374 WRITINGS OP JOSEPH HENRY. [1855- 



the disc of wax were placed above the man's head while in 

 the standing position it would not screen the repulsive energy 

 in the cloud, which like gravitation acts through all bodies; 

 the induction would take place as before, the head would 

 become highly negative, while the natural electricity which 

 had been driven down would escape into the earth. The 

 effect would therefore be the same as if the individual were 

 standing on the earth without the intervention of the non- 

 conducting material. A descending bolt would be attracted 

 towards the head, and if the tenacity of the bees-wax were not 

 sufficient to withstand a disruptive discharge, the body would 

 be injured. From a mis-apprehension of these principles 

 it has been supposed that the protection is increased by 

 a slight covering over the body of silk or feathers, or by in- 

 terposing a plate of glass between the sky and body; but 

 it is well known that fowls and other large birds are struck, 

 the slight covering of feathers affording no protection while 

 the feet are in connection with the earth. 



From the conducting capacity of the soot usually lining 

 a chimney, and of the smoke and heated air which ascend 

 from the flue, it will be clear that the vicinit}' of the fire- 

 place during a thunder-storm is not the safest position that 

 may be chosen in a house. A person leaning out of an open 

 window may also not be in a very safe position, because the 

 outside of the house, wetted with rain, will be rendered a 

 partial conductor, and a descending charge along the wall 

 may reach the body projecting beyond the surface. The in- 

 duction is always greater where there is a large amount of 

 conducting material, hence barns filled with damp hay will 

 be more liable to be struck than when empty. Besides the 

 action of induction in this case, it is generally supposed that 

 the danger is increased by the ascent of vapor from the 

 barn at the season mentioned ; and this supposition, which 

 is in accordance with scientific principles, is apparently 

 borne out by observation. 



On the principle of the increase of induction in the col- 

 lection of a large number of conducting bodies in a given 

 space, the assemblage of persons in churches, or other places 



