474 



It must be obvious from the above section, that, to carry 

 out the improvement, the air-courses, as shown on section, 

 should be at an elevation from the workings, represented by 

 the letters W W, with the furnaces at a convenient distance 

 from the upcast shaft; also two inclines, as shown on the 

 section, X X, at about forty-five degrees, so as to prevent 

 the current coming into contact with the furnaces U U ; the 

 air-courses to be connected by two small shafts, as shown by 

 the letters S S. I beg it to be understood that the air- 

 courses, with small shafts, may be carried to any point that 

 is most desirable, but always to be at the extent of the 

 workings ; and with reference to the present goafs, or where 

 there is an accumulation of gas, it may be carried off by 

 five-inch bores, as shown by the letters V V; so that the gas 

 would always be carried ofi" by the returning current along 

 the air-courses, W W. 



The advantage to be derived by air-courses above the 

 workings, as shown on section (and which is applicable to all 

 mines), is obvious, from the fact that any quantity of pure 

 atmospheric air may be admitted into the works, and in direct 

 currents to every workman in the mine, being returned at 

 the head of the works, as shown on section, along the 

 air-courses, W W, to the upcast shaft or compartment; so 

 that there would be a constant current coursing the whole 

 works, thus rendering an accumulation of gas in the mine an 

 impossibility. It will be observed that, as the air descends 

 the mine, the power given by the elevation of the furnaces 

 and air-courses immediately circulates the whole, and it is 

 carried ofi" in advance of the workmen by the shaft and air- 

 courses already referred to, without ever coming into contact 

 with the workmen. The coal, as it becomes extracted, in- 

 creasing the goafs or void, would always be drained of its 

 gases by the circulating currents through the mine ; conse- 

 quently the fullest ventilation is secured, and may be extended 



