970 TARTAR 



of lamps, and other purposes. The dead oil contains paraffine, and is an excellent 

 lubricator for machinery : the uses of pitch need not be enumerated. See ANILIXE, 

 GAS-COAL, DESTRUCTIVE DISTILLATION, NAPHTHA, and PETROLEUM. 



TAR, WOOD (Goudron, Fr. ; Theer, Ger.), is the viscid, brown-black, resino- 

 oleaginous compound, obtained by distilling wood in close vessels, or in ovens of 

 a peculiar construction. Stockholm tar, Archangel tar, and American tar come into 

 our markets. According to Eeichenbach, tar contains the peculiar proximate prin- 

 ciples, paraffine, eupion, creosote, picamar, pittacal, besides pyrogenous resin or 

 pyretine, pyrogenous oil or pyroleine, and vinegar. 



The Stockholm tar is regarded as the best ; we have a description of the mode in 

 which it is prepared, by Dr. Clarke, in his ' Travels in Scandinavia ' : 



' The situation most favourable to the process is in a forest near to a marsh or 

 bog, because the roots of the fir, from which tar is principally extracted, are always 

 most productive in such places. A conical cavity is then made in the ground 

 (generally on the side of the bank or sloping hill), and the roots of the fir, together 

 with logs and billets of the same, being neatly trussed in a stack of the same conical 

 shape, are let into the cavity. The whole is then covered with a turf to prevent the 

 volatile parts from being dissipated, which, by means of a heavy wooden mallet and 

 wooden stamper, worked separately by two men, is beaten down and rendered as 

 firm as possible about the wood. The stack of billets is then kindled, and a slow 

 combustion of the fir takes place as in working charcoal. During this combustion 

 the tar exudes, and a cast-iron pan being at the bottom of the funnel, with a spout 

 which projects through the side of the bank, barrels are placed beneath this spout to 

 collect the fluid as it comes away. As fast as the barrels are filled they are bunged 

 and ready for immediate exportation.' Wood-tar is obtained as a secondary product 

 in the manufacture of acetic acid, in the dry distillation of wood. 



Tar Imported in 1873 : 



Barrels 



From Eussia 174,280 value 239,169 



Sweden 12,670 19,127 



,, Germany 9,558 13,094 



United States of America . . 16,218 22,072 



Other countries .... 2,604 3,670 



Total . 215,330 297,132 



Tar Imported in 1874 : 



238,810 Barrels; value 269,7492. 



TAKE, or Vetch. A well known fodder-plant ( Vicla sattva). 



TARPA.UI.ITr (from Tar). Canvas imbued with tar, used to cover the hatch- 

 ways of a ship to prevent rain or sea water from entering the hold, and for other 

 purposes. 



TARSAS. See TRASS. 



TARSIA (Intarsiatura, Ital.) A mosaic wood-work practised in Italy in the 

 fifteenth century. 



TARTAR (Tartre, Fr. ; Weinstein, Ger.); called also argal or argol, is the crude 

 bitartrate of potash, which exists in the juice of the grape, and is deposited 

 from wines in their fermenting casks, being precipitated in proportion as the alcohol 

 is formed, in consequence of its insolubility in that liquid. There are two sorts of 

 argol known in commerce, the white and the red ; the former, which is of .1 pale- 

 pinkish colour, is the crust let fall by white wines ; the latter is a dark red, from 

 red wines. 



The crude tartar is purified, or converted into cream of tartar, at Montpellier, by 

 the following process : 



The argal having been ground under vertical millstones and sifted, one part of it 

 is boiled with 15 of water in conical copper kettles tinned on the inside. As soon as 

 it is dissolved, 3 parts of ground pipe-clay are introduced. The solution, being well 

 stirred and then settled, is drawn off into crystallising vessels to cool ; the crystalc 

 found concreted on the sides and bottom are picked out, washed with water, and dried. 

 The mother-water is employed upon a fresh portion of argol. The crystals of the 

 first crop are re-dissolved, re-crystallised, and exposed upon stretched canvas to the 

 sun and air to be bleached. The clay serves to abstract the colouring-matter. The 

 crystals formed upon the surface are the whitest, whence the name ' cream of tartar ' is 

 derived. 



Purified tartar, the bitartrate of potash, is thus obtained in hard clusters of small 

 colourless crystals, which, examined by a lens, are seen to be transparent four-sided 

 prisms. It lias no smell, but a feebly acid taste ; is unchangeable in the air, has a 



