Sugar-refineries are built eight or nine stories high, and the raw sugar is first hoisted to the upper story, where it is dissolved in large tanks of hot water, care being taken to use as little water as possible for the purpose. A quantity of bullock's blood is stirred into the solution of sugar, and the heat being gradually raised, the albumen of the blood coagulates, and rises to the surface in the form of a thick light scum, bringing with it nearly all the mechanical impurities floating in the fluid. The liquor, still hot, is then passed into bag-filters. Those filters are made of a very closely woven cotton cloth, capable of retaining the minutest mechanical impurity. In order to facilitate the passage of the liquor through the bags, they are suspended in a kind of iron closet, and sur rounded by an atmosphere of steam to keep the liquor hot. From the bag-filters the liquor, now freed from all mechanical impurities, but of a dark color, flows into a lofty cylindrical iron filter, of about 5 or 0 ft. diameter, and 20 or 30 ft. high, filled with animal charcoal, that is, charcoal made of bones. This charcoal is reduced to coarse powder; and the dark offensive liquor is allowed to percolate very slowly through the mass. The result is, that it flows out at the bottom a perfectly transparent and pure solution of sugar. The charcoal can only be used for a few days at a time, because it gradually loses its purifying power; when the liquor begins to flow through it without being purified, it is taken out of the filter, and reburned, which completely revives its powers.
The liquor as it flows from the charcoal filter is a mixture of pure sugar and pure water, and perfectly transparent. The application of heat is the only mode of expelling the water, and this unfortunately blackens the sugar again. In order to get rid of the water with as little heat as possible, the colorless liquor is boiled in the vacuum-pan as in the early process of the manufacture. The liquor boils in vaeuo at about 150° F., and even this moderate heat has the effect of turning it quite brown. When it has been sufficiently concentrated by boiling in the vacuum-pan, which takes from lf to 21 hours, it is run into the sugar-loaf forms; which, after cooling, are carried to a room kept warm by means of steam-pipes. This warmth facilitates the flow of the treacle or syrup out at the aperture at the bottom of the form. To get rid of the coating of colored treacle which still hangs about the crystals of sugar, a small quantity of a saturated solution of pure white sugar is poured on the top of the form. This strong liquor is unable to dis solve any more sugar, but being more fluid than the sticky coatings of treacle or syrup adhering to the crystals, it mixes with the coatings, and makes them fluid enough to flow down to the bottom of the form, leaving the crystals clear of syrup or treacle, and consequently free of all color. This process of washing off the coloring matter from the crystals of sugar is the same in principle as the "slaying" used in the production of sugar. The loaves of sugar, after standing some time, to admit of all the liquor drain ing off, are wrapped in paper, and dried in stoves heated by steam. The liquor draining from the forms is reboiled in the vacuum-pan, and forms loaves of an inferior quality; and the liquor draining from the inferior loaves is again boiled into the yellow sugars known among sugar-refiners as bastards.
Crushed or crashed sugar is simply inferior loaves crushed while still soft and moist, and packed in hogsheads, instead of being left in the loaf form.
The syrup which drains from refined sugar is reboiled, and constitutes the golden .syrup of the shops.
Crystal Sugar.—In making the sugar crystals, all the processes are carried on as in refining, until the syrup is clarified. Then it is boiled or concentrated in a vacuum-pan of larger size than ordinary, and the concentration is carried on until minute crystals appear. Fresh syrup is then added from time to time, great care and experience being required to insure a regular feeding of the first-formed crystals, and prevent the forma tion of a second crop. When the crystals are large enough, the contents of the pan are transferred to the centrifugal machines, which quickly separate the crystals in a perfectly dry state from the uncrystallizable syrup. The crystals are of a square tabular form, with a deep groove across in one direction, dividing the crystal into equal parts. This kind of sugar is much liked for coffee, etc., but the crystals dissolve with difficulty The commerce in sugar is prodigious, and is rapidly increasing; but its consumption is very unequally distributed. Thus, in the six principal countries, America consumes the most, and Russia and Austria least.. The proportions are as follow: Great Britain, 30 lbs. per head; France, 4 lbs. ; Belgium, 6 lbs.; Russia, 1+ lbs.; Austria, 1+ lbs.; 'United States of America, 40 lbs. The quantity of all kinds imported into Great Britain in 1877 amounted to the enormous sum of 831,047 tons unrefined; 171,492 tons refined; and 14,913 tons of molasses; the total value of all of which was £27,327,988.
Saceltarum, a genus of grasses, natives of tropical and sub-tropical countries. The common sugar-cane (S. ogieinarum) is originally a native of the East Indies, was brought to the s. of Europe by the crusaders, and iu the 15th and 16th c. found its way into all the European colonies within the tropics. In Europe the culti vation of the sugar-cane has always been very limited, and is scarcely practiced except in Sicily and Andalusia. In China it extends to 30° n. lat., and in North America to 32'; in the southern hemisphere only to 22° s. lat. The plant is a perennial with a creeping root, sending up a number of culms or stems, generally 8 to 12 ft. high, which have many joints, are of various colors, and about 1to 2 in. thick. They are filled for about two-thirds of their length with a loose, sweet, juicy pith. The leaves are ribbon-shaped, and 4 to 5 ft. long, with a strong whitish middle nerve. The flowers are in great diffuse pyramidal panicles of a yard in length. The violet-colored sugar-cane (S. violaceum) is particularly esteemed, and much cultivated in the West Indies.—The Chinese sugar-cane (S. sinense), cultivated in China, has the stem in great part covered with the sheaths of the leaves. Cultivation has produced many varieties of these species; if, indeed they are originally distinct species, and not themselves mere varieties.—The species of sac-Mai-um are numerous; they contain much silica in the rind, and some of them are much employed in India for thatching and for making mats, as well as for screens and light fences. The Bengalese make their pens of the hollow stems of S. semideeumbens and S. fuscum.