Chemical Science. 461 



lightning roll on the earth near the lightning-rod. Tlie chimney 

 nearest to the lightning-rod was much broken above, as was 

 also the hearth beneath, from whence upwards two lines of tiles 

 were shattered to pieces. Within the roof two pieces of car- 

 pentry were broken to pieces at the place where an iron bolt had 

 fastened them together, and from this spot the course of the 

 lightning could be traced by its effects to the place where it 

 had struck the domestic (one of the three before spoken of) 

 on the shoulder and thence to the ground, and the courses also 

 of two other branches of the lightning, one within, and one on 

 the roof of the house, could be traced. 



The effects on the lightning-rod were as follows : — ^The brass 

 point was slightly fused, but the iron head, being very strong 

 and solid, had not been affected. The conducting wire of iron 

 was three lines in diameter, and at the place where it commu- 

 nicated with the iron head, had been heated red hot for the 

 length of a fathom (brasse) as was proved by the black colour 

 it had evidently very recently assumed, and by the softened or 

 annealed state of the metal : still more decided marks of a red 

 heat were found on the iron wire, which descended along 

 the trunk of an apple-tree, and which was only two lines in 

 thickness. The earth in this place had been moved, and not- 

 withstanding the heavy rain which had fallen, the part at the 

 foot of this tree was dry though covered with verdure. 



Hence it appears that the lightning had first descended entire 

 on the conductor, but, that the wire being too small to convey 

 the whole current away, the electricity divided there into several 

 portions ; the larger, probably, of these was led off by the con- 

 ductor heating the wire in its passage ; and the circumstance 

 that the upper wire had not been heated red near the roof may 

 be explained by supposing a portion of the electricity to be 

 dissipated on the roof itself. The second wire, forming the 

 continuation of the conductor was much thinner than the first, 

 and passed down over the trunk of the tree. In consequence 

 of its smallness it was more highly heated, and had, with the 

 electricity, carbonized the part of the tree over which it passed. 

 The earth at the foot of the conductor, being dry and sandy, 



