611 



similar, but less powerful, action is produced by the same cause on 

 the mass of the floe itself. 



In the artificial freezing of sea- water, the ice was found to be ver 

 tically striated, and often divisible into two or more layers, while 

 the under surface was always marked by fine lines intersecting each 

 other at definite angles. From the bottom of the vessel thin plates 

 of ice formed in the unfrozen liquid. They varied in length from 

 J in. to 2^ in., and contained less salt than the ice formed on the top. 



To explain the observation of Dr. Kane as to the freshness of ice 

 formed from sea- water under 30, the author supposes that it may 

 have depended on the freezing of a portion of sea-water which was 

 covered at the time of its congelation with a stratum of fresh-water 

 produced by the melting of bergs. On the 12th of April, 1857, 

 whilst lying off Brown's Island, within about 4 miles of a glacier 

 surrounded by bergs, the author observed a layer of fresh-water, 

 2 or 3 inches in depth, floating, like oil, on the surface of the salt- 

 water. To this cause he attributes the occasional occurrence of 

 hummocks from the upper portions of which ice perfectly free from 

 salt can be obtained, while on digging deeper into these hummocks, 

 the ice is always found to lose its freshness. 



III. " Inquiries into the Phenomena of Respiration." By ED- 

 WARD SMITH, M.D., Assistant-Physician to the Hospital 

 for Consumption, Brompton. Communicated by Sir B. C. 

 BRODIE, Bart, P.R.S. Received December 16, 1858. 



(Abstract.) 



The author gives in this communication the result of numerous in- 

 quiries into the quantity of carbonic acid expired, and of air inspired, 

 with the rate of pulsation and respiration, 1st, in the whole of the 

 twenty-four hours, with and without exertion and food ; 2nd, the 

 variations from day to day, and from season to season ; and 3rd, the 

 influence of some kinds of exertion. 



After a description of the apparatus employed by previous ob- 

 servers, he describes his own apparatus and method. This consists 

 of a spirometer to measure the air inspired, capable of registering 

 any number of cubic inches ; and an analytical apparatus to abstract 



VOL. ix. 2 T 



