Intelligence and Miscellaneous Articles. 393 



B culvert, 5 feet by 6 feet, connecting the upcast pit with the mine ven- 

 tilator ; thus an uninterrupted communication is established with the whole 

 of the air-passages of the colliery. 



DD are two cylinders of masonry, 14 feet interior diameter, and 16 feet 

 lon|. 



EE are interior cylinders, 9 feet 6 inches long, and 4 feet 6 inches dia- 

 meter : the space between the cylinders is filled with water, 7 feet deep, 

 and marked J. 



FF are two aerometers, of 12 feet in diameter and 8 feet 6 inches long, 

 made to balance each other, and to move vertically in the water by means 

 of guides. 



GG, connecting-rods, with the chains from the crank shaft, and which 

 also serve as guides. 



HH, two cranks, placed in opposite direction on a shaft, and to which an 

 engine is attached to give them a rotatory motion. 



II, two chains connecting the cranks with the aerometers, and giving a 

 vertical motion to the aerometers. 



KKKK, four sets of inlec-valves to admit the air from the mine. 



LIXL, four sets of outlet- valves for the discharge of the air into the at- 

 mosphere. 



M is the framing, which supports two shelves, of 2 feet in diameter, over 

 which the chain moves, and which have to support the whole weight of the 

 aerometers. 



N, embankment formed from the cuttings of the foundations. 



The operation of the machine is as follows : — A steam-engine or other 

 power gives a rotatory motion to the shaft and cranks HH, and by means 

 of the chains 11, a reciprocating motion is given to the aerometers FF, 

 equal to twice the length of the cranks ; in this case the machine can 

 work a 4-feet or a 6-feei stroke : the aerometers balance each other, and 

 descend by their own weight — the lower inlet-valves opening at the same 

 moment as the upper outlet-valves,a rapid passage of air takes place through 

 the pumps. 



The water forms the packing, or hermetical seal, which prevents air 

 escaping, or being admitted, except through the inlet or outlet-valves. 

 This machine is capable of discharging 40,000 cubic feet per minute when 

 moving at the rate of 200 feet per minute ; and there is no reason why it 

 may not be worked much faster. The machine is moved by a five-horse 

 power high-pressure engine. 



The following testimonial has been received from Me&srs. Penrose 

 and Evans, relative to the patent mine ventilator, which has been 

 lately erected at the Eaglesbush colliery, 



" Dear Sir, — Your patent mine ventilator has now been at work 

 at our colliery for a month, and gives us perfect satisfaction. In 

 our case not only is the gas and foul air dravsTi from the stalls and 

 general workings of the mine, hut the old goaves and abandoned 

 parts are likewise kept clear. Our men now all work in their stalls 

 with naked lamps. We work the ventilator from about five in the 

 morning till six in the evening, it heing unnecessary to work it at night, 

 as on entering the mine in the morning the overman takes a Davy 

 lamp with him ; and however much of gas there may be there, it is 

 immediately drawn off on the working of the ventilator. Our men 

 say that the mine is now cool, and wholesome to work in, and we 

 observe that they finish their labour in a much shorter time. The 



