218 PROCEEDINGS OP THE AMERICAN ACADEMY. 



Investigatio>s on Light and Heat, made and pdblished wholly or in part with 

 Appbopriation from the Rujjford Fund. 



XI. 



CONTRIBUTIONS FROM THE PHYSICAL LABORATORY OF THE 

 MASSACHUSETTS INSTITUTE UF TECHNOLOGY. 



XLV.— MELTING POINTS OF ALUMINUM, SILVER, 

 GOLD, COPPER, AND PLATINUM. 



By S. W. Holmax, with R. K. Lawrence and L. Barr, 



Presented November 13, 1895. 



The following melting points are offered as provisional only, but 

 with the belief tliat they are more reliable than previous data. The 

 absolute values dejiend in jiart upon the assumption of 1072° C. as 

 the melting point of pure gold, the recent determination of Holborn 

 and Wien at the Reichsaustalt. Should that datura, however, be 

 shown to reijuire revision, the validity of the present measurements 

 would not be impaired, but new values of the melting points could be 

 readily computed from them, which would be consistent with the better 

 value for gold. 



Al Ag 



660° 970° 



The Pure Metals used were of a high degree of fineness, except 

 unfortunately the platinum. 



The gold contained less than 0.01 per cent total impurities, these 

 being, if any, probably minute traces of silver and platinum. It was 

 obtained as part of a specially prepared lot from the United States 

 Assay Office in New York through the courtesy of Professor H. G. 

 Torrey, upon whose authority the above statement is made. The 

 purity was at least as great as the best " proof " metal used at the 

 United States or London mints. 



The silver was from the same source, and equally pure. 



The aluminum was manufactured and given by the Pittsburg Reduc- 

 tion Company, of Pittsburg, Penn., and was stated by Mr. Alfred E. 



