MANURES. 285 



There therefore still remain to be considered those 

 materials, of a more or less artificial or manufactured 

 character, which are beginning to be largely imported to 

 supplement the local manures. 



The chief "artificials," as they are commonly called, 

 supply only one important plant food to the land and may 

 conveniently be classified as: 



(a) Nitrogenous manures. 

 (&) Phosphatic 



(c) Potash 



In the following pages only the more important members 

 of each class will be dealt Avith. 



NITROGENOUS MANURES. 



The two great nitrogenous manures of the present day 

 are nitrate of soda and sulphate of ammonia, both of which 

 are beginning to be extensively used in Egypt. 



NITKATK OF SODA. 



This, in view of the immense quantities now employed 

 in agriculture, must be regarded as the more important 

 manure of the two. 



Nature. When perfectly pure, nitrate of soda (sodium 

 nitrate, NaN0 3 ) is a white crystalline salt easily soluble 

 in water, one part dissolving in about one part of water 

 at ordinary temperatures. It crystallises without water of 



