348 MOULDERING OF BODIES. 



the air and the component parts of water take part. But the 

 composition of mouldered wood must change according as the 

 access of oxygen is more or less prevented. White mouldered 

 beech-wood yielded on analysis 47*67 carbon, 5*67. hydrogen, 

 and 46*68 oxygen; this corresponds to the formula C 83 H 2 6 

 24 . 



The decomposition of wood assumes, therefore, two different 

 forms, according as the access of the air is free or restrained. 

 In both cases carbonic acid is generated ; and in the latter case, 

 a certain quantity of water enters into chemical combination. 



It is highly probable that in this putrefactive process, as well 

 as in all others, the oxygen of the water assists in the formation 

 of the carbonic acid. 



Wood-coal (brown coal of Werner) must have been produced 

 by a process of decomposition similar to that of mouldering. 

 But it is not easy to obtain wood-coal suited for analysis, for it 

 is generally impregnated with resinous or earthy substances, by 

 which the composition of those parts which have been formed 

 from woody fibre is essentially changed. 



The wood-coal, which forms extensive layers in the Wetterau 

 (a district in Hesse-Darmstadt), is distinguished from that found 

 in other places, by possessing the structure of wood unchanged, 

 and by not containing bituminous matter. This coal was sub- 

 jected to analysis, a piece being selected upon which the annual 

 circle could be counted. It was obtained from the vicinity of 

 Laubach ; 100 parts contained 



Carbon - 5728 



Hydrogen ------ 6*03 



Oxygen 36'10 



Ashes 0'59 



100-00 



The large amount of carbon, and small quantity of oxygen, 

 constitute the most obvious difference between this analysis and 

 that of wood. It is evident that the wood which has undergone 

 the change into coal must have parted with a certain portion of 



