348 



EECEEATIYE SCIENCE. 



transition state, in tlie process of retro- 

 grade decay of tlie vegetable tissue, is dis- 

 tinctly traceable, and the preserved or un- 

 coalified vegetation is seen to pass, by insen- 

 sible gradations, into tbe structure of cannel- 

 coal. 



We now refer to a mineral fuel, tbe na- 

 ture of wbich has occasioned more curious 

 and legal, as well as scientific, controversy 

 tban any other, and which might, indeed, be 

 termed " Recreative Science," to the lawyers 

 on the one hand, and to those who laugh at all 

 science as unpractical on the other. The fuel 

 alluded to is known as the Torbanehill mi- 

 neral, and the legal question arose, whether it 

 was a mere mineral, or whether it was coal. 

 Many scientific men, of great reputation, had 

 spent much time in this inquiry, previously 

 to the trial (Gillespie versus'Russel). Amongst 

 these was Professor Bennett, of Edinburgh, 

 who caused to be prepared, and care- 

 fully examined, various kinds of household 

 coal, which might be considered as typical 

 or standard examples. Next he examiiied 

 three sections of the Torbanehill mineral, 

 and was struck with the remarkable dissimi- 

 larity which existed between them. Nume- 

 rous sections of cannel-coal were then pre- 

 pared, and the difference between the ap- 

 pearances presented by the true coals and 

 by this mineral having been previously de- 

 termined, the Professor was readily enabled 

 to distinguish the difference between them. 

 Though the various cannel-coals, and one es- 

 pecially, approached in structural character 

 to the Torbanehill mineral, yet there was 

 at least one element which characterized 

 all the coals, and was absent from this mine- 

 ral. Several other inquirers contended that 

 " the Torbanehill mineral is widely different 

 from every kind of coal." It is also said, 

 that every kind of coal may be at once 

 distinguished from the Torbanehill mineral 

 by the rings contained in a well-made trans- 

 verse section ; and Professor Bennett main- 

 tains that such an appearance constitutes. 



in the majority of cases, a practical and evi- ■ 

 dent test which is distinctive of genuine 

 coal ; and that, by means of it, aU kinds 

 of known coal, whether household or cannel, 

 can at once be distinguished from the Tor- 

 banehill mineral. He affirms that every kind 

 of coal has a distinctly woody basis, which is 

 easily demonstrated by its longitudinal and 

 transverse sections ; that the cannel-coals 

 have, in addition to this woody structure, a 

 greater or less number of bituminoid marks 

 imbedded in it ; and that the Torbanehill 

 mineral has no such woody texture, but is 

 essentially composed of the bituminoid marks 

 imbedded in clay. 



The theory which this same Professor is 

 disposed to put forward, as most in harmony 

 with the various facts and arguments elicited 

 and stated in this curious inquiry, is briefly 

 as follows : — 1st. That the various organic 

 substances found in the sections and ashes 

 of coal, are explicable on the supposition 

 that coal is wood chemically altered, and for 

 the most part, but by no means exclusively, 

 coniferous wood, or wood allied to it in struc- 

 ture ; because, from a careful comparison of 

 recent fir- wood with the various kinds of coal, 

 he finds the structural appearances of the 

 cellular tissue, resin-cells, and ducts to bo 

 very similar. This assumption not only ex- 

 plains its structure, but accounts for the 

 large amount of bitumen and resin or inflam- 

 mable matter it contains, resin being a weU- 

 known abundant product of the coniferous 

 tribe of plants. 2ndly. Though the Torbane- 

 hill mineral is rich in the bituminoid sub- 

 stance, it presents no essential traces of vege- 

 table structure. The bituminoid or resinous 

 matter found in the real coal, which lies in 

 its neighbourhood, probably flowed out, mixed 

 itself with, and solidified in the essentially 

 earthy substance of the TorbanehiU mineral. 

 This result may have been produced by 

 enormous pressure, conjoined with chemical 

 changes and heat. 



On the other side, Dr. Kedfern, who made 



