71C 



SUGAR. 



tho loaves or tillers are properly trimmed, and 

 then dried by baking for several days in ovens 

 heated by steam to 130 or 140. 



Certain mechanical methods have been re- 

 sorted to for expediting and perfecting the 

 draining and cleansing of the sugar in the 

 loaves or bulk, some of them already referred 

 to under the raw manufacture ; as, by applying 

 compressed air upon the loaves, by the vacuum 

 or " pneumatic process," and by centrifugal 

 action: in the last, the plan of whirling the 

 loaves in the moulds, being regarded as danger- 

 ous, has not come into general use; but tho 

 method with the hydro-extractor or small cen- 

 trifugal machine has succeeded well, being re- 

 sorted to in the making of crystals, and of the 

 soft refined sugars. The drainings from the 

 loaves are usually once or oftener mixed with 

 raw sugar and concentrated for sugars of in- 

 ferior quality, commonly soft, and then known 

 in the business and trade as " pieces," " bas- 

 tards," etc. ; but ultimately such drainings, in 

 some cases with and in others without a sepa- 

 rate purification, are sold as " syrups." 



" Cut-loaf" sugar is formed from the loaf by 

 means of different forms of simple mechanism ; 

 as in tho use of one of the machines invented 

 by Mr. William Holier, by first sawing into 

 thin slabs by parallel circular saws, and then 

 dividing thos"e into blocks of convenient size 

 for table use, by cutting them one at a time 

 with a series of knife-blades, set on a stamp- 

 head and crossing at right angles. " Crushed " 

 sugar is prepared by crushing the loaf to lumps 

 of varying size and shape; "granulated," by 

 screening out from the crushed sugars, or from 

 fragments or even entire loaves finely crushed 

 up for the purpose, the separated crystals; 

 and " pulverized " or " powdered " sugars, by 

 grinding the crushed loaf, and usually with the 

 debris or sugar-dust from the other operations, 

 to a more or less fine flour; the different fine- 

 Besses being then, as may be done also in case 

 of granulated sugars, separated by screening. 

 In England, the term "crushed "is applied to 

 an inferior refined sugar, corresponding, it 

 would appear, to the coffee sugars. 



For the preparation of "crystals," sometimes 

 known as " centrifugal sugar," vacuum-pans of 

 unusually large size, and provided with extra 

 heating surface by means of additional coils, 

 are employed. The object being to secure 

 large crystals, the pan is several times charged 

 with small charges, each in succession being 

 concentrated, but the aim being to keep the 

 solution just dense enough to continue feeding 

 the crystals first formed, without favoring tho 

 formation of successive crops of them ; and 

 further, in order to keep up this action, for 

 several times in succession but one-half the 

 contents of the pan are at a time discharged 

 Into the heater, the remaining one-half being 

 reserved to afford nuclei for the succeeding 

 charges of solution. The mass in a semi-fluid 

 condition is at the proper moment speedily re- 

 moved to centrifugal machines, and the syrup 



being discharged, the surface of the crystals \s 

 further cleansed by sprinkling liquor iuto the 

 machines by means of a watering-can a few 

 pints to each hundred weight. If the crystals 

 be made too large, they dissolve with difficulty, 

 and are so far less desirable for general con- 

 sumption. (UuE.) The manufacture of crys- 

 tals in Great Britain is especially carried on in 

 London and Bristol, and in some Scotch refin- 

 eries. 



Recent Improvements in Sugar- Refining. In 

 Cuba, as preparatory to the application of lime, 

 Mr. Swift has, since 1860, employed the acu 1 

 phosphate of lime, and M. Reynoso, more re 

 cently, the acid phosphate of alumina, as clari 

 fying agents ; either of these being put directly 

 into the expressed juice, and a very thorough 

 purification being thus secured. The latter salt 

 (superphosphate of alumina) was employed in 

 England as early as 1857, by Mr. Oxland. Re- 

 garding the use of blood for clarifying as liable 

 to leave in the syrup some uncoagulated matters 

 and salts, tending to promote fermentation in it, 

 Mr. Oxland. clarifies instead with the alumina 

 salt named 12 oz. to the ton of sugar and 

 powdered animal charcoal. The solution was 

 thus so completely purified that less bone-black 

 was subsequently required ; and the method was 

 considered to render very impure raw sugars 

 available. Note in Amer. Jour, of Science, v. 

 25, Jan., 1858. 



Mr. J. 0. Tucker, of New York, obtained, in 

 I860, a patent for the decoloring or defecation 

 of saccharine liquids, by use of hydrate of 

 alumina, prepared by decomposing a solution 

 of the sulphate of that earth by cream of lime, 

 and to be used either with or without animal 

 charcoal. 



The use of alumina, as also of baryta, ap- 

 pears to have originated with the beet-sugar 

 manufacture, in one mode of which it is still a 

 common plan to add hydrate of lime directly to 

 the juice or solution from the roots, and then 

 to introduce ammonia-alum, at once to convert 

 the lime into a sulphate, and to aid the clarifica- 

 tion by the alumina set free. Baryta is still to 

 some extent employed in France and Belgium, 

 as a defecating agent for beet juice, in lieu of 

 lime; though at some refineries it has, after 

 trial, been rejected, on account of the noxious 

 character of the residues, and the risk of poison- 

 ous baryta-salts in the sugar. Mr. Goessmarm 

 (previously cited) quotes M. Kessler Repert. 

 de Ghim. Appliquee, 1863 as strongly favoring 

 the use of caustic magnesia for defecating beet 

 juice; though the former, from personal ob- 

 servation in Cuba, and from some experiments 

 made by himself, questions whether magnesia 

 will serve in the warmer climates for cane juice, 

 while at the same time he believes it would 

 answer well for clarifying solutions of raw 

 sugar. 



Although, in boiling with the vacuum-pan, 

 the saccharine solutions may be kept generally 

 at from 180 F. down to 160, or lower, yet 

 the steam used to heat the solution has had 



