in the vicinity of Dalkeith. 121 



There is very little ironstone found in the strata, less than in 

 any other Scotch coal-field ; so much so, that none has been got 

 for the purpose of making iron in the district now treated of. 

 Bands and balls of good ironstone have been found, and a little 

 wrought, at the verge of the coal-field near Abcrlady and Goss- 

 ford, on the estate of Lord Wemyss. 



Lastly, it is a remarkable fact, that no inflammable air has been 

 found in any of the mines of this district, however deep, though 

 found in abundance in the coal mines in the counties of Stirling, 

 Lanark, Renfrew, and Ayr. The Lothian mines, being free 

 from this most destructive pestilence, is a great comfort, and no 

 common blessing to the miners. Carbonic acid gas is fre- 

 quently found, but happily few misfortunes arise from it. 



As the carburetted hydrogen is certainly produced from the 

 coal, we might have expected it in the Lothian coal-field, which 

 affords parrot or cannel coal of the best quality for producing 

 the greatest quantity of gas, as each pound of this coal produces 

 from 4 to 5 cubic feet of gas. 



With regard to the depth of the coal strata of this coalfield^ 

 in which the beds of coal and organic remains are found, I am 

 of opinion, that in the deepest part of the basin it will extend 

 to at least 500 fathoms or 3000 feet, which shews how very deep 

 the valleys have probably once been ; and the more so, if the 

 theory of the mountains having been at one period much higher 

 than they now are, is taken into account. 



In an economical point of view, relating to the quantity of 

 coal in Great Britain, upon which the numerous manufactories 

 and population depend for fuel, — 'it is frequently asked, Will 

 not the coals in the kingdom be soon exhausted ? That they 

 are rapidly exhausting, is evident to any one of the least obser- 

 vation, particularly from the increased depth of the coal-pits ; 

 and it being estimated that more coal has been wrought during 

 the last hundred years, since the general application of the 

 steam-engine, in working the mines, and at manufactories, than 

 was wrought and used for the 500 years preceding, when coals 

 first began to be commonly used for domestic purposes. Never- 

 theless, great as the consumption is, and greatly as this has been 

 increased during these last twenty years, still the quantity of 

 coals remaining to be wrought is uncommonly great, so that the 



