380 TILKERODITE. 



of Hydrous Oxide of Iron or Limonite, and 

 passes sometimes by the increase of the 

 quantity of iron into Brown Ironstone. The 

 red varieties contain the greatest amount of 

 copper, and the broAvn the greatest amount 

 of iron. 



BB becomes black, but is infusible ■with- 

 out addition; with borax yields a dirty- 

 green glass. 



Localities.--- English. Cornwall, at Huel 

 Edward, St. Just, and in several mines near 

 Eedruth. — Foreign. The Banat. Hungarj'. 

 Thurmgia. Saxony. Silesia. The Harz. 

 Norway. Siberia. "Chili, &c. 



Brit. Mus., Case 17. 



TiLKERODiTE. The name applied by 

 Haidinger to those varieties of Clausthalite 

 in which cobalt replaces part of the lead. 



Analysis, from Ciausthal, by H. Rose : 

 Selenium . . . . 3r42 

 Lead ..... 63'92 



Cobalt 3-14 



Iron 6-45 



98-93 

 Nmne. It received the name Tilkerodite 

 in consequence of its being found at Tilke- 

 rode, in the Harz. 

 Brit. Mus., Case 4. 



Tin Hematites, Kirwan. Fibrous oxide 

 of tin. See Wood-Tin. 



Tin-ore, Allan. The name given by 

 Cornish miners to the Tin Ore Cassiterite. 

 The term black tin is specially given to the 

 ore as prepared for the smelter, w^hilst the 

 metal is called ivhite tin. See Cassiterite. 

 Tin Pyrites, Allan, Dana, Jameso7i, 

 Kirwan, Occurs massive and disseminated. 

 Colour steel- grey, when pure, but often 

 inclining to brass-yellow, owing to an ad- 

 mixture of Copper Pyrites. Opaque. Lustre 

 metallic. Streak black. Brittl'e. Fracture 

 uneven, sometimes inclining to imperfect 

 conchoidal. H. 4. S.G. 4-35 to 4-5. 



Comp. Sulphostannate of iron and copper, 

 or 2Fe,SnS2+2CuS,SnS2 3. sulphur 2977, 

 copper 29-77, tin 27-44, iron 13-02 = 100. 



Analysis, from St. Michael's Mount, by 

 Johnston : 



Sulphur .... 29-93 



Tin 31-62 



Copper 23*55 



Zinc 10-11 



Iron . . . . . 4-79 



100-00 

 BB on charcoal, sulphurous odours are 

 given off, and the charcoal is covered with 

 ■white oxide of tin, after which it fuses 



TINDER-ORE. 

 readily to a black scoria : after long roasting 

 it yields a brittle metallic globule, which 

 colours fluxes like iron and copper, and with 

 a mixture of carbonate of soda and borax 

 it yields a hard, pale red, somewhat brittle 

 globule of metal. 



Dissolves readily in nitric acid, forming a 

 blue solution, and separating oxide of tin 

 and sulphur. 



Localities. — English. Cornwall, at Cara 

 Brea Mines; also at Huel Rock, Stenna 

 Gwynn. Huel Primrose, Botallack Mine, St. 

 Michael's Mount, in small granite veins. &c. 

 — Foreign. Zinnwald, in the Erzgebirge, 

 with Blende and Galena. 



Brit. Jdus., Case 9. 



M.P. G. Wall-case 9, on principal floor 

 (British). 



Tin Pyrites may be distinguished from 

 either Copper Pyrites or Grey Copper, by 

 its peculiar 3'ellowish tinge, frequently re- 

 sembling that of bell-metal, and by its 

 black streak. 



Tin Spar, Kirwan. The name often 

 given to the yellowish grey Weiss Scheelerz. 



Tin Stone, Jameson, Kirwan. The name 

 generally given to massive oxide of tin. See 

 Cassiterite. 



Tin- -WHITE Cobalt, Jameson, Phillips. 

 See Smaltine. 



TiNCAL or TiNKAL. - (The Oriental name 

 for Borax.) Crude Borax is imported into 

 this country, under the name of Tincal, 

 chiefly from the East. Large quantities 

 are, however, furnished by the lagoons near 

 Monte Cerbole, in Tuscanv, from which 

 10,000 to 12,000 lbs. were daily produced a 

 few years ago. These lagoons occupy a 

 large extent of surface, and consist of nu- 

 merous low volcanoes and springs in a furious 

 state of ebullition. The vapours constantly 

 bursting forth from the boiling lagoons con- 

 tain boracic acid, which is obtained by 

 causing the vapours to pass through pans, 

 and in so doing to impregnate the water in 

 them with the acid. The water so im- 

 pregnated with the acid is kept boiling by 

 the heat of the lagoons, and the water being 

 evaporated, the acid is obtained in crystals. 



Brit. Mus., Case 41. 



3LP.G. Horse-shoe Case, No. 204. 



Tinder Ore;. An impure arsenical sul- 

 phide of antimony and lead ; apparently a 

 mixture of Heteromorphite, Mispickel, and 

 Pyrargyrite. It occurs in soft, flexible 

 flakes resembling tinder of a dirty reddish 

 colour, and with little lustre. 



Analysis, from Andreasberg, by Born- 

 tr'dger • 



