Intelligence and Miscellaneous Articles. 34 1 



through the air a distance of about ten feet, through a dormer win- 

 dow, breaking the sash, and scattering the fragments across the 

 street. It was evidently attracted to this point by the upper end of 

 a perpendicular gutter, which was near the window. It passed silently 

 down the gutter, exhibiting scarcely any mark of its passage until 

 it arrived at the termination, about a foot from the ground. Here 

 again an explosion appeared to have taken place, since the windows 

 of the cellar were broken. A bed, in which a man was sleeping at 

 the time, was situated against the wall, immediately under the bell- 

 wire ; and although his body was parallel to the wire, and not distant 

 from it more than four feet, he was not only uninjured, but not sen- 

 sibly affected. The size of the hole in the chimney, and the fact that 

 the lightning passed along the copper wire without melting it, show 

 that the discharge was a small one, and yet the mechanical effects, 

 in breaking the plaster, and projecting the window-frame across the 

 street, were astonishingly great. 



These, effects the Professor attributes to a sudden repulsive energy, 

 or expansive force developed in the air along the path of the discharge. 

 Indeed, he conceives that most of the mechanical effects which are 

 often witnessed in cases of buildings struck by lightning, may be re- 

 ferred to the same cause. In the case of a house struck within a few 

 miles of Princeton, the discharge entered the chimney, burst open the 

 flue, and passed along the cockloft to the other end of the house ; and 

 such was the explosive force in this confined space, that nearly the 

 whole roof was blown off. This effect was, in- all probability, due 

 to the same cause which suddenly expands the air in the experiment 

 with Kinnersly's electrical air thermometer. — From the Proc. of the 

 American Philosophical Society, June 20, 1845. 



OBSERVATIONS ON CAPILLARITY. BY PROF. HENRY. 

 In 1839, the author presented the results of some experiments on 

 the permeability of lead to mercury ; and subsequent observation had 

 led him to believe that the same property was possessed by other 

 metals in reference to each other. His first attempt to verify this 

 conjecture was made with the assistance of Dr. Patterson, at the 

 United States Mint. For this purpose, a small globule of gold was 

 placed on a plate of sheet iron, and submitted to the heat of an as- 

 saying furnace ; but the experiment was unsuccessful ; for, although 

 the gold was heated much above its melting-point, it exhibited no 

 signs of sinking into the pores of the iron. The idea afterward sug- 

 gested itself, that a different result would have been obtained had the 

 two metals been made to adhere previous to heating, so that no oxide 

 could have been formed between the surfaces. In accordance with 

 this view, Prof. Henry inquired of Mr. Cornelius, of Philadelphia, if, 

 in the course of his experience in working silver-plated copper, in 

 his extensive manufactory of lamps, he had ever observed the silver 

 to disappear from the copper when the metal was heated. The an- 

 swer was, that the silver always disappears when the plate is heated 

 above a certain temperature, leaving a surface of copper exposed ; 

 and that it was generally believed by the workmen, that the silver 

 evaporates at this temperature. 



