ON THE TORBANEHII.L MINERAL, ETC. 185 



snow was falling, water was dripping everywhere, the birds 

 were singing joyously, and a dead calm prevailed, 



I am not prepared at the present time to enter into any 

 discussion respecting the circumstances of these forinations. 

 They involve, I have reason to believe, very compound con- 

 ditions. As anything that I could say at the present time 

 would require the confirmation of repeated observations and 

 experiment, I am prepared to follow out the ixives ligation as 

 far as possible, and to defer all conclusions for the present. 



Ayi Investigation into the Structure of the Torbanehill 

 Mineral, and of various kinds of Coal. By John Hughes 

 Bennett, M.D., F.R.S.E., Professor of the Institutes of 

 Medicine in the University of Edinburgh. (From the 

 Transactions of the Royal Society at Edinburgh.) 



The investigation, of which I am now about to give an ac- 

 count, was undertaken with the view of determining whether 

 the structure of the Torbanehill mineral was similar to or 

 unlike that of coal, I was aware that the subject would 

 be brought before a court of law, and that many scientific 

 persons of gieat eminence had already spent much time in the 

 inquiry. With the understanding, therefore, that my evidence, 

 should it be required, was to be limited to the structure of 

 coal and of the mineral in question, I gave directions to Mr. 

 Bryson, the optician, of this city, to make thin sections of 

 attested specimens of various coals and of the mineral, con- 

 ceiving that a careful examination of them would easily deter- 

 mine the point. It was soon apparent, however, that a far 

 more extended series of researches was necessary than I at first 

 anticipated ; but as it was also evident, from the nmrked 

 structural differences which were observed in the sections, that 

 the investigation would not be destitute of positive results, I 

 determined on pursuing it to a conclusion. 



The plan adopted was, in the first instance, to make myself 

 familiar with the structure of the ordinary household coals 

 used in this city, of which those called the Zetland and the 

 Dalkeith or Buccleuch coals may be considered as the types. 

 I then examined the structure of the Wallsend, Newcastle, 

 and various other kinds of household coal, in every case ob- 

 serving, with magnifying powers of various diameters, thin 

 sections made horizontally and longitudinally with the line of 

 stratification. I next examined similarly-made thin sections 

 of the Torbanehill mineral, and was struck with the remark- 

 able dissimilarity which existed between them. I now had 



