156 



were seen accurately. This occurred in a gentleman who was 

 labouring under catarrhal inflammation of the conjunctiva, and 

 ceased with the removal of the disease. 



Dr. Hare made the following verbal communications. 



For effecting the congelation of water by the evaporation of ether, 

 it had been usual to expose a bulb, containing water and moistened 

 by the ether, to a current of air. Recently Dr. Hare had succeed- 

 ed far more satisfactorily by exposing a quantity of water, twenty 

 times as large as that usually employed, covered by ether in a capsule 

 to a blast of air, proceeding from a vessel in which it had been con- 

 densed by a pressure equal to one or two atmospheres. By these 

 means, the freezing of the water might be seen by five hundred spec- 

 tators. 



Having mentioned that the pure hyponitrous ether recently obtained, 

 caused a cold of 15° by its evaporation, it would of course be inferred, 

 as he had found to be the fact, that this last mentioned ether might 

 be advantageously employed. 



When hydric ether is employed, it should not exceed 730 in spe- 

 cific gravity. 



Dr. Hare further said, that it would probably be remembered, 

 that about two years since, he had published an account of a new 

 process for freezing water by the evaporation of ether, caused 

 by a diminution of atmospheric pressure. In the process then 

 described, concentrated sulphuric acid was interposed between the 

 retort holding the water and ether, and the air pump. Since that 

 time he had rendered the process more rapid and interesting by 

 interposing an iron mercury bottle, with two cocks between the re- 

 ceiver holding the acid and the pump. The ether and water were 

 introduced into the retort. The beak of the retort, pi-operly bent, 

 entered the receiver, through the tubulure to which it was luted. 

 The beak was of such a length and curvature, as to cause its orifice 

 to be below the surface of the acid. The neck of the receiver com- 

 municated with the cavity of the bottle, that of the bottle with the 

 pump. The apparatus being thus arranged, the bottle was exhausted, 

 and the cock, communicating with the pump, closed. Under these 

 circumstances, on opening a communication between the bottle and re- 

 ceiver, the pressure in that vessel and in the retort was so much 

 reduced as to cause the instantaneous ebullition of the ether, so that 

 little, if any subsequent aid, was required from the pump. But the 



