426 The Neglect of Chemistry hj Practical Farmers. 



Having now described a few of the principal properties of the 

 bodies comprising the ultimate elements of organic matter, we 

 have to notice the forms and properties they acquire when com- 

 bined as proximate elements, for it must be borne in mind that 

 the two states are never co-existent in the same substance, but 

 that the latter are the tangible forms in which the former 

 combine. 



Proximate Elements. — Proximate elements are those into which 

 a compound body is resolved by the first operations of analysis : 

 they are classed as — 



Azotised. — Azotised, or nitrogenised, which signifies that they 

 contain nitrogen as well as the other three organic elements ; and 



Unazotised. — Unazotised, or unnitrogenised, when nitrogen is 

 absent. 



Ammonia. — This gas is not an ultimate element, being a com- 

 pound of nitrogen and hydrogen ; and yet it can scarcely be 

 considered as a proximate element, when viewed in connexion 

 with the others under this head : I have therefore given this 

 column an intermediate place between the ultimate and proximate 

 elements, as will be seen by reference to the table. This gas is 

 sometimes called the volatile alkali, and must be well known to 

 all farmers, it being the cause of the pungent odour that pervades 

 an ill-ventilated stable, and of the strong smell from guano ; it is 

 a product of all animal and many vegetable substances when in a 

 state of putrefaction : it is highly volatile, as its common name 

 implies, but has a great affinity for water, which tends to fix it^ 

 if in sufficient quantity. I need not mention here the powerful 

 effect it has in promoting the gi'owth of plants. The common 

 smelling salts are composed of ammonia and carbonic acid. 



It is not intended by the quantities given in this column that 

 the actual quantity of ammonia there stated is present in the 

 crops, but that when decomposed the said crops would generate 

 that amount ; or, in other words, that that amount of ammonia 

 would be required to supply the nitrogen in the crops, supposing, 

 with Liebig, that all the nitrogen is assimilated in the form of 

 ammonia, and that none is lost. 



I have now to describe the properties of the proximate ele- 

 ments, in the general acceptation of that term. 



Albumen, Gluten, Casein. — These three azotised proximate 

 elements invariably contain a small quantity of free sulphur, 

 and, according; to Liebio;, the veo-etable albumen is identical in 

 properties and composition with the animal albumen as contained 

 in the white of an egg, or the serum of blood ; the vegetable 

 gluten, with the fi brine of blood ; and the vegetable casein, with 

 the casein of milk. The whole of these substances are supposed 

 by chemists to be nearly, if not quite, identical in composition ; 



