608 SELECTIONS FROM ADDRESSES. 



in ; the other two will have left much of their color and nearly 

 all the smell with the clay and the charcoal which have ab- 

 sorbed them. Experiments have been made showing that 

 soils containing even moderate portions of clay, mixed with 

 thin sanJ, would absorb all the alkalies and their salts which 

 are put 0!i as manure, and that tliis absorbent power resides 

 entirely in the clay. Professor Way, of England, affirms that 

 clay will even decompose the salts of ammonia, potash and 

 soda, so that the plant may use them as wanted ; so far, how- 

 ever, my experience does not go. The absorbent powers of 

 charcoal are thus shown to be also great and of immense im- 

 portance in absorbing and retaining the vast quantity of am- 

 monia which comes down in the annual snow and rain, as 

 well as what is put on the ground as manure — and as an absor- 

 bent in the compost heap it is invaluable. It is not at all 

 improbable also that it undergoes in the soil an extremely slow 

 natural combustion, furnishing thereby carbonic acid to dis- 

 solve many inorganic substances insoluble without its acid. 

 But this, like a thousand other momentous questions in agri- 

 culture, will only be truly tested when a more general liberal 

 education throws open the door of investigation to thousands 

 of young and inquiring minds. 



It appears from this and many other practical experiments 

 that there arc two substances which possess in a high degree 

 this important power of absorbing and retaining for the use of 

 vegetation, the most valuable portions of manure, charcoal and 

 clay. 



Now charcoal, in an agricultural sense, means not only wood 

 charcoal but carbonized animal or vegetable fibre of any kind; 

 it forms therefore the chief mass of peat muck, of leaf mould, 

 of the manures of animals, which has been carbonized by un- 

 dergoing gradual and slow close combustion in a dung heap, 

 by the action of the oxygen of the atmosphere, just as wood or 

 animal matter (bones) is artificially burnt into charcoal by a 

 more rapid close combustion with fuel. The extraordinary 

 powers of absorption and retention of the valuable salts of ma- 

 nure of both kinds of charcoal are the same — but all kinds, ex- 

 cept artificial wood charcoal, are generally found mingled with 



