192 PROFESSOR BALFOUR ON CERTAIN VEGETABLE ORGANISMS 



that the bodies called by some spores, and which exist in many coals, especially 

 cannel coals, may be the larger spores contained in the other sporangia of this 

 plant. These fossil spores are large, and appear in the form of a thickened ring, 

 probably from the pressure to which they have been subjected. Here, then, we 

 seem to have evidence, that Acrogenous fructification is found in coal, leading to 

 the conclusion that the plants which produced these sporangia flourished at the 

 coal epoch, and aided in the formation of this substance. 



It is probable also, that the inflammable yellow-brown matter which enters 

 into the composition of Lycopodes at the present day, and which has caused their 

 small spores to be denominated vegetable sulphur, may also have been present in 

 fossil plants of a similar nature, and have contributed to form the yellow substance 

 which exists in great quantity in some coals. 



A substance derived from the organic kingdom also occurs abundantly in the 

 Fordel coal. This is the resin-like matter called Middletonite. This was seen 

 about thirty years ago by Dr Fleming,. in the splint coal of Balbirnie in Fife, and 

 afterwards at Clackmannan. Dr Fleming is also disposed to think, that certain 

 veins of a rich wine-yellow, which occur in Boghead coal, contain Middletonite. 

 This organic substance has been described by Professor Johnston of Durham.* 

 He found it about the middle of the main coal or Haigh More seam, at the 

 Middleton collieries near Leeds. It occurred sometimes in small round masses, 

 but more commonly in thin layers, scarcely thicker than ^gth of an inch, between 

 layers of coal. In Mr Daw's specimens, the quantity of the substance is very 

 large, occurring both in layers and in granular pieces, and giving a peculiar rusty- 

 brown aspect to the surface of the coal. Specimens are seen with several distinct 

 layers of this substance, separated by thin laminae of coal of about { th of an inch 

 thick, which also seems to be penetrated by the Middletonite. 



Middletonite is hard, brittle, easily scraped to powder b\y a knife. In small 

 fragments it is transparent ; by reflected light it shows a reddish-brown colour, 

 by transmitted light a deep-red colour. It has a resinous lustre. It blackens by 

 long exposure to the air, and then can only be distinguished from the coal by a 

 slight peculiarity in the lustre. It burns like resin, and leaves a bulky charcoal. 



In one analysis, Johnston gives the following composition : — 



Carbon, . ... . . . 86-437 



Hydrogen, 8-007 



Oxygen, 5 563 



On examining this substance, and comparing it with the appearance presented 

 by Lycopode powder, as well as with that exhibited by the inner surface of the 

 Fordel sporangian valves, I am disposed to hazard the conjecture, that the two 

 may be closely connected. It seems not improbable, that the inflammable spores 



* Brewster's Journal, xii. (1838), 261. 



