VEGETABLE PLANTS. 57 



readily absorbs them, especially the former, from 

 the atmosphere, or from any thing containing 

 these gases with which it may chance to come 

 in contact. Plaster, but no lime, should there- 

 fore be placed in all composts or mixtures which 

 are to be used as surface manures. The kind 

 of land most likely to be benefited by lime is 

 therefore that which already contains a large 

 amount of muck, or any vegetable matter. 

 Our best market-gardeners generally apply lime 

 to their grounds the year following a heavy ap- 

 plication of stable manure, the first crop being 

 fed by the parts of the manure which are readily 

 soluble, and the lime serving to decompose the 

 residue for the second year's use. 



SPECIAL OR COMMERCIAL FERTILIZERS. 

 This is a subject which is commanding a great 

 amount of thought and attention of late. There 

 being few localities where an abundance of 

 stable manure can be obtained, the importance 

 of finding a substitute is apparent. The three 

 principal elements required by the majority of 

 our farm and garden crops, and which are not 

 already to be found in sufficient quantities in 

 the soil, are ammonia, potash, and phosphoric 

 acid. Ammonia most largely abounds in all 

 animal substances, all nitrogenous bodies. Pot- 



