408 



BOGHEAD COAL 



to the decomposition of the sulphides of copper, especially of the yellow copper pyrites, 

 which are liable to this change when placed under the influence of moist air, or of 

 water containing air. See COFFEE. 



BOG. The name given to accumulations of peat-earth. See PEAT. 



BOG-BUTTER. A hydrocarbon compound, like spermaceti, found in the bogs 

 of Ireland. See ADIPOCEBE. 



BOG-EARTH. A soil formed of vegetable fibre and sand. 



UOGHEAD CO AXi, aiid other Brown Scotch Cannel Coals. The brown cannels 

 are chiefly confined to Scotland, and have been wrought, with the exception of the 

 celebrated Boghead, for the last forty years. They are found at Boghead, near 

 Bathgate ; Eocksoles, near Airdrie ; Pirnie, or Methill ; Capeldrea, Kirkness, and 

 Wemyss, in Fife. The first-named coal, about which there has been so much dispute 

 as to its nature, has only been in the market about fourteen years. It is considered the 

 most valuable coal hitherto discovered for gas- and oil-making purposes ; but, strange 

 to say, the middle portion of the Pirnie, or Methill, scam, which was unnoticed for 

 a long period, is nearly as valuable for both purposes. 



BOGHEAD. Amorphous; fracture subconchoidal, compact, containing impressions 

 of the stems of Sigtilaria, and its roots (Stiffmarice), with rootlets traversing the mass. 

 Colour, clove-brown, streak yellow, without lustre ; a non-electric ; takes fire easily, 

 splits, but does not fuse, and burns with an empyreumatic odour, giving out much 

 smoke, and leaving a considerable amount of white ash. H 2'5. Specific gravity, 

 1-2. 



According to Dr. Stenhouse, F.K.S., its composition is : 



Carbon 6572 



Hydrogen 9'03 



Nitrogen o - 72 



Oxygen 4-78 



Ash 19-75 



100-00 



Dr. Stenhouse's analysis of the ash of Boghead coal (the mean of three analyses), 

 was as follows : 



Silica . . 58-31 



Alumina . 

 Sesquioxide of iron 

 Potash 

 Soda . 



33-65 

 7-00 



. 0-84 

 0-41 



Lime and sulphuric acid traces. 



Dr. Andrew Fyfe, F.E.S.E., found on analysis that the coal yielded, from a picked 

 specimen, 70 per cent, of volatile matter, and 30 per cent, of coke and ash. From a 

 ton he obtained 14-880 cubic feet of gas, the illuminating power of which was deter- 

 mined by the use of the Bunsen photometer, the gas being consumed by argands 

 burning from 2J to 3 feet per hour, according to circumstances. The candle referred 

 to was a spermaceti candle, burning 140 grains per hour. 



The Pirnie or Methill brown cannel, on examination, gives the following results : 



Specific gravity T126 



Gas per ton 13,500 feet 



Illuminating power . 

 Coke and ash . 



Hydro-carbons condensed by bromine 

 Sulphuretted hydrogen 



Carbonic acid 



Carbonic oxide .... 



Volatile matter in coal 

 Specific gravity of gas . 



28 candles 

 36 per cent. 

 20 



