1077 



TITANIUM. 



TITLA11KS. 



1078 



bears. The properties of titanium were not however satisfactorily 

 determined until 1822, when Dr. Wollaston examined and described 

 it as it occurred in its perfect metallic and crystallised state, in the 

 slag of an iron furnace at Merthyr Tydfil in South Wales. The form 

 of the crystals is the cube ; their colour resembles that of bright 

 copper ; they are sufficiently hard to scratch rock-crystal, and their 

 specific gravity is 5'3. 



Titanium enters into a great many minerals, some of which are 

 described under their names ; the remainder will be described here. 



Anaatate, Octacdrite, or Oisamte. This is protoxide of titanium 

 nearly pure. It occurs in attached and imbedded acute octohedral 

 crystals. Primary form a square prism. Cleavage parallel to the 

 terminal planes and to those of the octohedron. Fracture conchoidal, 

 indistinct. Hardness : scratches phosphate of lime, and is scratched 

 by quartz. By friction it becomes negatively electrical, and when 

 heated gives out a reddish-yellow phosphorescent light. Colour 

 various shades of brown, more or less dark, sometimes indigo-blue. 

 Streak white. Lustre adamantine. Translucent, transparent. Specific 

 gravity 3-826. It is found in Cornwall, in Dauphiuy, at Bourg-d'Oisans, 

 in Spain, Switzerland, and some other places. It consists almost 

 entirely of oxide of titanium, probably the protoxide. 



Rutile, or Titanile ; Peroxide of Titanium, or Titanic Acid. It 

 occurs crystallised and in crystalline masses. Primary form a square 

 prism. Cleavage parallel to the lateral planes. Crystals frequently 

 geniculated. Fracture uneven. Hardness : scratches glass, and some- 

 times quartz. Colour red, reddish-brown, and occasionally yellowish. 

 Streak very pale brown. Lustre adamantine. Translucent, trans- 

 parent, opaque. Specific gravity 4-249 to 4'4. It occurs not unfre- 

 quently inclosed in quartz, in fine red filamentous crystals. Rutile is 

 found in Perthshire, Bohemia, Switzerland, especially at St.-Gothard, 

 and in various other parts of Europe ; and also in Brazil and North 

 America. According to H. Rose, it consists of oxygen, 33'95 ; 

 titanium, 66-05. It ia frequently more or less mixed with oxide of 

 iron and of manganese, and lometimes with oxide of chromium. 



The minerals which are next described are the titaniates of iron : 

 they vary greatly both in form and composition, some being crystal- 

 lised and others granular; the latter are frequently termed titan- 

 iferous iron-sand. 



Kibdelop/ian Axotomous Iron. It occurs in imbedded crystals. 

 Primary form a rhomboid. Cleavage perpendicular to the axis, dis- 

 tinct. Fracture conchoidal. Hardness 5'0 to 5'5. Brittle. Colour 

 dark iron-black. Streak black. Lustre imperfect metallic. Opaque. 

 Specific gravity 4-661. It is found at Gastein in Salzburg, in Sweden, 

 and Siberia. The following is an analysis of a specimen from Gastein, 

 by Kobell : 



Titanic Acid 59-00 



Protoxide of Iron 36'00 



Peroxide of Iron . . *-. . .4-25 



Protoxide of Manganese 1-65 



100-9 



Ilmenitc. It occurs in imbedded crystals. Primary form a right 

 rhombic prism. No cleavage observed. Fracture uneven to con- 

 choidal, with a vitreous lustre. Hardness 5'0 ; scratches glass slightly. 

 Colour black. Opaque. Specific gravity 5-4 3. It is found near Lake 

 I linen in Siberia. The analysis by Mosander gives 



Titanic Acid 46-92 



Protoxide of Iron 37'86 



Peroxide of Iron 1074 



Protoxide of Manganese .... 273 



Magnesia 1-14 



99-39 



(Ji-ichtonite. It occurs in attached crystals. Cleavage parallel to 

 the axis. Fracture conchoidal, splendent. Hardness : scratches fluor- 

 spar, but not glass. Brittle. Does not obey the magnet. Colour 

 "hining black. Streak black. Lustre imperfect metallic. Opaque. 

 Specific gravity 4. It hag not been completely analysed; but, accord- 

 ing to Berzeliun, it consists of titanic acid and oxide of iron. 



Granular Titaniate of Iron and Titaniferous Iron-Sand present the 

 following varieties : 



AV'//-in. It occurs in flat rounded grains of about the size of a pea, 

 with occasional indications of a crystalline form. Structure foliated. 

 Very hard. Brittle. Colour grayish-black. Lustre metallic. Specific 

 gravity 4-445. It is found in Transylvania. Its analysis by Klaproth 

 gives- 

 Titanic Acid 84 



Protoxide of Iron 14 



Protoxide of Manganese 2 



100 



Menacctcnite occurs in small angular grains. Structure imperfectly 

 lamellar. Fracture fine-grained, uneven. Hardness: yields to the 

 knife. Colour grayish-black. Lustre glistening. Opaque. Specific 

 gravity 4-427. It occurs in rivulets in the parish of St. Keverne, 

 Cornwall ; and has also been found in New South AValea. The picked 

 grains, analysed by Dr. G'ol'iiihoiin, given- 

 Titanic Acid 57-187 



Protoxide of Iron 39-780 



Protoxide of Manganese .... 2-175 



99-142 



Iierine occurs in very small flattish angular grains, which have a 

 rough glimmering surface. Structure lamellar. Cross fracture con- 

 choidal. Very hard. Slightly attracted by the magnet. Opaque. 

 Lustre semi-metallic. Specific gravity about 4'5. It is found on the 

 Rieseugebirge, near the origin of the river Iscr in Silesia ; in Bohemia; 

 in the river Don in Scotland, and that of the Mersey opposite Liver- 

 pool. By the analysis of H. Rose it consists of 



Titanic Acid 50-12 



Protoxide of Iron 49'88 



100 



It is probably a variety of Menaccamte. 



Sphene Spinthire Silico-Titaniate of Lime occurs in attached and 

 imbedded crystals, and massive. Primary form an oblique rhombic 

 prism. Cleavage indistinct. Fracture even, slightly conchoidal. 

 Hardness : scratches phosphate of lime, but is scratched by felspar. 

 Colour various shades of gray, green, yellow, and brown. Streak 

 white or grayish-white. Lustre adamantine, resinous. Transparent, 

 translucent, opaque. Specific gravity 3'468 to 3-6. Sphfene is found 

 interspersed in primary rocks, as in granite and gneiss, and more par- 

 ticularly in syenite, in Norway, Germany, Switzerland, and also in 

 America. The results of the analysis of sphftne vary considerably ; 

 the following is by Klaproth .- 



Titanic Aoid 33 



Silicic Acid . 35 



Lime 33 



101 



jEschynite Titaniate of Zirconia and Cerium, <fcc. occurs crystal- 

 lised. Primary form a right rhombic prism. Cleavage difficult, and 

 only parallel to the bases of the primary form. Fracture eonchoidal. 

 Hardness : scratches phosphate of lime, and is scratched by felspar. 

 Colour black ; streak grayish-black. Lustre resinous. Opaque. Spe- 

 cific gravity 5'1 4. It is found at Miask, in the Uralian Mountains 

 Siberia. The analysis by Hartwall gives 



Titanic Acid 56-0 



Zirconia 20'0 



Oxide of Cerium 15'0 



Lime 3-8 



Oxide of Iron 2'6 



Oxide of Ziuo 0-5 



97-9 



[BBOOKITE ; MOHSITE ; GBEENOVITE ; PEROVSKITE ; PYRRHITE ; WAR- 

 WIOKITE; PTROCHLORE; ZIBCONIA; ENCELADITE ; POLYMIGNITE.] 



TITLARKS, the common name for the species of Anthus, a genus 

 of Birds belonging to the family Alaudinte. [ ANTHUS.] The species 

 are also called Pipits. The following are British species : 



Anthus trivialis, the Tree-Pipit; A. pratensis, the Meadow-Pipit; 

 A. obscurug, the Rock-Pipit (A. pelrosus, Flem., Jen. ; A. aquaticus, 

 Selby, Gould ; Alauda obscwa, Auct.) ; and Anthus Ricardi, Richard's 

 Pipit. 



Foot of Tree-Pipit. (Yarrell.) 



Trcp-Pipit (AnlTitu tririalis'). (Gould.) 



The Titlark of Pennant is the Meadow-Pipit of the above list.; and 

 Mr. Yarrell well observes that scarcely any two British birds have been 



