802 Miscellaneous Intelligence, 
because heat is generated by pressure and by friction attending the ciren- 
lation of the hot liquid. Expansion and contraction for a given change 
of temperature are equal in amount and also in mechanical power, and 
both may rust. As 
the circulating liquid, the power causing the circulation is equivalent in 
amount of heat expended to the heat produced by the friction in the cir- 
culation, so that there can be no increase from this source. Since gravitar 
tion can 
s. 
7. Shower of Mud at Corfu.—Dr. G. Lawson describes a mud shower 
as having occurred at Corfu on the 2ist of March, 1857. ‘The day was 
squally and showery, and with the rain came down a light shower of 
mud which covered lightly the leaves of the trees and gant atc 
i i ; i und to 
Notes on American Land Shells, No. 4; by W. G. Brxyer, me 
Mr. Binney in thi 
catalogue of American Terrestrial Mollusks, with full lists of synonym 
which will be found of great convenience to all interested In this =e 
9. Memoirs of the Geological Society of reat Britain, and oe 
Museum of Practical Geology. The Iron Ores of Great Britain. ix 
rious analyses, made under the direction of Dr. Percy. | 64 PP. B70 
London, 1858.—The South Staffordshire iron works occur an 
collection being deposited there, with the prospect of its : ed neti0ds 
great convenience of the country, a medium of communi are sh 
and encour iso 
and general progress of the Institution the past nications 
