JOO On the Fetililation of Coal-Mir,es. [March, 



ment, than an argument against it ; and I conceive it must now be 

 admitted that there is no mode known in the collieries of producing 

 complete ventilation ; if there had, I take it for granted it would 

 have been employed at the Felling works after the first accident, 

 and a recurrence of the calamity would have been avoided. 



I have practically employed in the mines in which I was engaged 

 all the modes of ventilation that are commonly in use, and in many, 

 or perhaps most cures of mines, there are sufficient ; but they are 

 often attended with more expense in the end than the one I have 

 proposed, and I am satisfied will never be found so effective. 



The principle I mean to insist on is the removal of the noxious 

 air by some apparatus proper for the purpose, connected with pipes 

 which are to be fixed so that they may be made to draw from any 

 part or parts of the works, as occasion may require. How the 

 exhaustion is produced is immaterial, so tliat the means employed 

 be capable of a powerful effect. I thought of employing steam to 

 produce a vacuum, and in a receiver which should thus draw air 

 from the mine, and I had contrived an apparatus for doing the same 

 thing by a stream of water alternately admitted and discharged frorn 

 a proper vessel ; but, though either of these schemes are practicable, 

 there are good reasons for preferring the machine I adopted. As 

 the capacity of exhaustion is the great thing to attend to, I shall 

 just mention, that I conceive it easy to make an engine of this sort, 

 which might be constructed by any mining carpenter at a moderate 

 expense, and that might be worked at an easy rate, capable of 

 pumping out 40,000 cubic feet of air in the hour. 



If this should not be deemed sufficient, another equal in effect 

 might be connected to the same pipes, to work in aid of the other, 

 either constantly or occasionally. 



A very important object might likewise be obtained by this 

 machine, that is, that it could be made to furnish samples of the 

 air of the mine at any instant on the surface, and delivered by a 

 very simple apparatus into proper vessels in any convenient room or 

 place where they might be immediately examined by proper tests, 

 and thus the state of the air might be watched, and the increase or 

 diminution of that which produces danger ascertained, and due 

 notice could be given when there was cause for alarm. 



A daily record of the changes that take place in this respect 

 appears so desirable a thing connected with a plan of ventilation, 

 that I should deem it important to render it as easy as this would 

 do, and which the proprietors could command attention to by 

 appointing one of their agents to make the proper experiments, and 

 register them at stated periods. 



Numerous schemes have been proposed for ventilating mines : 

 many of these have been extremely frivolous, others were founded 

 on an imperfect knowledge of the gases when chemical science was 

 in its infancy, and some were defective for want of the necessary 

 plculation as to the amount of effect requisite to be produced. 



Where numbers have failed, it is not surprising that mere prac- 



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