The Endeavour Journal of Joseph Banks 1768–1771 [Volume Two]
Octr 25. 1768. 17 Miles south of the line — Mr Greens machine
Octr 25. 1768. 17 Miles south of the line
Mr Greens machine
The machine was made by Watkins;1 it workd with a flat plate of Glass inches in diameter; the Jar was of Glass 8 inches high and 7 deep coated with varnish between the Lead and the stopper which was of cork, no varnish comeing between that and the neck; the Electrometer was divided into 30 parts which containd 1 inch and ⅛.
 The plate at first refusd to go round as mine had before done the cushions being drawn together by the Glass which they seemd to adhere to probably from their dampness. After some time turning however this went off and in about 10 minutes Electripity was excited.
The Electrometer was then applied which went off at No 7.
2 Electricity was kept in the Phial 30 seconds without loosing any sensible part
3 a hole was struck through two cards by the discharging wyer.
4 Shocks were given to several people much greater than any that could be Given by my machine.page 279
5 the Phænomenon of the floor cloth proving a conductor was tried more fully than before. A wyer (b) was passd round the Phial (a) the two ends of which were taken hold of by two people (cc) who each took hold of another person (dd). The operator (e) then touched the Phial with his discharging wyer and receivd the shock through both his arms as did (cc) and (dd) sometimes, tho at others (dd) felt it only in the arms by which they held (cc). The comparative force of the blows which each felt was very dificult to ascertain but we supposd that (cc) felt more than (dd) and probably the operator most of all.
The chief reason why this machine workd better than mine seems to me to be that the bottle was coated with varnish between the stopper and coating of Lead. This probably did not condense the damp of the air near so readily as Glass and consequently the machine workd well when mine refusd to work at all.
1 Presumably F. Watkins, a London instrument-maker, of whom little seems to be known.