Cf ou7 
~» XTK. On Freezing of Alcohol. By Ricuarp 
Waker, sq. 
To Mr. Tiiloch. 
Sir,— By inserting the following remarks on ‘ Freezing 
of Alcohol,” in the next number of your Magazine, you 
will much oblige Your obedient seryant, 
KicHakD WALKER. 
Havince prepared a comparative scale of thermometers, 
for genera} circulation, of which you did me the favour to 
insert a copy in a ae number of vour Magazine, in 
which [ have assumed —9}° as the greatest degree of arti- 
ficial cold hitherto produced; it becomes necessary for 
me, I think, to make some observations respecting the 
Discovery of a New Method of producing Artificial Cold, 
by Mr. Hutton, of EF dinburgh; from which account we 
may be Jed to conclude that a cold of —110°, or there- 
about, has been effected. 
Knowing myself the great difficulty of effecting extreme 
degrees of “cold, I was not a little surprised at the extraor- 
dinary degree ef cold produced by Professor Leshe by 
means of the air pump. Consequently the discovery an- 
nounced by Mr. Hutton, in which the subject of cold is 
earried so far beyond what has hithert o been known, na- 
turally arrested my attention. 
Astonishing as the fact is to myself, not impeaching, 
however, in the least, the fidelity with which the author 
has related the result of his process; I shall beg leave to 
Mention a circumstance or two, in which scientific men of 
eminence have unintentionally delivered as facts, what 
they were afterwards convinced w Heh not so. 
_ A philosopher of celebrity in Germany, at the time the 
congelation of mercury was a novel experiment, published 
an account, which was credited, of a successful experi- 
ment, as he believed, in the congelation of mercury; but 
which, I well knew, could not possibly have been effected 
by the means mentioned. Some time afierwards I chanced 
to see this gentleman (Professor Blumenbach) : upon men- 
tioning the circumstance to him, he canduily declared to 
me, that he had been deceived ; and that he had announced 
his error in print*, 
* It once happened to me, in an attempt to freeze mercury, that through 
inadvertency a portion of the freezing mixture came in contact with the 
mercury, in consequence of which the mercury assumed a degree of tenacity 
which had the appearance of being partially frozen. 
; H3 More- 
