274 "Journal of Experiments, April, 1773 



of the quantity of electricity which is given to it with the same degree of 

 electrification if the bottom plate is not touched. 



Compound plate 

 On Tuesday D excess in Plate air i 



I'OO 



Plate air 4 



2-16 



561] Fr. Apr. 2 [1773]. Th. about 55. N. about 10. 



It was tried whether a parallelepiped box included within another box of 

 the same shape and communicating with it would receive any electricity on 

 electrifying the outer box*. 



The experiment was tried just in the same manner as that with the globe 

 in p. 26 [Art. 513]. The inner box was 12 inches square and 2 thick. The outer 

 box was 14 inches square and 4 thick on the outside, and 13 square and 3-4 

 thick within. 



The boxes were made of wainscot and well salted. I could not perceive that 

 the inner box was at all over or undercharged, for if I previously electrified the 

 cork balls positively sufficiently to make them separate in touching the inner 

 box, they would separate as much if I previously electrified them negatively 

 in the same degree. 



Globe within hollow globe tried again f . 

 562] Sun. Apr. 4 [1773]. Th. 58. N. n. 



The globe included between the 2 hemispheres was tried again in the same 

 manner, except that the hemispheres were coated with tinfoil and were made 

 to shut closer. 



I could not perceive the inner globe to be at all electrified either way. 



In order to see how small a degree of electricity I could perceive this way, 

 I separated the two hemispheres as far as in the experiment, and electrified 

 the 2 na thermometer tube with the same strength of electricity as was used in 

 the experiment, and communicated its electricity to the jars i and 2, then 

 touched the inner globe with one of those jars and drew up the cork balls, 

 previously positively electrified, against the globe. I found them to separate 

 very visibly. 



I then repeated the experiment in the same manner except that the balls 

 were negatively electrified in the same degree. 



The elect, of the thermometer tube was diminished by communicating to 

 the 2 jars in the ratio of 105 to 6339 J, or of r to 60, so that if the redundant 

 fluid in the globe had been so much as ^ of that in the hemispheres, I must 

 have perceived it. 



* [Exp. n, Art. 235.] t [ Ex P- I- Ar t. 218.] 



J [Charge of 2 n<l thermometer tube = 80-7 glob. inc. = 124-3 ciic. inc., by 

 Art. 675, jar i + jar 2 = 6234, by Art. 506.] 



