220 PHYSIOGRAPHY. 



Sulphuric Acid. 



SULPHURIC ACID. Liquid Sulphuric-Acid. 

 MOHS. 



Liquid. Transparent, in different degrees. 



Sp. gr. = l'846 URE, when pure, but varies to a little 

 above 1*0 according to its dilution. Taste strongly acid 

 and caustic. 



1. The anhydrous sulphuric acid is solid, and, according to BERZEL- 

 lus, consists of 



Sulphur 40-14 



Oxygen 59-86 



This is obtained from the first portions which come over from the distil- 

 lation of fuming sulphuric acid ; the fumes concrete upon the sides of the 

 receiver in tough, silky filaments, which are entirely free from water. 

 The strong, liquid sulphuric acid, contains at least 18-5 p. c. of water. 

 When it is diluted to a sp. gr. of 1-780, it crystallizes at 45 F. ; when 

 of a sp. gr. between 1-786 and 1-775 at 32, and when it is as high as 

 1-843, at 15. The crystals have the figure of six-sided prisms termi- 

 nated by six-sided pyramids. Common sulphuric acid is an oily looking 

 fluid^ limpid and inodorous, and eminently destructive of animal and veg- 

 etable bodies. It rapidly absorbs moisture from the air, and evolves heat 

 when mingled with water in every proportion. 



2. It is produced in many places from the decomposition of water and 

 Iron Pyrites. A remarkable locality of it, called the sour spring, ex- 

 ists in Byron, Genesee co. (N. Y.) near the Erie canal. The acid is 

 produced from a hillock 230 feet long and 100 broad, elevated about five 

 feet above the surrounding plane. It contains an abundance of Iron- 

 Pyrites in exceedingly minute grains ; and is covered with a coat of 

 charred vegetable matter to the depth of four or five inches, occasioned 

 by the action of the sulphuric acid. Wherever holes have been sunk in 

 this hill, the acid accumulates ; also in the depressions in the contiguous 

 meadow ground. When the season is dry, it collects in a perfectly con- 

 centrated state. This acid, similarly produced, occurs in a cavern near 

 Sienna in Tuscany, and at Aix in Savoy. A considerable lake of it ex- 

 ists in the ancient crater of Mount Idienne in Java ; and a stream of it, 

 called the Rio de Vinegro, flows from the extinct volcano Purace neap 

 Popayan, whose waters are fatal to fish, and the spray arising from them 

 irritating to the eyes of animals. 



