85 



while the portion soluble in dilute acids is the index of what may 

 by decomposition become the food of plants. This undecomposed 

 portion of the soil may often, by the application of liine, ashes, 

 and other caustic manures, be more speedily decomposed and ren- 

 dered available. 



The analysis should include also, if possible, the sub-soil, as 

 well as the surface soil, in order to guide the farmer in the pro- 

 cess of deepening his soil. There are, of late, many advocates 

 of indiscriminate deep-plowing. But a fertile soil may be under- 

 laid by a barren sub soil, by throwing up large quantities of 

 which the fertility of a field may be destroyed for years. The 

 sub-soil, not unfrequently, contains large quantities of protoxide 

 of iron and other substances which are injurious to vegeta- 

 tion until they have been subjected to the action of the atmos- 

 phere. On the other hand, the sub-soil often contains elements 

 of fertility which are riot so abundant in the surface soil, in 

 which case, deep plowing will improve both. It is important 

 that the agriculturist should know these differences in order 

 that he may know where he should plough deep, and where 

 refrain. 



A still more important consideration is, that no analysis can be 

 of any value to the farmer who is not himself a chemist, unless it 

 be accompanied by a discussion of the indications it affords, and a 

 recommendation of suitable means of improvement. Our agri- 

 cultural journals and reports abound in analyses which are about 

 as intelligible to the unscientific farmer as the inscriptions on the 

 pyramids, or a chapter from La Place's Miechanique Celeste. 

 Most of our intelligent farmers know that lirne, phosphoric acid, 

 and the alkalies, play important parts in the economy of vegeta- 

 tion, but few of them have any idea how much of each of these val- 

 uable ingredients is requisite to fertility, or what are the best 

 means of supplying their deficiency. Until every farmer is also 

 a chemist, an analysis of a soil or manure which is not followed by 

 a commentary on its defects or virtues, leaves him just where the 

 diagnosis of a disease, without a prescripton for its relief, leaves 

 the patient. He is no wiser nor better off than before. It will 

 not do to presume that when the chemist pronounces what a soil 

 contains, the argiculturist will know what it ought to contain, and 



