Page:The American Cyclopædia (1879) Volume VI.djvu/73

 DEWSBURY of Orange, and thrown into prison and tor- tured. On his release, Jan was waiting for him at the gate, when both were seized by a mob and murdered. The states general demanded an investigation of the affair ; but the stadtholder neglected to do anything about it, and was therefore believed to have countenanced the assassination. The brothers, by their ability, courage, and integrity, had commanded the respect and admiration even of their political opponents. Jan was the au- thor of several works of political interest. DEWSBURY, a manufacturing town and par- ish of England, in the West Riding of York- shire, situated on the left bank of the Calder, and on the London and Northwestern railway, 28 m. S. W. of York; pop. in 1871, 24,773 (in 1851, 5,031). It is at the head of what is called the shoddy trade of England, vast quan- tities of refuse woollen rags, called " devil's dust," being collected from all parts of the kingdom and made into cloth, blankets, and carpets. About 3,000 persons are employed in these manufactures. There are collieries and iron works in the immediate neighborhood. DEXTER, Samnel, an American statesman and jurist, born in Boston, May 14, 1761, died at Athens, N. Y., May 4, 1816. He graduated at 1 Harvard college in 1781, and was admitted to i the bar in 1784. After practising at various ] places in Massachusetts, he took up his resi- i dence in Boston. He was elected to the legis- lature of Massachusetts several times, and be- came a member of congress in 1793. In 1798 he was elected senator of the United States. He was appointed secretary of war by John Adams in 1800, and in 1801 secretary of the treasury, but returned to practice in 1802. He was a member of the federal party, but did not sympathize with it in regard to the war of 1812. In 1814 he was nominated by the re- publican party for the office of governor, on account of his opposition to the Hartford con- vention, but was defeated. He was the first president of the first temperance society in Massachusetts. DEXTRINE (Lat. dexter, right; called also British gum, Alsace gum, starch gum, and tor- refied starch), an isomeric condition of starch, having the composition C 8 Hio0 5 or Ci 2 Hi Oio. It is also isomeric with gum arabic, which it much resembles in appearance and in many properties, but differs in the remarkable one, from which it derives its name, of turning the plane of polarization to the right when polarized light is passed through a solution of it, instead of to the left, which is the case when a solu- tion of gum arabic is used. Starch will also turn the plane of polarization to the right, but in a much less marked degree than dextrine ; the latter having an optical rotary power of 138'68. Dextrine is an intermediate stage between starch and grape sugar, passing into the latter by combining with H 2 O, but differ- ing from starch in physical qualities only. Another intermediate modification between DEXTRINE 65 starch and dextrine exists, according to Maschke and others, called soluble starch, which possesses a higher degree of right-hand polarizing power than dextrine and is turned blue by iodine. (See STABCH.) Dextrine may be produced by several processes. 1. By care- fully roasting starch in shallow pans or revolv- ing cylinders, heated between 300 and 310 F. "When the starch presents a light brown color, and emits the odor of strongly baked bread, the transformation is effected. 2. By subjecting starch to the action of nitric acid. Pay en's method was to mix 1,000 parts of dry starch with 2 parts of nitric acid of 36 Baume diluted with 300 parts of water, and place the mixture in layers about an inch thick on brass drawers in an oven heated to about 240 F. The transformation is effected in an hour and a half or two hours. 3. By boiling starch with dilute sulphuric acid, about 11 parts of water, 4 of starch, and 1 of sulphuric acid being used. The starch is stirred in part of the water, and the acid diluted with the re- mainder. Both portions are then raised to about 194 F. and gradually mingled ; the tem- perature being maintained until as great a quantity as possible of dextrine is obtained, when the liquid is boiled to arrest the pro- duction of grape sugar, which is always formed in the process. The dextrine can only be ob- tained pure by repeatedly dissolving it in water and precipitating with alcohol. 4. By the action of diastase on starch. If 8 or 10 parts of malt are stirred in about 400 parts of water at 80 F., and the mixture is raised to about 140, and then 100 parts of starch are stirred in, the temperature being again raised to 158-167, and there maintained for about half an hour, the starch will be converted into dextrine; but unless the temperature is changed the latter will pass into grape sugar. By raising the mixture to the boiling point, however, the transformation is arrested. Dextrine, when pure, is solid, translucent, and uncrystallizable. It is ordinarily a brownish- colored powder, nearly tasteless, soluble in hot or cold water and in dilute alcohol, but insoluble in absolute alcohol. It is not colored blue, but red, by the action of iodine. When boiled with dilute acids and caustic alkalies, it is converted into glucose or grape sugar. If a small quantity of caustic potash is mixed with a solution of dextrine, and a dilute solution of sulphate of copper added drop by drop, the liquid will acquire a deep blue color, and will not yield a deposit while cold ; but if heated to 185 F., it will be decomposed, with precipi- tation of oxide of copper. This test (Trom- mer's) distinguishes it from gum arabic. It has been found that the presence of dextrine pre- vents the blueing of starch by iodine, and will even discolor iodide of starch. Dextrine is used for stiffening cotton goods to prepare them for printing, and for sizing paper. It is a superior substitute for gum arabic, to give an adhesive layer to postage stamps and the