52 Structure of a peculiar Combustible Mineral, 
Is that a part of the course that you teach ? — Yes. 
In the course of teaching that class, are you in the habit of examining 
mineral substances with a view to noticing their structure ? — I examine 
fossil plants. I have a large collection of specimens of fossil plants. 
Have you been in this case shown some specimens of different minerals 
with a view of examining them ? — Yes. 
What were they ? — I have seen specimens of the Torbanehill coal, the 
Methil coal, the Capeldrae coal, the Lesmahagow coal, and several other 
parrot and other common coals. 
Did you visit the ground at Torbanehill ? — ^Yes, I went to the pits and 
examined the coal, and brought specimens from the place. 
Did you visit the Methil pit ? — Yes. 
And got some specimens from Methil ? — Yes, out of the pit. 
And where did you get the other specimens that you refer to ? — I got 
them from various sources. Some were sent me authenticated by Mr. 
Eussel, some were given me by Dr. Maclagan, also by Dr. Eedfern, Dr. 
Aitken, and Professor Harkness. 
Did you make sections of these minerals with a view to a microscopical 
investigation of them ? — Yes. 
Did you make such a variety of sections as to enable you to judge in all 
directions ? — Yes, so as to judge fully of the structure. 
Now, from that examination, are yon able to say whether you dis- 
covered in these specimens traces of organic structure ? — Certainly organic 
structure. 
In all the specimens ? — In all the specimens more or less. 
Now, in the Torbanehill mineral did you find marks of organic struc- 
ture ? — Certainly. 
And in the Methil ? — And in the Methil. 
Was there any difference, or any resemblance, between the appearance of 
the Torbanehill mineral and the Methil mineral? — A remarkable similarity. 
Was there some Lesmahagow coal ? — Yes. 
And some Capeldrae also ?— Yes. 
And I think some Kinneil coal ? — Some Kinneil. 
Which is a cannel also ? — ^Yes. 
Did you take the assistance of Dr. Greville? — I took his assistance in 
delineating what we saw under the microscope. 
Did you see his delineations?— Yes. 
Did they appear to you to be successful ? — Most correct, I think. 
You believe coal generally to be a vegetable formation, I suppose ? — 
Certainly. 
Of what species of plants is it generally supposed to be composed ? — The 
coal plants are numerous. We have, in the first place, a mass of ferns, 
stigmarias, sigillarias, lepidodendrons, calamites, and various other genera. 
The ferns supposed to form coal-beds are very gigantic ferns compared 
with the present ferns ? — They are tree ferns. 
Is it a cryptogamic plant ? — Yes. 
In such plants, what is the particular appearance or structure you 
would expect to find ? — In all these plants, as well as in other plants of a 
woody stem, we have cells and vessels ; but in the tree ferns we have a 
structure which may be said to be pretty regular, which is called scalari- 
form, or ladder-like, from the bars visible upon it. They are vessels or 
tubes. 
Did you see in the Torbanehill coal appearances that seemed to you to 
indicate cellular structure ? — Certainly. 
No doubt of that ? — No doubt of that. 
And also some appearances indicative of scalariform structure ? — Yes. 
