1814.] On the Ventilation of Coal-Mines. 197 



because the ventilation of mines at one time occupied a good deal 

 of my attention. 



The works in which I was engaged, and in which I succeeded in 

 carrying perfect ventilation much further than had been attempted 

 before, were copper-mines, in the western part of the county of 

 Devon. In these, though the destructive effects produced by 

 explosive gases are unknown, yet the labours of the workmen are 

 frequently impeded by the deterioration of the air ; this takes place 

 when the levels extend beyond a certain distance, from a Commu- 

 nication with the atmosphere. 



It is usual in the mines of the district above-mentioned, and In 

 those of Cornwall, to sink a greater number of shafts on this 

 account than would otherwise be required ; and as it was a very 

 important object, in an undertaking of which I had the manage- 

 ment, to save the expense of many deep shafts, which would liave 

 been necessary if ventilation had not been obtained in some other 

 way, I endeavoured to accomplish this end, which, after some trials 

 of unequal success, was at length effected. 



For a description of the apparatus I employed, I beg leave to 

 refer your readers to the Transactions of the Society for the Encou- 

 ragement of Arts, Manufactures, and Commerce, for 1810. The 

 paper in that volume is accompanied by a drawing of the machine, 

 which has no peculiar merit besides that of combining simplicity of 

 construction with considerable exhausting power at a small expense 

 of moving force. The paper contains, besides, an account of its 

 application to the tunnel of the Tavistock canal, and some calcula- 

 tions and suggestions as to it? use in other cases. 



I may state here, in addition, that as it had been effectually 

 employed, for two years, when that paper was written, its use lias 

 been continued and extended in the four years which have ^ince 

 elapsed. That whereas in most similar works shafts are placed at 

 every 60 or 70 fathoms on the course of an adit or tunnel, my 

 shafts are distant from each other from 240 to 260 fathoms. That 

 the spaces between each have been kept as free from any of the 

 usual impediments as it is possible to conceive ; so much so, that 

 in the last shaft which was completed, it having been found difficult 

 to sink it, on account oi the (juantity of water met with, more 

 than half of it was done l)y working upwards from the tunnel; and 

 that though this woik was carried up perpendicularly between 30 

 and 40 f;ithonis, to meet the part which had been sunk ; and 

 though this was done at a point in the tunnel 230 fathoms distant 

 frorrt any opening to the surface, and where several men weiv 

 working day and night, yet no inconvenience for want of good air 

 was |)erccptible. 



1 should not have obtruded all this, however, on your readers, 

 had not the account of another explosion in the Felling Colliery 

 just met my eye, by which 22 men and boys are added to the 

 victim» of this dciiructive calamity, leaving 8 widows and ly 



