336 C. Barns — Status of High Temperature Research. 



MELTING POINTS. BOILING POINTS. 



Substance. Equation (4). Equation (8). Substance. Equation (4). Equation (3). 



Zinc 420° 420° Mercury.. 357° 357° 



Aluminum. 635° 638° Sulphur... 446° 446° 



Silver 956° 986° Selenium.. 687° 694° 



Gold 1048° 1091° Cadmium . 770° 782° 



Copper... 1054° 1096° Zinc 905° 929° 



Nickel 1382° 1476° Bismuth.. 1346° 1435° 



Palladium. 1472° 1585° 



Platinum.. 1614° 1757° 



With regard to preferences in choosing between these two 

 curves there is, at present, little opportunity for discretion. 

 The lower temperatures are determined by the melting points 

 of silver, gold and copper, systematically investigated by 

 Yiolle ; while the higher temperatures are in accordance with 

 the boiling point of zinc as found by Deville and Troost, 

 Violle, Mensching and Meyer, and in a measure by myself, 

 some of the researches being remarkably elaborate. As is 

 usual in such cases, the truth is to be sought somewhere 

 between the extremes ; and thus one finds in the recent work 

 of Holborn and Wien* at the Reichsanstalt that silver, gold, 

 and copper melt at 970°, 1082° and 1070° respectively ; or at 

 temperatures 16°, 25° and 28° higher than given by Yiolle. 

 These points are indicated by the letter R in the chart and 

 they lie cpuite within the limits indicated by the two curves. 

 It will be seen too, that if I were to neglect outlying stragglers 

 in my data at very high temperatures, where measurements are 

 made under increasing difficulties, my results could be nearly 

 reconciled with those of Holborn and Wien. 



The purpose of this paper, however, is to show in a system- 

 atic way that to clear away the anomalies now existing in 

 high temperature data either the boiling point of zinc must 

 come down from 930° to 905°, or else the melting points of 

 silver, gold and copper must move up 30° to 40°, or both must 

 move towards each other by corresponding amounts. I hope 

 myself to make some contributions toward a solution of these 

 discrepancies. 



I desire in conclusion to express my indebtedness to Prof. 

 Alexander Graham Bell, by whose generosity I have in the 

 past year, materially profited. 



Washington, July, 1894. 



* Holborn and Wieu: Berl. Acad., June, 1892. 



