30 Messrs. Faraday and Lyell on 



contraction of the stream of air in the ordinary use of blowing 

 machines. But even these are, in our opinion, not required; 

 for from the powerful draught in the return of the Haswell 

 Works, we are at present fully persuaded, that if the goaf 

 ventilation pipe, of the size proposed, simply entered the up- 

 cast shaft, there would be draught enough to draw away the 

 atmosphere of the goaf. It is true, that if the atmosphere in 

 the goaf vault, to which the end of the pipe might penetrate, 

 were pure fire-damp, we should have to consider its lightness, 

 and the vertical height between that extremity and the end in 

 the upcast shaft. But this probably is a state of things which 

 could happen very rarely, if ever, in the Haswell Pit; explo- 

 sive or still lower mixtures, there and in most cases, are rather 

 to be expected, and these, as has been shown, are not so much 

 lighter than air as to offer difficulty in this respect. If a case 

 of pure fire-damp, or a mixture so rich as to offer difficulty 

 on account of its lightness, were to be reached by the pipe, 

 then, indeed, it would be well worth putting on the mechanical 

 means already referred to, to drain it out*. 



The goaf end of the pipe offers more difficulties, but we do 

 not see at present that there are any that are not easily sur- 

 mountable. It has to rise up into the cavity of the goaf, at 

 the point nearest to the highest part of its edge ; to enter into 

 this cavity, four, five, or six feet or even more, if possible; 

 and to be temporary, moveable, and tight. The iron tube 



[* In the Phil. Mag., First Series, vol. xxxviii. p. 120, was reprinted from 

 the Transactions of the Society for the Encouragement of Arts, vol. xxviii. 

 (for 1810), a paper by Mr. John Taylor, "On the Ventilalion of Mines ^ with 

 the Description of a new Machine for that purpose" dated April 9, 1810. 



The method of ventilation proposed in this paper and effected by the 

 machine described, *' instead of using the machines which serve as con- 

 densers," is that of exhaustion — pumping out of the mine all the air that 

 was impure as fast as it became so. 



In Thomson's Annals of Philosophy (for March 1814), vol. iii. p. 196, 

 Mr. John Taylor published a paper " On the Ventilation of Coal Mines," in 

 which he refers to the paper cited above, extracts from it certain sugges- 

 tions relative to the application to coal mines of the method of ventilation 

 he had proposed and successfully practised, and enters into some details 

 on this particular subject, insisting on the principle of "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." To this paper Dr. Thomson 

 appended a figure and description of the machine extracted from the paper 

 in the Trans. Soc. Arts, We recommend the perusal of these papers to 

 all who are interested in the subject. 



In a lecture on mines, delivered at the London Institution, at the Soiree 

 of February 13, 1833, Mr. Taylor (who was at that time one of the mana- 

 gers of the Institution) exhibited a working model of the machine he had 

 described in 1810, showing its action by experiment, and explaining the 

 metliod of ventilating mines by its means. — Ed. Phil. Mag.] 



