best Methods of producing artificial Cold. 287 
some of the same ether, but which had been purified by agi- 
tating it with eight times its weight of water, applied exactly 
as in the last experiment, the thermometer sunk to 12 0 . Water 
tried in the same manner, at the same temperature, sunk the 
thermometer to ^6°. 
A whirling motion was given the thermometer during each 
experiment. 
The lint was renewed for each experiment, and the bulb 
required to be dipped into the ether thrice ; the first time suf- 
ficiently to soak it, after which the thermometer was held at 
the window till it ceased to sink ; then, a second quick immer- 
sion, and likewise a third, exposing the thermometer in like 
manner after each immersion. 
In this manner a little water in a small tube may be frozen 
presently, by good ether not purified, at any time, especially if 
a small wire be used to scratch or scrape the sides of the tube, 
below the surface of the water. 
During the warmest weather of last summer I frequently 
froze water in this way. 
EXPLANATION OF THE PLATE. (Tab. XXIII.) 
Fig. i. is a vessel in one piece, open at the bottom ; a, a, 
the body, holding inverted two pints ; b, the tube, holding five 
ounces ; the lower or smaller part (formed by a contraction, 
or lessening of the tube in diameter, merely for the purpose 
of leaving a small shoulder for a temporary partition), holding 
rather less than one-fifth of the whole. 
Fig. 2. is a vessel consisting of two parts; a, a, the body, 
P p 2 
