66 SCIENTIFIC AGRICULTURE. 



ferences being principally hydrogen and the metals : it is not 

 found in an uncombined state in nature. The most charac- 

 teristic property of this gas is its bleaching power ; it decom- 

 poses readily the most permanent organic coloring principles ; 

 the presence of water is necessary to develop the bleaching 

 properties of chlorine. 'This gas is a highly disinfecting agent. 

 Common salt is a compound of chlorine and sodium. 



IODINE. 



Iodine is a solid substance, in shining lead-colored scales. 

 It is volatilized or converted into vapor by a moderate haat, 

 the vapor has a beautiful violet color, and an odor resembling 

 chlorine. It is soluble in water, and more perfectly so in 

 alcohol. It is obtained from the ashes of marine plants, but 

 has not as yet been detected in any of the plants cultivated 

 for food. Both plants and animals confined in the vapor of 

 iodine soon perish. 



SULPHUR. 



Sulphur exists in considerable abundance in nature; the 

 most common source of the sulphur of commerce is volcanic 

 action : it is sublimed and thrown out in large quantities from 

 the earth, it exists also in natural waters. It is a yellowish 

 green powder, having little taste or smell, it is but slightly 

 soluble in water. When heated it exhales white fumes of an 

 intensely suffocating odor, these fumes are called sulphurous 

 add. This gas is destructive to both animal and vegetable 

 life: it possesses bleaching properties. There are several 

 compounds of sulphur which are essential to the growth of 

 vegetation. 



PHOSPHORUS. 



Phosphorus is a solid substance, having the consistence of 

 wax, and of a pale yellow color: when exposed to the air, it 

 takes fire spontaneously and burns with a pale blue flame, 

 scarcely visible except in the dark. When heated, however, 



