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broad; the inlets or passages for air are exactly one-third 

 of its diameter; the interior of the drum contains six 

 fanes, extending from the extreme diameter of the inlet to 

 the outer circumference of the drum; one-third of the 

 space between each fane is left open for the delivery of air ; 

 the remaining two-thirds are closed by a plate, called a 

 vacuum plate, which prevents the atmosphere from lodging 

 behind the fane. This machine performs 230 revolutions per 

 minute, is fixed over a Staple Pit, which is connected with 

 the Back Pit or Engine Pit, and throws off exactly the same 

 number of cubic feet at every revolution, which the drum 

 contains. The inlets at the sides consist of a cast iron rim 

 turned true on the face, revolving against a fast face of iron, 

 also turned true, and screwed to a wood pipe, which I find 

 answers well to be in breadth two-thirds the length, con- 

 sequently in the form of a parallelogram ; the depth of this 

 pipe is discretionary, as circumstances require; I recommend 

 six feet. The top of the pipe lifts off, to admit the drum 

 and the shaft into their proper place ; the plummer-blocks 

 and brasses are outside of the pipes, and level with the 

 parting in them. By constructing a machine as above you 

 need no case, and avoid all clearances between the fan 

 and the case, — a very great evil in the common fan. This 

 machine runs without noise." 



The Author's attention was first called to the subject by 

 the Report from the Select Committee of the House of 

 Commons " On Accidents in Mines" which recommended 

 greater care and caution to be used by all grades of indi- 

 viduals engaged in mining operations, and that nothing 

 could be done which could be more effectual than the 

 plans they had brought before them ; and that with proper 

 and careful use of the Safety Lamp, the painful calamities 

 they had to investigate would, to a great extent, be avoided. 

 Mr. Fourness, however, was of opinion that to prevent 



