186 



rilVSlOl.oiiV <! MrSCI-KS AM> NKKVES. 



difference in ten-ion between /.' ;md S can be nil ered 

 liy chanLMiiM; tin- ]>n>ition of ,S', tlio slide X m:iy he 

 placed in such a ]>o-it inn tliat the t w<> inflm -n- < - rxnctly 

 halanci' facli ntluT, <>r, in ntli.T ^-i>nl>. in >u<-li ;i |msition 

 tliat tin- multiplier indicates no di-lli-ctinn. Thus it is 

 evident tliat 



S - I! 



l>iflVri-ur<- in tr-n-inn nt 

 '.Mi jioints i if tin- I 



li a 



= 



the two 

 doctor. 



or S R = b -- n ; 



in trnsinn at 

 -: of the con- 



flu- difference, that is, of the tension l>et\\ en 1> and a 

 is equal to the difference of tension between S and R. 



111.. 17. lM );c>l~-Kl.YM<>M>'> KOI'M) ( . M ![ \> \ mi;. 



The Litter i> e\]ires-ed in i nill line) r< >, each nf \\hich 

 intlieiite- a certain cnii-t;mt anmunt \\hen a delinite 

 vhenclmrd \\ire is u>cd. and when the current which is 



cd tlimn^li the lulter is of a delinitr >1n-n^th. 

 'J'o facilitate lie a-iii-riin nts of this kind, du Hois- 



