McFAIT'S EXPERIMENTS IN 1752 307 



matter most copiously ; and from thence supposes, that a very sharp-pointed rod, fixed to the 

 extremity of the top-mast of a ship, with a wire conducted down from the foot of the rod 

 round one of the shrouds, and over the ship's side into the sea, would silently lead off the 

 electrical fire, and save the ship from thunder in hot countries ; and that, by a similar method, 

 buildings might be preserved. 



"So useful a proposal deserves to be examined: variety of experiments may give hints 

 for new improvements. For this reason the following observations are communicated, though 

 not so complete as might be wished, being the result of one trial only. 



"It seldom thunders in this northern clime. In June, 1752, there seemed to be some 

 thunder at a distance from Edinburgh; but from the beginning of July to the beginning of 

 October we had nothing almost but continual rains. The last summer was uncommonly warm 

 and dry; and yet we had only a few claps of thunder at Edinburgh, one evening, and my 

 attempts for making any of those experiments were entirely unsuccessful until Saturday night, 

 September 15, when we had a very great storm. 



" I used a round iron rod, two-tenths of an inch diameter, about eleven feet long, 

 sharpened at one end ; the other end was inserted in a glass tube, and that tube stood in a 

 common glass bottle, which I held in my hand. 



"I used also another rod about three feet long, sharpened in like manner at one end, 

 which stood with the other end in a glass tube, which was stuck in the ground. I began 

 upon the Gallon Hill. The lightning and fire in the air abounded greatly, and yet it was 

 some time before anything else appeared. At last some rain began to fall, and the air 

 turned moister; then fire appeared upon the extremities of each of the rods in a small pretty 

 blaze, very like the fire which is discharged from the point of a sword in the dark, when the 

 person that holds it is electrified, and stands upon glass or resin; or like that which appears 

 upon any sharp point, when presented to an electrified gun barrel, but in greater quantity. 

 I touched the long rod with my finger, but had no sparks from it. The short rod was 

 accidentally taken out of its tube, and yet continued to burn and blaze as formerly. In like 

 manner the flame continued upon the end of the long rod, though I took hold of it anywhere 

 at pleasure above the glasses, until I moved my hand or finger along, within a few inches 

 of the flame; then it was attracted by my hand, and vanished. 



" I went from the Calton Hill to the Castle Hill, at the other end of the town ; and in 

 passing through the streets no fire appeared upon either of the rods; but almost immediately 

 when I got clear of the houses, upon the open hill, the point of the longer iron rod took 

 fire. In the dark I had lost the tube belonging to the shorter rod, and the point of it did 

 not catch fire when the longer one was kindled. Perhaps I did not wait long enough for a 

 proper trial, for I soon touched the flame upon the long rod with the sharp point of the 

 short one, and then it also took flame, and continued burning, as before, without any further 

 dependence upon the longer one. 



" I held the shorter rod by the sharp end, and approached the blunt end of it to the 

 flame upon the point of the longer rod ; then this blunt end caught the fire, and the flame 

 upon the points of the two rods continued rather stronger than on the single one before, so 

 long as I kept them in contact, and the fires within three or four inches of one another ; but 

 when I drew them farther asunder the flame upon the extremity of the blunt rod vanished. 

 This happened as often as I tried it, and it is evident that in like manner I could have got 

 the fire to fix upon the points of a great many rods, and so have had them all flaming 

 together. Once or twice a flash of lightning seemed to dart directly against the point of 

 the rod; then the fire, as I thought, expanded itself and united with the lightning, but it 

 immediately began to shine again when the lightning was past. 



