118 SUGAR-CANE. 



green state afford excellent food for horses and cattle ; when dry 

 they are used for thatching- houses. After the first cuting, fresh 

 sprouts arise, which require no other attention than hoeing. In good 

 soils one planting will yield five or six harvests by successive 

 shoots ; but I have heard planters affirm, that the produce in sugar 

 diminishes from year to year. In Venezuela, cane-pieces are re- 

 planted every five or six years. 



The cane with its top struck off is carried to the mill, where the 

 juice is expressed, and the stems, which are spoken of under the 

 name of trash, are dried and used as fuel. 



The expressed juice contains crystallizable sugar, an azotized 

 substance analogous to albumen, and some saline matters dissolved 

 in a large quantity of water, which is dissipated by boiling, and the 

 sugar finally won by crystallization. The manufacturing process is 

 conducted with very different degrees of perfection in different 

 places. In some the produce is obtained almost without admixture 

 of molasses, in others the quantity of this article which drains away 

 from the sugar is very large. It is now generally agreed that mo- 

 lasses proceeds in great part from imperfections in the manufacturing 

 processes employed, especially to changes which the sugar under- 

 goes in the course of its concentration by boiling at a high tempera- 

 ture. By the employment of what are called vacuum pans of vari- 

 ous construction — pans from which the pressure of the atmosphere 

 is removed either by the air-pump, or the condensation of the vapor 

 as fast as it is formed, rapid evaporation is effected at a temperature 

 much below that of boiling water, by which it is found that the rela- 

 tive quantity of sugar to that of molasses is greatly increased. I 

 was long believed, indeed, and that on the authority of the first 

 chemists, that there were two kinds of sugar contained in the sugar- 

 cane, one crystallizable, the other uncrystallizable, and constituting 

 the molasses or treacle. The researches of M. Peligot* have 

 shown definitively that this conclusion is erroneous, that the cane con- 

 tains no sugar that is not crystallizable, and that the pre-existence 

 of uncrystallizable sugar or molasses is entirely chimerical. M. 

 Plague had indeed come to the same conclusion some considerable 

 time ago — as far back as 1826 ; but his labors were not made known 

 by publication till 1840. M. Casaseca, professor of chemistry at 

 Havana, has very lately confirmed these conclusions, so important 

 for the sugar husbandry of the world. f The composition of the 

 juice of the sugar-cane is therefore less complex than it was once 

 believed to be ; making abstraction of very minute quantities of an 

 albuminous azotized substance, of several salts and a little silica, 

 substances which altogether do not amount to more than two or 

 three hundredths, cane juice may be said to consist of water and of 

 crystallizable sugar in the proportion of from 17 to 20 per cent | 

 The Otaheite cane analyzed by M. Peligot actually yielded : 



■^ Ann. Mdiivimcs et Coloniales, Aug. 1842. 



I Vide Comptes Rendus, 1844. % Peligot, op tit 



