MECHANICS AND USEFUL ARTS. 31 



Oural I have bent as many as 9 times without showing the break. 

 Coupled with this quality the glance must be taken into consider- 

 ation, as good polished iron will not take so much paint as the 

 inferior polished." Bulletin of the American Iron and Steel 

 Association. 



COAL AND SMOKE CONSUMPTION. 



On the Pennsylvania Railroad, experiments are now being 

 made, says the " Chicago Railroad Review," with an apparatus 

 for bituminous coal invented by J. T. Rich, of Philadelphia, who 

 puts into the fire-box a "dead-plate" extending from side to 

 side, sloping from a short distance beneath the door and then 

 turning down perpendicularly to the grate bars. Above is a 

 fire-brick arch extending from the back well forward, around 

 which the ascending flame must pass towards the front. Outside 

 the door is a hopper, constantly supplied with coal, which passes 

 in, as that already in the fire-box works down to the dead-plate. 

 A fire being started in the grate, cokes the coal on the dead- 

 plate ; and the heat is utilized by passing around the arch and 

 through the flues. As the coke, thus made, burns away, its heat 

 and gases, without smoke, passing through the flues, new coal 

 constantly works down and undergoes the same process. The 

 experiment thus far shows there is no doubt that the process will 

 result in almost entire freedom from smoke ; but the practical 

 question, whether steam can be made fast enough, _is not yet 

 decided. Journal Franklin Institute. 



AERO-STEAM ENGINES. 



The advocates, says the " Engineering," of what is known here 

 as the Warsop system claim that the application of that system to 

 a boiler and engine prevents the formation of incrustation, does 

 away with priming, and effects a considerable economy of fuel. 

 Now we have no wish to deny that under certain circumstances 

 results have been obtained which appear to warrant the above 

 claims, in those particular cases; but what we object to is, that 

 these results should be made the foundation of totally fallacious 

 arguments as to the value of the " aero-steam " system of work- 

 ing. It may be that the injection of heated air into a boiler is, 

 under certain circumstances, a good way of promoting the circu- 

 lation in that boiler, and thus preventing the evils by which a want 

 of proper circulation is attended ; but it by no means follows 

 from this that the injection of air is the best way of producing cir- 

 culation under all circumstances. On the contrary, until we have 

 clear evidence afforded to us that the injection of air so far im- 

 proves ths economic evaporation of, not a bad, but a thoroughly 

 good boiler, as to more than repay the cost of forcing in that air, 

 we shall regard the system merely as a means of counteracting 

 faults of construction which should not have any existence. 



As with the boiler so with the engines. Non-condensing 

 engines having unjacketed cylinders, supplied with steam at 



