F., which is 31° F. above the mean temperature of Paris. It rises 40 to 
50 feet above the surface, and is discharged at the rate of 600 gallons 
per minute. 100. parts, after filtration, contained carbonate of lime 
6°80, carbonate of magnesia 1-42, bicarbonate of potash 2°96, sulphate 
of potash 1-20, chloride of potassium 1-09, silica 0-57, organic azotized 
matter 0°26. J. L. 8. 
27. Ancient Coins:—M. Morssard has analyzed seven kinds of 
ancient coins, and finds them to consist of copper and tin, with occa- 
_ sionally a little silver, or traces of arsenic. 
. Varnish for Eggs, Crabs, Insects, §c.—Dissolve gum arabic 
4 02z., and gum tragacanth $ oz., in 3 pints of water, add to the solution 
s of corrosive sublimate and 20 drops of oil of thyma dissolved 
in 4 oz. spirits of wine, mix well and let it stand a few days to sepa- 
rate: the clearer part is to be used as varnish, the thicker as cement. 
29. Goadby’s solution, for the preservation of specimens of soft ani- 
mals without bones or shells, consists of corrosive sublimate 4 grains, 
alum 2 0z., common salt 4 oz., water 1 quart.. Specimens should first 
be steeped in equal parts of water and this solution, and then put into 
the solution itself. It is reeommended.as the only material by which 
Medusz can be preserved. 
30. Freezing of Water by the Air Pump, without the aid of Sulphu- 
ric Acid or any other desiccating agent; by J. Lawrence Smitx, 
(communicated by the author.)—In attempting to freeze water under 
the air-pump, without the aid of a desiccating agent, the cooling of the 
water to the point of congelation is prevented by the heat received from 
the containing vessel. I have lately found that by obviating this diffi- 
culty, water may be readily frozen by its own evaporation. 
Tt was first shown by Count Rumford, that water does not wet a soot- 
ed surface, but forms in globules, like quicksilver. ‘Three drops of 
water were placed i ina sooted watch-glass; the spheroidal globule lay 
on the soot, exposing a large surface for evaporation, at the same time 
that the water was insulated from any’ source of heat. Arranged in 
this manner and placed under an air-pump, two or three minutes were 
sufficient to freeze the water.. The glass was sooted over an oil lamp 
with great care; the experiment fails if the globule of water touches 
the glass even by a small point. 
In place of the sooted watch-glass, make a shallow cavity in the sad 
of a large cork, and over a lamp, burn it, sooting it at the same time. 
By. putting three drops of water into the cavity thus prepared, and sub- 
jecting it to the action of the air-pump under a pint receiver, the water 
froze solid in a minute and a half; and in two and three fourths min- 
utes, 20 grains of water congealed, though at 73° Fahr. when introdu- 
ced. Under a receiver of three quarts POs 20 grains of water 
Srconp Series, Vol. I, No. 2.—March, 1846. 
