270 Journal of Experiments, March, 1773 



the bulb. The tube was coated 3-4 inches from the ball with gummed paper 

 dipped in salt water and bound on with iron wire. This ball was placed in a 

 glass of $ surrounded with iron filings and placed on machine near M, and 

 heated by a spirit lamp, the $ in which the ball was immersed being made to 

 communicate with the ground, and a bit of iron wire bound round the wire Mm 

 being dipped into the $ in bulb. 



The crown glass plate * and the plate A of Nairne, which was coated 

 as a sliding plate, being put on negative side. 



The I st column being the number of square inches which it was necessary 

 to give to the coating of the sliding plate in order that the balls might sep. 

 pos. and the 2 nrt column that they might sep. neg. The charge of the crown 

 glass plate being equal to that of the sliding plate when its coated surface is 

 33 square inches. 



Tu. Mar. 23 and Wed. Mar. 24. [43 obs. Art. 649.] 



557] Allowance for connecting wires in p. 86. [Art. 554.] 



The allowance to be made for the charge of the connecting wires was en- 

 deavoured to be found by suspending the two circles of 9-3 inc. horizontally 

 by silk lines at n inches distance from each other and finding their charge by 

 means of the forked electrifying wire as in 1772 p. 7 [Art. 472], both when the 

 plates were connected by a wire similar to that used for connecting the rosin 

 plates, and without any connection. 



The event was as follows. 



Fr. Mar. 26 th [1773. 8 obs. See Art. 647.] 



2 i 

 Therefore the plates contain about J square inc., or 1-41 inc. el. more with 



the connecting wire than withoutf- 



Sat. Mar. 27 [1773]. 



It was tried by usual machine whether the 4 rosin plates contained more 

 el. when at a distance than near. The trial plate B id est the largest trial plate 

 used for D & a being placed on neg. side. 



* [So in MS.] f [See Art. 647.] 



