TREATMENT OF MANUFACTURED IRON AND STEEL. 281 
pieces cut from several rails and always with practically the same 
result, shows how dangerous it is to punch holes in any position 
in steel if it be at all hard. 
The falling weight test described—modified to suit varying 
sections—is invariably applied to rails, and is the most reliable 
that can be adopted to ascertain the capabilities of such material 
to withstand the jars and shocks to which it will be subjected 
when in use. The amount of deflection under the blows readily 
informs the inspector of the quality of the rolled steel, and if the 
deflection is too great, the steel is too soft and has inferior wear- 
ing properties. With tyres and axles, as their dimensions vary 
considerably, the hardness of the material is usually ascertained 
by carrying out tensile tests after the falling weight experiments | 
have been performed. Although these remarks relate to material 
that is not used in constructional work, the author has referred to 
them, as he thinks they may be of interest to some members. 
Reverting to constructional work ; in dealing with plates for 
boilers, after having been planed, they are bent by small increments 
at a time to the required curvature and not in one operation, as 
such treatment is unfair and injurious to the material. Small 
holes are then made to bolt the work together and the rivet holes 
drilled out of the solid and through the plates when coupled 
together. 
For wrought iron boiler shells, the plates are frequently punched 
before being bent, but this is not a good practice, as a flat place 
is formed at the ends of the plates due to the metal bending more 
readily at the punched holes, and the joints are not, in consequence 
so perfect as they would have been had the plates been bent before 
the holes were made. With regard to the flanged ends of boilers, 
the best practice is to form them by hydraulic pressure and to 
thoroughly anneal them after forging. This annealing is especially 
necessary if any of the forging &c. is done by hammer. Angle 
and tee stiffeners for girder work are also best manufactured if 
bent in presses or under a hammer having suitable dies. 
