. 66 ANNUAL OF SCIENTIFIC DISCOVERY. 



and 75 parts of ammoniacal salt (hydrochlorate, carbonate, or 

 other). A mixture is made of the whole, which is then calcined 

 and reduced to powder. To make use of the powder thus ob- 

 tained, M. Lietar proceeds as follows: Suppose two pieces of 

 iron, or two pieces of steel, or even a piece of iron and a piece 

 of steel, should be required to be soldered or welded one to the 

 other. The composition is placed between the two pieces at the 

 place to be united ; the whole is put in the fire until the pieces 

 have attained a temperature which permits the powder to become 

 fused, which happens when the pieces have attained a cherry-red 

 temperature. The pieces are then withdrawn and welded in the 

 usual way. If the dimensions of the pieces, or any other obstacles, 

 hinder their being put in the fire together, they may be welded as 

 follows : Heat first one of the pieces to a cherry-red temperature 

 at the place where the soldering or welding is to be made ; then 

 place the composition and apply the second piece, heated this 

 time to white heat ; then weld the whole together. This method 

 is particularly applicable to the repair of large pieces. Mechanics' 

 Magazine. 



WHAT MAKES IRON FIBROUS. 



When Mr. Bessemer began to manufacture wrought iron from 

 cast, by blowing air into the molten metal, it was objected to the 

 product that it had no fibre, as common puddled iron had, and 

 that iron without fibre must necessarily be weak. In this infer- 

 ence which was wholly theoretical we did not concur, and 

 the question then arose, what does fibrous iron really mean ? 

 When the particles of wrought iron are brought to a high temper- 

 ature, without the presence of any intervening material, they co- 

 here in every direction, and the iron is not fibrous. But when 

 slag is intermingled, as in common puddled iron is the case, there 

 are intervening layers of cinder, which, when the iron is passed 

 through the rolls, are not wholly expelled, but are only greatly 

 attenuated ; and as these planes are then very numerous, and pass 

 in every longitudinal direction, they prevent, to some extent, the 

 lateral adhesion of the particles, which, however, adhere end to 

 end, and a fibrous iron is thus produced. It is now well known 

 that homogeneous iron is much stronger than fibrous iron. But 

 at the beginning of the manufacture, fibre was accounted as neces- 

 sary in iron as in ropes or thread, a theory resulting merely 

 from the accident of the production of fibre by the modes of man- 

 ufacture then exclusively employed. In the case of iron produced 

 by the common process, any bubble or vacuity in the metal be- 

 comes filled with slag, which hinders the sides from being effectu- 

 ally welded under the hammer. But in the Bessemer iron, as the 

 sla<r is absent, the sides of the bubble cohere w r hen the ingot is 

 subjected to pressure while still hot. It is better to hammer the 

 ingots while still hot, after having been poured, than to allow 

 them to cool and to heat them afterward ; for in the one case 

 the heart of the ingot is the hottest part, and in the other the 

 coldest. Engineering. 



