Ashes of Sugar- Canes Ji'om the Wesi '■ Indies. 5S7 



canes were carefully collected ami returned to the soil in an 

 available state, I do not see why cane crops might not be 

 grown upon the same land almost indefinitely. 'ladT .:> 

 *'; Under the present system, however, the crU^lf^"''<;ttW6s 

 ^hich have been passed through the sugar-mill to squeeze out 

 the juice they contain, are burned under the coppers of the 

 boiling-house to concentrate the syrup. As this operation re- 

 quires a strong, brisk fire, the furnace in which they are burned 

 has usually a considerable draught, and therefore so high a 

 heat, that the ashes, from the large amount of alkalies and 

 silica they contain, are invariably fused into a hard, insoluble 

 glass or slag, ^"his slag or glass is usually thrown away, but 

 even if it were pulverized and spread upon the fields, from its 

 almost total insolubility, I apprehend it would be found nearly 

 useless as a manure. The only way to render the cane-ashes 

 available for this purpose, is either to burn the canes in an 

 open fire, at a much lower heat, so as not to fuse them, oi-, 

 what will probably be found much more advisable in practice, 

 to reduce the slags to a fine powder, and then to i'use them 

 for an hour or so, either in a large iron crucible, or in a re- 

 verberatory furnace, with an intimate mixture of one and a 

 half part American black ashes and one of carbonate of soda. 

 This operation, which is by no means either difficult or ex- 

 pensive, has the effect of reconverting the slags into soluble 

 alkaline silicates, and thus rendering them quite available for 

 the nourishment of the canes. After fusion with excess of al- 

 kalies, the slags may be readily reduced to powder, and with 

 a small quantity of either bone-dust or guano they will form 

 an excellent manure for either canes or wheat. It is advisable 

 to apply the guano and the fused ashes separately, as the ex- 

 cess of alkali present in the ashes would have the eff*ect of 

 dissipating part of the ammonia of the guano. The ashes of 

 almost any kind of wood, if burned in an open fire, so as not 

 to be melted, would, I believe, be found very beneficial to the 

 sugar-cane, and of course the more potash the ashes contained 

 so much the better. 



The fluxing of the cane-ashes with alkalies, just recom- 

 mended, might, I think, be readily effected in most of the co- 

 lonies themselves, as a great deal of fuel is by no means ne- 

 cessary, and a bright red heat kept up for an hour or so is am- 

 ply sufficient; but as the quantity of cane-ashes produced on 

 an estate will not exceed a very few tons in a year, probably 

 not more than four or five, if so much, they might perhaps be 

 advantageously sent to Great Britain, where fuel is much 

 cheaper, and then returned to the colonies in a mainifactured 

 state. 



Glasgow, November 11, 1845. 

 Phil. Mag. S. 3. No. 183. Suppl. Vol. 27. 2 N 



