Chemical Science. 391 
solved very nearly the whole of it, leaving a small trace of silica, 
and producing a solution similar to the former. Hence the Taschium 
in this button of silver was nothing else than iron; and from the 
‘presence of silicious sand it may be supposed to have been intro- 
duced into the button through the inaccuracy of the preparatory 
manipulations.—M. F. 
27. Liquefaction of Sulphurous Acid.—In the Annales de Chimie et 
Physique for May last, M. Bussy is stated to have obtained the above 
acid liquid, and free from water, by causing it to pass in its gaseous 
state through a tube containing fused chloride of calcium, and after- 
wards into a flask surrounded by a mixture of ice and salt, where it 
completely liquifies, and remains in a liquid state under atmospheric 
pressure at the temperature of 0°. Itis a colourless, transparent, and 
very volatile liquid, of a specific gravity ='1.45. It boils at about 
10° centigrade below 0 = 14° Fahrenheit, but in consequence of the 
cold produced by the evaporation of the portion which is volatilized 
the residue remains liquid, being reduced to a temperature much 
below its boiling point. It occasions intense cold, and rapidly eva~ 
porates when dropped upon the hand, Poured into water at com=- 
mon temperatures one portion is dissolved and another volatilized ; 
but as the solution approaches to saturation, the acid collects in 
drops at the bottom of the vessel, like an oil heavier than water. 
If in this state it be touched by the extremity of a glass tube, it 
passes into vapour, occasioning ebullition, and ice forms upon the 
surface of the water. 
The bulb of a thermometer enveloped in cotton, and dipped into 
the liquid acid, falls spontaneously, when exposed to the air, to 
— 57°. (= — 70° Fahr.) The atmosphere being at 50° F. In the 
vacuum ofthe air-pump a cold of —68° (=—90° F.) is thus easily 
obtained*. Mercury therefore is easily frozen by the aid of this 
acid, simply by dipping the bulb of a mercurial thermometer sur- 
rounded with cotton into it, and agitating the air with it. The ex- 
periment succeeds better when a little mercury is put into a cup 
with a small quantity of sulphurous acid upon it, and the whole 
put under the exhausted receiver. By the evaporation of the acid 
in vacuo, M. Bussy has frozen alcohol of a strength below 33° (of 
a specific gravity below .852 at 55°). By passing chlorine and am~- 
monia through tubes cooled by the evaporation of sulphurous acid, 
M. B. liquefied those gases; and by a similar method cyanogen was 
obtained in the form of a crystallized solid. 
* M. Bussy says these low temperatures can only be accurately measured 
by an air thermometer. 
