THE TORBANEHILL MINERAL, ETC. 191 



orjjanic substance ; Srd, Black fibres, separated or in masses, 

 evidently the woody fibre carbonized ; 4th, Flat carbonaceous 

 plates, presenting? round apertures corresponding; in size to 

 the woody cells which passed through them, and exhibiting at 

 their margins sections of larger circles, which doubtless 

 bounded the large resin cells in the recent wood. None of 

 these appearances are visiljle in the ash of the Torbanehill 

 mineral, when care is taken to exclude such portions of it as are 

 free from the stigmaria or other plants imbedded in it. Indeed 

 1 myself have never seen such appearances in the ash, even 

 when no such precaution has been taken. Dr. George Wilson 

 gave me a considerable quantity of it, which everywhere ex- 

 hibited nothing but an amorphous material, such as might 

 result from the incineration of clay or other earthy non-organic 

 substance. In all the cannel coals, traces of these forms, 

 though not so numerous or abundant, can be seen. Mr. 

 Quekett has even applied this test to Welsh anthracite, in 

 which substance no rings or fibrous structure can be made out 

 in sections, yet where, he says, the ash gives unmistakable 

 evidence of the presence of woody tissue.* 



II. Such, then, are the facts which an investigation into the 

 structure of coals on the one hand, and of the Torbanehill mi- 

 neral on the other, has elicited. If the account I have given of 

 them be correct, it must be evident that the differences tliey 

 present are marked and distinctive ; that the one is essentially 

 a woody structure, whilst the other is not. Every kind of coal, 

 including the brown Methil, may be at once distinguished 

 from the Torbanehill mineral, by the rings contained in a 

 well-made transverse section. 1 further contend that such an 

 appearance constitutes, in the majority of cases, a practical 

 and evident test, distinctive of genuine coal, and that by means 

 of it all kinds of known coal, whether household or cannel, 

 can at once be distinguished from the Torbanehill mineral. 



Now if this be the case, it may well be asked how it hap- 

 pened that, at the late celel)rated trial, so many persons, all of 

 whom represented themselves as being skilful observers with 

 the microscope, should have been made to give diametrically 

 opposite evidence, not only as to matters of opinion, but as to 

 what appeared to be matters of fact ? In endeavouring to 

 place the remarkable histological controversy which has origi- 

 nated out of the trial of Gillespie vej^sus Russel on its correct 

 basis, it must be remembered that unquestionable organic 

 structure is only present in the Torbanehill mineral at certain 

 places. No one, for instance, can doubt that the stalariform 

 ducts seen by all parties are of vegetable origin ; but it is no- 

 * ' Quarterly Journal of Microscopical Science,' No. VI., p. 43. 



