714 



SEGAR. 



cally one above the other, the fire being ap- 

 plied under the uppermost one, and the flue 

 thence diving beneath a second and a third, 

 and entering the chimney the pans having 

 "inclined longitudinally-corrugated evaporating 

 Burfaces," of greater extent in succession, de- 

 scending, and each of the upper ones being at 

 will discharged by a pipe into the next below. 



The principle of endosmose, discovered by 

 Dutrochet, and substantially that known in cer- 

 tain forms, since the researches of Professor 

 Graham, under the names of "diffusion" and 

 " dialysis " (see DIALYSIS, in the article CHEMIS- 

 TRY, ANNUAL CYCLOPAEDIA, 1862), was applied 

 by M. Dubrimfaut for the extraction of sugar (it 

 would appear) directly from the beet root ; the 

 process being patented by the latter in April, 

 1854, but then superseded by the plan of clari- 

 fying the beet juice with baryta. The same in- 

 ventor patented in June, 1863, another refining 

 apparatus on the dialytic principle, the porous 

 membrane through which diffusion was to take 

 place being of parchmentized paper ; and this 

 he applied for the recovery of sugar from mo- 

 lasses. More recently, according to a statement 

 in the London Produce Market Review, M. Ro- 

 bert, of Seclowitz, in Prussian Silesia, has ap- 

 plied the principle of diffusion to withdraw the 

 sugar (and incidentally also mineral salts, which 

 can afterward be removed,) from the crude 

 juice of the beet. It is said that he has thus 

 obtained ten per cent, of sugar from the beet 

 root, leaving scarcely a trace in the residue ; 

 that the process is believed to be applicable to 

 the cane, and seemingly in the way of slicing 

 up and directly macerating the stalks ; that a 

 patent has also been taken out in England for 

 Mr. Minchin, of Aska, Madras, covering the 

 employment of the like principle in the extrac- 

 tion of sugar from (it appears) the cane grown 

 in India ; that probably fifteen per cent, of the 

 sugar in the juice can thus be obtained, and 

 more cheaply than the less quantity secured 

 by the ordinary modes ; and that the method 

 promises to be applicable to the extraction of 

 sugar from sorghum and maize. 



Many of the improvements which have now 

 been named are, in fact, such as originated 

 either in course of the investigations carried on 

 at the outset of the beet-sugar manufacture in 

 France, or else in the way of new agents or 

 methods applicable to the business of refining, 

 and which were later transferred to the work- 

 ing of raw cane sugar. Conflicting opinions at 

 present exist in regard to the question how far 

 the raw manufacture, as conducted on the sugar 

 estates, admits ultimately of improvement; as, 

 while some authorities urge the practicability 

 of producing there a perfectly pure, crystalline 

 sugar, others, although admitting that great 

 improvements in the raw product generally are 

 likely still to be made, claim that loaf and lump 

 sugars cannot on the estates be successfully and 

 economically manufactured. It is certain that 

 in Louisiana, in Cuba, Java, Mauritius, and 

 elsewhere, including (spite of a swampy soil and 



the large amount of saline and other foreign 

 matters in the cane juice) even Demarara, 

 wherever improved mechanism, as the vacuum- 

 pan, bone-black filters, etc., and a more skilled 

 supervision have been introduced, a considerable 

 increase in the yield of sugar, often as high aa 

 30 to 40 per cent., and sometimes more, and 

 also a higher market value, have been the re- 

 sults. 



In an account, in 1861, of the sugar crops of 

 Cuba, it is stated that in the previous season, 

 while, of 1,365 sugar estates in operation, 409 

 were still dependent on the primitive plan of 

 ox-power only, and T employed water-power, 

 the other 949 were using steam-power ; and it 

 maybe inferred that among this class improved 

 methods of manufacture are also pretty gener- 

 ally introduced. In Mauritius, in 1863, about 

 100 estates were using the vacuum-apparatus ; 

 and while all of these manufactured a superior 

 quality of very light-colored sugar, it is in the 

 same connection asserted that the vacuum pro- 

 cess proves in reality quite as cheap as the ear- 

 lier, inferior, and more wasteful modes. The 

 Messrs. Travers (quoted in the Journal of tli& 

 Society of Arts, March, 1866,) say that, without 

 resort to Reynoso's and other very recent pro- 

 cesses, a point has already been reached when, 

 by means of vacuum boiling, centrifugal ma- 

 chines, etc., white sugar can be made as cheaply 

 as brown, and when, but for the effect of the 

 scale of duties [speaking for England, where the 

 better grades of white raw sugars have paid a 

 duty 30 or 40 per cent., or upward, higher 

 than the brown or common qualities], all sugars 

 might be received in a state suitable for imme- 

 diate use. 



Outline of the Processes of Sugar-Refining. 

 Raw sugars are likely to contain, besides some 

 water and uncrystallizable sugar, also remains 

 of lime or other purifying agents, and of saline 

 matters from the cane juice, some albumen and 

 other vegetable impurities, sometimes minute 

 portions of sand and clay, and substances of an 

 organic nature among them, caramel which 

 impart color; while in some cases they are in- 

 fested with the disgusting mite known as the 

 sugar-insect (acarus sacchari). Even the whitest 

 raw sugars will, as yet, usually contain more or 

 less of such impurities ; and indeed the refining 

 process itself seldom, if ever, turns out an abso- 

 lutely pure sugar, though, with care and skill, 

 it succeeds in removing all admixtures of a nox- 

 ious or offensive character. The fallacy, how- 

 ever, of the supposition, still to some extent 

 current, that brown sugars possess greater 

 sweetening power than the refined, is sufficiently 

 evident ; the deception having probably arisen 

 from the more ready dissolving of raw sugars 

 in the mouth, and from the flavor of some of 

 their non-saccharine ingredients, which is liable 

 to be mistaken for sweetness. 



The older and simpler modes of sugar-refining 

 have, of late years, been replaced by the far 

 more effective one of which the essential fea- 

 tures are the new methods of filtering, concen- 



