494 On.artificial Cold, 
hyperbole. The climate, too, has disagreed with me and 
all the gentlemen of my mission,-so that ‘I have been obliged 
to solicit H. R. H. the Prince Regent’s gracious permission 
to allow me to return to Engiaad}} in the: spring of 1814, 
Gore OUSELEY. 
LXXI. On artificial Cold. By Ro, Waker, Esq, ; 
To Mr. Tilloch. ad 
Srr,— Prrcervine that the experiments on artificial cold, 
as prosecuting by several philosophical gentlemen, at this 
time, excite a considerable degree of interest, and as the 
most favourable season of the year for pursuing such inve3- 
tigation is approaching, viz. January ; I beg leave to pre- 
sent a brief description of the means I should adopt, were 
Tat leisure, and possessed of a proper apparatus for the 
‘purpose. 
I ‘ahold attempt to combine all the known powers of pro- 
ducing artificial cold, thus : Procuring an apparatus, which 
I stippose might be “éoristtweted, in which the power of 
-condénsing the air, and likewise of rarefying it, were com- 
bined in the same glass vessel, or receiver as it is called, I 
should proceed thus : 
The subject, alcohol, or any thing else, to be submitted 
to the experiment, being contained in a convenient glass- 
tube, or bulb, covered with a single stratum of fine lint, and 
this placed, in an appropriate cup, containing a portion of 
sulphuret of carbon, within the glass receiver—This glass 
receiver is then to be cooled as much as possible, or as 
much as is convenient, in a freezing mixture, contained 
in a vessel adapted to the purpose. 
When the freezing mixture has produced its full effect, 
removing this, the tube, or bulb with a tube to it, immersed 
in the sudphuret of carbon, is to be raised out, and imme- 
diately, and as expeditiously as possible, the condensed air 
first let out, and then the air, still remaining in the vessel or 
receiver, barehed as much and as expeditiously as possible, 
by means of the rarefying power attached to it — Thus 
changing the air in the receiver,as quickly as possible, from 
a state of exlreme condensation to that of extreme rarefacs 
tion. I am, sir, 
Your obedient servant, 
Oxford, Dee, 13, 1813. Rp. WALKER. 
LXXII, Oz 
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