refining of sugar is mainly a bleaching process, conducted on a large scale in England. There are two varieties produced by this bleaching, viz. clayed and loaf sugar. For clayed sugar, the sugar is removed from the coolers into conical earthen moulds called formes, each of which has a small hole at the apex. These holes being stopped up the formes are placed, apex downwards, in other earthen vessels. The syrup, after being stirred round, is left for from fifteen to twenty hours to crystallise. The plugs are then withdrawn, to let out the uncrystallised syrup ; and, the base of the crystallised loaf being removed, the forme is filled up with pnlverised white sugar. This is well pressed down, and then a quantity of clay, mixed with water is placed upon the sugar, the formes being put into fresh empty pots. The mois ture from the clay, filtering through the sugar, carries with it a portion of the colouring matter, which is more soluble than the crystals themselves. By a repetition of this process the sugar attains nearly a white colour, and is then dried and crushed for sale.
But loaf sugar is the kind most usually produced by the refining processes. The brown sugar is dissolved with hot water, and then filtered through canvas bags,from which it exudes as a clear, transparent though reddish syrup. The removal of this red tinge is effected by filtering the syrup through a mass of powdered charcoal ; and we have then a perfectly transparent and colourless liquid. In the evaporation or concentration of the clarified syrup, which forms the next part of the refining process, the boiling is effected (under the admirable system introduced by Mr. Howard) in a vacuum, at a temperature of about 140° Fahr. The sugar-pan is a large copper vessel, with arrangements for extracting the air, admitting the syrup, admitting steam pipes, and draining off the sugar when concen trated. In using the pan, a quantity of syrup is admitted ; and an air-pump is set to work, td extract all the air from the pan, in ordei• that the contents may boil at a low temperature. The evaporation proceeds ; and, when com pleted, the evaporated syrup flows out of the pan through a pipe into an open vessel beneath, called the granulating vessel, around which steam circulates, and within which the syrup is brought to a partially crystallised state. From the granulators the syrup or sugar is transferred into moulds of a conical form, which were formerly made of coarse pottery, but are now usually of iron ; in these moulds the sugar crystallises and whitens, the remain ing uncrystallised syrup flowing out at an opening at the bottom of the moulds. This
syrup is re-boiled with raw sugar, so as to yield an inferior quality of sugar ; and when all the crystallisable matter has been extracted from it, the remainder is field as treacle. The loaves of sugar, after a few finishing processes, are ready for sale; The improvements introduced into the pro cesses of sugar-refining allow loaf sugar to be now sold at a price so little exceeding that of raw sugar, that the manufacture ha's lately vastly increased.
Sugar-Candy is a Idnd of crystallised sugar made in China and India. The crystals are formed around small strings or twigs, from which they are afterwards broken off. When heated to 385° Fehr. sugar melts into a viscid colourless liquid which when cooled suddenly, becomes barley-sugar.
Beet Root Sugar is briefly described under BEET. The manufacture is not in a flourishing state, as it cannot well compete commercially with thitt from the sugar-cane. There is a pro ject at present on foot for establishing the beet sugar manufacture in Ireland. It is proposed to establish a Company with a capital of half a million sterling ; and to buy Irish beet root with a view of extracting sugar from it by processes which have recently been patented, and the patents for which are to be held by the Company. The projectors start upon the basis that the climate, soil, and labour-supply of Ireland are highly favourable to the culture ; and that the patent processes are calculated to perform the extraction of sugar well and cheaply. It remains to be shown how far these anticipations are capable of being borne out ; if commercially advantageous at all, Ireland must unquestionably be benefited by it. The Company's calculations give 400 tons of sugar and 100 tons of molasses for 0000 tons of beet-root ; and shadow forth a flatter: ing rate of prospective dividend. So do the calculations of the Irish Peat Company ; and we can only at Present express a wish that the anticipations may be realised. (April 1851.) It has just been announced that there are now 303 Beet-Sugar Manufactories in France ; and that the produce of French Beet-Sugar in 1850 was 74,628,007 kilogrammes— about 160,917,900 lb.
Sugar Trade.—Before the discovery of America, sugar was a costly luxury used only on rare occasions. About 1459 Margaret writing to her husband, who was a gentleman and land-owner in Norfolk, begs that he will 'vouchsafe' to buy her a pound of sugar. The consumption has gradually but steadily increased throughout the world.