56 THE COMPOSITION OF FERTILE AND BAKKEN SOILS. 



conditions quite true theoretically which are affected by consi- 

 derations of . s. d. They may or may not be profitable. " Will 

 they pay ? " is the question the farmer puts to the chemist ; but 

 if the latter is a sensible man he will not give an answer to that 

 question. 



How the Chemist assists the Farmer. 



" It is the business of my life," says the agricultural chemist, 

 " to instruct you in the right principles of science as applied to 

 agriculture ; I can assist you to understand those principles ; but 

 your making of money is your business, not mine, and 1 give you 

 hints which you may apply if you please ; on their proper use 

 success depends in a great measure ; if you do not choose to apply 

 them you may be left behind, and others, sharper or more deter- 

 mined, will use them in the right way, and make them profitable." 

 It is, in fact, altogether necessary that the farmer should use his 

 own discretion as to the application of manures, &c. I will 

 make this plain by reference to the composition of sandy soils. 

 These soils are generally naturally sterile, or are capable of pro- 

 ducing very little they are called hungry soils, because they 

 swallow up manure ; observe the difference between these soils 

 and clay. Phosphoric acid is only just traceable in them; lime 

 is greatly deficient ; indeed, they are made up almost entirely of 

 silica, and remembering that plants do not live alone by silica, 

 but by lime and phosphoric-acid and other things as well, we see 

 why sandy soils require much good manure. Farmyard manure 

 would do ; it is a perfect manure, containing all the constituents 

 of the fertile soils ; whilst in most artificial manures we have only 

 two or three of the most fertilising constituents present ; hence, 

 there is danger in using, on bad land, special manures ; I do not 

 think that special manures can be used extensively on very 

 barren soils, constituted chiefly of silica, because in artificial 

 manures we have special constituents some of them, doubtless, 

 the most important to fertility, and I would guard against being 

 supposed to speak disparagingly of those manures, only they 

 must be used with great judgment, when they will answer well ; 

 but in sandy soils it is extremely hazardous to use artificial ma- 

 nures alone. Soils of that kind require a different process of 

 cultivation, because they are deficient in requisite mineral sub- 

 stances. 



Absorbent Powers of Soils. 



But there is another point which has to be taken into considera- 

 tion in speaking of the composition of soils. I refer to the atmos- 

 pheric food which soils absorb, some in small and others in large 

 quantities. Clay, which is of the class of fertile soils, has in a 

 very high degree the power of absorbing ammonia, and other 



