COMBUSTIBLE MINERALS, NOT GASEOUS. 191 



lace of the lcd;re. Oii making an excavation, tiie coal widened to twenly-two inclies ; but it 

 tiii'ii (hininislied to a narrow scam, and the working was abandoned. This locality was about 

 a thousand feet above the Hudson. The coal is said to be light and shining, and it burns 

 with a moderate llaine. Other veins of a similar kind have been noticed in the same range.* 



LIGNITE. 



[From the Latin lignum, wood ; in allusion to its origin.] 

 Lignite. Clfiirdiiiiil ixni Ihiichinl. — Wood Coal. Thomson. 



Description. This mineral, which is often described as a variety of coal, still dillers con- 

 siderably Ironi it. All its varieties have undoubtedly originated from wood, and the process 

 of change has probably taken place at a period not very remote. In most cases the texture 

 of the wood is preserved, and it burns exactly as wood does, leaving a residue of ashes, but 

 often more abundant. 



The odour wliich lignite exhales is diiferent from that ot burning coal or bitumen. It is 

 usually unpleasant, sometimes sharp or fetiil. It also differs from coal, in yielding, when 

 subjected to distillation, a peculiar acid liquor. 



Varieties. Jet. This is deep black, opaque, and so solid and hard that it may be turned 

 on a lathe. Fracture conchoidal. Lustre resinous. 



Brittle Lignite. Differs from jut, by its great brilllencss. Colour black, with a shade of 

 brown. It is less shining than jet. The surface is easily divisible into cubical or trapezoidal 

 fragments. 



Bituminous WooJ. This is made up of tlic roots, branches or trunks of trees, usually 

 somewhat compressed. Texture ligneous, with little lustre. Colour brown, or brownisii 

 black. 



Composition. Carbon 71.71, hydrogen 4.85, oxygen and nitrogen 21.67, ashes 1.77 

 {Richardson and Regnault). 



Geological Situation. Lignite is usually found in the more recent formations. When 

 in sufficient abundance, it is converted to the same uses as coal and anthracite ; but this is 

 seldom the case. 



localities. 



Richmond County. Near Rossville is a stratum of lignilc from three to six inches thick, 



near or below high water mark. Someiimcs the mineral has the colour and ajipearance of 



wood slightly charred ; at others, it is (juite compact, has a dark brown or nearly black colour, 



and resembles jet. Crystals of iron pyrites occur in the hssures of the lignite, and these are 



* J. Phmcc. Aoicri':an Journal of ISciencc, \l. bG. 



