62 MR. WILLIAM STURGEON ON LIGHTNING 



one o( the angles. The Ughtning descended along the tower 

 about 49 feet, and afterwards made its way across the roof of 

 an attached building, in order to arrive at a cast-iron water- 

 pipe, by means of which it found its way to the ground. 

 The distance between this tube and the angle of the tower 

 first struck, is about 56 feet. The distance between the 

 nearest lightning-rod and the angle struck, is about 152 feet; 

 but as the roof of the building to which that conductor is at- 

 tached, is 34 feet lower than the top of the tower, the latter 

 is considerably more lofty than the point of the conductor. 



1 1. Case D. — The powder magazine at Bayonne, which 

 was guarded by a conductor of the most perfect kind that 

 the philosophy of France could suggest, was injured by 

 lightning, February 23, 1829. The building is about 

 17^ yards long, and about 12 yards broad. Its gables are 

 covered with large plates of lead securely joined together, 

 and to others which cover the ridge of the roof. The 

 gutters around the roof are also of the same metal. The 

 conductor, which was an iron rod, pointed at its upper end,* 

 rose to the height of about 19 feet above the roof. It 

 passed through a leaden socket, attached by solder to one 

 of the leaden plates that covered the ridge of the roof, by 

 which means the whole of the metallic parts of the roof 

 were in communication with the conductor. 



The lower part of the conductor, instead of proceeding 

 jnto the ground at the foot of the wall, in the usual way, 

 was bent at right angles about 2g feet above the ground, 

 and continued in a horizontal direction, supported on 

 wooden posts, to the distance of about 10 or 11 yards, where 

 it was again bent at right angles downwards, and entered a 

 pit two yards square, partially filled with bruised charcoal. 

 The sides of the pit were sustained by masonry, having 



* As the Koyal Academy of Science had recommended the use of pla- 

 tinum wire for the superior termination of conductors, it is probable that 

 this conductor was surmounted in that manner. 



