328 



TENTH ANNUAL REPORT OF 



Since the magnetic and cliemical effects are always proportional to 

 each other, the quotient of the quantity of gas divided by the number 

 of degrees must always be the same, if there are no errors of observation ; 

 but this is only approximately the case. The mean of all the quotients 

 is 0.08386 ; thus we get the current force expressed in chemical mea- 

 sure, by multiplying the number of degrees v read on the instrument, 

 by 0.08386, or, 



S= 0.08386 V. 



Let us now consider a similar series of experiments, instituted to 

 determine the relation of two tangent compasses to the chemical unit. 

 The current was passed simultaneously through a decomposing appa- 

 ratus and the two compasses, the larger of which had a ring 38 centi- 

 metres in diameter, the smaller one of 30 centimetres. That the needles 

 of the two compasses might have no influence upon each other, they 

 were placed twenty-five feet apart. The following are the results of 

 the observation : 



