316 Mr. E. II. Hall on the new Action of 



obtained with it and those obtained with the strips of No. 6, 

 ahwulv described, and of No. 4, which is to be described next. 

 "With No. 5 were made four series of observations, resulting 

 thus : — 



MxV 



March 8th, 



M. 



6400 



C. 



o 



k x tan 42 



26 



E' ' 

 161 x 10 10 



9) V 



„ 10th, 



6330 

 6440 



i. » 26 



5) J) ^ 



2 

 48 



163 „ 

 162 „ 



» ii 



6440 



Mean . 







164 „ 

 = 1625 xlO 9 



The next plate used was 



Gold Foil, No. 4 (soft). 



Length when weighed . . =7-64 centims. 



Width „ . . = 2-13 „ 



Area, including projections =18*46 square centims. 



Weight = -0478 grni. 



Thickness = -000134 centim. 



With this plate four series of observations were made in one 

 day. 



The results obtained (March 12th) were 



MxV 



M. 



6480 



C. 

 £xtan22 2l 



E' ' 

 155 xlO 10 



J) 



„ „ 26 25 

 „ „ 42 16 

 „ „ 28 43 



155 „ 

 154 „ 

 154 „ 





Mean . . 



= 1545xl0 9 



Measurements had now been made with three plates of gold 

 foil ; and, considering the irregularity likely to be produced by 

 the impossibility of determining accurately the effective thick- 

 ness of the strips, the results seemed to agree satisfactorily, 



MxV 



indicating — ^— to be a constant for this metal. If the expe- 

 riments in gold had begun with these particular plates, they 

 would probably have ended with them for the present. Owing, 

 however, to the great discrepancy observed between these 

 results and those obtained with the very thin plates, it seemed 

 desirable to go further ; and I therefore constructed a plate, 

 using 



