1878] WRITINGS OP JOSEPH HENRY. 531 



ing sparks and flashes between different objects within the 

 premises. 



7. If the discharge passes through metallic conductors and 

 disintegrates them, note any appearance which might tend 

 to indicate whether the effect is produced by heat or bv 

 repulsive energy imparted to the atoms at the moment of 

 the discharge. 



8. If the discharge takes place between two surfaces, note 

 if there is any apparent transfer of material from one to the 

 other. 



9. Note any peculiarity of odor that may be observed. All 

 mechanical effects produced by the discharge should be men- 

 tioned, and special notice taken as to whether they are not 

 in most cases produced by a violent repulsive energy given 

 to the air in the path of the discharge, and whether the 

 effects are greater in the direction of the axis of the dis- 

 charge than in that at right angles to the same. 



10. Note the effect upon man and animals ; whether a 

 part of the discharge passed through the body, or whether 

 inductive shocks were felt. 



A Notice of Two Thunder-Storms. — The following account of 

 two thunder-storms which occurred last summer may per- 

 haps be thought worthy the attention of your society, and 

 of a permanent record in a scientific publication. 



The first one I shall describe, and of which I had an 

 opportunity to examine the effects, occurred at New London, 

 Conn., where a violent discharge of electricity took place on 

 the premises of Mrs. Alger, of that city. Mrs. Alger's house 

 is situated on an elevation overlooking the river and the 

 surrounding country, on one side of a lawn on which, at a 

 distance of 150 feet from the dwelling, stood a tall flagstaff 

 ninety feet high. Across this, at about twenty feet from the 

 top, was a spar like the yard-arm of a ship, which was braced 

 by two iron rods, joining the top of the mast with the two 

 ends of the cross-piece. The lightning struck the mast, and 

 brought the whole down to the ground. The upper part, 

 including the cross-piece, came down unbroken, it being 

 probably protected by the iron rods. The remaining seventy 



