94 



MANUFACTURE OF SUGAR. 



in solution, which, by fermentation, is quickly converted 

 into various other substances, as glucose, gum, vinegar, 

 alcohol, &c. &c. This also shows the necessity of imme- 

 diate defecation. Dr. Evans says, that ripe healthy canes 

 contain from one to four parts in a thousand of dextrine ; 

 and Dr. Davy says, he invariably detected starch in the 

 matter separated from the fresh juice by filtration, using 

 iodine as a test, and aided by the microscope. 



Of the substance designated by Hervey, " matiere deli- 

 quescente," I shall give his own description. He says, — ■ 

 " It is soluble in water, neither sweet nor salt, leaving no 

 ashes on incineration. We are inclined to think that in 

 manufacturing on a large scale, it may play an important 

 part in the production of melasses, that is, if it does not 

 combine with the sugar, it tends naturally to augment the 

 viscosity of the crystallizations from the melasses. The 

 substance is colourless when obtained by evaporation in 

 vacuo, or at a low temperature, but becomes coloured by the 

 action of heat. Its aqueous solution offers two distinguish- 

 ing characteristics : it is precipitated by tannin, and ab- 

 sorbed by pure animal charcoal, in such a manner that 

 cold water no longer removes." Dr. Evans says of it, — 

 " When a portion of sugar cane, cut into thin slices and 

 dried, is infused in cold alcohol, a peculiar substance 

 remains in solution, which is obtained on evaporation. It 

 is neither sweet nor salt to the taste, is uncrystallizable, 

 and highly deliquescent. It is the f matiere deliquescente' 

 of Hervey. Its composition is unknown." 



