116 JOURNAL OF THE [October, 



traces of lines from the matrix are seen to penetrate to the 

 interior of the polygons. This specimen is from the tire of a 

 steel wheel, is very hard, and contains 6 per cent of manganese. 

 Wheels of such steel have given a very large mileage. Specimen 

 No. 2 is from a rejected heat of rails, and contains .90 of carbon. 

 The ingot was maintained at too high a heat in the reheating 

 furnace, coarse crystals resulting in the head of the rail, and, as 

 will be seen, they are quite well defined. In the fracture the 

 crystals have separated from each other through the matrix with- 

 out breaking the individual crystals. This shows first the over- 

 heating of the steel, which, in a large head of a rail, does not re- 

 ceive sufficient work to break up this coarse crystallization. The 

 distance across the axis of the crystals measures j\%\ to -j^W °^ 

 an inch, which, for a good wearing rail, I consider coarse, though 

 the majority of rails in the track are much coarser. Specimen 

 No. 3 is from the same rail, taken near the top of the head, and 

 shows that the mechanical treatment of rolling has broken up 

 the coarse crystallization, rendering it practically amorphous, very 

 fine in texture — in fact, much finer than can be expected in rails 

 until higher carbons are reached than has been until recently con- 

 sidered advisable to put in the tracks. As we increase the carbon 

 in rails we increase the hardness, raise the elastic limit and ten- 

 sile strength, but, on the other hand, decrease the elongation, and, 

 without great care, render the steel brittle under shock instead 

 of retaining sufficient toughness in the rails to render them safe 

 in the track during winter in this latitude. The element phos- 

 phorus tends to render rails brittle, or cold-short, and as the car- 

 bon is increased the phosphorus must be decreased, at least with 

 ordinary sections having deep heads and thin bases. Phosphorus- 

 exists in the pig iron, or the ores from which the pig iron is made^ 

 and to such an extent in many ores that they are unsuitable for 

 Bessemer metal, and it requires some care to select ores which 

 will run from .08 to .10 of i per cent of phosphorus, about the 

 limit to be combined with .35 to .40 of i per cent of carbon. 

 While rails, many years since, containing .35 to .40 in carbon were 

 suitable for the traffic at that time, they wear too rapidly under 

 the present traffic. To increase the carbon for better wearing 

 qualities, it is first necessary to introduce a section for heavy 

 rails which would cool more uniformly, reducing the coarseness 



