MECHANICAL AND USEFUL AKTS. 63 



as rings, buckles, and links — and several kinds of cutlery, and parts 

 ,of small machinery. It is claimed for the invention, that it not only 

 makes a far better kind of malleable cast-iron, but can be done at 

 much less expense, as the time of keeping up the heat is greatly 

 reduced, and the product of the packing material is valuable. 



The formula of the process is as follows : — Oxide of zinc : zinc, 

 32 ; oxygen, 8 ; total, 40. So that if a mass of iron, or a number 

 of pieces of castings, containing 6 lb. of carbon, were packed in 

 40 lb. of oxide of zinc, the S lb. of oxygen would separate from the 

 zinc, and combine with the carbon of the iron, producing 14 lb. of 

 carbonic oxide gas, which would be lost in the atmosphere, and 

 leaving 32 lb. of pure metallic zinc, and the castings 6 lb. lighter. 

 So that, if the oxide of zinc costs 4£ cents per lb., and the metal 

 was worth 7 cents, there would be a gain as follows : — 40 lb. oxide 

 zinc, 4i cents, 1 dol. SO cents ; 32 lb. metallic zinc, 7 cents, 2 dols. 

 24 cents ; gain, 44 cents. So that one heat, using 40 lb. of oxide 

 of zinc, would cost 44 cents less than the price of the fuel required 

 in the process, and the time of keeping up the heat is not more than 

 one quarter of the old method. Another important fact connected 

 with this way of decarbonizing iron to render it malleable is the cer- 

 tainty with which the manufacture can be carried on. Nothing is 

 left to guess-work, or, what is nearly the same thing, the conjecture 

 of experience ; for when the zinc ceases to distil, if there is an 

 excess of the oxide of zinc present (which can always be provided 

 for), it is certain there is no more carbon to be extracted from the 

 iron and unite with the oxygen, and the process of decarbonization 

 is necessarily perfect. The specimens that have been dealt with by 

 this method are found to be nearly chemically pure iron — silicates 

 and phosphates being removed. — American Railway Review. 



MALLEABLE IRON CASTINGS. 



A NEW method of " malleableizing" Iron Castings is announced in 

 the New York Tribune to have been discovered by Professor A. It. 

 Eaton, of that city. It consists in exposing the castings to the 

 contact of oxide of zinc, as a substitute for the oxide of iron in the 

 furnace. It is stated that the employment of the oxide of iron 

 which combines with the excess of carbon in iron castings when long 

 exposed to red heat, leaves a spongy residuum on the castings, which 

 is obviated by the zinc oxide, because the zinc is volatile and passes 

 off, leaving the oxygen gas to combine with the carbon in the iron ; 

 although, were both metals equally fixed, the zinc would rather 

 deprive the iron of oxygen than the iron the zinc. 



METHOD OF CONVERTING IRON INTO CAST-STEEL. 



PLACE layers of small pieces of iron in a crucible, with a mixture 

 of the carbonate of lime. Six parts of the carbonate of lime, being 

 either chalk, marble, limestone, or any other calcareous substance, 

 and six parts of the earth of pounded Hessian crucibles, must be 

 employed for twenty parts of iron : and this mixture is to be so 

 disposed, as that, after fusion, the iron may be completely covered 



