12 5 
the Production of artificial Cold. 
It appeared reasonable to expect that the power of this salt for 
producing cold, might be assisted by the combination with, or 
addition of, other salts, as has been found to be the case in other 
instances, to a considerable degree ; and, conceiving from my 
former experiments, that the muriate of soda and nitrate of am- 
monia promised the greatest success in this way, these alone 
producing with snow a cold of — 25 0 , I was naturally led to 
combine these with the muriate of lime; but I obtained no 
advantage by this, or by any other means, worth noticing.* 
In the course of last winter, and the summer preceding, I 
repeated my former experiments with more accuracy; and like- 
wise made some additional ones, on the power of muriate of 
lime for producing cold with ice, the result of which I shall 
here briefly state. 
In order to reduce the experiments made with the muriate of 
lime to a greater certainty, I carefully obtained the respective 
specific gravities to which this salt should be reduced by eva- 
poration, before it be set by to cool, in order to become solid, in 
either instance : thus, when the muriate of lime is to be of that 
strength which is to be prepared and used at the temperature 
of -j- 32 0 , the specific gravity of the liquor should be, at the 
temperature of 8o°, 1,450; and when of that strength to be 
• M. Van Mo ns tried the effect of the caustic soda (which alone produces a cold 
— i5°with snow) combined with the muriate of lime, and found the effect increased 
very considerably. By this means, he says, « In my new experiments on the effects of 
te artificial cold, I have carried itto — 53 0 , old division” ; (viz. 87° of Fahrenheit.) 
He does not mention the temperature at which the materials were mixed, to produce this 
effect. — M. Van Mo ns effects a chemical union of these two salts thus : he slakes 
quicklime with a solution of muriate of soda this mixture, when become cold, he 
filters, and afterwards evaporates, until when cold it will become solid, Annales de 
Cbimie. Tom. XXIX. 
