G2G GELATINE 



GAS SINGEING MACHINE. See CALICO PRINTING. 



GAUXiT sometimes GOAT, a local term in some parts of England for clay, has 

 been adopted into geological nomenclature to denote the argillaceous strata which 

 separate the Upper and Lower Greensands. It is a dark blue or grey clay, used for 

 making bricks and tiles ; it affords a poor agricultural soil, which is generally con- 

 verted into pasture. H. W. B. 



GATTXiTHERXA OIXi, or Wintergreen Oil. A volatile oil obtained from the 

 Gaultheria procumbcns, the Wintorgreen or Canada tea. It has an agreeable aromatic 

 odour, and is used for scenting soaps. 



GAUXiTHERXNE. One of the hydrocarbons isomeric with oil of turpentine 

 which exists in Wintergreon oil, and the oil obtained by distilling the Betula Icnta, 

 the sweet or cherry birch. 



GAUZE. See CBAPE. 



GAUZE WIRE CLOTH is a textile fabric, either plain ortweeled, made of brass, 

 iron, or copper wire, of very various degrees of fineness and openness of textures. 

 Its chief uses are for sieves and safety lamps. 



GAY-IiTTSSITE is a white mineral of vitreous fracture, which crystallises in 

 oblique rhomboidal prisms ; specific gravity from T93 to 1'95 ; scratches gypsum, but 

 is scratched by calcspar ; affords water by calcination ; it consists of carbonic acid, 

 28-66; soda, 20'44 ; lime, 1770; water, 32-30; clay, 1-00. It is, in fact, by 

 I)r. lire's analysis, a hydrated soda-carbonate of lime in atomic proportions. This 

 mineral occurs abundantly in insulated crystals, disseminated through the bed of 

 clay which covers the urao, or native sesquicarbonate of soda, at Lagunilla in Columbia. 

 It is known to the natives as clavos, or nails. Gay-Lussite is also found in Little Salt 

 Lake, near Kagtown, Nevada. 



GAZOXiINE. A name given to one of the mineral oils. See NAPHTHA. 



GEDGE'S AXiXiOY. A hard alloy of copper, zinc, and iron, said to be well 

 adapted for sheathing ships. A good alloy contains about copper 60, zinc 38 '2, and 

 iron 1'8 per cent. 



GEHXiENITE. A silicate of lime, alumina, and sesquioxide of iron ; occurring in 

 grey or brown crystals belonging to the pyramidal system. A product agreeing with 

 gehlenite in both chemical composition and crystalline form occurs among blast- 

 furnace slags. 



GELATINE (Eng. and Fr. ; Gallerte, Leim, Ger.), is an animal product which is 

 never found in the humours, but it may be obtained by boiling with water the soft and 

 solid parts, as the muscles, the skin, the cartilages, bones, ligaments, tendons, and 

 membranes. Isinglass consists of from 86 to 93 per cent, of gelatine. This substance 

 is very soluble in boiling water ; the solution forming a tremulous mass of jelly when 

 it cools. Cold water has little action upon gelatine. Alcohol and tannin precipitate 

 gelatine from its solution ; the former by abstracting the water, the latter by combin- 

 ing with the substance itself into an insoluble compound, of the nature of leather. 

 No other acid, except thetannic, and no alkali, possesses the property of precipitating 

 pc-latine. But chlorine and certain salts render its solution more or less turbid ; as the 

 nitrate and bi-chloride of mercury, the proto-chloride of tin, and a few others. Sul- 

 phuric acid converts a solution of gelatine at a boiling heat into sugar. Gelatine con- 

 sists of carbon, 47'88 ; hydrogen, 7'91 ; oxygen, 27'21. 



Gelatine is produced by boiling the skin of animals in water, which in its crude 

 but solid state is called glue, and when a tremulous semi-liquid, size. See those 

 articles. 



A fine gelatine for culinary uses is prepared and sold as Nelson's patent gelatine. It 

 is thus prepared : After washing the parings, &c., of skin, he scores their surfaces, and 

 then digests them in a dilute caustic soda lye during ten days. They are next placed 

 in an air-tight vat, lined with cement, kept at a temperature of 70 Fahr. ; then 

 washed in a revolving cylinder-apparatus with plenty of cold water, and afterwards 

 exposed to the fumes of burning sulphur (sulphurous acid) in a wooden chamber. 

 They are now squeezed to expel the moisture, and finally converted into soluble gela- 

 tine, by water in earthen vessels, enclosed in steam-cases. The fluid gelatine, is 

 purified by straining it at a temperature of 100 or 120 Fahr. 



A sparkling gelatine has been prepared under a patent granted to Messrs. J. and 

 G. Cox, of Edinburgh. By their process the substance is rendered perfectly pure, 

 while it possesses a gelatinising force superior even to isinglass. It makes a splendid 

 calves' -feet jelly and a milk-white blanc-mange. The patentees also prepare a sojni- 

 solid gelatine, resembling jujubes, which readily dissolves in warm water, as also in tho 

 mouth, and may be employed to make an extemporaneous jelly. 



, The gelatine of bones may be extracted best by tho combined action of steam 

 and a current of water trickling over their crushed fragments in a properly-constructed 



