1824.] Scientific Notices — Chemistry. 307 



5. On the Production of Liquid Anhydrous Sulphurous Acid, 

 and its Use in the Liquefaction of some other elastic Fluids. 

 By M. Bussy. 



The gas is produced in a matrass from a mixture of equal 

 parts of mercury and sulphuric acid ; it first passes into a vessel 

 surrounded with melting ice to condense the greater part of the 

 vapour of water that comes over with it, and from thence it is 

 conveyed through a long tube, filled with fused muriate of lime, 

 into a small matrass surrounded by a freezing mixture, composed 

 of two parts of ice, and one of common salt. The gas condenses 

 in the last vessel into a liquid, under the mere pressure of the 

 atmosphere. 



The liquid acid is colourless, transparent, of sp. gr. about 

 1-45, and boils at a temperature of 10° below 0° (14° Fahr.). It 

 may, however, be easily preserved a considerable time at com- 

 mon temperatures, for the cold produced by the volatilized por- 

 tion lowers the temperature of the remainder below its boiling- 

 point. Dropt on the hand it volatilizes completely, and produces 

 intense cold. Poured into water at the common temperature, it 

 produces a kind of effervescence from the volatilization of part 

 of the acid, and a thick coat of ice forms at the surface of the 

 water. By cautiously pouring it into the water, it sometimes 

 sinks without mixing with it, and collects in little drops at the 

 bottom of the vessel ; if these be touched with the end of a glass 

 rod, they instantly assume the elastic form, and occasion a sort 

 of ebullition in the water. 



Mercury was readily frozen in a thermometer tube, by sur- 

 rounding the ball with cotton wetted with the liquid acid, and 

 still more conveniently, by placing a small quantity of the metal 

 in a watch-glass, adding a little of the liquid sulphurous acid, 

 and evaporating it under the exhausted receiver. In this way 

 between 200 and 300 grains of mercury may easily be solidified 

 in four or five minutes, and at the moment of congelation, irre- 

 gular depressions may be observed on its surface, owing to the 

 great contraction the metal experiences at the instant it crys- 

 tallizes. 



Alcohol, of the specific gravity '852, was frozen in a bulb sur- 

 rounded by cotton wetted with the liquid acid, and exposed to 

 the vacuum of an exhausted receiver; but neither ether nor 

 absolute alcohol could be congealed in the same manner. The 

 latter, however, became more viscous than usual. 



" I have recently succeeded in some attempts to liquefy other 

 elastic fluids by the cold produced by the evaporation of sul- 

 phurous acid. I pass the gas, well dried by chloride of 

 calcium, into a tube having a thin glass bulb on its horizontal 

 branch; while the vertical branch dips into ajar containing 

 mercury. 1 surround the bulb with cotton, wet it with some 



x2 



