APPENDIX 



ELECTRICITY 



25th October 1768, about five miles south of the line. 

 My machine was made by Bamsden, and worked by a flat 

 plate 8 inches in diameter. The phial used was 6j inches 

 in height and 5|- in diameter without the neck ; the distance 

 between the stopper and the coating, 3 inches, the stopper 

 made of wood and fastened to the glass on the inside by a 

 red cement (probably sealing-wax). The electrometer was 

 divided into thirty parts of 1|- inch as nearly as possible. 

 About nine in the morning the machine was set up, the day 

 being rather cloudy, and the ship going between three and 

 four knots. 



When the plate was first turned round the cushions 

 appeared to be damp, adhering to the glass so much that it 

 was with difficulty made to move very slowly, although the 

 cushions were screwed on as tightly as possible. After 

 wiping them very well the plate was made to go round, 

 and in about ten minutes electricity was excited, though 

 but in a small degree ; the motion of the ship and the shaking 

 of the table, caused by turning the machine, made the 

 electrometer (which was a very unsteady one) move back- 

 wards and forwards visibly, so that it was impossible to 

 ascertain exactly at what distance it discharged the phial, 

 it however was guessed to be about a line when at the 

 greatest distance. 



It continued to work in this manner about half an hour, 

 in which time several attempts were made to give a shock, 

 but they succeeded very badly, the shocks being very slight, 



