186 DR. BENNETT, ON THE STRUCTURE OF 



numerous sections prepared of various cannel coals, and having 

 previously determined the appearances presented by true coal 

 and by the mineral, I was readily enabled to distinguish the 

 various shades of differences between them. I saw that 

 although the cannel coals, and especially one of them, the 

 Brown Methil, approached in structural character to that of 

 the Torbanehill mineral, it could still be distinguished from 

 it by a practised eye ; and that although gradations existed 

 between these different substances, there was at least one 

 element which served readily to characterize all the different 

 kinds of coal I had hitherto examined, and which was not 

 present in the mineral. I now went over the sections of coal 

 in the rich collection of Mr. Alexander Bryson of this city, 

 and subsequently carefully examined the numerous sections 

 made by Dr. Adams of Glasgow. Before the trial of Gillespie 

 versus Russel came on, Dr Adams, Mr. Quekett, and myself, 

 spent nearly an entire day together, examining each other's 

 specimens, and carefully reinvestigating the whole subject. 

 It was then that the character of the aslies in the various sub- 

 stances we had examined was pointed out to me by Dr. Adams, 

 who, in my opinion, is entitled to the greatest credit for the 

 laborious, skilful, and successful efforts he has made in deter- 

 mining the structure of numerous coals, and pointing out the 

 differences they exhibited, when compared v.'ith the Torbane- 

 hill mineral. At this meeting, also, we compared the structure 

 of coal with various kinds of recent woods ; we incinerated the 

 mineral and certain coals, and carefully examined the ashes ; 

 and there was established, as the result of this conjoined in- 

 vestigation, as well as from the independent researches made 

 by Dr. Adams in Glasgow, by Mr. Quekett in London, and 

 by myself in Edinburgh, the most perfect accord with regard 

 to all the facts which had been elicited during the inquiry. 



At the commencement of the present session, I brought the 

 subject under the notice of the Physiological Society of this 

 city, who appointed a committee, composed of four gentlemen 

 in addition to myself, all of whom had long been accustomed 

 to the use of the microscope, and were familiar with vegetable 

 and animal structures. Three of these gentlemen, viz.. Dr. 

 Cobbold, and Messrs. Barlow and Kirk, made farther inquiries 

 and researches, which served to elicit additional facts, and to 

 demonstrate, in the language of their report, that " the Tor- 

 banehill mineral is widely different from every kind of coal." 

 Lastly, with a view of meeting certain theoretical objections 

 which have been advanced, 1 have carefully examined the 

 structure of various kinds of peat, as well as tlie stems of recent 

 ferns and several fossil plants, which have only served to 



