396 Foreign and Miscellaneous Intelligence. 



dred and fifty feet wide, the length enclosed by the wall is four 

 hundred and eighty feet, the width three hundred and sixty feet. 

 The prison has three conductors on it, about equidistant from each 

 other, say eighteen feet. The lightning passed down each of these 

 without any injury to the building, except starting a few slates near 

 the ridge post. Now what appears singular in this case is, that no 

 person out of nearly three hundred officers and convicts was in the least 

 injured, although almost every one was more or less affected by it. 

 Nearly all of these persons had either a steeled hammer, a musket 

 with bayonet fixed, or some metallic utensil in their hands. Within 

 a yard of my situation is an armory with thirty guns and as many 

 steel-pointed pikes, the points and bayonets pointing up. I can 

 account for our escape only by supposing that the fluid was attracted 

 by so many different objects on all parts of the building, and all 

 over the yard, that it divided itself just before it reached us, and 

 passed off in such small quantities as almost to lose its effects. It 

 is singular that men standing five hundred feet distant from me 

 should be affected in the same degree. I suppose that one hundred 

 tons of iron "are exposed on the different buildings in grates, doors, 

 pillars, &c. &c. One of the officers had a saw in his hand, which, 

 he says, seemed to be " light red fire." Another was stooping and 

 picking up nails from the floor, and the instant after the flash found 

 himself standing bolt upright, with his hands tightly clenched to- 

 gether. The effects of this shock were felt over a surface of one 

 hundred and seventy^two thousand five hundred feet in nearly the 

 same degree, without any permanent injury being sustained*.' 



3. BECQUERE^/'ON THE ELECTRIC EFFECTS PRODUCED BY SEAT 

 AND PRESSURE. 



M. Becquerel has lately examined the changes which take place in 

 the electric state of bodies by the action of heat, contact, pressure, &c. 

 of which the following is an abstract : It has been long known that 

 if a body, which receives positive electricity by friction with another, 

 be raised to a high temperature, it gradually loses this power, and at 

 a certain temperature receives negative electricity. 



Iceland spar, which is positive when rubbed with any substance, 

 becomes negative when its temperature is sufficiently raised. The 

 author expected to find the same property in different metals re- 

 garded as electro-positive and electro-negative. He expected that 

 caloric, by separating the atoms of metals, would produce similar 

 effects with cleavage in crystallized bodies. When the plates of mica, 

 or sulphate of lime, are suddenly separated by cleavage, the parts 

 thus separated are found to be in opposite electric states. If the 

 parts thus separated be again pressed together and suddenly sepa- 

 rated, they are again found in the same electric states, and the 

 difference in those states is more marked as the temperature is 



* Silliman's Journal, xvii. 193. 



