214 ANNUAL OF SCIENTIFIC DISCOVERY. 



effect of at least 12 per cent., and from that to upward of 30 per 

 cent. ; one cause of this is obviously a more even distribution and 

 extension of the Hume under the surface of the boiler, and a 

 nearer approach, as machinists say, of the power to the work. 



" As these experiments were conducted with limited amounts 

 of fuel, far below the capacity of the furnace, it is to be expected 

 that larger advantages will be shown, as from other trials it was 

 observed that the velocity of combustion was enhanced, and a 

 greater efficiency produced, as the amount of fuel burned was in- 

 creased. 



" These results establish the fact that the cheaper varieties of 

 coal can be made even more efficient than the qualities now in the 

 market. They give us a stock of fuel already mined and ready at 

 once for consumption, amounting at least to a third of the fuel 

 used in this country during the past year, and probably to ten 

 times that amount. 



" Take the amount of coal mined by any one mine this year, 

 allowing that one-third of it is waste, not now used, by burning 

 the waste as pulverized fuel with one quarter of the lump which 

 would now alone be used, and we find that the result is an actual 

 increased efficiency of more than 50 per cent, in the coal mined. 



" To employ pulverized fuel requires a slight modification of 

 the ordinary form of furnace, which was found to give results with 

 lump coal far above the common average, and no change what- 

 ever is made in the ordinary horizontal grate bars. The works 

 of Messrs. Whelpley & Storer, at East Boston, were placed at 

 the disposition of the board of engineers for these experiments, and 

 the method of burning waste coal was the one adopted and for sev- 

 eral years used by them in their metallurgic operations and for 

 the generation of steam. 



"The inventors are now preparing a machine to employ this 

 method of using fuel in locomotives, where, as is well known, the 

 loss from smoke, imperfect combustion, a'nd other causes is enor- 

 mous. It is somewhat singular that the prophetic mind of the 

 greatest authority in practical steam engineering that has yet ap- 

 peared, foresaw the conditions under which the fuel problem must 

 be solved, while he did not by any means understand the details 

 and mechanism of the solution which has now been reached. In 



* Bourne on the Steam Engine,' ed. 1861, p. 358, we read: 



* Nearly all of the expedients hitherto introduced for burning 

 smoke in locomotives are adaptations of the devices heretofore in 

 use for burning smoke in land engine furnaces. But the rapid 

 combustion which a locomotive boiler requires renders the burn- 

 ing of the smoke by any of these ancient devices a matter of 

 very difficult attainment, and it seems to be indispensable that a 

 method founded on a t >tully new principle should be introduced. 

 It appears to us that the fuel and air must be fed in simultane- 

 ously, and the most feasible way of accomplishing this object 

 seems to be in reducing the coal to dust and blowing it into a 

 chamber lined with lire brick, as the coal dust may be ignited by 

 coming into red-hot surfaces, after having been mingled with the 

 quantity of air njcessary for combustion. This, however, iu com- 



