INDUCTION APPARATUS — MODE OF DIVIDING CHARGES. 15 



the division was found with 122°, this amount at least may be taken as what it had 

 received. On the other hand 124° minus 1°, or 123°, may be taken as the half of the 

 transferable charge retained by app. i. Now these do not differ much from each 

 other, or from 124°-5, the half of the full amount of transferable charge; and when 

 the gradual loss of charge evident in the difference between 254° and 250° of app. i. 

 is also taken into account, there is every reason to admit the result as showing an 

 equal division of charge, unattended hy any disappearance of power except that due 

 to dissipation. 



1210. I will give another result, in which app. ii. was first charged, and where the 

 residual action of that apparatus was greater than in the former case. 



App. i. App. ii. 



Balls 150° 

 .... 152° 



.... 148 

 divided and instantly taken 

 70° ... . 



.... 78 



. . . . 5 immediately after discharge. 

 immediately after discharge. 



1211. The transferable charge being 148°— 5°, its half is 71°*5, which is not far re- 

 moved from 70°, the half charge of i. ; or from 73°, the half charge of ii. : these half 

 charges again making up the sum of 143°, or just the amount of the whole transfer- 

 able charge. Considering the errors of experiment, therefore, these results may again 

 be received as showing that the apparatus were equal in inductive capacity, or in 

 their powers of receiving charges. 



1212. The experiments were repeated with charges of negative electricity with the 

 same general results. 



1213. That I might be sure of the sensibility and action of the apparatus, I made 

 such a change in one as ought upon principle to increase its inductive force, i. e. I 

 put a metallic lining into the lower hemisphere of app. i., so as to diminish the thick- 

 ness of the intervening air in that part, from 0*62 to 0*435 of an inch : this lining 

 was carefully shaped and rounded so that it should not present a sudden projection 

 within at its edge, but a gradual transition from the reduced interval in the lower 

 part of the sphere to the larger one in the upper. 



1214. This change immediately caused app. i. to produce effects indicating that it 

 had a greater aptness or capacity for induction than app. ii. Thus, when a transfer- 

 able charge in app. ii. of 469° was divided with app. i., the former retained a charge 

 of 225°, whilst the latter showed one of 227°, i- e. the former had lost 244° in com- 

 municating 227° to the latter : on the other hand, when app. i. had a transferable 

 charge in it of 381° divided by contact with app, ii., it lost 181° only, whilst it gave 

 to app. ii. as many as 194° : — the sum of the divided forces being in the first instance 



