226 ELEMENTS OF SOILS. 



Sulphur. This well known substanco is wiilely ilisseniinatod in the mineral kingdom, 

 and is also found sparingl}' in the vegetable and animal kingdoms. The two most conmion 

 combinations are sulphurets and sulphates. In the former condition it is combined with 

 the metals ; in the latter, with oxygen, forming sulphuric acid. In this stale it combines 

 with earths and alkalies, and forms salts, as sulphate of lime, of soda, of magnesia, etc. 

 It is an important substance. It is obtained mostly from Sicily, and is a volcanic product, 

 resulting from the sulilimation of a native sulphurct. It may be also procured in this State, 

 by the roasting of certain ores in whicli it abounds. 



Phosphorus. In it^ pure state, this is a white solid, highly inllammable, comparatively 

 soft and flexible at blood heat, and taking fire readily by friction. It is cjuite abundant in 

 the animal kingdom, in combination with oxygen, forming phosphoric acid, which, like 

 the sulphuric acid, combines with lime and other bases, forming salts. The phosjiliate of 

 lime is its most common combination. It is an essential constituent of bones, and of the 

 coverings of many marine animals, forming in lioth cases the hard substantial part of the 

 animal. It is also met with in the mineral kingdom. It is contained in all good soils, 

 but only in small quantities when compared with the other elements. It exists in combi- 

 nation with lime, iron and alumina, and is detected with difficulty. Both phosphorus and 

 sulphur form constituent parts of protci/ie, whicli is regarded as the basis of albumen, fibrine 

 and caseine. 



Carbonic acid. It is a constant constituent of the atmosphere. Its origin is not known : 

 it is, however, a constant product of comliuslion and respiration, and in this way continu- 

 ally escapes into the atmosphere. It also escapes from the earth in the neighborhood of 

 volcanoes ; but it is here one of the results of comlnistion, or of the action of heat on the 

 limestone contained in the interior of the earth. It is heavier than atmospheric air, and, 

 hence, if operated on by its specific gravity only, would always be found on the surface of 

 the earth; but gases, when mixed, never liehave like liquids, wliere the heaviest finds 

 the bottom and the lightest the top : they, on the contrary, become equally mixed, and all 

 parts of a volume will be found to contain tlie same proportion of the heavier and the 

 lighter gas. 



Carbonic acid is a poison. When inhaled, death speedily follows, unless means are soon 

 instituted for counteracting its effects. It is not simply a deprivation of oxygen. It extin- 

 guishes a burning taper if immersed in it, or even if it be simply poured over the taper. 

 Hence by trying a suspected gas with a lighted taper, it may be known whether carbonic 

 acid is present. When mixed with air in the proportion of 1 to 10, it still remains irrespi- 

 rable, producing stupor and death like a narcotic poison. Its specific gravity is 1.52. II 

 dissolves in water, forming an agreeable acid taste. It turns litmus paper red. 



Carbonic acid is liquid under a pressure of 36 atmospheres :^ 15 lbs. x 36 on the square 

 inch. If the pressure is suddenly removed, the evaporation is so rapid that a portion of 

 the liquid solidifies from the loss of heat. 



Carbonic acid has a wide range of affinity. It is one of the important and most common 

 of the compound elements. This importance is due partly to the ease with which it may 



