1 70 Mr. Faraday on Ventilating the Coal-Mine Goaf. 



tions which have occurred to me since the Report was written, 

 and also some practical results which were brought generally 

 before our members here at the last Friday Evening Meeting. 

 I need hardly say that the Report proposes to draw away the 

 lower aerial contents of the goaf by an iron pipe laid down 

 in one or other of the ways of the mine, and either entering 

 into the return way, or having a fanner or bellows or other 

 blowing apparatus upon it. The points I wish to speak to 

 now are, first, the draught, and next the nature and place of 

 the pipe. 



By experiments which I have made with a small furnace, 

 flue and pipes of 6 inches diameter and less, I am quite sa- 

 tisfied that such a draught as that of the return at the Haswell 

 mine would be sufficient to effect that which we propose in the 

 Report without the use of any extra blowing or withdrawing 

 apparatus, so that the plan is so far relieved from the necessity 

 of keeping a man or boy working at such a machine. 



With regard to the pipe, I think that instead of laying it 

 down in the flue of the mine, it had better be hung up or sus- 

 tained upon props in the open space of that way or passage 

 which may be chosen for its direction. If then any derangement 

 of position occur it can easily be remedied. 1 have had pipes 

 6 inches in diameter, made both of air-proof cloth and com- 

 mon sheet-iron; the former were kept open by whalebone 

 rings run round them at equal distances of 2 feet, and an- 

 swered in my trials exceedingly well. Square trunks, also 

 made by nailing four boards together with copper or iron 

 nails, are easily available as tubes. Such tubes it may be said 

 when placed as proposed in the air would easily be deranged 

 by falls. No doubt a fall might destroy a part of the tube, but 

 if it did there seems to be no great difficulty in restoring it; 

 and further, if a judicious selection were made for the direction 

 of the tube, there appears no reason why the roof over it can- 

 not be as well and securely propped up as the roof of the 

 mothergate, the rolley way, or any other important part. 



Finally, it is not necessary, on the principle proposed, ihat 

 the goaf end of the tube should always be at the very extre- 

 mity of the goaf towards the rise, but only that it should be 

 3, 4, or more feet above its upper edge ; so that a jud or two 

 may sometimes be drawn in advance before the goaf end of 

 the pipe need be readjusted. Apparently there can be no diffi- 

 culty in selecting the place of the goaf end of the pipe so 

 that there shall be no interference with the general plan upon 

 which the coal itself is worked. 



I am, my dear Sir, 



Your faithful Servant, 

 Royal Institution, January 20, 184'). M. Faraday. 



