ARTICLE XIV. 



E?igraving and Description of an Apparatus, and Process, for the rapid Congela- 

 tion of Water, hj the explosive Evolution of Ethereal Vapour, consequent to the 

 combined influence of Rarefaction and the absorbing Porver of Sulphuric 

 Acid. By Robert Hare, M. D. Read May 15, 1840. 



In a verbal communication to tlie society, made in December last, I alluded 

 to my having previously published a notice of a process for freezing water by 

 the vaporization of ether; in which the congelation was expedited by the em- 

 ployment of sulphuric acid to absorb the ethereal vapour. I afterwards pro- 

 ceeded to state that, by the interposition of a vessel previously exhausted of 

 air, with which a communication could be made by opening a cock, the pro- 

 cess had been still farther improved, so as to cause a vaporization of the ether, 

 and a freezing of the water, so rapid as to project the resulting ice against the 

 upper internal surface of the containing vessel with a violence quite audible, 

 as well as visible, to a large audience of my pupils. 



