5 1 8 Mr. cavallo’s Account of 
ratus necefiary for this purpofe, viz. a bottle capable of con- 
taining about one ounce of ether, two pointed tubes (in cafe 
that one ffioukl break) a tube in which the water is to be 
frozen, and the wire. With the quantity of ether contained 
in this fmall and very portable apparatus, the experiment, 
when carefully performed, may be repeated about ten times. 
A perfon who wifhes to perform fuch experiments in hot cli- 
mates, and in places where ice is not eafily procured, requires 
only a large bottle of ether, befides the fmall apparatus de- 
Jfcribed above. 
It is a known faff, that the moment a quantity of water 
becomes ice, a thermometer kept immerfed in it, rifes a few' 
degrees, and accordingly this is obferved in our experi- 
ment, viz. the mercury of the thermometer, which is im- 
merfed in the water of the tube AB, will fuddenly rife, fome- 
times as much as ten degrees, when the water becomes fir ft 
opaque. Electrization increafes very little the degree of cold 
produced by the evaporation of ether. Having thrown the 
eleCtrified, and alfo the unele&rified, ft ream of ether upon the 
bulb of a thermometer, the mercury in it was brought down 
two degrees lower in the former than in the latter cafe. 
o 
As various perfons may, perhaps, be induced by this paper 
to repeat fuch experiments, and as ether is a fluid which can 
with difficulty be preferved, it may be ufeful to mention, that 
a cork confines ether in a glafs bottle much better than a 
glafs ftopple, which it is almoft impoflible to grind fo well 
as intirely to prevent the evaporation of ether. When a ftop- 
ple, made very nicely out of a uniform and clofe piece of cork, 
which goes rather tight, is put upon a bottle of ether, the 
fmell of that fluid cannot be perceived through it ; but I never 
law a glafs ftopple that could produce the fame effeCt By open- 
ing 
