COBALT, 

 cite. These change gradually, and merge one 

 into the other, and in the South Wales coal- 

 field the bituminous coal passes into anthra- 

 cite in a westerly direction. The conver- 

 sion of the vegetable matter into coal was 

 apparently produced by a kind of moist pu- 

 trefaction, accompanied by the exclusion of 

 all access of air. Under those circumstances 

 the oxygen escaped in the form of carbonic 

 acid, while the hydrogen, being disengaged 

 in the form of carburetted hydrogen, the 

 carbon became in consequence more con- 

 centrated. In this manner by the removal 

 of all the hydrogen, bituminous coal be- 

 comes converted into anthracite. S.G. 1*20 

 to 1-59; mean S.G. of 31 samples 1-3. 



Analysis * from Graigola in S. Wales 

 (S.G. 1-3) : 



Carbon .... 84-87 

 Hydrogen . . . .3-84 

 Nitrogen . . . . 0'4i 

 Sulphur .... 0-45 

 Oxvgen . . . .7-19 

 Ash 3-24 



100-00 

 Coke left by the Coal 85-5 per cent. 



The specific gravity of Coal varies from 

 1'2 to 1'6. Thirty-one varieties examined 

 by Sir Henry De la Beche and Dr. Lyon 

 Playfair gave an average specific gravity 

 of 'l'3. See Albert Coal, Anthracite, 

 Coking Coal, Cannel Coal, Torbanite, 

 &c. 



Cobalt Arseniate, Haliy. See Ery- 

 thrine. 



Cobalt Arsenical, Haily. See Smal- 



TINE. 



Cobalt Bloom. See Erythrine. 

 Cobalt-coating is Cobalt-bloom con- 

 taining some free arsenous acid. It is pro- 

 duced by the weathering of Cobaltine on 

 which it immediately rests, and may be re- 

 garded as a mixture of Cobalt-bloom and 

 arsenious acid, often with the addition of a 

 small quantity of Cobalt-sulphate. Occurs 

 botryoidal, reniform or massive ; scaly or 

 earthy. Colour varying from peach-blos- 

 som-red to pale-rose. Opaque. 



Analysis -by Kersten, from the Wolfgang- 

 Maassen mine at Schneeberg : 



Arsenous acid . . . 51*00 

 Arsenic acid . . . . 19'10 

 Oxide of cobalt . . . 10-60 

 Protoxide of iron . . 2-10 



* Report on the Codls suited to the Steam 

 Navy, by Sir Henry T. De la Beche and Dr. Lyon 

 Playfair ; Memoirs of the Geological Survey of 

 Great Britain, vol. ii. part 2. 



COBALTINE. 89 



Water 11-90 



Nickel, lime, . . } , 



Sulphuric acid . . | traces. 



100-70 

 Localities. Schneeberg, and Annaberg, 

 in Saxony. 



Brit. Mus., Case 56. 



Cobalt Crust. A name for earthj^ va- 

 rieties of Erythrine (Arseniate of Cobalt). 

 Cobalt eclatant, Brochant. \ See Co- 

 Cobalt Glance, Jameson. | baltine. 

 Cobalt-gris, Haily. See Cobaltine. 

 Cobalt Ivies, v. Leonhard. See Lin- 

 n^eite. 



Cobalt SIica. See Erythrine. 



Cobalt Ochre, Nicol. \ ^^% J^^^^ 



Cobalt Oxide noir, ^««>. j °cobIl?. 



Cobalt Pyriteux, Necker ; Cobalt Py- 

 rites. See Linn^eite. 



Cobalt- ScoRODiTE. The name given by 

 Lippmann to a mineral occurring in small 

 bluish crystals, with Hypochlorite and 

 Quartz, at Schneeberg in Saxony. 



Cobalt Sulfure, Lucas. See Linn.e- 



ITE. 



Cobalt Terrelix rayonne rough, 

 Brochant. See Erythrine. 



Cobalt Vitriol. See Bieberite. 



Cobaltic Germinations, Kirwan. See 

 Erythrine. 



Cobaltide, Leymerie. See Wad, or 

 Earthy Cobalt. 



Cobaltine, Beiidant, Haidhiger. Cubi- 

 cal. Occurs in the cube and its varieties ; 

 its crystalline forms resembling those of 

 Iron Pyrites; the planes of the cube are 

 generally striated, those of the modifications 

 smooth. It also occurs arborescent, stalac- 

 titic, botryoidal, an. I amorphous. Colour 

 silver- or yellowish-white, with a tinge of 

 red ; inclining to steel-grey, or greyish- 

 black when much iron is present. Lustre 

 metallic. Streak greyish- black. Brittle. 

 Fracture uneven and lamellar. Yields with 

 difficulty to the knife. H. 5-5. S.G. 6 to oS. 



Fig. 120 



Fig. 122. 



Camp. (Co, Fe, Ni) As. 

 Analysisoi massive Cobaltine from Schnee« 

 berg, by Hofmann : jt 



Iron ..... U-71 

 Copper. , . . . 13-95 



