1873.] Louis Schwendler — On differential Galvanometers. 5 



but 



^ = it follows that U = 

 dg 



d^a 1 ^U 



Now 



df \ dg 



dV /^N ^ ^'N\ , , d^ „ ^'N ^ . 



-r- = — I — ; — H 2q——- ), but — r- as well as —r-^ being invariably 



positive, it follows tbat — is invariably negative, and as further V is always 



d^a 

 positive it follows finally that ~ is always negative, or the value of g ob- 

 tained by equation — - = corresponds to a maximum sensitiveness of the 



California Academy of Sciences 



Presented bv Asiatic Rociety of* 

 Bengal . 



Apri l 



, 1902^ 



aed by equa- 

 le differential 



bhe problem. 

 3losely to the 



lunts cannot 



i,s long as the 



quantity of 



action on the 



;r that in the 

 in the above 

 equations are nuu tnuse au wiiiv;ii ua,xa,ii>^<^ c*v^i<^«,xxj ^x^^. — , — ^hose at which 

 balance would arrive if no shunts were used, i. e., the resistance at which 

 balance is established when using shunts must be multiplied by the multi- 

 plying power of their respective shunts, before they are to be substituted 

 in the equations a,h, c and d. 



Mechanical arrangement designed hy p. — The condition which must 

 be fulfilled in the construction of any differential galvanometer to make a 

 simultaneous maximum sensitiveness possible was expressed by 



i?^ = — c. 



ni' nf 



while p = and it will be now instructive to enquire what special 



m n A 1. 



physical meaning equation c has. 



