452 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



bon, and was as clear of other materials as I could get it. The 

 clay pots had too much silex in them, and it injured the metal. 

 One of the greatest difficulties that Bessemer had to contend with, 

 was that he used such a hot blast. The materials of the lining 

 would mix with his steel, and he had to reline at every charge. 



JVew subjects. — ^Ir. Stetson suggested the subject of "Explosive 

 missiles of war," for future consideration. The subject of " So- 

 luble glass," was selected for the next meeting. 



Adjourned to meet on Wednesday next at 7^ P. M. 



American Institute, Polytechnic Association, ? 



JVovember 27, 1861. ) 

 Prof. Cyrus Mason in the chair. 



Mr. Enos Stevens presenied a new system of written music, 

 styled Tonography, representing every musical sound by a dis- 

 tinct letter, so that music may be printed like ordinary types. 

 Referred to the Section of Mechanics. 



CRUCIBLES, STEEL, FRANKLINITE. 



Mr. J. H. Churchill said that the lime used for lining crucibles 

 should be pure shell lime, with a very small proportion of silex. 

 Lime perfectly pure will crack, but with the addition of five per 

 cent, of silex it Avill stand a very high heat. He had not been 

 able to discover in what way lime was supposed to injure steel. 

 Swedish iron, say those who object to it, owes much of its supe- 

 riority to its cold-shortness, from an admixture of phosphorus. 

 Lime is sometimes used for removing phosphorus, in converting 

 cold-short into soft iron from melted metal, as mentioned by Lt. 

 Mather of Mexican iron work. If the removal of phosphorus 

 would be an injury to some steel, it is possible that lime would 

 not answer for lining crucibles to be used for it. Otherwise, it 

 would be a very suitable material, and all Swedish iron does not 

 contain phosphorus. 



Mr. Tillman. — So far as I have been able to learn, plumbago 

 pots are preferred for melting steel to all others. 



Prof. Seely. — I believe Dixon's pots are as good for melting 

 steel as any others, and better, excepting in cases where peculiar 

 combinations are required. For specific purposes the proportion 

 of clay should be specific; and for some purposes a peculiar kind 

 of clay may be required. 



Mr. Fisher inquired with reference to the practicability of cast- 



