56 Prof. Thomson on some remarkable effects of Lightning. 



with reference to this point, and I received the following 

 answer : — " Moniemail, Cupar-Fife, 



Nov. 30, 1849. 



a • * J received your letter to-day, and immediately called 

 at Hall-hill, in the parish of Colessie, the farm-house which 

 had been struck by the lightning. * * 



" I find that Dr. Thomson's suggestion is fully borne out 

 by the facts. I at first thought that the bell- wire did not 

 run along the line of discoloration, but. I now find that such 

 was the case." * * 



[From a drawing and explanation which Mr. Leitch gives, 

 it appears that the wire runs vertically along a corner of the 

 room, from the floor, to about a yard from the ceiling, where 

 it branches into two, connected with two cranks near one 

 another and close to the ceiling.] 



" The efflorescence [the stains previously adverted to] was 

 on each side of this perpendicular wire. In some places it 

 extended more than a foot from the wire. The deposit 

 seemed to vary in thickness according to the surface on which 

 it was deposited. There was none on the plaster on the roof. 

 It was thinnest upon the wall-paper, and thickest upon the 

 wood facing of the door*. This last exhibited various colours. 

 On the thickest part it appeared quite black; where there 

 was only a slight film, it was green or yellow. * * 



" I may mention that the thunder-storm was that of the 

 11th of August last. It passed over most of Scotland, and 

 has rarely been surpassed for terrific grandeur, — at least 

 beyond the tropics. It commenced about 9 o'clock p.m., 

 and in the course of an hour it seemed to die away alto- 

 gether. The peals became very faint, and the intervals be- 

 tween the flashes and the reports very great, when all at once 

 a terrific crashing peal was heard which did the damage. 

 The storm ceased with this peal. 



" The electricity must have been conducted along the lead 

 on the ridge of the house, and have diverged into three 

 streams; one down through the roof, and the two others 

 along the roof to the chimneys. One of these appears to 

 have struck a large stone out from the chimney, and to have 

 been conducted down the chimney to the kitchen, where it 

 left traces upon the floor. It had been washed over before I 

 saw it, but still the traces were visible on the Arbroath flags. 



* These remarkable facts are probably connected with the conducting 

 powers of the different surfaces. The plaster on the roof is not so good a 

 conductor as the wall-paper with its pigments; and the painted wood is 

 probably a better conductor than either. — W. T. 



