824 Aft". nAikne’s Experiments to Jhew the 
tal, and thence continue it down along the lide of the 
wall to any kind of moifture in the ground^. 
Others again are of a direCtly contrary opinion; 
thinking a conductor fhould not only terminate in a 
point, but be confiderably elevated above the higheft 
part of the building^. 
As it moll; certainly would be of great confequence to 
mankind to know which is the molt eligible of thefe 
opinions, I have attempted, by what I could learn from 
the artificial lightning of our electrical machines, to de- 
termine which method is belt to fecure buildings from the 
effects of lightning : whether I have fucceeded I leave to 
the judgement of others to decide from the following 
experiments and obfervations, which are fubmitted with 
all due deference. 
In pi. xiii. fig. r. is a reprefentation of the elec- 
trical machine and the apparatus ufed in the following 
experiments. The diameter of the glafs cylinder a, fig. 
i. was eighteen inches; the length of the conductor b, 
which was of wood covered with tin-foil, was fix feet, 
and the diameter of it one foot. At the end of this con- 
ductor was fcrewed a brafs ball c, of four inches and a 
half diameter. This conductor, when charged by the 
(b) Mr. Wilson’s Letter to the Marquis of Rockingham, Phil. Tranf. 
Yol. LIV. p. 247. 
(c) Ibid. p. 203, 
glafs 
