364 -THE SCIENTIFIC PAPERS OF 



fail under the test of a falling weight. That difficulty increased 

 very much with the reduction of temperature. On a hot summer's 

 day such a rail might resist the test, but on a cold winter's day it 

 would not. Another very essential condition was that the steel 

 rail containing \ per cent, of phosphorus should contain certainly 

 less than -^ths per cent, of carbon, and considerably less in order 

 to withstand the falling weight test, and it must contain not less 

 than T 7 oths per cent, of manganese. Such metal would stand 

 almost any ordinary mechanical test that could be applied to it. 

 He could quite believe the result which had been given by Mr. 

 Price, that he had produced a metal containing T %ths per cent, of 

 phosphorus, and -^ths per cent, of carbon, which would stand the 

 Admiralty test, but he could not go with Mr. Price further than 

 that. It might be said that manganese was to the steel maker 

 what charity was to religion : it covered a multitude of sins, and 

 these were of a lucifer kind phosphorus and sulphur. If you 

 gave him the worst class of iron, and wished him to make steel of 

 it that would stand the Admiralty test, he would undertake to do 

 it ; but such steel, nevertheless, should not be used in such appli- 

 cations as were now contemplated of mild steel no boiler should 

 be made of it, no forging should be made of it, and he thought 

 also no ship should be made of it. Steel of that description 

 depended for its mechanical qualities on the larger dose of 

 manganese which it contained. Now every practical steel maker 

 knew that manganese was a somewhat treacherous element in 

 steel. Its distribution was never so uniform as to make a homo- 

 geneous compound. Then, in the working of a plate containing 

 a large amount of manganese, the manganese was apt to be burnt 

 out, and in attempting to flange it, although sometimes it would 

 stand the test, at other times it would break. That was a question 

 to which the users of steel should direct particular attention in 

 order to prevent failure in the application of a comparatively new 

 material. Good mild steel, such as could be safely recommended 

 to the boiler maker, should contain only mere traces of man- 

 ganese ; T Vth per cent, was about the limit which he considered 

 such steel could contain with entire safety, when the material 

 had to undergo certain preparations in order to put it into its 

 definite shape. Then, again, we heard a good deal about the 

 liability of mild steel to corrode, and some results which had lately 



