395 







1814.] Scientific InleU/getice. 



*' a and I are square vertical lubes 

 formed of wood, and separated by a par- 

 tition f, which at the upper part is perfo- 

 rated with a number of oblique openings 

 inclined from a towards L d is a funnel 

 through which a current of water is ad- 

 mitted into the tube /-, (by a throat of 

 smaller dimensions than the tube,) and 

 thus conducted to any required depth ; — 

 and from the other tube a, a branch e is 

 given off, which communicates with the ^ 

 place from whence the air is to be drawn 

 out. The water in it? descent from the 

 funnel carries along with it a quantity of 

 air, which is continually supplied in the 

 direction of tlie darts tlirougii tlie tubes 

 a and e, and discharged below at the ter- 

 mination o{ h ; the funnel being kept 

 always lilled to a suflicient heiglit to give 

 considerable velocity to the current wi)ich 

 descends from it, and the opening of its 



throat proportioned accordingly to the stream which feeds the appa- 

 ratus. 



*' In one of the engines of this description which was employed 

 in ventilating a level, the throat of the funnel was about three 

 inches in diameter, and the pipes three or four inches in the side ; 

 the water fell 13 fathoms in the pipe b, and it was sup[)osed by a 

 rough estimation, that the apparatus would act with effect at the 

 distance of about CO fathoms. This distance is not more than one 

 fourth of the range of Mr. Taylor's engine; but tlure is some 

 ambiguity in the note that I took at Leadhills upon ti^is point, and 

 the distance is probably greater than I have specified. 



" I am not sufficiently acquainted with the publications on the 

 practice of mining, to be enal)Ied to state whether this madiine 

 has been descril)cd in any of them ; but in its mode of action it 

 differs essentially from the engines in common use for vm'ilation, 

 which operate in general by forcing in fresh air: and its etitct, as 

 an exhauster, is such as has been suggested by yourself and Mr. 

 Taylor as the best security against the exj)lo!.ioii of mflamoiable 

 gas. An engine is described in the Philosophical Transactions for 

 17'i5, vol. xliii., whicli, from the account given of it in the 

 Abridgment, (vol. ix. p. lO;^,) appears to have been employed at 

 Lead/till^ to blow the smelting furnaces, and to convey fre>>h air 

 into tlie mines. The contrivance for these purposes may be under- 

 stood from what has been already mentioned, by referring to the 

 dotted lines in the lower part of the annexed sketcli; tlie water 

 discharging the air which it had carried with it, in a birge receiver, 

 from whence it passed out in n continued stream through the pipe 

 n: and the transition from that contrivance to the engine abuva 



