CARBON. SULPHUR. 



23 



and estimating the weight of 100 cubic inches of 

 carbonic acid at 47.377 grains, every cubic yard of 

 pure limestone would contain 17,092 cubic feet of 

 carbonic acid gas. If, then, all the carbon contain- 

 ed in the various rocks^ were set free over the sur- 

 face, the quantity would be immense, and animal 

 life immediately destroyed. It is well known that 

 vegetation could not be supported without carbon. 

 All vegetables absorb it, while animals give it off by 

 respiration. Thus a purifying process is constant- 

 ly going on by means of the vegetable kingdom, 

 without which carbonic acid gas would soon abound 

 to such an extent as to extinguish animal life. This 

 gas is given off in immense quantities from numer- 

 ous springs and fissures in the earth. M. BischofF 

 estimates that 219,000,000 pounds of this gas are 

 evolved from the vicinity of the Lake of Larch in 

 one year, equivalent to nearly two billion cubic feet 

 in volume. 



Sulphur is a well-known solid, brittle, shining sub- 

 stance, of a bright yellow colour. When subjected 

 to heat, it evaporates, and is condensed upon any 

 cool substance, in the form of a fine powder, called 

 flowers of sulphur. Sulphur is most abundantly 

 found in connexion with volcanoes,* from whence it 



* M. Von Leonhard, in his Lectures on Geology, remarks, 

 that "out of the crater of Parace, in Columbia, vapours of sul- 

 phur rise so copiously, that crusts of sulphur eighteen inches 

 thick are formed ; pieces of wood, exposed to the influence of 

 these vapours for several days only, are covered with crystals 

 of sulphur. The rocks which surround the crater of Alaghez^ 

 the volcano from which flows such immense quantities of lava 

 that they now load the plain of Armenia on the north, are en- 

 tirely covered with sulphur; the inhabitants in the vicinity 

 gather large quantities of it, and in a very peculiar manner. As 

 the summit is inaccessible, they employ guns, as Dubois relatoe, 

 and shoot through the covering of sulphur; the pieces then fall 

 down at their feet. The Greek island of Milo is very rich in 

 sulphur. Numberless caves are full of sulphur and alum- 

 When the walls of these ca'^'erns, which are covered with 

 crystals of these substances, are illuminated, a most magnificent 



