968 TANTALUM 



remelting the tallow, and mixing -with it some substances which render insoluble the 

 gelatinous matters, and precipitate the adventitious admixtures. See CANDLES and 

 FAT. 



Tallow and Stearine Imported in 1874 : 



Cwts. 



FromKussia . . 81,704 Value of 183,183 



Argentine Republic 

 United States 

 Australia . 

 Other countries . 



171,696 335,669 



440,421 894,862 



282,293 535,101 



178,685 369,436 



Total . . . 1,154,799 2,318,251 



, MINERAL See HATCHETTINE. 



TALLOW, PINEY. See OILS- 



TAIiIVIZ GOAD. An alloy known also as ' Abyssinian gold ; ' it is much used 

 for making imitation jewellery. Dr. C. Winkler says : ' The alloy is not galvanieally 

 gilt, but is plated, that is to say, a very thin sheet of gold is made to adhere to a 

 yellow metal (in 100 parts copper, 9074; zinc, 8'33) by rolling the metals together 

 and afterwards shaping, moulding, and chiselling it by means of steel tools, the amount 

 of gold varying from T03 to 0'03 per cent.' Articles made of this alloy are said to 

 wear really well. See ABYSSINIAN GOLD. 



TAMBAC. See TOMBAC. 



TAMPING is a term used by miners to express the filling up of the hole which 

 they have bored in a rock, after the gunpowder for blasting has been placed in the 

 bottom of the hole, with sand, the debris of the rock, or other matters. This, being 

 beaten hard together, presents nearly as much resistance to the mechanical force of 

 the powder, "when exploded, as the rock itself. See MINING. 



TANGIiE. Laminaria digitata. See ALG.ZE. 



TANNENITE. An ore of bismuth. See BISMUTH. 



TANNIN, or TANNIC ACID. (Tannin, Fr.; Gertstof, Ger.; Under the 

 name tannin were formerly included all those astringent principles which were 

 capable of combining with the skins of animals to form leather, of precipitating gela- 

 tine or of forming bluish-black precipitates with the persalts of iron, and of yielding 

 nearly insoluble compounds with some of the organic alkalis. But it has of late 

 years been proved that there are several different kinds of tannic acid, most of which 

 possess an acid reaction. 



These principles are widely diffused in the vegetable kingdom ; most of our forest 

 trees, as the oak, elm, pines, firs ; pear and plum trees contain it in variable quantities. 

 It is also found in some fruits. Many shrubs, as the sumach and whortleberry, 

 also contain it in great quantities, and on that account are largely used in dyeing 

 and tanning. The roots of the tormentilla and bistort are also powerfully astrin- 

 gent from containing it. Coffee and tea also contain a modification of this principle. 

 The astringent principle in all the above mentioned (except coffee) precipitate the 

 persalts of iron bluish-black, or if a free acid be present the solution becomes 

 dark green. The astringent principle of many vegetables precipitate the persalts 

 of iron of a dark green ; such are catechu, kino, &c. Some few plants contain 

 another modification of this astringent principle, which precipitates the persalts of 

 iron of a grey colour, such are rhatany, the common nettle, &c. 



Many of these tannic acids have received names which refer to the plants from 

 which they are obtained. The most important and best known of all these is 

 the gallo-tannic acid, or that which is extracted from gall-nuts. There are also 

 querci-tannic acid, from the oak ; moritannic acid, or that from the fustic (Mortis 

 tinctoria), &c. See LEATHER. 



The Table on the next page shows the quantity of extractive matter and tan in 100 

 parts of the several substances there named. 



TANNING. (Tanner, Fr. ; Gdrberei, Ger.) This is the name given to the process 

 employed for converting the skins of animals into leather, and is strictly a chemical 

 process, consisting in the combination of the tannic acid of the different tanning 

 materials with the gelatine of the skins. 



Many attempts have been made to quicken the tanning process, but the leather so 

 formed is generally of inferior quality and less durable. See LEATHER. 



TANSY, Tanacetum vulgare. A plant common to Britain, growing in waste places ; 

 sometimes placed in beds to drive fleas from them. It is very bitter, and has an aro- 

 matic odour. 



TANTAliVM. This is an exceedingly rare substance, found in the minerals 

 tantalite and yttro-tantalite. It was discovered by Mr. Hatchett, in a mineral 



