546 TRANSACTIONS OF THE 



proper flux be employed. Platinum will fuse at a dull red lieat if arsenic 

 be used as a flux, 



Mr. Tillman. — That is precisely tlie point we want to get at. Iron will 

 melt at no temperature lower than its normal melting point except a flux 

 be used. 



Mr. Seeley. — The melting point of an alloy is always lower than the 

 mean of the melting points of its components. Manganese requires a 

 higher temperature than iron ; iron than zinc. The modes of measuring 

 high degrees of temperature being alluded to, it may be well to describe 

 what may be called the "flame thermometer." All substances will burn in 

 a flame — cast iron will burn in a candle. Throw minute filings of cast iron 

 into the flame of a candle, and they will burn with brilliant scintillation. 

 Platinum will also melt in the flame of a candle, if presented in the form 

 of a very fine wire. Upon this fact the flame thermometer is based. A 

 Bunsen gas lamp, which gives a definite size of flame is used, and when pure 

 oxygen is employed as the supporter of combustion, a temperature of 

 16,000° is obtained, which is the highest that has been measured. By 

 adding nitrogen to the oxygen, the temperature of the flame can be reduced 

 ad libitum, the amount of mixture determining the temperature. 



Mr. Serrell melted franklinite pig-iron readily, and cast it into plates, 

 cylinders and irregular forms, with ease. He was much interested in the 

 experiments by Dr. Vander Weyde the last evening, showing how this iron 

 could withstand the action of nitric acid in a Grrove's cell. About a year 

 ago, he had ascertained that though it will remain untouched while sus- 

 pended in the cell, yet, if it be made a part of the circuit, it is soon acted 

 upon and corroded. 



The Chairman feels certain it was never found in Europe to any amount ; 

 that it is peculiar to this country, and will prove invaluable in manufactures. 



Messrs. Stevens, Serrell and Seeley, were appointed a committee to col- 

 late all the information elicited by the club on this subject for a final 

 report. 



The subject "Aluminum," was selected for the nest meeting. After 

 which the Association adjourned. 



Polytechnic Association, American Institute, ) 



January 12, 1860. ) 



Prof. C. Mason in the chair. Mr. Johnson, Secretary. 



Mr. Garvey presented a steam gauge invented by Mr. James Mont- 

 gomery, of Newark. This gauge depends for its action upon a weight 

 instead of a spring, the piston resting upon a silk diaphragm. Mr. Garvey 

 said this diaphragm had been used two years with satisfactory success. 

 Mr. Patrick presented a patented variable exhaust. The chairman believed 

 that the interest of inventors and the public good would be promoted by 

 the deposit of a model in each case ; he should therefore ask this from 

 each inventor in subsequent >'ases. The variable exhaust and the steam 

 gauge were referred to a committee, consisting of Messrs Butler and Diven. 



