(F.) 



AMERICAN INSTITUTE— CONVERSATIONAL MEETING- 



Professor J. I. Mapes, Chairhi. Henry Meigs, Sec^y. 



The following report is respectfully submitted to the Instilutey 

 January 13, 1844. 



Among other adjuncts of the American Institute, they have estab- 

 lished conversational meetings, the object of which is to elicit from 

 members such facts in relation to the subject of conversation as each 

 member by reading or experience may be possessed of. Thus each 

 member can avail himself of the reading and experience of an hun- 

 dred practical or theoretical men, for twenty years, in the short space 

 of a single hour. 



By the following example, it will be seen that the information col- 

 lected during the evenings in which iron was the subject of conver- 

 sation, w fully equal if not superior to any treatise yet published. 



Iron. — Cast iron is composed of alternate molecules of a spherical 

 form, of carbon and iron rp.echanically and not chemically aggregated. 



Cast Steel is a chemical and not a mechanical admixture of car- 

 bon nnd iron, in the same proportions as in cast iron — only differing 

 in their conditions. 



Wrought Iron is the result of cast iron, after having been freed 

 of its carbon. The process by which this is produced is called pvd- 

 dling. 



Steel is made by placing bars of wrought iron in contact with 

 carbon, and by a process called cementation. Each ultimate particle 

 of iron receives in chemical combination its equivalent of carbon — 

 thus increasing its strength or ability to resist mechanical forces, some 

 twenty times or more. 



Cast Iron. — The improvement in the quality of cast iron pro- 

 duced from American ore, has been very great, and the expense at 

 which castings can now be produced, is less than one-quarter of that 

 charged some twenty years since, while the quality has been materi- 

 ally improved. 



The modes of treatment in the cupola, bloomery, blast (hot and 

 cold) and other furnaces, were fully described, but are too volumi- 

 nous for detail here. 



Many methods of manufacturing wrought iron with anthracite and 

 other coal, were described, and the superior quality of the American 

 boiler iron -plate was fully shown. 



To build a boiler of English boiler tro7i,it is first necessary to make 

 a frame, called a gallows frame, on which the plates are butted, and 

 each edge attached to the bar, by a row of rivets — the two ultimate 



