VOL. LXVIII.] PHILOSOPHICAL TKANSACTIONS. 337 



attention of the ablest philosophers. I am, sir, your majesty's most faithful 

 and most dutiful subject, 



Nov. 12, 1777. Benjamin Wilson. 



Nejv Experiments and Observations on the Nature arid Use of Conductors, by 

 Benjamin Wilson, F. R. S., of the Imperial Academy of Sciences at Peters- 

 burg, of the Royal Society at Upsal, and of the Academy of Institutes at 

 Bologna. 



The experiments I propose to give an account of in this paper, were made in 

 consequence of the accident from lightning, which happened to one of the build- 

 ings belonging to his majesty's magazine of gunpowder at Purfieet, on the 1 5th 

 ot May last. Soon after that event, an official and particular account having 

 been sent by the Board of Ordnance to the k. s., a committee of the members 

 was immediately appointed, to examine the damage done to that building, and 

 afterwards to make a report of the same. When that report was laid before the 

 society, I thought it my duty, in particular, to stand forth, and offer some 

 objections to the using pointed conductors at Purfleet, or indeed any where else. 

 This public proceeding was, I apprehended, the more necessary, as I had, on a 

 former occasion, in the year 177'2, declared my dissent from the report then 

 made by the committee, who had recommended sharp-pointed conductors for 

 that magazine, to be fixed 10 feetliigher than the respective buildings. But 

 though I had read the paper alluded to above, I did not apprehend that my duty 

 was fully discharged, without trying other methods of having so serious and 

 interesting a subject further inquired into. I had the satisfaction, soon after, 

 to meet with sufficient encouragement to induce me to consider of some experi- 

 ments, which might make the subject in dispute more intelligible. 



The plan I conceived to be the most proper for this purpose, was to have a 

 scene represented by art, as nearly similar as might be, to that which was so 

 lately exhibited at Purfleet by nature. To carry a design of that kind into 

 execution, it was necessary that attention should be given to the several circum- 

 stances concerned in the event at Purfleet. The most material of those circum- 

 stances I apprehend to consist in having a substitute for a thunder-cloud, as it is 

 vulgarly called, and large enough, or sufficiently long, to admit of being 

 charged with a considerable quantity of the matter of lightning by artificial 

 means; and also, that this substitute should admit of being easily moved, and 

 with any velocity the experiment required: or, at least, so as to equal the 

 motion of a thunder-cloud. An apparatus sufficiently large for these purposes 

 could not conveniently be put in motion: therefore I proposed to get rid of 

 this difficulty, by moving the building itself, instead of the substitute; as that 

 would answer the same end. In order to obtain a considerable charge of artifi- 

 cial lightning, I proposed to have one great cylinder covered with tin-foil, and a 



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