1030 Transactioxs of the American Institute. 



"was accomplished by the use of elastic type, made of the same mate- 

 rial that is used for the inking rollers of printing presses. 



Mr. J. Johnson remarked that these sheets were probably rolled 

 out, two or three together, that is, a pile of two or three, laid one on 

 top of the other, was probably passed through the rolling mill at 

 once. 



Dr. Feuchtwanger said this was the way in which tin-foil is made ; 

 or rather it is more frequently rolled between large plates, but then 

 tin-foil is much softer than iron. 



New Rails for Railways. 



Mr. Edwin Ferguson exhibited a rail of peculiar construction. It 

 is so made that, when necessary, it may be inverted, and the lower 

 surface made to perform the part of the upper surface. It is iixed in 

 a sliding chair. The rail is made of iron, and case hardened or car- 

 bonized on tlie exterior. 



Dr. D. D. Parmelee, after some inquiries in regard to the methods 

 used for carbonizing the rails, said there is no known method by 

 which large plates of iron can be carbonized, except by cementation. 

 All the plans for plunging, etc., are humbugs. It is true that by 

 various processes of case-hardening the surface can be rendered hard, 

 but then it takes eight hours to penetrate one-sixteenth of an inch, 

 and after that depth has been reached the process becomes still slower. 



In reply to a question of Mr. Fisher, Mr. Ferguson stated tliat it 

 cost forty dollars per ton to carbonize the rails. Mr. Fisher said this 

 would make it altogether too expensive. Besides that, if the central 

 ribs were taken away, there is aothing left except the old English rail. 



Mr. Ferguson replied, yes, if the top and bottom is taken away, 

 there will be nothing left at all. The old English rail cannot be 

 turned over and again be reversed, and so utilize all the four edges ; 

 and it is well knoAvn that it is the inner edges of the rail that suffer 

 most severely, as they come in contact with the tread of the wheel. 



Dr. P. Yanderweyde. — It is a curious fact that all those sub- 

 stances which are best for case-hardening, contain nitrogen. One of 

 the best substances for this purpose is prussiate of potassa ; a little 

 of this sprinkled on a piece of iron carbonizes the surface instantly. 



Dr. D. D. Parmelee. — Yes, but the iron is carbonized to such a slight 

 depth that it is good for nothing where there is much wear. 



The Chairman presented the following notes on scientific pro- 

 gress : 



