328 Messrs. Cross and Bevan on Pseudo- Carbons. 



substances. The subject is one that may be safely left to de- 

 velop itself in the minds of all who contemplate the science in 

 relation to plant-life, and will lead to the conviction of the 

 indefinitely wide potentiality of cellulose. 



Although the passage of cellulose into coal is an obvious 

 fact, the processes by and through which the transformation 

 has occurred lie outside the range of observation, and must 

 remain therefore to that extent a matter of speculation. On 

 the negative side, however, greater certainty is attainable ; 

 and the statements of Zirkel* and Bichterst, which formulate 

 the older views of the composition of coal, viz. that it is a 

 mixture of pure carbon with bituminous substances more or 

 less, may be altogether dismissed. Balzer, we believe, was 

 the first to combat these loose ideas; and in his excellent little 

 treatise on the Formation of Coal|, he advances, on the basis 

 of a careful consideration of the origin and chemical charac- 

 teristics of the coal-substance, the hypothesis that it consists 

 of a mixture of complicated compounds, genetically if not 

 homologously related, the most important feature of whose 

 atomic structure is the union of the carbon atoms with one 

 another, progressive condensation in this direction being ex- 

 pressed by decreasing susceptibility to the action of reagents. 

 This treatment of the subject, however imperfect its develop- 

 ment within the narrow limits of the treatise in question, has 

 the merit of throwing the onus of proof of the presence of ele- 

 mentary carbon in coals and other pseudo-carbons upon those 

 who have assumed it, and of opening up the question in its 

 objectivity. We do not propose to enter into it more fully at 

 present, than to say that we have obtained, by the action of 

 chlorine upon a (Wigan)coal, a chlorinated derivative similar 

 to those obtained by us from lignified fibres, and also observed 

 that the whole coal-substance was so profoundly modified by 

 the action of hydrochloric acid (diluted) and potassium chlorate 

 as to be subsequently entirely soluble in alkalies. Our investi- 

 gation of these points is proceeding ; but even at this stage 

 they indicate very clearly the developmental connexion of the 

 coal with the cellulose constituents of growing plants. 



We cannot, however, leave Balzer's brochure without noti- 

 cing an incidental allusion § to the reducing-action of the 

 pseudo-carbons, notably charcoal, upon sulphuric acid, in 

 which he states, as a well-received fact, that the reducing- 

 agents are the compound constituents of the pseudo-carbons, 

 and not elementary carbon. We have made a number of ex- 

 periments upon all the pseudo-carbons, both in their normal 



* Petrographie,i. p. 361. f Chcm. Centr. 1870, p. 245. 



\ Vierteljahrss. Zurch. naturf. Ges. acvii. II. 1 (1872j. § Page 15. 



