[ 241 3 
XIII. An Account of "Experiments made by Mr. John M c Nab, 
at Henley Houfe, Hudfon’s Bay, relating to freezing Mix + 
tures . By Henry Cavendifh, Efq* F* JR* $• and A * S. 
Read February 23, 1786. 
IN my obfervations on Mr. Hutchins’s Experiments* 
A printed in the LXXIIId volume of the Philofophicai Tran- 
fa£lions, I gave my opinion concerning the caufe of the cold 
produced by mixing fnow with different liquors. As there 
were fome circumftances, however, which feemed to form a 
difficulty in the way of this opinion, I was defirous of having 
further experiments made on the fubjeft; and at the fame 
time I thought that, by proper management, a greater 
Degree of cold might be produced than had hitherto been 
done. On mentioning the experiments I wifhed to have 
made to Mr. Hutchins, he very obligingly defired Mr. 
M c Nab, Matter at Henley-Houfe, to try them; who was fo 
good as to undertake the bufinefs, and has executed it in the 
moft fatisfa&ory manner ; as he has not only taken great pains* 
but has (hewn the utmoft attention and accuracy, in obferving 
and relating all the phenomena which occurred, and has mani- 
fefted great judgement in frequently adapting the manner of 
trying the experiments to appearances which occurred in for- 
mer ones, to wliich we are indebted for great part of the moft 
curious fa£is in this paper. His endeavours have alfo been 
attended with much fuccefs, as he has not only fhewn many 
remarkable circumftances relating to the freezing of the nitrous 
Vol. LXXVL . I i and 
