409 



GLUCIC ACID. 



GLUTEN. 



410 



and have ever since conducted it more successfully than the glovers of 

 other parts of England. Worcester has produced gloves for nearly 

 three hundred years ; first of the beaver, or oil-leather kind, and then 

 of the tanned or alumed leather, of which kid is an example. At 

 Woodstock gloves have been made ever since the time of Queen 

 Elizabeth. Ludlow, Leominster, and Yeovil, are other towns in which 

 leather gloves are made. The introduction of knitted or looped fabrics 

 for gloves, similar in texture to hosiery, has had the effect of removing 

 much of the glove manufacture to the counties of Nottingham, 

 Leicester, and Derby, where such fabrics are mostly made ; this 

 novelty, and the larger importation of French gloves on the lowering 

 of the duty, have had the effect of reducing the manufacture of leather 

 gloves in most of the above-named towns. 



The economy of the glove manufacture is generally somewhat as 

 follows. Taking Worcester as an example, the master-manufacturers 

 live in the town, while the glove-sewers live in all -the villages for 

 many miles round about. These sewers are mostly the wives and 

 daughters of country people, who eke out a scanty subsistence by this 

 means. The leather employed mostly undergoes its preparatory pre- 

 paration at some of the tanneries in Bennondsey, but it is finished at 

 Worcester. The dressed skins are cut out in workshops, either by the 

 shears and guide-pieces, or by cutting machines of quicker action. 

 All the necessary thumb-pieces, finger-side pieces, 4c., are cut out in 

 proportionate number ; and enough pieces for a dozen pairs are made 

 up into a parcel. The sewers either send to the warehouse and take 

 away the parcel of pieces, or agents of the manufacturer make a tour 

 among the neighbouring villages at stated intervals, bring glove-pieces 

 to be made up, take away the gloves which have been made since the 

 last visit, and pay for the labour bestowed upon them : there may be 

 branch establishments at a few of the villages, each of which is the 

 centre of a district of glove-sewers. The sewers use a clasp or clam, 

 which is held between the feet and knees, and which clasps the leather 

 or leathers while being sewn ; in some cases the sewer is aided by a 

 kind of brass comb or notched plate, for ensuring regularity in the 

 stitches. Some of the women and girls confine then- attention to 

 sewing the different pieces together ; some work the ornamental 

 stitching at the back of the glove, while others finish the top. It may 

 here be remarked, however, that sewing-machines are gradually finding 

 their way into the glove-trade ; but it is only a portion of the work 

 which can be done by their aid. 



About ten years ago it was estimated that 46,000 persona were em- 

 ployed at glove making in England, producing gloves valued at about 

 one million sterling annually. During the years 1856-7-8, French 

 gloves were imported to the number of about 4,000,000 pairs 

 annually. 



GLUCIC ACID(C I4 H lil 11 ,3HO); Kalitaccharic acid. Glucose, or 

 grape sugar, forms, with bases, definite combinations, termed glucosides. 

 Within a short time after the formation of such compounds their solu- 

 tions are decomposable by a current of carbonic acid with separation 

 of unaltered sugar ; but even at ordinary temperatures they soon begin 

 to undergo change ; the liquid, at first powerfully alkaline, becomes 

 neutral, and a substance of strongly acid character remains in combi- 

 nation with the base. To this substance is given the name yliicic acid. 

 On the addition of subacetate of lead to the neutral solution, sub-glucate 

 of lead is precipitated, and this, on being decomposed by sulphuretted 

 hydrogen, furnishes glucic acid. 



Glucic acid is colourless and uncrystallisable, in appearance it some- 

 what resembles tannin, is very soluble in water and alcohol, has an 

 acid taste, and combines with some bases to form neutral and acid 

 salts. These salts are difficult to obtain in a crystallised condition ; 

 but the general formula of the neutral ones appears to be Cj.H^MjO,, 

 +Aq. 



When solution of glucic acid is boiled, it absorbs oxygen, becomes 

 brown, and a new uncrystallisable acid a formed. To the latter 

 Mulder gives the name ajmjlucic acid. 

 GLUCINA. [GLUCINUM.] 



GLUC'INUM (01.), the metallic base of an earth or oxide (ylitcina) 

 discovered by Vauquelin in 1798, in the beryl, or aqua marina, and 

 afterwards in the emerald. Before the discovery of potassium, glucina 

 and all other earths were considered as simple substances. Glucinum 

 was first obtained from glucina in 1827 by Wohler, who procured it by 

 decomposing the chloride of glucinum. Obtained in this mode, glu- 

 cinum is a fine powder of a deep gray colour, which is very difficult of 

 fusion. But, according to more recent experiment*, it is, after fusion, 

 a white malleable metal of up. gr. 2'1, fusing at a lower heat than 

 silver. It does not burn when heated in air or oxygen, neither does it 

 decompose the vapour of water at a red heat. 



t Dilute acids and solution of potash dissolve glucinum, with the evo- 

 lution of hydrogen gas, and its consequent conversion into glucina. 



Olucina (G1,O,), the only known oxide of the metal, is obtained 

 from the minerals which contain it, by fusing with carbonate of potash, 

 and treatment with acids and with carbonate of ammonia, which dis- 

 solves the glucina, and leaves the alumina unacted upon; the carbonate 

 of ammonia being expelled by heat, pure glucina remains. 



The properties of glucina are, that it is a light white powder, which 

 has neither smell nor taste, infusible, insoluble in water and solution 

 of ammonia, but soluble in potash and soda ; its specific gravity is 

 about 3. 



Glucinum combines readily also with chlorine, iodine, bromine, 

 sulphur, &c. 



Chloride of glucinum (G1 2 C1 3 ) is obtained by cautiously evaporating 

 a solution of glucina in hydrochloric acid. The residue is colourless, 

 sweet, very fusible and volatile, and sublimes readily in white brilliant 

 needles ; it deliquesces in the air, and dissolves largely in water with 

 the extrication of heat. When procured by evaporation, it is a gummy 

 mass, which contains water, and when heated in the air is decomposed 

 into hydrochloric acid and glucina. 



tfulphide of glucinum is formed by heating the metal in the vapour 

 of sulphur. Much heat is given out, and a gray sulphide of the metal 

 is obtained, which is soluble in water and decomposed by acids, with 

 the evolution of hydrosulphuric acid. 



The salts which glucina forms with acids are not important ; we 

 shall therefore mention only their general properties. They are all 

 colourless, except the chromate, which is yellow ; the taste is sweet, 

 and hence the name of the earth, and slightly astringent. With potash 

 and soda they give a white precipitate of hydrate of glucina, which an 

 excess re-dissolves ; but ammonia in excess does not re-dissolve the 

 hydrate. The carbonate of ammonia in excess re-dissolves the pre- 

 cipitated carbonate, and so also do, slightly, the carbonates of potash 

 and soda. Neither ferrocyanide of potassium nor tincture of galls 

 gives any precipitate. With fluoride of potassium there is produced a 

 double salt, which crystallises in small scales, provided the solutions 

 are hot, and the admixture is continued till the solutions begin to be 

 turbid. 



GLUCOSE. [SuGAB.] 



GLUCOSIDES. A number of vegetable substances which yield 

 sugar under the influence of various chemical agents are compre- 

 hended under this term. The following is a list of the bfst known 

 glucosides : 



Phloridzin (C 1 .H, t O IO , 4Aq.), when boiled with weak acids, is 

 decomposed into grape-sugar and a resinous matter named pkloretin : 



Phloridzin. 



4HO = C 1S H 14 14 

 Grape sugar. 



C 30 H 14 10 

 1'hloretin. 



Quercitrin (C M H 18 20 + 2Aq.) is transformed into quercetin and grape- 

 sugar when boiled with dilute sulphuric or hydrochloric acids : 



Quercitrin. 



4HO = C,,H 14 14 + C Z ,H 8 10 

 Grape sugar. Quercetin. 



Arbuiin (C n H tl O u ), under the influence of synaptase, yields grape- 

 sugar and arcturin : 



C^H^O, + C,,H 14 0, ? 

 Arcturin. Grape sugar. 



CH t ,0,, + 2HO = 



Arbutin. 



culin (C (2 H 14 O M ), when digested with synaptase or boiled with 

 dilute acids, yields etculetin and grape-sugar : 



Eaculin. 



10HO = C,.H 6 0. 

 Eeculetin. 



Grape sugar. 



Descriptions of these glucosides are given under their respective 

 names. 



GLUE. [GELATINE.] 



GLUTEN is the name given to the viscid, sticky, and more or less 

 elastic substance that remains when wheaten flour, inclosed in a bag, 

 has been well kneaded under water. It is exclusively a vegetable pro- 

 duct, is a characteristic ingredient of all the cereal grains, but is 

 notably contained in wheat and rye. 



Gluten plays an important part in the manufacture of bread, a 

 portion of it inducing alteration of the starch and subsequent fermen- 

 tation, while another portion, on account of its elastic property, admits 

 of the expansion or rising of the dough, and by its adhesive property 

 gives permanence to that expansion by preventing the expanding gas 

 from escaping. [BREAD.] 



As an article of food, gluten is a nutritive or flesh-forming material, 

 containing about 16 per cent, of nitrogen ; and as large quantities of it 

 are produced in the manufacture of wheat-starch, it has, under various 

 forms, been introduced as an alimentary substance. Gluten bread, 

 given to diabetic patients, may be readily made, (jlufcn biscuits, also 

 have been proposed ; and a kind of maccaroni or vermicelli, similar to 

 the Italian pastes, was sometime since introduced into commerce. 

 Semola w, essentially, wheat-flour from which a large proportion of the 

 starch has been washed, and the residue dried and granulated. 



Gluten is not a single definite body, but contains four distinct prin- 

 ciples, glutin, vegetable fibrin, vegetable casein, and an oily matter. 

 [FIBRIN ; GLIADIN.] Gluten is soluble in cold acetic acid and weak 

 alkaline solutions ; from these liquids it is again precipitated on care- 

 fully neutralising. The mineral acids form compounds with it. In 

 the dry state it forms a brown horny-looking mass, that may be 

 preserved for any length of time; but in the moist condition it rapidly 

 putrefies. 



