14 DR. FARADAY'S EXPERIMENTAL RESEARCHES IN ELECTRICITY. (SERIES XI.) 



feet and instantaneous discharge^ giving then no charge to the carrier ball, whatever 

 part of the ball B it may be applied to (1218.). 



1206. With respect to the balance electrometer all the precautions that need be 

 mentioned, are, that the carrier ball is to be preserved during the first part of an ex- 

 periment in its electrified state, the loss of electricity which would follow upon its 

 discharge being avoided ; and, that in introducing it into the electrometer through 

 the hole in the glass plate above, care should be taken that it do not touch, or even 

 come near to, the edge of the glass. 



1207. When the whole charge in one apparatus is divided between the two, the 

 gradual fall, apparently from dissipation, in the apparatus which has received the 

 half charge is greater than in the one originally charged. This is due to a peculiar 

 effect to be described hereafter (1250. 1251.), the interfering influence of which may 

 be avoided to a great extent by going through the steps of the process regularly and 

 quickly ; therefore, after the original charge has been measured, in app. i. for instance, 

 i. and ii. are to be symmetrically joined by their balls B, the carrier touching one of 

 these balls at the same time ; it is first to be removed, and then the apparatus sepa- 

 rated from each other ; app. ii. is next quickly to be measured by the carrier, then 

 app. i. ; lastly, ii. is to be discharged, and the discharged carrier applied to it to 

 ascertain whether any residual effect is present (1205.), and app. i. being discharged 

 is also to be examined in the same manner and for the same purpose. 



1208. The following is an example of the division of a charge by the two apparatus, 

 air being the dielectric in both of them. The observations are set down one under 

 the other in the order in which they were taken, the left hand numbers representing 

 the observations made on app. i. and the right hand numbers those on app. ii. App. i. 

 is that which was originally charged, and after two measurements, the charge was 

 divided with app. ii. 



App. i. App. ii. 



Balls 160° 

 .... 0° 

 254° .... 



250 ... . 

 divided and instantly taken 

 .... 122 

 124 ... . 



1 . . . . after being discharged. 



. . . . 2 after being discharged. 



1209. Without endeavouring to allow for the loss which must have been gradually 

 going on during the time of the experiment, let us observe the results of the numbers 

 as they stand. As 1° remained in app. i. in an undischargeable state, 249° may be 

 taken as the utmost amount of the transferable or divisible charge, the half of which 

 is 124°*5. As app. ii. was free of charge in the first instance, and immediately after 



