302 Dr Davy's Agricultural Discourse. 



in the grain and straw ; in the former, chiefly phosphate of 

 lime and azote ; in the latter, chiefly silica. The summary 

 or shorter way, last mentioned, is the improved method, the 

 result of scientific research ; the tedious way, first noticed, is 

 the result of mere experience unaided by such research, and 

 is in many respects imperfect. The same remarks, I believe, 

 are applicable to. every kind of crop. Take the most impor- 

 tant with which the interests of the West Indies are con- 

 nected, the sugar cane. For its most successful cultivation, 

 that is, its most profitable, as regards its produce and returns, 

 supposing the fallow system to be put aside as least judicious, 

 it needs to be determined what kind of manure is best fitted 

 to bring the cane to its perfection of growth as a sugar bear- 

 ing plant, and with most economy, keeping in view the ba- 

 lance sheet of an estate. If the problem is entered upon by 

 the agricultural chemist, as I apprehend it should be, he 

 will have to consider what are the elements constituting 

 sugar; they are oxygen, hydrogen, and carbon, elements de- 

 rived from the atmosphere, either directly or indirectly : he 

 will have to consider what are the elements of the saccharine 

 juice, as extracted by pressure from the plant ; these, besides 

 sugar, are, I believe, chiefly starch and albuminous matter, 

 or a matter containing azote, and capable of exciting the 

 vinous fermentation, and one or more vegetable acids : he 

 will have to consider what are the elements of the cellular 

 structure of the plant in which the saccharine juice is con- 

 tained, and the composition of the other parts of the cane ; 

 these appear to be very much the same as the constituent 

 elements of the stalk and leaves of the other grasses, viz. — 

 phosphate of lime, silica, lime, magnesia, and potash, with 

 the common elements, carbon, oxygen, and hydrogen. Hav- 

 ing given consideration to all these matters, he may ofi^er 

 suggestions for trial. As the cane contains little azotized 

 matter, and pure sugar none, he may suggest that the ma- 

 nure most likely to be successful is one composed chiefly of 

 vegetable matter, or one in which the proportion of animal 

 matter is small. As the sugar and other exports, viz. rum 

 and molasses, contain very little of any matter of a mineral 



