126 



PROCEEDINGS OP THE AMERICAN ACADEMY. 



It is, of course, desirable to make the flow of water along the two faces 

 of the disk such that the indication received from any one pair of wires, 

 one above and one below, shall be about the same as that given by any 

 other such pair of wires, and much thought has been given to the attain- 

 ment of this end. The result is not quite all that could be wished for ; 

 but it is such that any important error from the inequalities observed is 

 very unlikely. The following tables show the. results of tests made 

 under conditions as nearly uniform as it was found practicable to keep 

 them. The galvanometer deflection credited to each pair of junctions is 

 the mean obtained from two short sets of observations, the various pairs 

 being used first in the order in which they are here given, and then in 

 the reverse order. Between these forward and back series of observa- 

 tions with single pairs a short set of observations with all the pairs in 

 multiple was made, and the mean deflection from this set, corrected for 

 the difference of resistance of the multiple and single arrangements, is 



also given below. 



Temperature about 28° C. 



Junctions. 



13 and 13' 



1' 

 4' 



1 and 



4 and 



7 and V 



10 and 10' 



2 and 2' 



:> and -V 



Mill 8' 



11 and 11' 



3 and 3' 



(', and 6' 



9 and '.l' 



12 and 12' 



Deflections. 

 11.1 



11.0 



11.1 



12.li 1 

 12.2/ 



10.!) 



10.8 r 



11.7 J 

 11.6 > 



10.6 v 

 10.7 

 10.5 | 

 11.1 ' 



11.6 



11.3 



1U.7 



M-- in, 1 1.2 



10.8 



11.1 



11.0 



All in multiple, 1 1 .3 



