THE TORBANEHILL MINERAL, ETC. I 97 



2nd, The Torbanehill mineral, although it presents essen- 

 tially no traces of vegetable structure, is rich in the bituminoid 

 substance ; — a circumstance, I think, explained by the fact 

 that it is found in the neighbourhood of coal, so that the bitu- 

 minoid or resinoid matter formed in the partially-woody struc- 

 ture of the latter has flowed out, mixed itself with, and 

 solidified in tlie essentially earthy substance of the former. 

 It is easy to conceive how enormous pressure, conjoined with 

 chemical change and heat, may have effected this, and how 

 sometimes such fluid bituminoid matter may have run into 

 neighbouring beds of peat, of clay, or even of sandstone. 

 Facts, indeed, are not wanting to show that occasionally large 

 collections of such substance, almost pure, may be formed, 

 unmixed with either peat or clay, of which the remarkable 

 specimen I now exhibit to the Society, taken from the Binnie 

 Quarry, and for which I am indebted to Dr. Christison, is an 

 example. Fragments of this substance, under the microscope, 

 closely resemble the yellow masses which exist in the Tor- 

 banehill mineral. 



In conclusion, I would remark that the controversy on this 

 subject is only an example of a far more extensive one which 

 is now everywhere taking place throughout the natural sciences, 

 in reference to the influence which more improved methods 

 of research in chemistry and histology should exercise on our 

 thoughts and nomenclature. Those who, with myself, recog- 

 nise that differences in structure indicate differences in func- 

 tion, and that these should be studied as the foundation for a 

 correct classification, will recognise in the question, what is 

 coal ? an analogue to the questions, what is wood or coral ? — 

 what is bone or tooth ? — what is a fibrous or a cancerous 

 tumour ? The progress of science, and especially of micro- 

 chemistry, has already answered some of these questions, and 

 will ultimately determine others ; and in doing so, will over- 

 threw the more vague and incorrect views and terms which 

 previously prevailed. At the trial, indeed, it was very plau- 

 sibly argued, that, in a bargain between man and man, scien- 

 tific terms were of no value, and that a whale among whalers 

 was still a fish.* But in this Society, as no naturalist, con- 



varieties aud even genera of the j^lants of the coal-formation, there is still 

 much to be discovered. But so far as my examinations have gone, the 

 appearances observed warrant the general inference stated in the text, one 

 which has also been arrived at by Mr. Quekett. (' Mic. Journal,' No. vi., 

 p. 42.) The important fact to be kept in remembrance is, that coal is 

 fossil or transformed wood, whilst the Torbanehill mineral, and all the 

 shales which I have examined, are not. 

 * Mr. Lyell's Report, p. 231. 



