Ckeinkal Science. 391 



for a long time, to separate all the sulphuric acid, a peculiar acid 

 was formed at the same time with the sugar above described. 

 This was dissolved out from the evaporated sugar, by rectified 

 alcohol, but as a portion of sugar was also taken up, it was eva- 

 porated to a syrup, and agitated with ether. The ether upon 

 evaporation gave an acid nearly colourless, very sharp, almost 

 caustic, and setting the teeth on edge. It was deliquescent and 

 uncrystallizable. It became brown in the air by degrees, if 

 warmed ; and, when heated in a capsule, it turned black and 

 began to decompose below the heat of boiling water. If di- 

 luted in this state with water, flocculi of carbonized vegetable 

 matter separated, and sulphuric acid was detected in the fluid. 

 If heated above the boiling point of water, its decomposition is 

 very rapid, and much sulphurous acid is disengaged. 



This acid does not affect metallic solutions. Nitrate of barytes 

 and sub-acetate of lead are not troubled by it. It acts on car- 

 bonates with effervescence. It appears to dissolve all metallic 

 oxides, forming soluble salts, uncrystallizable, deliquescent, and 

 insoluble in rectified alcohol. It dissolves iron and zinc, liber- 

 ating hydrogen. It forms with barytes and oxide of lead, salts, 

 very soluble, and of a gummy appearance. It will even dissolve 

 a certain quantity of sulphate of lead. It is composed of 

 sulphur, carbon, hydrogen, and oxygen; or, of a vegetable matter 

 and the elements of sulphuric acid, but the state of combination 

 is unknown. 



If sulphuric acid be allowed to act on silk for a short time 

 and then the mixture be diluted with water, a mucilage is 

 obtained resembling gum tragacanth. More water being added 

 it precipitates entirely, but a large quantity of hot water dis- 

 solves it. If the silk be treated in a mortar with sulphuric acid 

 for 24 hours, a different result is obtained. It is then entirely 

 soluble in water, and when the acid is separated by chalk, and 

 the solution evaporated, a reddish transparent substance is ob- 

 tained resembling glue, the solution of which is abundantly 

 precipitated by infusion of galls, and sub-acetate of lead. 



Gum, treated with sulphuric acid, gave results very nearly 

 the same us cloth. Sugar became darkened by the acid, but de- 



