MOULDERING OF BODIES. 



113 



a distinct idea of the manner in which coal 

 is formed, to consider a peculiar change 

 which woody fibre suffers by means of 

 moisture, when partially or entirely ex- 

 cluded from the air. 



It is' known, that when pure woody fibre, 

 as linen, for example, is placed in contact 

 with water, considerable heat is evolved, 

 and the substance is converted into a soft 

 friable mass which has lost all coherence. 

 This substance was employed in the fabri- 

 cation of paper before the use of chlorine, as 

 an agent for bleaching. The rags employed 

 for this purpose were placed in heaps, and 

 it was observed, that on their becoming 

 warm a gas was disengaged, and their 

 weight diminished from 18 to 25 per cent. 



When sawdust moistened with water is 

 placed in a closed vessel, carbonic acid gas 

 is evolved in the same manner as when air 

 is admitted. A true putrefaction takes place, 

 the wood assumes a white colour, loses its 

 peculiar texture, and is converted into a rot- 

 ten friable matter. 



The white decayed wood found in the in- 

 terior of trunks of dead trees which have 

 been in contact with water, is produced in 

 the way just mentioned. 



An analysis of wood of this kind, ob- 

 tained from the interior of the trunk of an 

 oak, yielded, after having been dried at 212, 



Carbon 

 Hydrogen 

 Oxygen 

 Ashes 



47-11 

 6-31 



45-31 

 1-27 



lOO'OO 



48-14 

 6-06 



44-43 

 137 



100-00 



Now, on comparing the proportions ob- 

 tained from these numbers with the compo- 

 sition of oak wood, according to the analysis 

 of Gay-Lussac and Thenard, it is imme- 

 diately perceived, that a certain quantity of 

 carbon has been separated from the consti- 

 tuents of wood, whilst the hydrogen is, on 

 the contrary, increased. The numbers ob- 

 tained by the analysis correspond very nearly 

 to the formula C33 H27 O24.* 



The elements of water have, therefore, 

 become united with the wood, whilst car- 

 bonic acid is disengaged by the absorption 

 of a certain quantity of oxygen. 



If the elements of 5 atoms of water and 3 

 atoms of oxygen be added to the composi- 

 tion of the woody fibre of the oak, and 3 

 atoms of carbonic acid deducted, the exact 

 formula for white mouldered wood is ob- 

 tained. 



Wood 



To this add 5 atoms of water 



3 atoms of oxygen 



C36 H22 O22 



H 5 O 5 



O 3 



C36 H27 O30 



Subtract from this 3 atoms car- 

 bonic acid - - C 3 O 6 



C33 H27 O24 



The process of mouldering is, therefore 

 one of putrefaction and decay, proceeding 

 simultaneously, in which the oxygen of 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'(>8 

 oxygen; this corresponds to the formula 

 C33 H25 O24. 



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 putrefac- 

 tive 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 decom- 

 position 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 containing ao 

 bituminous matter. This coal was subjected 

 to analysis, a piece being selected upon 

 which the annual circle could be counted. 

 It was obtained from the vicinity of Lau- 

 bach; 100 parts contained 



Carbon .... 57'28 



Hydrogen - - - 6 '03 



Oxygen - '.',.. . . 26'10 



Ashes - - 0'59 



100-00 



The large amount of carbon, and small 

 quantity of oxygen, constitute the most ob- 

 vious 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 

 its oxygen. The proportions of these num 

 bers are expressed by the formula C33 H21 

 016.* 



When these numbers are compared with 

 those obtained by the analysis of oak, it 

 would appear that the brown coal was pro- 

 duced from woody fibre by the separation: 

 of one equivalent of hydrogen, and the ele- 

 ments of three equivalents of carbonic acid. 



1 atom wood - C36 H22 022 



Minus 1 atom hydrogen and 3? r 1 a TT i n c 

 atoms carbonic acil - J C81 



Wood coal, C33 H21 O16 



* The calculation from this formula jrives in 100 * The calculation gives 57'5 carbon, and 5'98 

 parts 47'9 carbon, 6'1 hydrogen, and 46 oxygen. ; hydrogen. 



15 



