Charges on coated plates of different substances 221 



With small trial plate. 



P +28 did not. 



+ 36 did. 



Q 4- o separated rather more. 



O +9 sep. a little. 



+ 18 sep. about as much as Q at o. 



N +28 sep. a little. 



These experiments were tried in the morning. In the afternoon hygrometer 

 corks closed in about 30 seconds. 



460] The plate B was coated with a circle 279 inches diameter, computed 

 power = 40, and the plate D was coated with a circle 2-73, computed power = 46. 



A piece of the white glass was also coated with a circle 2-85 in. diameter 

 where the thickness was -182, computed power 44-6. 



They were tried with the same trial plates. 



With large trial plate. 

 D + o sep. neg. 



+ 3 very little, rather doubtful. 

 B +33 very little. 

 N +21 very little. 

 D + 3 rather doubtful. 



With small plate. 



B +48 very little. 



D +15 do. 



N +39 do. 

 White + 32 sep. a little pos. 



B +48 did not quite sep. 

 White + 18 nearly same as B. 



+ 24 sep. supposed nearly same as ist time. 



N +27 sep. very little. 



+ 30 nearly same or rather more than W at 24 with large plate. 



N +14 sep. a little neg. 



W + 10 do. 



B +32 do. 



W + 8 do. 



N +14 do. 



461] The plate A was coated with a circle 2-16 inches diameter, computed 

 power = 22-6 ; a plate of rosin also, the first which was pressed out after hard- 

 ening, was coated with a circle 2-51, thickness -102, computed power = 2-51*; 

 they were tried with the trial plates described in p. 16 [Art. 457]. 



Tried with small plate. 

 Rosin + 19 sep. a little pos. 



A + 36 do. 



Double plates A & B + 36 do. 



Rosin + 16 do. 



* [Should be 61-7.] 



