262 



journal of Experiments, Feb. 1773 



JS7 



539] Experiment to determine whether the charge of a Leyden vial bears the 

 same proportion to that of another body when elect, is very weak as when it is 

 strong *. 



AB is a tin cylinder 14 feet 8-7 inches long and 17-1 inches in circumference. 

 DC is a brass wire 37-1 inches long and -15 in. 

 diameter; both supported by non-conductors; 

 with the middle sized cork balls hung at D. 



FE communicates with the prime conductor 

 and is charged till light paper electrometer sepa- 

 rates. A brass wire is suspended by silk, so as 

 to be made alternately to touch E and DC. 



Mon. Feb. 15 [1773]. Th. 55. N. 22. 



The cylinder AB and wire DC were elec- 

 trified negatively till the balls separated about 

 i diameter. On touching DC twice with the wire, 

 the corks separated about as much positively. 



The wire was 27-6 inches long and -15 in. 

 diameter. 



The cylinder AB was then taken away and 

 the plates D and E placed under the wire DC. 

 The wire was obliged to be changed for one 20-8 

 inches long to exhibit the same phenomenon. [See Art. 666.] 



Tu. Feb. 16 [1773]. Th. 57. N. 20. 

 Same exper. repeated. 



Cylinder touched twice with wire 31 inches long; changed from about 

 i diam. neg. to D pos. 



D and E with wire 24 inches D. 

 cyl. with wire 31 D. 

 cyl. with 27^ did not. [See Art. 666.] 



540] Lane's electrometer compared with straw and paper electrometers. 

 In the afternoon. Th. 56$. N. 19. I tried the distance to which the spark- 

 would fly by Lane's electrometer. 



Distance 

 [Lane] 



Knobs touched 

 027 

 038 

 044 

 047 

 051 



053 



038 



knobs at -965 inc. dist . 



Divisions on 

 electrometer -f- 



o+5 



+ 48 



i+ 5 

 i+ 15 



1 -I- 20 

 1 + 25 

 1 + 27* 

 i+ 5 



25 + 28 



Straw elect, sep. 1 + 3 

 2 + ij 



2 + 2\ 



2 + 3 



3 + oi 



3+ i 

 light paper elect, just sep. 



* [See Arts. 358, 606, and Note 25.] 



f [Revolutions and 6o"> parts of a revolution. One revolution = -038 inch.] 



