532 THE LABORATORY. [DEC. 



In the above processes, ..he principal things to 

 attended to, are, 



Whether there be any metallic, or aluminous 

 salts, as these are absolute poisons, and therefore a 

 to be decomposed by quick-lime. 



Whether there be such a proportion of neutral or 

 earthy salts as to be hurtful, in which case, the solu- 

 tion in process (second) will taste salt : a soil contain- 

 ing them in so large a proportion, will hardly ever 

 admit of culture for grain. 



Whether there be calcareous earth, and in what 

 proportion, as that ascertains the propriety of apply- 

 ing any manure containing it, and the quantity of 

 that manure. 



What the proportion of sand and clay is, vvhic 

 ascertains the propriety of adding sand or clay. 



Whether there be pyrites, as that shews why and 

 when a soil will be long of being brought into culti- 

 vation. 



Pyrites are best destroyed by fallowing, and after- 

 wards applying lime/* 



When Mr. Professor Davy, of the Board of Agri- 

 culture, shall publish his excellent leclures, a mo 

 exacl analysis will be explained. 



If in this method of analyzing a soil the propor- 

 tion of calcareous earth be large, the trial of the gun- 

 barrel will give a quantity of gas proportioned to such 

 quantity of calcareous earth, for which allowance 

 must be made ; but if that quantity be small, the 

 ounce measures of air or gas gained from an ounce of 

 soil, and its degree of inflammability, will be the ea- 

 siest test of the fertility of the specimen tried. 



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