TREATMENT OF MANUFACTURED IRON AND STEEL. MET 
The chief officials in good firms are invariably anxious that no 
material shall leave their works that will not give perfect satisfac- 
tion and reflect credit upon the works over which they have charge; 
but the workmen, who would be blamed for turning out a quantity 
of faulty material, naturally endeavour to dispose of it when made, 
and it is, therefore, advisable to employ an inspector who has no 
connection with the works, and who is perfectly independent with 
regard to giving offence to any of the works contractors, and who 
will do his best to see that no faulty material leaves the rolling 
mills for his employers. 
Steel requires to be most rigidly examined for flaws, because, 
owing to its homogeneous character, a defect would cause a frac- 
ture in that metal which would only extend a short distance in 
iron. Steel is therefore rejected for defects that would be passable 
in iron. The harder the steel is, the more closely should the 
inspection for flaws be carried out, and in such articles as rails) 
where the steel has a breaking strength of about forty tons per 
square inch, they are not accepted if they have defects that have 
a sharp appearance or of such a form that would start a crack. 
All plates, bars, &c., that may have been bent in transit are 
straightened either by rolls or press. None of them should be 
warmed ; the smiths term this “taking the chill off,’ but by so 
raising iron or steel to what is termed the “blue heat,” about 
six hundred degrees Fahr. and then working it at that temperature 
the character of the material is altered and it becomes brittle. 
This is especially noticeable in steel. Again, iron and steel both 
deteriorate if heated to too great an extent, and if iron is made 
too hot and burnt, it becomes both “red short” and “cold short.” 
Steel is more easily injured when raised to a high temperature ; 
and the harder the steel the greater the injury; and not only 
does the raising of such material as tool steel to a high tempera- 
ture permanently alter its character and make it “cold short,” 
but if the heat be lower than the burning point and is main- 
tained for a considerable time, the same injury is effected. 
