SUGAR 



789 



carried out in high buildings, so that the materials 

 may gravitate from higher to lower levels in order 

 to avoid the cost of pumping. The first operation, 

 that of discharging the hogsheads of muscavado, 

 bags of beet, mats of jaggery (as most of the sugar 

 from the East is called), or other packages, takes 

 place on the highest floor of the refinery. Here 

 the sugars are mixed, and thence delivered on to 

 the next lower or 'blow-up' floor by means of 

 shoots. The ' blow-ups ' are large vessels in which 

 the sugar is dissolved in hot water to a syrup of 

 25 27 B. when hot, equal to 27 30 B. when 

 cold. The syrup next flows through filter-bags, of 

 which a large number are required, owing to the 

 slimy nature of the suspended matter, and is then 

 caused to gravitate down large iron cylinders 

 packed with granulated animal charcoal. This 

 is produced by heating bones to redness in closed 

 vessels without access of air, and possesses the 

 power of removing colouring (and other) matters 

 not only from sugar solutions, but from most 

 organic liquids. After a time the charcoal becomes 

 spent ana ceases to act, but regains its proper- 

 ties upon reburning, an operation which is carried 

 out in a refinery as many as a hundred times. 

 The first syrup running from the char-cisterns is 

 quite colourless, and this portion is collected apart 

 and boiled for the production of loaves or crystals. 

 The last portions of syrup yield the ' pieces ' or 

 yellow moist sugar. The boiling is effected in 

 vacuum-pans, and a small quantity of sulphurous 

 acid is added to the pan and greatly improves the 

 colour of the ' pieces. ' In boiling this class of 

 goods the object is to form a 'false grain' i.e. 

 an aggregation of small grains having the appear- 

 ance of larger partiles ; in this way a soft-looKing 

 sugar of primrose complexion and carrying a large 

 quantity of syrup, which pleases the eye much 

 more than a gray -looking 'piece' sugar of bolder 

 grain, is obtained. The thick mass from the pan 

 w discharged through an opening in the bottom 

 into centrifugal machines, which, with the aid 

 of a little wash water, separate the crystals from the 

 syrup. This operation of ' machining,' it should be 

 mentioned, is frequently applied to hard grainy 

 beet-sugars in the initial stage of refining, and the 

 resulting ill-smelling impure syrup treated apart 

 from the grayish white and comparatively pure 

 crystals left upon the machine. 



Lump sugar is made by draining a very stiff 

 masse-cnite of small grain in moulds, and afterwards 

 drying the concreted loaves ; for the production 

 of cube sugar moulds of peculiar shape are used, 

 which when filled are placed in centrifugal 

 machines to facilitate the removal of tne syrup. 



Analysis. Three estimations are chiefly neces- 

 sary for the analysis of raw sugar, the determina- 

 tion of polarising value, of glucose, and of ash 

 or mineral matter. The polarimeter is an instru- 

 ment by which the rotatory power of sucrose (or 

 other sugars) upon a ray of polarised light is made 

 available for purposes of quantitative measure- 

 ment. Those instruments are the best that require 

 the use of the yellow light of the sodium ray. The 

 two Nichol prisms of the polarimeter being crossed 

 and the vernier at zero, a filtered solution of sugar 

 containing a known weight of the sample in unit 

 volume is introduced into a tube 20 centimetres 

 long and placed between the prisms. The result 

 is a transmission of light requiring for its sup- 

 pression the rotation of the analysing prism, the 

 one nearest to the eye. From the angular degrees 

 of thi* rotation the polarising value of the sample 

 is deduced. 



In actual instruments an ingenious device is 

 made use of for the sake of gaining delicacy. This 

 consists in covering one-half of the optical field 

 with a half- wave plate of quartz, or, in the modern 



instrument made by Field & Co. of Birmingham, 

 by a less expensive but equally efficacious half- wave 

 plate of mica ; the field in these instruments is 

 always more or less bright, but the slightest move- 

 ment of the prism in either direction from the 

 neutral point causes an unequal shadowing of the 

 two semi-discs, and very sharp observations can be 

 made. The presence of glucose in sugar, and the 

 amount, are ascertained by titration with standard 

 Fehling's solution made by dissolving in every litre 

 34 '64 grains of crys. sulphate of copper, 70 grams 

 of caustic soda, and 180 grains of Kochelle salt. 

 This liquid is not affected by sucrose, but when a 

 solution of a sample containing glucose (also 

 maltose, lactose, &c. ) is delivered into a known 

 volume of the copper solution diluted with water, 

 and kept at the temperature of boiling, the copper 

 is precipitated as redsuboxide, and the supernatant 

 liquid becomes colourless. The volume of the solu- 

 tion of sugar required to effect this result is a 

 measure of the glucose present. The ash of sugar 

 is ascertained by burning 1 gram of the sample 

 in a platinum capsule at a red neat ; but, owing to 

 the difficulty of obtaining a white ash from the 

 fusible salts, it is usual in technical practice to add 

 two or three drops of strong sulphuric acid before 

 ignition, and to deduct one-tenth for the extra 

 weight thus introduced. From the various deter- 

 minations made as described the rendenient or 

 refining value of the sample is deduced by sub- 

 tracting five times the percentage of ash plus 

 the percentage of glucose from the percentage 

 of sucrose indicated by the polarimeter ; in the 

 case of sugar from the cane only three times the 

 ash is deducted by some analysts. 



Besides sucrose the only saccharoses of practical 

 importance are lactose and maltose. Lactose is 

 the natural sugar of milk. It is a solid substance 

 of sweetness inferior to sucrose, crystallising in 

 hard, white, semi-transparent masses, having the 

 composition CuHjaOn+HjO, and soluble in water, 

 but unsoluble in alcohol or ether. When boiled 

 with dilute sulphuric or hydrochloric acid it is 

 converted into the two glucoses dextrose and 



falactose. It is not fermented by yeast alone, 

 ut in contact with yeast and putrefying casein it 

 ferments, yielding alcohol and lactic acid. Koumiss 

 is a product of such fermentation acting upon the 

 milk of mares. Lactose reduces Fehling's solution 

 and rotates the plane of polarisation to the right. 



Maltose, CuHjjOii, occurs in fine crystalline 

 needles, soluble in water and in alcohol, but to a 

 less extent than sucrose. This sugar reduces 

 Fehling's solution, and has a dextro-rotatory 

 polarisation. It derives its chief interest and 

 importance from the fact that it is the principal 

 ingredient in beer worts, in which it owes its 

 presence to the action of an enzyme, diastase, 

 possessing the power of hydrolysing starch, and 

 forming from it maltose and dextrin, but not 

 glucose, as was formerly supposed. It is probably 

 not directly fermentable by yeast, but is rapidly 

 inverted by that organism and converted into 

 alcohol and carbonic acid. 



The world's product and consumpt of sugar 

 especially beet-sugar has increased largely within 

 recent years. In an average year of the period 

 1853-55 the total was estimated, in papers pub- 

 lished by the British Board of Trade in 1889, at 

 1,423,000 tons; in 1871-73, at 2,786,000; in 1886- 

 87, at 5,187,000. In the same years beet- 

 sugar production was respectively 190,000 tons, 

 1,042,000 tons, and 2,433,000 tons; cane-sugar 

 from British colonies, 261,000 tons, 336,000 tons, 

 580,000 tons. For 1898 the total crop of beet-sugar 

 was estimated at 4,500,000 tons. Of the total 

 supply the United States is believed to consume 29 

 per cent. , and the United Kingdom 21 per cent. The 



