Experiments of comparison and combination 163 



Fifth. The charge of H was equal to that of the three plates A, B 

 and C together. 



Therefore the charges of D, K, A and H were to each other as 

 i. 3'05, 8-28 and 24-9*. 



319] It appears, therefore, that the proportion which the charge of K 

 bears to that of D, and which H bears to that of A, is very nearly the same 

 as that of their computed charges, but the proportion which the charge 

 of A bears to that of K is near T ' 5 part less than it ought to be. 



This in all probability proceeds from the effect of the instantaneous 

 spreading of the electricity bearing a greater proportion to the whole in 

 the plate K than it does in A , the diameter of whose coating is near three 

 times as great. 



320] In order to form some judgment, if possible, how great the effect 

 of this instantaneous spreading of the electricity was, I took off the coatings 

 from the plates A and B], and put on others of just the same area in the 

 form of a rectangular parallelogram (that of A was 6-414 long and 5-310 

 broad, and that of C 6-398 long and 5-201 broad), and compared their 

 charges with that of the plate B, whose charge, as was before said, was 

 just the same as those of these two plates before their coatings were 

 altered. 



321] I then took off these coatings J, and on A I put a square coating 

 6-388 each way with slits cut in it, as in Fig. 23, each -fa broad, so as to 

 divide it into 9 smaller squares, each 1-863 inches each way. The narrow 

 communications marked in the figure between these squares were each 

 Y^ of an inch broad. 



. 

 9 



On C I put an oblong coating 6-377 l n g an< ^ 6-343 broad, with four 

 parallel slits cut in it, as in Fig. 24, each T % broad, the narrow space left 

 between these slits and the outside being ^ broad. Having done this, 

 I compared their charges with that of the plate B as before. 



* [See also Arts. 656 to 658.] f [C, see Art. 536.] J [Art. 537.] 



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