fame Thermometncal Expe> intents, 5 1 7 
being rummer, between two and three times the quantity of 
the fame ether mu ft be ufed to produce the fameefFeft. 
There fcems to be fomething in the air which, belides heat, 
interferes with the freezing of water, and perhaps of all fluids, 
though I cannot fay from experience whether the above men- 
tioned difference between the freezing of water in winter and 
hummer, takes place with other fluids, as milk and other 
animal fluids, oils, wines, &c. 
The proportion between the quantity of the ether and of the 
water that may be frozen, by it, feems to vary according to the 
quantity of water ; for a larger quantity of water feems to : 
require a proportionably lefs quantity of ether than a fmaller 
quantity of water, fuppofmg that the water is contained in 
cylindrical glafs veflels ; for I have not tried whether metal 
veffel in Head of a glafs one, and whether fome other fhape' 
belides the cylindrical, might not facilitate the congelation. In 
the beginning of the fpring I froze about a quarter of an ounce 
of waiter with nearly half an ounce weight of ether, the appa- 
ratus being larger, though fimilar to that defcribed above. 
Now as the price of ether, fufficiently good for the purpofe, 
is generally between eighteen pence and two (hillings /rr ounce, 
it- is plain, that with lefs than two (hillings a quarter of an 
ounce of ice, or ice cream, may be made in every climate, and 
at any time, which may afford great fatisfadtion to thofe per- 
foils, who living in places where no natural ice is to be had, 
never (aw or tafted any fuch delicious refrefhments. 
When a fmall piece of iee r for inftance, of about ten grains 
in weight, is wanted, the necefiary apparatus is very lmall, 
and the expence of the ether not worth mentioning. I have 
a fmall box, which is four inches and a half long, two inches 
broad, and one inch and a half deep, which contains all the appa- 
ratus. 
