lM*ROVINq. POOR SOILS. SQ3 



ife ; and their products are in many instances the same Observatiorxs 

 l(as carbon.) Nowj in order to illustrate the present sub- respecting the 

 ject, 1 would carry the comparison further than it has improvement 

 hitherto been done, and I v,'ouId draw an inference by 

 analogy from the process of fusion, and shew how re- 

 quisite it is to make a due mixture of earths for the support 

 of vegetable life, from the necessity there is of mixing 

 these very earths in certain proportions, in order to render 

 them capable of being acted upon, so as to be chemically 

 combined, by means of fire. 



If I put pure clay, chalk, or flint into a crucible, and 

 place it in the hottest part of a furnace, no alteration or 

 change takes place ; it will indeed lose the water or air that 

 was attached to it, but the earth will remain the same, for 

 it is perfectly irreducible; if, however, I mix them in 

 certain proportions, and then apply the same degree of 

 heat, they will liquify, continue in a fluid state (so long as 

 the fire is kept up) and their particles, intimately com- 

 bined, will form a mixt mass with properties distinct froci 

 each in its simple state. 



Now the operations of vegetable life resembling, as we 

 said before, the chemical processes of combustion, may not 

 a due mixture of these earths, when presented to ?he mouths 

 or radicles of plants, render them equally capable of being 

 absorbed, and converted hy the action of the living 

 principle into food, as they are of being fused or rendered 

 liquid by fire? And thus am I not justified by the analogy, 

 to draw this conclusion, that, by such an union plants 

 derive their nourishment from the earths ?— for, if the con- 

 tact of these different particles of earth be alone necessary 

 to enable the fire to produce the wonderful difference be- 

 tween the state of a fluid and a solid, it is difficult to be 

 conceived, that the principle of life, so analogous to fire, 

 should be able to exhibit similar effects, in similar cir- 

 cumstances; and, taking advantage of the state of the 

 earths, when thus duly proportioned and mixed, be able 

 to absorb and convert them into nourishment? We see also 

 from this theory, the philosophy of ploughing, harrowing, 

 lioeing and rolling, operations indispensably necessary to a 



food 



