On Cooling Wines. 
[Auct, 
*J42 
III . — On Cooling Wines. 
Cool wine in a climate like that of India being so great a luxury, we cannot doubt 
that the re-publication of the following letters by Dr. Walker of Oxford, on the artifi- 
cial production of cold, as taken from the June and July numbers of the Philosophi- 
cal Magazine, for 1828, will be generally acceptable. 
To the Editors of the Philosophical Magazine and Annals. 
Guntlemf.n, 
It is now forty-one years since my discoveries on the “ artificial production of 
cold,” were first made public by their appearance in the Philosophical Transactions 
for the year 1787, and several succeeding volumes. Passing over what has already 
been published respecting them, I shall proceed to a detail of a few other circum- 
stances as a kind of appendix, which I have for several seasons intended to offer for 
publication, had not other matters, as professional avocations and professional com- 
munications, too much engaged my attention to allow of it. 
Immediately on the announcement of the discoveries, as above stated, I received 
various proposals from respectable persons respecting their practical utility in this 
country. I answered these by a declaration that wherever natural ice could be ob- 
tained and preserved, this must ever supersede the use of the artificial means allud- 
ed to. It is true, that I bad an eye to their application in hot climates, as between the 
tropics ; and so soon as my experiments became public, a treatise on the diseases 
of tropical climates appeared from the pen of Dr. Mosely, who fixed upon one, which 
he considered the most appropriate, and strongly recommended its adoption as a 
very valuable acquisition, as well in a medicinal point of view, as a luxury. 
Relinquishing, from various causes, the design of applying them myself to any 
such purpose, I took care, however, to point out, in my original communications, 
the complete efficiency of them for such intention to their utmost extent, and the 
best mode, as it appeared to me, of applying them in hot climates. 
Understanding a few summers ago, that a manufactory had been established for 
preparing ice creams, as well without the use of ice, as with it, and likewise for 
making for sale an apparatus for the purpose, — I was induced to visit it. I exam- 
ined the apparatus,— a very appropriate one for the purpose, and likewise the freez- 
ing powder, which I instantly recognised to be the weakest in power of my various 
compositions for the purpose, hut possessing the advantage of being readily recover- 
ed repeatedly for the same purpose with undiminisbed efi'ect. This powder, by its 
taste and appearance, I found to be a mixture of sal ammoniac and nitre, which I 
was informed was repeatedly recoverable in a fit state for refrigeration. I original- 
ly exerted every effort, in vain, to increase its power by the addition of a third in- 
gredient, possessing likewise the advantage, merely by evaporation to dryness, of 
being repeatedly recovered for the same use. This powder, as related in my origi- 
nal communications, consists of equal parts by weight of sal ammoniac and nitre. 
By way of test, I recovered it by evaporation twelve times, without any abatement 
of its efficacy, as originally stated. 
It is unnecessary to enter into a description of the apparatus just mentioned, or 
the principle and mode of its application, especially as the whole is embraced in the 
following statement. A circumstance occurred here (at Oxford) which occasioned 
tlie method to be put to the test of useful application. A confectioner, happening 
in a scarce season to be unprovided with natural ice, applied to me for assistance. 
I assured him that in the large way (as I have stated in my original communica- 
tions) the best method was to freeze water first, and then to use the ice in the usu- 
al way for freezing creams. Accordingly an apparatus of large dimensions, of ra- 
ther an oblong form, was made of tin, (fitter for the purpose if cased with wood,) 
consisting of channels so constructed that the water to be frozen should be subject- 
ed to the freezing mixture on both sides. This, properly prepared, was placed in a 
cool cellar during the night, and early in the morning (the temperature in the open 
air in the shade in the day time being above 80°) the ice w as collected, which 
amounted to several pounds in weight. This ice, which was as limpid as the finest 
flint glass, was applied in the usual way, and with the apparatus ordinarily used by 
confectioners for the purpose of freezing creams ; and the mixed powder, of which 
he had procured an adequate quantity, repeatedly recovered by evaporation over his 
hot iron plates, for fresh use. 
I shall now present the immediate object of my present communication ; viz. what 
I consider to he the best mode and fittest apparatus for cooling wine in summer, 
