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Dr. Jackson gave an account of some researches into 

 the composition and manner of formation of different 

 kinds of steel. 



As commonly known, steel is a combination of carbon and 

 iron, made by heating flat bars of pure iron, in combination 

 with charcoal. The carbon is first converted into oxide of 

 carbon, and then unites with the iron as carburet. The result 

 of this process is known as blistered steel, from the bubbles 

 generated by gases upon its surface. Shear steel consists of 

 parallel plates of pure iron and steel, welded by folding and 

 uniting the bars of blistered steel. Cast steel is fused in pots 

 of the most refractory material, and differs from cast iron, which 

 likewise contains carbon, in this respect, that cast iron is a mix- 

 ture of coarsely aggregated matters, graphite and iron, whilst 

 cast steel is a chemical combination of carbon and iron. 



From the researches of Berthier, it is known that manganese 

 will form an alloy with iron. When iron is mingled with a 

 considerable portion of manganese, a brittle compound results ; 

 but when combined with a very small proportion of manganese, 

 a steel of very fine quality is obtained, which has this advantage 

 over carbon steel : carbon steel becomes coarse when tempered 

 in thick masses, from segregation of the particles of carbon ; but 

 no such trouble arises with manganesian steel. Parties in Eng- 

 land have lately introduced excellent wire for piano-forte strings, 

 made of this kind of steel, as well as for cutting instruments, and 

 other purposes. In the wire. Dr. Jackson has found 1.12 per 

 cent, of manganese, and has established the fact that it resists, 

 to a very remarkable degree, the action of hydrochloric acid. 

 Sixteen years since, Franklinite iron was manufactured by Mr. 

 Osborn into very hard and fine steel. This steel required tem- 

 pering at a lower heat than carbon steel. Many of our manga- 

 nesian irons might be manufactured into steel, by the simple 

 process of fusion, and a steel of uniform character might be 

 made without previous cementation with carbon. 



Dr. Jackson explained, with the aid of diagrams upon the 

 blackboard, the reduction of iron in blast and reverberatory 



