawdu/ & salt2 ! comp\nd is a     
comb9ation ( coke & s&4 ,x comb9es at a 
v high heat1 su* z c be _h only f       
electricity4 ,:5 cool$ d[n ! product =ms
 into beautiful cry/als ) iridesc5t     
colors4 ,! pr$om9at+ colors are blue &  
gre51 & yet :5 subject$ to sunlight x   
%[s all ! colors ( ! sol> spectrum to a 
great] or less degree4 ,! cry/als =m    
into hexagonal %apes1 & sometimes !y are
 q l>ge1 f a qu>t] to a half in* on a   
side4 ,! salt does n ent] into ! product
 z a "p ( ! comp\nd1 nei!r does !       
sawdu/4 ,! salt acts z a flux to        
facilitate ! union ( ! silica & c>bon4  

,! sawdu/ is put into ! mixture to r5d] 
x por\s s t ! gases t are =m$ by !      
enorm\s heat c readily pass (f1 ?us     
prev5t+ a dang]\s explosion t might     
o!rwise occur4 ,9 fact1 ^! explosions h 
occurr$1 :i* l$ to ! necessity ( devis+ 
"s means = ! ready escape ( ! gases4  ,!
 process ( manufacture z x is c>ri$ on  
at ,niag>a is int]e/+4 ,! visitor is    
fir/ tak5 into ! rooms :]e are /or$ !   
crude mat]ial1 ! s&1 coke1 sawdu/ &     
salt4 ,! s& is ( ! f9e/ quality & v     
:ite4 ,! coke is fir/ cru%$ & scre5$1 ! 
"p :i* is r$uc$ to suffici5t f95ess is  
mix$ by ma*9]y ) ! "r proportion ( s&1  
salt & sawdu/4 ,! co>s] pieces ( coke   
are us$ = :at is call$ ! core ( !       
furnace1 :i* w be describ$ lat] on4     
,?is mixture is c>ri$ to ! furnace-room1
 :i* has a capacity = t5 furnaces1 b n  
all ( ^! w be f\nd 9 op]ation at "o "t4 
,"h ! workm5 w be tak+ ! manufactur$    
mat]ial f a furnace t has be5 complet$1 
& !re ano!r furnace is 9 process (      
con/ruction1 :ile a ?ird is "u full     

heat1 s t "o sees ! :ole process at a   
glance4 ,^! furnaces are built ( brick1 
ab\t sixte5 feet 9 l5g? & ab\t five feet
 9 wid? & dep?4 ,! ends & b$ ( ! furnace
 are built ( brick1 & might be call$    
/ation>y /ructures4 ,! sides are also   
built ( brick laid up loosely )\t mort>2
 ea* "t ! mat]ial is plac$ 9 ! furnace1 
& ea* "t ! furnace is empti$1 !         
side-walls are tak5 d[n4  ,a furnace is 
made ready = fir+ by plac+ a mass ( !   
mixture on ! bottom1 & build+ ! sides up
 ab\t f\r feet high 7or half ! height :5
 x %all be complet$74 ,a tr\gh1 ab\t    
tw5ty or tw5ty-"o in*es wide & half z   
deep1 is scoop$ out ! :ole l5g? ( !     
pulv]iz$ /uff1 & 9 ?is is plac$ :at has 
be=e be5 ref]r$ to z ! core ( ! furnace1
 namely1 pure coke brok5 into small     
pieces1 b n pulv]iz$1 z 9 ! case ( ! o!r
 mixture4 ,! am\nt us$ is c>efully      
weigh$1 s z to h ! core ! prop] size t  
exp]im5t has prov$ to give ! be/        
results4 ,! core is fill$ 9 & r\nd$ ov] 
till x is 9 circul> =m1 be+ ab\t        

tw5ty-"o in*es 9 diamet]4 ,at ea* end ( 
! furnace ! core connects ) a numb] (   
c>bon rods--ab\t sixty 9 all--t are     
?irty in*es long & ?ree in*es 9 diamet]4
 ,^! c>bon rods are connect$ ) a solid  
iron frame t /&s flu% ) ! out] end ( !  
furnace4 ,on ! inside ! spaces betwe5 ! 
rods are pack$ full ( graphite1 :i* is  
simply c>bon or coke ) all ! impurities 
driv5 out1 s z to make good electrical  
connections ) ! core4 ,?is core         
corresponds1 electrically speak+1 to !  
filam5t 9 an ord9>y inc&esc5t lamp1 only
 x is f\rte5 feet long & tw5ty-"o in*es 
9 diamet]4 ,! mix$ mat]ial is n[ pil$ up
 ov] ?is core1 & ! walls at ! sides are 
built up until ! :ole /ructure /&s ab\t 
eight feet f ! floor--a mass ( ! f9e    
pulv]iz$ mixture1 ) a core ( brok5 coke 
electrically connect$ at ! ends4 ,x is  
n[ ready = ! application ( electricity1 
:i* completes ! "w4  ,let u g back to ! 
trans=m]-room & exam9e ! electrical     
appliances t br+ ! curr5t d[n to a prop]
 voltage to produce ! heat necess>y to  

cause a union betwe5 ! silica ( ! s& & !
 c>bon ( ! coke1 :i* results 9 !        
beautiful c>borundum cry/als t we h     
h]et(ore describ$4  ,! curr5t is deliv]$
 f ! ,niag>a ,p[] ,company "u a pressure
 ( #bbjj volts4 ,! conductors run fir/  
into ! trans=m]-room1 :i* adjo9s !      
furnace-room1 & is !re trans=m$ d[n f   
#bbjj volts to an av]age ( ab\t #bjj    
volts4 ,! trans=m]s at ^! works h a     
capacity ( ab\t #aajj horse-p[]4 ,ab\t  
#d p] c5t ( ?is p[] is conv]t$ into heat
 9 ! process ( trans=mation1 mak+ a loss
 9 electrical en]gy ( a little ov] #dj  
horse-p[]4 ,?is heat w\ld be suffici5t  
to de/roy ! trans=m] if "s arrangem5t 7 
n provid$ to c>ry x (f4 ,we h already   
describ$ h[ ?is is done ?r\gh ! m$ium ( 
a circulation ( oil4 ,because ( ! l[    
voltage & enorm\s quantity ( ! curr5t   
pass+ f ! trans=m] to ! furnace v l>ge  
conductors are requir$4 ,! two          
conductors runn+ to ! furnace h a       
cross-section ( eight squ>e in*es1 & ?is
 enorm\s curr5t1 repres5t+ ov] #ajjj    

horse-p[]1 is pass$ ?r\gh ! core ( !    
furnace1 & is kept runn+ ?r\gh x        
con/antly = a p]iod ( tw5ty-f\r to      
?irty-six h\rs4  ,let u consid] = a     
mom5t :at #ajjj horse-p[] means2 z ?is w
 give u "s conception ( ! enorm\s en]gy 
exp5d$ 9 produc+ c>borundum4 ,a         
horse-p[] is suppos$ to be ! =ce t "o   
horse c ex]t 9 pull+ a load1 & ?is is ! 
unit ( p[]4 ,h[ev]1 a horse-p[] z       
arbitr>ily fix$ is ab\t "o-qu>t] great] 
?an ! av]age real horse-p[]4 ,if #ajjj  
horses 7 hit*$ up 9 s]ies1 "o 9 front ( 
! o!r1 & ea* horse %\ld occupy ! space (
 twelve feet1 say1 x w\ld make a l9e (  
horses #ab1jjj feet long1 :i* w\ld be   
some?+ ov] two miles4 ,imag9e ! load t a
 /r+ ( horses two miles long c\ld draw1 
if all 7 pull+ toge!r1 & y w get some?+ 
( an idea ( ! en]gy exp5d$ dur+ ! burn+ 
( "o ( ^! c>borundum furnaces4  ,)9 a   
half h\r aft] ! curr5t is turn$ on a gas
 beg9s to be emitt$ f ! sides & top ( ! 
furnace1 & :5 a mat* is appli$ to x1 x  
lights & burns ) a blui% flame dur+ !   

:ole process4 ,x is e/imat$ t ov] five &
 "o-half tons ( ?is gas is ?r[n (f dur+ 
! burn+ ( a s+le furnace4 ,?is gas is   
call$ c>bon monoxide1 & is caus$ by !   
c>bon ( ! coke unit+ ) ! oxyg5 ( ! s&4  
,:5 we consid] ! va/ am\nt ( mat]ial t  
comes away f ! furnace 9 ! =m ( gas x is
 easy to see :y x is necess>y to        
introduce sawdu/ or "s equival5t mat]ial
 into ! mixture1 9 ord] to give ! :ole  
bulk porosity1 s t ! gas c readily      
escape4 ,we %\ld also expect t aft] five
 & "o-half tons _h be5 tak5 away f !    
:ole bulk t x w\ld %r9k 9 size4 ,?is is 
f\nd to be ! case4 ,! top ( ! mass (    
mat]ial s9ks d[n to a consid]able ext5t 
by ! end ( ! "t x has be5 expos$ to ?is 
int5se heat4 ,gradually1 aft] ! curr5t  
has be5 turn$ on1 ! core becomes heat$1 
fir/ to a r$1 & aft]w>ds to an int5se   
:ite heat4 ,?is heat is communicat$ to !
 mat]ial surr\nd+ ! core1 produc+ v>i\s 
effects 9 ! diff]5t /rata1 ow+ to ! fact
 t x is n possible to keep a uni=m heat 
?r\gh\t ! :ole bulk ( mat]ial4 ,"s ( x w

 be ov]done & "s ( x und]done4 ,!       
mat]ial :i* lies imm$iately 9 contact ) 
! core w be ov]heat$1 & t1 :i* at "o    
/age 0 c>borundum1 has become           
dis9tegrat$ by ov]heat+4  ,! silica ( ! 
comp\nd has be5 driv5 (f1 leav+ a %ell (
 graphitic sub/ance =m$ f ! coke4  ,aft]
 ! curr5t is %ut (f & ! furnace has     
cool$ d[n1 a cross-section ?r\gh ! :ole 
mass becomes a v int]e/+ /udy4 ,! core  
itself1 ow+ to ! int5se heat x has be5  
subject$ to1 has _h ! impurities driv5  
out ( ! coke1 leav+ a sub/ance l black  
lead1 t w make a m>k l a lead-p5cil1 &  
is really ! same sub/ance1 kn[n z       
plumbago1 9 "o ( its =ms4 ,x is ! c>bon 
left aft] ! impurities h be5 driv5 out (
 ! coke4 ,surr\nd+ ! core = a di/ance ( 
t5 or twelve in*es1 radiat+ 9 e         
direction1 beautifully color$ cry/als ( 
c>borundum are f\nd1 s t a s+le furnace 
w yield ov] #djjj p\nds ( ?is mat]ial4  
,beyond ?is po9t ! heat has n be5 great 
en\gh to cause ! union betwe5 ! c>bon & 
silica1 :i* leaves a /ratum ( p>tly-=m$ 

c>borundum2 outside ( t ! mixture is    
f\nd to be un*ang$4  ,^! c>borundum     
cry/als are next cru%$ "u roll]s (      
enorm\s weight1 aft] :i* ! cru%$ mat]ial
 is sep>at$ into v>i\s grades = use 9   
mak+ gr9d+-:eels ( diff]5t degrees (    
f95ess4 ,?is cru%$ mat]ial is n[ mix$ ) 
c]ta9 k9ds ( clay1 to hold x toge!r1 &  
!n press$ into :eels ( v>i\s sizes 9 a  
hydraulic press1 & aft]w>d c>ri$ into   
kilns & burn$ ! same z ord9>y pott]y or 
porcela94 ,^! :eels v>y 9 size f "o to  
sixte5 in*es4 ,! sub/ances us$ z a bond 
9 manufactur+ :eels are kaol91 a k9d (  
clay1 & feldsp>4  ,:ile c>borundum has  
already a l>ge place z a comm]cial      
product1 !re is no d\bt b t ! uses to   
:i* x w be put w va/ly increase z "t    
goes on4 ,?is product may be call$ an   
artificial "o1 & nev] w\ld h be5 kn[n _h
 x n be5 = ! int5se heat+ effects t are 
obta9$ f ! use ( electricity4 ,x c]ta9ly
 nev] c\ld h be5 br\ght into play z "o (
 ! useful ag5cies 9 manufactur+ & !     
arts4 ,x is n kn[n to exi/ z a natural  

product1 :i* at fir/ ?\ght w\ld seem a  
little /range 9 view ( ! evid5ces (     
int5se heat t at "o "t exi/$ 9 ! e>?4   
,its abs5ce 9 nature is expla9$ by ,mr4 
,fitzg]ald by ! fact t ! temp]atures (  
=mation & ( decomposition lie v close   
toge!r4     ,,*apt] ,,xxvi4             
,,electrical                            
,,products--,,blea*+-,,p[d]4   ,ano!r   
indu/ry t has assum$ l>ge proportions at
 ,niag>a ,falls1 ow+ to ! va/ quantity (
 electricity produc$ !re1 is !          
manufacture ( a comm]cial product call$ 
blea*+-p[d]1 or *loride ( lime4 ,e "o   
kn[s t *loride ( sodium is simply common
 salt1 s ext5sively us$ :]ev] p &       
animals exi/4 ,simple & h>mless z x is1 
:ile x exi/s z a comp\nd ( ! orig9al    
elem5ts1 :5 sep>at$ into ^? elem5ts !y  
are ea* v unpleasant & ev5 dang]\s      
sub/ances to h&le4 ,salt is "o ( ! mo/  
common sub/ances 9 nature4 ,x is f\nd 9 
_m p>ts ( ! _w 9 solid b$s1 & is "o ( ! 
prom95t con/itu5ts ( sea-wat]4  ,salt is
 a comp\nd ( *lor9e & a metal call$     

sodium4 ,sodium 9 its pure /ate has a   
/rong aff9ity = oxyg51 s mu* s t :5 a   
lump ( x is ?r[n into wat] x takes fire 
& burns viol5tly ) a yell[ flame4       
,*lor9e1 ! sub/ance ) :i* x unites to =m
 common salt1 is a gre5i%-color$ gas1 ! 
fumes ( :i* are v (f5sive & v dang]\s   
ev5 to brea!1 if ! quantity is v        
consid]able4  ,x is a curi\s fact 9     
nature t two su* sub/ances z *lor9e &   
sodium1 bo? ( !m s difficult & dang]\s  
to h&le1 %\ld unite toge!r to =m su* a  
useful & h>mless comp\nd z common salt4 
,! important elem5t 9 blea*+-p[d] is !  
*lor9e :i* x conta9s4 ,x is ext5sively  
us$ 9 ! manufacture ( pap] & 9 all o!r  
mat]ials :]e blea*+ is requir$4 ,!      
object ( comb9+ x ) lime1 =m+ a *loride 
( lime1 is simply to h a conv5i5t me?od 
( hold+ ! *lor9e 9 a safe & conv5i5t    
mann] until x is ne$$ = use4  ,! *emical
 works at ,niag>a ,falls manufacture    
blea*+-p[d] on a v l>ge scale4 ,! "p t  
electricity plays is to sep>ate ! *lor9e
 f ! sodium z x exi/s 9 common salt4 ,at

 ! works ,i 0 fir/ tak5 into a room :]e 
a l>ge quantity ( salt 0 /or$4 ,a belt )
 little c>ri]-buckets on x pick$ up ?is 
salt & c>ri$ x into ano!r room1 :]e x 0 
?r[n into a va/ mix+-vat conta9+ wat]4  
,! salt 0 mix$ ) wat] until a saturat$  
solution 0 obta9$4 ,9 a l>ge room1 cov]+
 "o-half acre or m ( gr\nd1 7 assembl$ a
 great numb] ( %all[ vessels1 ab\t #d by
 #e feet squ>e & #a foot deep4 ,^!      
vessels 7 seal$ up s t !y 7 gas-tight4  
,communicat+ ) all ( ^! vessels 7 pipes 
connect+ ) ! great tank conta9+ !       
saturat$ solution ( salt4  ,f ! top or  
cov] ( ea* vessel is a pipe runn+ to a  
ma9 pipe t c>ries (f ! *lor9e gas into  
ano!r room z fa/ z x is =m$4 ,?r\gh ea* 
"o ( ^! vessels a curr5t ( electricity  
passes2 ! :ole sy/em consum+ ab\t #bjjj 
horse-p[]4 ,! electric curr5t1 z x      
passes ?r\gh ! br9e1 sep>ates ! *lor9e f
 ! sodium1 ! *lor9e pass+ 9 ! =m ( gas  
up ?r\gh ! pipes1 be=e m5tion$1 into !  
ma9 pipe1 :]e x is c>ri$ into ano!r l>ge
 room & dis*>g$ into a sy/em ( gas-tight

 *amb]s4 ,^u ! floor ( ^! *amb]s is     
spread a coat+ ( unslack$ lime gr\nd    
into a f9e p[d]4 ,! lime has a /rong    
aff9ity = ! *lor9e gas & rapidly absorbs
 x1 =m+ *loride ( lime4 ,:5 ! lime is   
fully saturat$ ) ! *lor9e ! gas is turn$
 (f f t *amb]1 :i* is !n op5$ up & !    
*loride tak5 out = %ipm5t4 ,a new coat+ 
( lime is n[ spread 9 ! *amb] & ! gas is
 turn$ on & ! process repeat$4  ,!re are
 a numb] ( ^! *amb]s1 s t ! op]ation 9  
all ( its phases is go+ on cont9u\sly4  
,! room :]e ! *lor9e gas is =m$ is      
?or\ghly v5tilat$1 a precaution :i* is v
 necess>y 9 case any "o ( ! vats %\ld   
spr+ a leak1 z !y sometimes d4  ,9 ea*  
"o ( ^! vats :]e ! electrolytic process 
is go+ on !re are two products con/antly
 pass+ (f2 "o1 z be=e m5tion$1 is *lor9e
 gas1 & ! o!r cau/ic soda 9 solution4 ,!
 solution 9 ! vat is con/antly be+ r5ew$
 by ! saturat$ solution ( salt f !      
res]voir be=e m5tion$4 ,!re is "o /ream 
cont9u\sly com+ into ! vat & two go+    
out1 caus$ by ! decompos+ p[] ( !       

electric curr5t4 ,! solution ( cau/ic   
soda is c>ri$ to l>ge evaporat+-pans1   
:]e ! wat] is driv5 out ( x1 leav+ !    
cau/ic soda 9 dry1 :ite /icks (         
cry/all9e =mation4 ,9 ?is process !     
electric curr5t1 :i* comes f ! p[]-h\se 
) an en]gy ( #bjjj horse-p[]1 has to be 
trans=m$ twice2 fir/1 to br+ x to !     
prop] voltage = ! "w ( decomposition1 &1
 secondly1 to *ange x f an alt]nat+ to a
 direct curr5t1 by :i* all electrolytic 
processes are c>ri$ on4  ,y w notice t !
 electrical en]gy exp5d$ 9 ?is          
e/abli%m5t is d\ble t us$ 9 !           
manufacture ( c>borundum4  ,! cau/ic    
soda1 :i* is "o ( ! products f !        
decomposition ( salt1 is tak5 to ano!r  
e/abli%m5t1 :]e1 by /ill ano!r          
electrical process1 metallic sodium is  
manufactur$4 ,! process "h be+ a secret 
"o1 ! writ] did n h ! privilege ( exam9+
 ! details4     ,,*apt] ,,xxvii         
,,electrical ,,products--,,alum9um4     
,ano!r comp>atively new article (       
manufacture n[ produc$ 9 l>ge quantities

 at ,niag>a ,falls is alum9um4 ,until )9
 ! la/ few ye>s ?is metal 0 n us$ to any
 ext5t by manufactur]s1 because ( !     
great exp5se att5d+ its production4 ,n[1
 h[ev]1 x is produc$ 9 su* quantities z 
to make x ab\t z *eap z brass1 bulk =   
bulk4 ,alum9um is a v light metal1 ) a  
color some:at light] ?an silv]2 its     
specific gravity be+ ab\t "o-?ird t (   
iron4 ,alum9um is f\nd 9 "o ( its       
comp\nds 9 great quantities 9 nature1   
especially 9 c]ta9 k9ds ( clay & 9 a    
/ate ( silicate1 z 9 feldsp> & its      
associat$ m9]als4 ,x is f\nd 9 great    
quantities 9 s\!rn ,georgia1 :]e x is   
mix$ ) ! r$ oxide ( iron t ab\nds 9 t   
region4 ,"h1 x exi/s z alum9a1 :i* is an
 oxide ( alum9um4 ,be=e x is tak5 to !  
r$uction-works ! alum9a is sep>at$ f all
 o!r sub/ances4 ,x is a :ite p[d]1      
ta/eless1 & n easily act$ ^u by acids4  
,electricity is ! *ief ag5t 9 !         
production ( metallic alum9um4 ,!       
r$uction company buys ?is alum9a1 :i*   
has be5 sep>at$ f ! clay or ores :]e x  

is m9$4 ,9 a l>ge room !re are locat$ a 
great numb] ( iron vats or crucibles1   
l9$ ) c>bon1 ab\t two or two & "o-half  
feet deep1 five or six feet long & f\r  
feet wide4  ,imm$iately ov] ea* vat is  
con/ruct$ a metal framework1 ?r\gh :i*  
are ins]t$ a l>ge numb] ( c>bon rods    
ab\t eighte5 or tw5ty in*es long & f two
 to two & "o-half in*es 9 diamet]4 ,?is 
framework is electrically insulat$ f !  
iron crucibles4 ,! framework & ! c>bons 
are connect$ ) ! positive conductor ( ! 
electric curr5t1 & ! vat or crucible ) !
 negative4 ,^! conductors are v l>ge1   
some?+ l a foot 9 wid? & an in* 9       
?ickness1 & made ( "s good conductor (  
electricity4 ,!y h to be v l>ge because 
!y c>ry a curr5t equal to #cjej         
horse-p[]4 ,! curr5t is "o ( great      
volume1 b v l[ voltage2 ! electromotive 
=ce at ea* vat or crucible be+ only ab\t
 sev5 volts4 ,z ! process is            
electrolytic1 & n simply a heat+        
process1 ! direct curr5t mu/ be us$1 &  
!re=e ! curr5t com+ f ! p[]-h\se mu/ be 

trans=m$ twice2 fir/ to br+ x to a prop]
 voltage & secondly to *ange x f an     
alt]nat+ to a direct curr5t4 ,^! iron   
vats or crucibles are connect$ up 9     
s]ies1 electrically1 & !n !y are fill$ )
 ! alum9a & c]ta9 o!r mat]ials1 :i* act 
ei!r z a flux or z a means ( increas+ ! 
conductivity ( ! mixture2 j :at ?is     
sub/ance is1 is probably "o ( ! secrets 
( ! process4 ,:5 all ( ! crucibles are  
fill$ ) ! mixture ! curr5t is turn$ on &
 is kept on cont9u\sly night & day sev5 
days 9 ! week4 ,all ( ! mat]ial 9 !     
diff]5t crucibles is heat$ to r$ness1 :5
 ! process ( sep>ation takes place4 ,!  
oxyg5 ( ! alum9a is ?r[n (f z a gas1 &  
o!r residuum floats to ! top ( !        
crucible & is skimm$ (f4  ,metallic     
alum9um 9 a melt$ /ate s9ks to ! bottom 
( ! crucible1 :]e x is dipp$ out f "t to
 "t ) l>ge iron ladles & p\r$ into s& & 
mold$ into blocks simil> to t ( pig     
iron4 ,f "t to "t1 z ! metal is dipp$   
out1 fre% alum9a ) ! o!r sub/ances are  
?r[n 9 on top ( ! crucible1 s t !       

process is cont9ually go+ on1 day &     
night1 week 9 & week out4 ,! heat 9 !   
process ( r$uc+ alum9a1 z we h be=e se51
 is n ! *ief factor2 x simply s]ves to  
r$uce ! comp\nd to a fluid /ate s t !   
electrolytic action c readily take      
place4  ,!re=e x is n necess>y to be    
br\ght to a :ite heat1 z x is 9 ! case (
 ! production ( c>borundum1 describ$    
else:]e4  ,x 0 extremely int]e/+ to     
obs]ve ! wond]ful magnetic effects t 7  
produc$ 9 iron :5 br\ght into proximity 
) ^! enorm\s electrical conductors4 ,!  
voltage 0 s l[ t "o c\ld h&le !m )      
impunity4 ,! iron crucibles became s    
magnetic t a heavy b> ( iron sev5 or    
eight feet long w\ld cl+ to _! sides1 s 
t x w\ld be held 9 an upright position4 
,b>s ( iron w\ld cl+ to ! conductor at  
any po9t along its l5g?1 &1 al?\gh ^!   
conductors 7 c>ry+ an en]gy ( ov] #cjjj 
horse-p[]1 !y produc$ no p]ceptible     
effect ^u ! human body4 ,! reason = ?is 
lies 9 ! fact1 fir/1 t ! body is n made 
( magnetic mat]ial1 &1 secondly1 !      

pressure is s l[ t ! body--be+ a poor   
conductor--w\ld n easily all[ !         
l[-pressure curr5t to pass ?r\gh x4     
,alum9um is fa/ becom+ an important     
article ( comm]ce1 & x is de/9$ to      
become m & m s on acc\nt ( its extreme  
lightness z comp>$ to o!r metals4  ,x is
 f\nd to be valuable also :5 us$ z an   
alloy ) _m ( ! o!r metals4 ,"o ( ! great
 drawbacks to its m ext5sive use lies 9 
! fact t z yet no satisfactory me?od has
 be5 devis$ = sold]+ x4 ,und\bt$ly 9 "t 
?is difficulty w be solv$1 :5 its use w 
be greatly increas$4 ,x is e/imat$ t 9  
its v>i\s comp\nds alum9um =ms ab\t     
"o-twelf? ( ! cru/ ( ! e>?4     ,,*apt] 
,,xxviii4  ,,electrical                 
,,products--,,calcium ,,c>bide4   ,ano!r
 important use to :i* electricity is put
 at ,niag>a ,falls is ! manufacture ( a 
new product1 call$ calcium c>bide4 ,l   
c>borundum & alum9um1 ?is product c\ld n
 h be5 produc$ 9 comm]cial quantities 9 
advance ( a means = produc+ electricity 
9 enorm\s volume4  ,calcium c>bide is a 

comp\nd ( calcium & c>bon4 ,calcium is a
 :ite metal n f\nd 9 ! natural /ate1 b  
exi/s *iefly z a c>bonate ( lime1 :i* is
 ord9>y lime/one1 includ+ ! v>i\s =ms ( 
m>ble4 ,z a pure metal x is h>d to obta9
 & v h>d to ma9ta91 z x readily oxidizes
 :5 9 contact ) ! air4 ,! symbol =      
calcium c>bide is ,ca,c#b1 :i* means t a
 molecule ( ?is c>bide is comp\nd$ ( "o 
atom ( calcium & two atoms ( c>bon4 ,ca 
/&s = calcium & ,c = c>bon4 ,:5 ! symbol
 has no figure foll[+ x1 x means t "o   
atom only ent]s into ! comp\nd2 b if a  
figure foll[s1 x means t z _m atoms ent]
 9 z ! figure repres5ts4  ,! process (  
manufactur+ calcium c>bide is z foll[s3 
,ord9>y lime be=e x is slack$ is gr\nd  
to a f9e p[d]2 !n x is mix$ ) p[d]$ coke
 or c>bon 9 ! prop] quantities1 s t :5 a
 *emical union takes place ! proportion 
w be z be=e /at$1 "o atom ( calcium to  
two ( c>bon4 ,z is well kn[n1 lime is   
procur$ by expos+ ord9>y lime/one to a  
r$ heat = "s h\rs toge!r4 ,! heat       
dis5gages ! c>bon dioxide1 leav+ only a 

comb9ation ( calcium & oxyg51 :i* is    
common lime4  ,! mixture ( gr\nd lime & 
coke is put into a crucible t surr\nds !
 arc ( an electric light ( enorm\s      
dim5sions2 ! c>bon conductors am\nt+ to 
an area ( "o squ>e foot or m4 ,9 ord] to
 cause ! c>bon to unite ) ! calcium a v 
int5se heat is requir$1 su* a heat z c  
be obta9$ only 9 ! arc ( an electric    
light4 ,:5 ! enorm\s curr5t is turn$ on 
7am\nt+ to ov] #cjjj horse-p[]7 !       
mixture is melt$1 & aft] an exposure to 
?is int5se heat = a giv5 l5g? ( "t !    
oxyg5 ( ! unslack$ lime is ?r[n (f & !  
c>bon unites ) ! calcium1 :i* rema9s 9 !
 proportions ( "o atom ( calcium to two 
( c>bon1 z be=e /at$4 ,?is1 x w be not$1
 is purely a heat process1 & an int5se  
"o at t4 ,no electrolytic action be+    
requir$1 ! alt]nat+ curr5t is us$ )\t   
trans=mation to ! direct curr5t1 z is   
necess>y 9 ! manufacture ( blea*+-p[d] &
 alum9um1 bo? ( :i* are electrolytic    
processes4  ,:5 ! op]ation is complet$ !
 curr5t is turn$ (f & ! comp\nd all[$ to

 cool4 ,9 cool+ x assumes a slate color1
 :i* is slightly iridesc5t :5 expos$ to 
light4 ,x also cry/allizes to a c]ta9   
ext5t4  ,! value ( ?is new product      
consi/s 9 its ability to evolve         
,acetyl5e gas 9 l>ge quantities4 ,a     
molecule ( acetyl5e gas is compos$ ( two
 atoms ( c>bon to two ( hydrog54 ,to    
evolve ! gas x is necess>y only to p\r  
wat] ^u ! calcium c>bide1 :5 a union    
takes place betwe5 ! c>bon ( ! c>bide & 
! hydrog5 ( ! wat] 9 ! proportions above
 /at$4 ,if !re is wat] en\gh ! :ole ( ! 
c>bon w pass (f ) ! gas1 leav+ a        
residuum ( slack$ lime4  ,! value (     
acetyl5e gas lies 9 its v int5se        
illum9at+ p[]4 ,?is is due to ! fact t !
 gas is v ri* 9 c>bon z comp>$ ) o!r    
illum9at+ gases4 ,x burns ) a pure :ite 
light :5 prop]ly mix$ ) air or oxyg51 b 
if !re is a lack ( air x burns ) a smoky
 flame4 ,9 ?is case ! c>bon is n all    
consum$ & escapes into ! air 9 ! =m (   
soot or smoke1 b :5 burn$ ) ! prop]     
mixture ( oxyg5 or common air x becomes 

"o ( ! mo/ brilliant ( illum9ants4      
,acetyl5e1 l mo/ o!r gases1 becomes     
explosive :5 mix$ ) air 9 c]ta9         
proportions4 ,:e!r x is m dang]\s to    
h&le ?an ord9>y illum9at+ gases ! writ] 
is n prep>$ to say1 z he has n _h !     
opportunity to make a ?or\gh comp>ison  
betwe5 x & o!r gases f an exp]im5tal    
/&po9t4  ,exp]im5t1 aft] all1 is ! only 
sure road to absolute k4 ,!ories are    
beautiful 9 books & lectures1 b !y (t5  
fail 9 ! laboratory4  ,acetyl5e is n[   
be+ introduc$ z an illum9at+ gas =      
dome/ic & o!r purposes4 ,sev]al me?ods (
 h&l+ x h be5 propos$4 ,"o is to cond5se
 x into /rong metal cyl9d]s & deliv] x 9
 t =m2 ano!r is to erect g5]ators at    
conv5i5t places & g5]ate ! gas z x is   
us$4 ,a v +5i\s contrivance has be5     
inv5t$ = regulat+ ! g5]ation ( ! gas4 ,a
 c]ta9 am\nt ( ! calcium c>bide is plac$
 9 a gas-tight vessel conta9+ wat]4 ,z  
soon z ! wat] comes 9 contact ) ! c>bide
 ! evolution ( ! gas beg9s4 ,:5 !       
pressure on ! inside ( ! vessel has     

rea*$ a c]ta9 degree x is made1 ?r\gh   
me*anical contrivances1 to lift ! c>bide
 out ( ! wat] & ?us /op ! evolution ( ! 
gas4 ,:5 ! pressure is reliev$ ?r\gh !  
consumption ( ! gas at ! burn]s x all[s 
! c>bide to drop into ! wat]1 :5 !      
evolution ( ! gas beg9s aga94  ,( c\rse 
!re is ! same objection to ?is mode (   
light+ t att5ds all op5 burn]s2 x is    
con/antly dis*>g+ into ! air ! products 
( combu/ion1 *iefly c>bon dioxide1 :i*  
is poison\s to animal life4 ,z has be5  
expla9$ 9 "s ( ! *apt]s on heat1 9      
,volume ,,ii1 ! illum9at+ prop]ty ( any 
gas is det]m9$ by ! numb] ( c>bon       
p>ticles t are conta9$ 9 x1 :i* become  
heat$ to inc&esc5ce z soon z !y come 9  
contact ) ! oxyg5 ( ! air1 & rema9 s1 = 
a brief p]iod1 dur+ _! passage betwe5 ! 
two extremes ( ! flame4 ,:ile acetyl5e  
equals electricity 9 its illum9at+      
prop]ties1 ! latt] /ill /&s )\t a rival 
:5 consid]$ f a sanit>y /&po9t1 z ! use 
( electricity does n 9 any degree       
vitiate ! air 9 a room :]e x is us$4    

,we h n[ giv5 some:at 9 detail ! foll[+ 
processes t are c>ri$ on at ,niag>a     
,falls ?r\gh ! ag5cy ( electricity1     
viz43 ,! r$uction ( alum9um f its oxide 
alum9a2 ! production ( ! new & useful   
comp\nd call$ c>borundum2 ! =mation (   
calcium c>bide us$ = ! production (     
acetyl5e gas1 & a l>ge *emical works1   
:]e blea*+-p[d] is made4 ,9 addition to 
^! works1 !re is an e/abli%m5t = !      
production ( sodium f cau/ic pota%1 :i* 
is "o ( ! products aris+ f !            
decomposition ( salt 9 ! blea*+-p[d]    
works4 ,!re is also ano!r e/abli%m5t = !
 production ( phosphorus made f ! bones 
& %ells obta9$ f ! phosphate b$s t ab\nd
 9 "s ( ! s\!rn /ates1 on ! coa/ ( !    
,atlantic ,ocean4 ,!re is 9 process (   
con/ruction a plant = ! purpose (       
manufactur+ *lorate ( pota% by an       
electrical process4 ,9 addition to ^!   
e/abli%m5ts m5tion$1 ! electricity is   
furni%$ = p[] purposes to ! ,niag>a     
,electric ,light ,company2 to ! electric
 railway betwe5 ,niag>a & ,buffalo2 to !

 ,niag>a ,falls ,railway1 on ! opposite 
side ( ! riv]2 to ! ,niag>a ,p[] &      
,conduit ,company ( ,buffalo1 & !       
,niag>a ,developm5t ,company4 ,?is is   
only a small beg9n+ ( ! uses to :i*     
electricity w be put z an ag5t = !      
developm5t ( heat1 light & p[] z well z 
= ! production ( all sub/ances :]e      
electrolysis is ! *ief factor4 ,sixte5  
companies or m are n[ us+ electricity f 
! ,niag>a p[]-h\se1--! :ole am\nt+ to   
ab\t #ce1jjj horse-p[]4     ,,*apt]     
,,xxix4  ,,! ,,new ,,era4   ,:5 we      
consid] ! numb] ( new products = ^:     
exi/5ce we are indebt$ to electricity1 &
 ! numb] ( old products t h h]et(ore    
exi/$ exp]im5tally1 9 ! laboratory ( !  
*emi/ only1 t h n[ be5 br\ght into play 
z useful ag5ts 9 ! v>i\s arts &         
indu/ries1 we beg9 to realize t ?is is  
truly an electrical age & ! dawn+ ( a   
new era4 ,h[ _m1 _m ?+s !re are1 famili>
 to ! *ildr5 ( to-day1 t 7 n ev5 imag9$ 
by ! *ildr5 ( tw5ty-five to fifty ye>s  
ago4 ,fifty ye>s ago ! only useful      

purpose to :i* electricity 0 put 0 t (  
transmitt+ news f city to city by !     
,morse telegraphic code4 ,x w be        
fifty-sev5 ye>s ! fir/ ( ,april1 #aija1 
s9ce ! fir/ telegraph-l9e 0 ?r[n op5 to 
! public4 ,less ?an ?irty ye>s ago b    
little advance _h be5 made 9 ! use (    
electrical appliances beyond ! p]fection
 ( c]ta9 private-l9e in/rum5ts1 & a     
means = multiple transmission4 ,ab\t    
tw5ty ye>s ago !re 7 evid5ces ( ! beg9n+
 ( a new era 9 electrical developm5t4   
,at no "t 9 ! hi/ory ( ! _w has wond]   
succe$$ wond] ) su* rapidity1 produc+   
su* a/\nd+ results t h revolutioniz$ all
 our modes ( do+ bus9ess & all ( !      
op]ations ( comm]cial & dome/ic life1 z 
dur+ ! la/ two decades4 ,we set our     
wat*es by "t furni%$ by electricity f "o
 c5tral po9t ( obs]vation4 ,we read !   
tape f h\r to h\r1 ^u :i* is record$ !  
comm]cial pulse ( ! _w1 z x ?robs 9 !   
m>ts ( trade1 by means ( ?is same spe$y 
mess5g]4 ,we ent] a /reet-c> t is light$
 & heat$1 & at ! same "t propell$ by !  

same wond]ful ag5t4 ,9 our homes & on   
our /reets night is turn$ into day by a 
light t outrivals all o!r illum9ants4   
,:5 we wi% to speak to a fri5d :o may be
 a mile or a ?\s& miles away we /ep to !
 end ( a wire t comes )9 ! walls ( our  
dwell+ & we talk to him z ?\gh face to  
face1 & means are at h& by :i* we may   
write a lett] to t same fri5d & deliv] x
 to him 9 our own h&writ+ & ov] our own 
signatures1 s quickly t x w appe> be=e  
him 9 full =m & complet5ess z soon z !  
la/ p]iod is made at ! end ( ! la/ l9e4 
,"o sees1 & he>s1 & lives m 9 a s+le day
 9 ?is age ( electricity & /eam ?an he  
did 9 twelve mon?s sixty ye>s ago4 ,&   
yet !re are ^? :o cry out aga9/ mod]n   
inv5tions & mod]n civilization1 & are   
con/antly quot+ ! days ( _! gr&fa!rs &  
great-gr&fa!rs :5 life 0 simple & !re 0 
"t to re/4 ,:y are we torm5t$ ) ?is     
?\ght-/imulat+ age8 !y say4 ,:y are our 
emotions call$ into action by mod]n     
music & mod]n art8 ,:y are we call$ ^u  
to help ! d[ntrodd5 & oppress$1 & to    

help to elevate mank9d to a high] level8
 ,:y _c we be left alone 9 peace &      
quiet1 to live 9 ! easie/ way8  ,if ?is 
be good philosophy1 !n ! sw9e1 if he 7 a
 reason+ be+1 ought to be rank$ among ! 
greate/ ( philosoph]s--:5 he seeks a    
wall[ 9 ! sun%9e & sleeps away 8 useless
 exi/5ce4 ,if he is useful x is because 
"s o!r be+ ( a high] ord] uses him to   
help along 8 own exi/5ce4 ,! man 9 ^!   
days :o does n keep up ) ! procession is
 soon trodd5 "u foot & "s o!r man uses  
him z a /epp+-/one to elevate himself4  
,yet ?is is a selfi% motive1 aft] all4  
,! _w is n[ rapidly advanc+ 9 light1 9  
k1 9 p[] to use ! inf9ite gifts t !     
,creator has hidd5 9 nature2 b hidd5    
only to /imulate & rew>d our seek+4 ,e  
man c help 9 ?is gr& progress1--if n by 
rese>* & positive ?\ght-p[]1 at lea/ by 
grateful acceptance & realization ( :at 
is ga9$4 ,look =w>d6 ,z ,em]son puts x3 
,to make habitually a new e/imate--t is 
elevation4     ,,index4     ,acetyl5e   
gas at ,niag>a1 #bcj4    ,alex&ria1     

temple ) load/one1 #bj4                 
,amb]--elektron1 #f4    ,amp]e1 !ory (  
magnetism1 #be4     unit ( electrical   
curr5t1 #he4     galvanomet]1 #ic4      
,alum9um at ,niag>a1 #bbc4    ,arabians1
 magnetic ne$le1 #ba4    ,arago1 g]m (  
electromagnet1 #ic4    ,ari/otle m5tions
 torp$o1 #f4     ref]s to magnet1 #bj4  
,atmosph]ic electricity1 ,*4 ,,viii1    
#gg4    ,atoms & molecules1 #ci4     (  
sub/ances diff] 9 weight1 #db4          
relations to heat1 #db4    ,aurora      
,borealis1 #ce4     ,ba9 *emical        
telegraph regi/]1 #aja4    ,b>l[ on     
galvanism 9 telegraphy1 #ic4    ,bell1  
,alex&] ,graham1 radiophone1 #aga4      
,blea*+-p[d] at ,niag>a1 #bah4          
,branly inv5ts ! coh]]1 #agi4           
,cables1 subm>9e4 ,see ,subm>9e ,cables4
    ,calcium-c>bide at ,niag>a1 #bbh4   
,capacity ( a circuit1 #aah1 #aai4      
,cau/ic soda1 #bba4    ,*9ese1 magnetic 
ne$le1 #ba4    ,*lor9e & sodium1 #bai4  
,circuit-break] at ,niag>a1 #aii4       
,clos$ circuit & curr5t1 #abb4    ,coh]]

 7wireless telegraphy71 #agi4           
,columbus1 compass v>iations1 #bb1 #cd4 
,cond5s] 9 resi/ance-coil1 #aah4     9  
,morse relays1 #aca4    ,conductors &   
non-conductors ( electricity1 #dg4      
relation to electric light1 #ej4        
diff]5t resi/ances1 #gd1 #hc4    ,cooke1
 ne$le telegraph1 #ajh4    ,crookes1    
,pr(41 ,x-ray1 #aba4    ,cuneus & !     
,leyd5 j>1 #h4    ,curiosities1 ,*4     
,,xx1 #aga4     ,daniell batt]y1 #he4   
,diff]5tial magnet1 #aae4    ,d9oc>es & 
! load/one1 #bj4    ,dolbe>1 ,amos ,e41 
wireless telegraphy1 #agh4    ,dupay    
discov]s positive & negative            
electricity1 #h4    ,duplex telegraphy1 
#aad4    ,dynamo-electric ma*9es1 #fg4  
inv5t$ by ,f>aday1 #ad1 #fi4     usual  
con/ruction1 #gj4     at ,niag>a1 #aib4 
,d\ble transmission1 #aae4     ,e>?     
electric curr5ts1 9 telegraphy1 #ii1    
#aaf1 #ahb4    ,e>? magnetism1 #cb4     
effects (1 on iron1 #ce4                
,aurora1 #ce4                           
telegraph-l9es1 #cf4     f sun's heat1  

#ge4    ,edison1 ,?omas1 railway        
telegraphy1 #aca4     electromotograph1 
#age4    ,electric curr5ts1 ,*4 ,,vi1   
#di4     n curr5ts b atomic motion1 #ed4
     induction (1 #ef4         gu>d$    
aga9/1 #afi4     at ,niag>a1 #aic4      
,electric g5]ators1 ,*4 ,,vii1 #fb4     
frictional1 #di4     galvanic batt]ies1 
#fb4     /orage-batt]ies1 #fd4          
dynamos1 #fg1 #aib4     metal heat+1    
#gd4    ,electricity1 sci5ce (1 #f4     
a*ievem5ts (1 #af4     eras 9 sci5ce (1 
#ah4     !ory (1 ,*4 ,v1 #ci4     n a   
fluid1 a =m ( en]gy1 #dj4     /atic &   
dynamic1 #df4     measurem5t (1 ,*4     
,,ix1 #hc4    ,electric light1 cause (1 
#ej4    ,electric ma*9es1 #di4          
frictional1 #ea4     galvanic or        
*emical1 #ea4     me*anical1 #gj4       
,electromagnet inv5t$ by ,f>aday1 #ad4  
comm]cial value1 #bc4     !ory ( 7s(t   
iron71 #bf4     p]man5t 7/eel71 #bh4    
condition ( use1 #cj4     ! e>? a1 #cb4 
g]m (1 #ic4     diff]5tial1 #aae4       
,electromotograph1 #age4    ,ellswor?1  

,miss1 s5ds fir/ telegraphic message1   
#if4    ,e!r1 l9es ( =ce1 #ca4          
nature (1 #dj4    ,e!r1 impress$ by     
atomic motion1 #ef4     induc+ electric 
action1 #ef4     ,f>ad1 unit ( capacity1
 #aah4    ,f>aday1 ,mi*ael1 #ad4        
,f>m]1 ,moses ,g41 d\ble transmission1  
#aad4    ,field1 ,cyrus ,w41 lays fir/  
,atlantic cable1 #aef4    ,field ( a    
magnet1 #ca4    ,fitzg]ald1 ,niag>a     
,falls *emi/1 #baj4    ,frankl9 cat*es !
 lightn+1 #h4     id5tity ( lightn+ &   
electricity1 #aj4     kite exp]im5t1    
#aa4     electric fir+-telegraph1 #hh4  
,frode1 hi/ory ( ,icel&1 #ba4           
,gad5hal5 uses magnetic ne$le #hfh      
,a4,d41 #ba4    ,galileo's se$-?\ght1   
#hi4    ,galvani1 ,luigi1 & galvanism1  
#ab4    ,galvanic batt]ies1 #fb4        
au?or's exp]i5ce1 #fe4    ,galvanomet]1 
#ge1 #ic4    ,gilb]t1 ,dr41 frictional  
electricity1 #g4    ,g9tl1 d\ble        
transmission1 #aad4    ,gray1 ,eli%a1   
con/ructs voltaic pile1 #fe4            
electrically transmits music1 #ia4      

exp]im5ts on transmission ( music1      
articulate spee*1             & multiple
 messages1 #abc4     files telephone    
caveat1 #ace4     musical exp]im5ts1    
#acf4     spee* receiv]s1 #aci4         
boys' telephone1 #ada4     fir/         
telephone specification on record1 #adc4
     dial-telegraph1 #afa4              
automatic-pr9t+ telegraph1 #afc4        
telautograph1 #afe4     electric musical
 receiv]1 #age4    ,gray1 ,/eph51       
electrician1 #h4    ,gri]1 ,john ,a41   
quot$1 #fg4    ,guyot ( ,prov5ce m5tions
 m>9]'s compass1 #ba4     ,halske1 d\ble
 transmission1 #aad4    ,h>monic        
telegraphy1 #abj4     receiv]s1 #abe4   
relay1 #acj4    ,hawksbee1 ,francis1    
electrician1 #g4    ,heat1 a mode (     
motion1 #dj4     relat$ to atoms1 #db4  
beg9s & ends 9 matt]1 #dd4              
electrical & me*anical en]gy ! same1    
#df4    ,h5ry1 ,joseph1 fir/ practical  
telegraph]1 #ij4     con/ructs          
long-di/ance l9e1 #id4     produces     
induction1 #agg4    ,h]aclea & !        

load/one1 #bj4    ,h]tz exp]im5ts 9     
e!r-waves1 #agh4    ,hom] ref]s to      
load/one1 #bj4    ,horse-p[]1 #bad4     
,h\se1 ,royal ,e41 pr9t+ telegraph1     
#ajh1 #aaj4    ,hughes1 ,david ,e41     
pr9t+ telegraph1 #ajh1 #aab4            
,induction1 #ef4     gu>d$ aga9/1 #afi4 
produc$ by ,h5ry1 #agg4     ,keep] ( a  
magnet1 #ca4    ,kelv91 ,"l 7,sir ,w4   
,?ompson71 cable message receiv]1 #aeh4 
,kick1 9 telegraphy1 #aae1 #aah4        
,klei/ & ! ,leyd5 j>1 #h4     ,let h]   
buzz1 #c4    ,leyd5 j> inv5t$1 #h4      
,lightn+1 electricity2 ,frankl91 #h4    
re/oration ( equilibrium1 #gh4          
,lightn+-rods1 #hj4     dang]\s         
conductors1 #ha4    ,load/one1 #bj1 #ba4
     ,maury1 ,lieut41 deep-sea s\nd+s1  
#aee4    ,magnes1 ,magnesia1 #bj4       
,magnet1 electro4 ,see ,electromagnet4  
,magnetic e>? poles1 #bc1 #cb4          
,magnetic l9es ( =ce1 #ca1 #cd1 #fj4    
,magnetic ne$le1 #ba4     v>iation (1   
#bb4     dip (1 #bb4     action (1 #cc4 
,magnetism1 hi/ory (1 #bj4     &        

electricity mutually dep5d5t1 #bd4      
!ories (1 #bd4     9 iron & /eel1 #be4  
9 ! e>?1 #cb1 #cf4     & sun-spots1 #cg4
    ,magnetization1 limit (1 #ca4       
,m>coni1 wireless telegraphy1 #agh-ahj4 
,measurem5t ( electricity1 #hc4         
amp]e1 unit (1 #he4     me?od (1 #hf4   
,m]cury lum9\s by %ak+1 #g4             
,micro-f>ad1 unit ( capacity1 #aai4     
,molecules ( iron & /eel natural        
magnets1 #be4     & atoms1 #ci4         
,morse1 ,s4 ,f4 ,b41 devises code (     
telegraphic signals1 #ie4     induces   
,congress to con/ruct l9e1 #if4         
transmits batt]y curr5t ?r\gh wat]1     
#agg4    ,motion univ]sal1 #ch4         
causes s\nd1 heat1 light1 & electricity1
 #ci4    ,multiple transmission1 ,*4    
,,xiii1 #aad4     duplex1 #aaf4         
quadruplex1 #aah4    ,multiple          
transmission1 musical1 #abj4    ,musical
 message receiv]s1 #abe1 #aci4          
,musical tones transmitt$1 #ia1 #ib1    
#abj1 #acf4    ,mus*5broeck1 ,pr(41 & ! 
,leyd5 j>1 #h4    ,newton1 ,sir ,isaac1 

electrician1 #h4     ,niag>a ,falls     
,p[]1 ,*s4 ,,xxii to ,,xxviii1 #ahf to  
#bcc4     ,introduction--rock1 wat]1    
p[]1 #ahf4     ,appliances3             
tunnel1 p[]-h\se1 #aij4       %aft1     
dynamos1 #aib4       curr5t1 #aic4      
gov]nor1 #aid4       wat]-head1 #aie4   
crane1 #aif4       circuit-break]1 #aii4
       trans=m]1 #bjj4                  
electromotive =ce1 #bjd4     ,electrical
 ,products--,c>borundum1 #bji4          
mat]ials1 #baj4       furnaces1 #baa4   
electric curr5t1 #bac4       horse-p[]1 
#bad4       me?od ( "w1 #bae4           
,blea*+-p[d]1 #bah4       *lor9e &      
sodium1 #bai4       me?od ( "w1 #bbj4   
cau/ic soda1 #bba4     ,alum9um1 #bbc4  
crucibles & me?ods1 #bbd4       magnetic
 effects1 #bbf4     ,calcium c>bide1    
#bbh4       process1 #bbi4              
acetyl5e gas1 #bcj4     ,o!r products1  
#bcb4    ,o]/$1 galvanic curr5t on      
magnetic ne$le1 #ic4    ,ohm1 ,g4 ,s41  
resi/ance unit1 #gd4                    
,pat5ts--,caveat & application1 #ace4   

,plante1 /orage-batt]y plates1 #fd4     
,pl9y m5tions electrical prop]ties (    
amb]1 #fg4     load/one1 #bj4           
,preece1 d\ble transmission1 #aad4      
,prescott1 ,geo4 ,b41 quot$1 #ajd1 #ajf1
 #afc1 #agd4    ,ptolemy ,philadelphus &
 load/ones1 #bj4    ,py?agoras ref]s to 
natural magnets1 #bj4     ,radiophone1  
#aga4    ,railway tra9 telegraphy1 #aca4
    ,ri*man1 ,pr(41 kill$1 #ab4         
,reiss1 metallic telephone transmitt]s1 
#abb4    ,resi/ance1 unit (1 #gd4       
-coil1 #aah4     ,siem5s1 d\ble         
transmission1 #aad4    ,sel5ium 9       
radiophone1 #agb4    ,%eph>d1 ,*>les    
,s41 induction-coil1 #abb4    ,/ag]1    
,g54 ,anson1 telegraph]1 #aaj4          
,/e>ns1 ,joseph ,b41 cures ! kick 9     
d\ble transmission1 #aae4               
,/orage-batt]y1 #bd4    ,/rada1 load/one
 telegraph1 #hh4    ,subm>9e cables1 ,*4
 ,,xvii1 #aed4     fir/ l9es1 #aed-e4   
,maury's deep-sea s\nd+s1 #aee4     fir/
 ,atlantic1 #aef4     ret>dations1 #aeg4
     receiv]1 #aeh4    ,sun-spots &     

magnetic /orms1 #cg4     ,telautograph1 
,*4 ,,xix1 #afe4    ,telegraph3         
helio/at1 #fh4     semaphore1 #fh4      
load/one1 #hh4     ,frankl9's electric  
fir+1 #hh4     electrically dropp$      
balls1 #hh4     electric transmission ( 
musical tones1 #ia4       ( signals1    
#id4     ,morse regi/]1 #ie4     fir/   
l9e1 #ig4     description1 #ih4         
read+ by v>i\s s5ses1 #ajj4     ,ba91   
*emical record]1 #aja4     ,cooke ne$le1
 #ajh4     ,:eat/one ne$le1 #ajh4       
,h\se pr9t+1 #ajh1 #aaj4     ,hughes    
pr9t+1 #ajh1 #aab4     automatic sy/ems1
 #aji1 #aab4     multiple transmission1 
#aad4     musical transmission1 #abj4   
musical receiv]s1 #abe4     ,way duplex1
 #abi4     f mov+ railway tra9s1 #aca4  
repeat]1 #aej4     %ort-l9e dials1 #aei4
     pr9t+1 #afc4     wireless1 ,*4     
,,xxi1 #agf4    ,telegraphic messages1  
receiv+1 #ajc4    ,telephone1 ,*s4 ,,xv1
 ,,xvi1 #acd1 #ade4     au?or's fir/    
exp]im5t1 #ia4     exp]im5ts1 #abc4     
caveat1 #ace4     spee* receiv]s1 #aci4 

boys' telephone1 #ada4     fir/         
specification (1 on record1 #adc4     h[
 telephone talks1 #ade4     simple      
con/ruction1 #adf4     two me?ods (     
transmission3 magneto & v>i$            
resi/ance1 #adb1 #adi4     limit (      
transmission1 #aec4     c5tral /ation1  
#afd4     affect$ by heat-lightn+1 #ahc4
    ,telephote1 #agc4    ,?ales (       
,miletus fir/ describ$ electrical       
prop]ties ( amb]1 #f4    ,!ophra/us     
m5tions amb]1 #f4    ,!rmo-electric     
pile1 #ge4    ,torp$o1 !1 #f4           
,trans=m]s at ,niag>a1 #bjj4            
,transmission1 multiple1 ,*4 ,,xiii1    
#aad4    ,tr[bridge1 ,pr(41 telephones  
?r\gh ! e>?1 #ahh4    ,tunnel at        
,niag>a1 #aij4    ,tyndall1 & ,gray's   
exp]im5ts1 #ib4     ,unre/ ( ! univ]se1 
#ch4     ,volt1 unit ( electrical       
pressure1 #he4    ,volta1 ,aless&ro1 & !
 voltaic pile1 #ac4     ,watt1 ,james1  
#hf4     unit ( electrical p[]1 #hf4    
,way duplex sy/em1 ,*4 ,,xiv1 #abi4     
,:eat/one transmits musical tones       

me*anically1 #ib4     ne$le telegraph1  
#ajh4     dial-telegraph1 #aei4         
,wireless telegraphy1 ,*4 ,,xxi1 #agf4  
signal+ by e!r-waves1 #agf4     ,morse &
 ,h5ry1 #agg4     ,tr[bridge1 ,dolbe>1  
,h]tz1 #agh4     ,branly1 ,m>coni1 #agi4
     ,m>coni's sy/em1 #ahj4     by      
e>?-curr5ts1 #ahb4    ,wolim]1 ,k+ (    
,go?s1 a natural batt]y1 #g4