240 
FREE HYPOSULPHUROUS ACID. 
ART. XL VII. — FREE HYPOSULPHUROUS ACID. By M. Lang- 
lois, Professor of Chemistry in the Military Hospital of Instruction, of 
Strasbourg. 
M.Herschel and M. Gay Lussac have in vain attempted to 
isolate hyposulphuric acid from hyposulphate of strontian ; 
the former employing sulphuric acid, the latter an alcoholic 
solution of hydrochloric acids. M. Langlois has succeeded 
in decomposing the hyposulphite of potassa, by means of 
perchloric acid, added by degrees to a cold solution of this 
salt. He separated by the filter the perchlorate of potassa, 
and concentrating the liquid in vacuo, obtained the hyposul- 
phurous acid, as a colorless liquid,of a syrupy consistence, and 
of a strongly acid and bitter taste. At the temperature of 80°c. 
this acid is decomposed, producing sulphurous acid gas and 
a deposit of sulphur. It does not affect the salts of lime, 
strontian, iron, zinc, and copper, but it precipitates the salts 
of lead, silver, mercury, and platinum. Nitric and chloric 
acids immediately decompose it. 
Comptes rendes a V Institut, and Journ de Phatm. 
