96 On Sjyore-cases in Coals. 



which I give the theoretical composition of pure cellulose or woody 

 fibre, according to Payen and Mitscherlich, and an analysis of the 

 suberin of Cork, from Quercus suher, from which the ash and 2*5 

 per cent, of cellulose have been deducted* 



Cellulose. Cork. Lj'copodium. 



Carbon 44-44 .. .. 65-73 .. .. 64-80 



Hydrogen .. .. 6-17 .. .. 8 '33 .. .. 8 '73 



Nitro''en — .. .. I'SO .. .. 6-18 



Oxygen 49-39 .. .. 24-44 .. .. 20-29 



100-00 100-00 100-00 



" This difference is not less striking when we reduce the above 

 centesimal analyses to correspond with the formula of cellulose, 

 CiiH.^Oofl, and represent Cork and Lycopodium as containing 24 

 equivalents of carbon. For comparison I give the composition of 

 specimens of peat, brown coal, lignite, and bituminous coal.f 



Cellulose C24 H20 O20 



Cork C24Hi8i%06J^ 



Lycopodium C24 Hi9^ N Osxtt 



Peat(Vau.x) C24 Hi4^ Oio 



Brown coal (Schrother) C24Huy% OiOt% 



Lignite (Vaux) .. , C24 Hu^s^ Oe^^ 



Bituminous coal (Kegnault) C24 Hio Oa-^ 



" It vrill be seen from this comparison that, in ultimate composi- 

 tion, Cork and Lycopodium are nearer to lignite than to woody 

 fibre ; and may l^e converted into coal with far less loss of carbon 

 and hydrogen than the latter. They in fact approach closer in 

 composition to resins and fats than to wood, and moreover like those 

 substances repel water, with which they are not easily moistened, 

 and thus are able to resist those atmospheric influences which effect 

 the decay of woody tissue." 



I would add to this only one further 'consideration. The nitrogen 

 present in the Lycopodium spores no doubt belongs to the protoplasm 

 contained in them, a substance which would soon perish by decay ; 

 and subtracting this, the cell-walls of the spores and the walls of the 

 spore-cases would be most euitable material for the production of 

 bituminous coal. But this suitableness they share with the epideiTaal 

 tissue of the scales of strobiles, and of the stems and leaves of Ferns 

 and Lycopods ; and above all, with the thick corky envelope of the 

 stems of Sigillariae and similar trees, ,which, as I have elsewhere 

 shown,t from its condition in the prostrate and erect trunks con- 

 tained in tlie beds associated with coal, must have been highly car- 

 bonaceous and extremely enduring and impermeable to water. In 

 short, if instead of " spore-cases " we read " epidermal tissues in 



* Gmelin, ' Handbook,' xv., 145. f ' Canadian Naturalist,' vi., 253. 



I "Vegetable Structures in Coal," ' Journ. Geol. Soc.,' xv., 626; "Conditions 

 of Accumulation of Coal," ib., xxii., 95 ; 'Acadian Geology,' 197, 464. 



