On Agricultural Chemistry. 



239 



especially as there are so many agriculturists in this country who 

 possess property in the West Indies, and the application of 

 scientific principles would increase the production of sugar and 

 reduce the expense of its cultivation to an extent not very readily 

 imagined. Although sugar is found in almost every plant at 

 certain periods of its growth, it is only extracted profitably from 

 three or four, of which the cane is the most important. Sugar 

 belongs to a class of carbonaceous substances, all of which are 

 developed in the greatest perfection in the hottest regions. 

 Among these are starch, gum, and oil ; and although each plant 

 possesses organs necessary to perfect its peculiar carbonaceous 

 products, the same laws must govern the formation of them in 

 all. In wheat I have shown that the carbonaceous product, 

 starch, increases with a supply of ammoniacal manures, under 

 the influence of a high temperature and the absence of rain ; 

 owing, however, to the moisture of our climate, and the want of 

 that temperature which is required for producing and depositing 

 starch, there are difficulties in the way of increasing this carbon- 

 aceous compound, which would not be met with if the same 

 principles were applied to produce sugar in the cane. If I could 

 depend upon a constant climate in England similar to that of 

 1846, I could produce annually 40 or 50 bushels of wheat upon 

 an acre with the same facility that I now produce 33 or 34 ; but, 

 as it is, were I to supply the proportion and quantity of mineral 

 and organic manures necessary to produce 50 bushels, in a wet 

 and cold summer — it would unduly develope the circulating con- 

 dition of the plant, its vascular structure would be increased to 

 an injurious extent, and the crop would be laid. Those who 

 farm very highly have often experienced this misfortune, and con- 

 sequently they dread a wet summer. 



To the farmer whose land is out of condition, however, a wet 

 summer is favourable, inasmuch as it increases the supply of 

 those elements of which his crop is in need. In the sugar-cane 

 the carbonaceous product is required in a circulating condition ; 

 therefore those sulDstances should be applied as manures which 

 increase the vascular action of the plant : at the same time the 

 soil should be rendered as dry as possible by draining. In soils 

 where the elements of fertility exist naturally, or where they are 

 properly supplied in the manures, the richest juice and largest 

 amount of sugar would be produced in the driest season. In 

 the absence, however, of the proper amount of organic matter 

 in the soil, the vital actions of the plant would, under the 

 same climate and circumstances, be weakened. The combustion 

 of the cane for fuel is a process which cannot be too much con- 

 demned. It involves the necessity of a much greater outlay in 

 manures every year ; for, if the mineral matter which remains after 



