BY A STATIONARY ELECTRIC CURRENT. 209 



quantity of electricity passing through the transverse section in 

 the unit of time. It is usually termed the intensity of the cur- 

 rent, and may here therefore be represented by J, whereby the 

 foregoing expression becomes 



+V.J. 

 Let us now assume that at the other transverse section the same 

 conditions are fulfilled, and let the values of V corresponding 

 to the first and second transverse sections be denoted by Vq 

 and Vi, then the work accomplished within the entire portion 



will be 



W=(V.-V„).J, • . (6) 



and the heat produced 



H=A(V.-V„).J, (7) 



But, according to Ohm^s law, 



J = ^% (8) 



in w^hich / denotes the resistance to conduction of the portion 

 occurring between the two transverse sections, and consequently 

 the two preceding equations pass into 



W=/.J2 (9) 



H = A./.P (10) 



The last of these equations contains the two laws discovered by 

 Joule, and subsequently confirmed by Lenz and Becquerel. 



The reader is requested to correct the following Errata in the author's memoir 

 " On the Mechanical Equivalent of an Electric Discharge." 



Page 16, line 9 from bottom, for his read this, 

 „ 19 „ 17 from bottom, for (r^j read (\ 



Q2 Q2 



„ 21 „ 9 from bottom, for- ^. const, read ^. const. 



5 o 



„ 22 „ 2 from top, for incomplete read complete. 



„ 22 „ 4 from bottom, for quantity of work read capacity of discharge, 



n s' vl s' 



„ 23 „ 7 from bottom, for -— read r-, Q. 



ns n s ns rt g 



