TREATMENT OF MANUFACTURED IRON AND STEEL. 263 
THE TREATMENT OF MANUFACTURED IRON AND 
STEEL FOR CONSTRUCTIONAL PURPOSES. 
By Wm. Fiextp How, Assoc. M. Inst. C.E., M. I. Mech. E., Wh. Se. 
[Read before the Royal Society of N. S. Wales, September 6, 1893. ] 
Durine the execution in Great Britain of contracts for the New 
South Wales Government and other large purchasers of material 
and works of various descriptions, the author had to deal with 
constructional work built of iron and steel, and this paper has 
been prepared with the hope that members of the Royal Society 
of New South Wales will be interested in matters relating to 
some of the methods adopted by firms of the highest repute, when 
executing such contracts in accordance with strict specification 
S 
and instructions. 
No attempt is made to describe the manufacture of the iron 
and steel, that being entirely beyond the scope of this paper, 
rolled material and the treatment to which it is subjected only 
being considered. 
Wroucut Iron. 
Wrought iron is largely used for the manufacture of light 
girders, roofs, &c., owing principally to the fact that the superior 
strength of steel cannot be taken full advantage of by using thin 
plates, angles, channels, &c.; as those details are not at present 
rolled from that material of the small dimensions required, unless 
at a considerable extra cost. Again, in some instances, thicker 
plates than actually required are used to ensure rigidity in light 
structures. 
It is therefore cheaper in such cases to use the thicker iron, 
which also possesses an advantage where oxidation occurs to any 
