ORDER III. GASEOUS SULPHURIC-ACID. 23 



2. This acid is found most commonly in the neighbour- 

 hood of, or stagnating upon, acidulous springs ; also in se- 

 veral marshes, and in the solfataras. In various circum- 

 stances it is formed upon the surface of the earth. It oc- 

 curs in several excavations, both natural and artificial, as 

 in the grotta del cane near Naples ; and in a cave in the 

 Biidb's hegy, a porphyry mountain in Transylvania ; besides 

 also in many mines, where in some places this dangerous 

 gas is known by the name of Schwaden or Swath. The ga- 

 seous Carbonic-acid, obtained by art, is employed for various 

 purposes. 



GENUS II. MURIATIC-ACID. 

 1. GASEOUS MURIATIC-ACID. 



Aeriform Muriatic Acid. JAM. Man. p. 4. Salzsaure. 

 HAUSM. III. S. 801. 



Amorphous. Transparent. Expansible. 

 Sp. Gr. = 1-278 BERZ. 1-274} BIOT and ARAGO. 

 Odour pungent. Taste strongly acid. 



OBSERVATIONS. 



1 . The gaseous Muriatic-acid consists of 



Muriatic acid 75-31. 



Water 24-69. BERZELIUS. 



It is unfit for respiration, suffocates animals, and extin- 

 guishes fire. The blue colour of an infusion of litmus is 

 changed by it into a durable red one. 



2. It occurs in the vicinity of active volcanoes, near 

 Mount Etna and Vesuvius ; it is also said to be produced 

 by stagnant waters in salt-mines. 



GENUS II. SULPHURIC-ACID. 

 1. GASEOUS SULPHURIC- ACID. 



Aeriform Sulphuric Acid. JAM. Man. p. 4. Schweflichte 

 Saure. HAUSM. III. S. 797- 



