MECHANICS AND USEFUL ARTS. 47 



considered it would be of advantage to reheat the axletrees of locomotive 

 engines after they had run for some time, so that the fibrous structure* 

 from whatever cause it was rendered crystalline, might be restored. Mr. 

 Roberts was not disposed to admit that any change is produced in the 

 quality of iron by wear. If the iron were of good quality and perfect at 

 first it would remain so till it was worn out. He observed that bars of 

 iron are frequently different at their opposite ends, for whilst one is tough 

 the other may sometimes be broken with a slight stroke of the hammer. 



NEW METHOD OF ADJUSTING VALVES OF LOCOMOTIVES. 



H. "W. Farley of East Boston, has invented a method of setting the 

 valves of locomotives, which is at the same time cheap, simple, and very 

 economical of time, space, and manual power. The invention applies 

 only to the method of obtaining a rotary motion for the wheels. The 

 setting of the valves correctly, is a matter of vital importance, and it is 

 necessary in its accomplishment to revolve the wheels many times. This 

 is usually done by moving the locomotive along on the track, a method 

 quite inconvenient on account of the space required in the shop. Mr. 

 Parley places a suitable shaft just beneath the floor, on which shaft are 

 two wheels, at distances corresponding to the gauge of the track. The rail 

 being cut away at that point, these rollers are placed with their upper 

 surfaces flush with the top of the rail, and by so locating the locomotive 

 that the driving-wheels rest on that point, any desired motion may be 

 given by rotating the shaft. For engines with a single pair of driving- 

 wheels, the operation is exceedingly simple, but when (as is now almost 

 universally the case) two pairs are coupled together, either the side rods 

 are to be disconnected or the hinder pair lifted so as to turn clear of the 

 rails. 



IMPROVED STEAM COCK. 



Mr. O. C. Phelps of Boston, is the inventor of a cock designed to take 

 the place of the ordinary ones in almost every situation where considerable 

 pressure is experienced. The object is to compel the pressure of the fluid 

 to keep the device always tight. In passing through this cock the fluid, 

 whether steam, water, or gas, turns a right angle, and the axis of the plug 

 is in line with that part of the pipe through which the fluid is received. 

 The plug is conical and partially hollow, the larger and hollow end being 

 preserved for the reception of the fluid, which is of course discharged 

 through a hole in the side. From, this description it will be evident that 

 the plug must be inserted from the inside, the stem to which the handle is 

 attached being merely a continuation of the smaller end. This invention 

 appears to be particularly applicable as test cocks in high-pressure boilers. 



