Melting-points of Aluminium, Silver, Gold, Copper, fyc. 51 



discussed. A statement of the extreme error which may have 

 been introduced into the results by this source should, how- 

 ever, be added. This is believed to be for aluminium less than 

 ±2°, for silver less than +2°, for copper less than +0*5°, 

 and for platinum less than +10°. 



Comparison with the temperatures computed by the Ave- 

 narius equation shows errors by the latter to be about 1*5 

 times as great for water and naphthalin, and of the same 

 signs. It is therefore much less reliable, especially for the 

 platinum temperature, and no weight is attached to its results. 



Melting-points by various Authorities. — A collection of these 

 is given in Table IV. Except in the case of the Barus data, 

 the results are set down directly as given by their authors. 

 A further discussion of these with reference to the purity of 

 the metals used, and the characteristic errors of the methods 

 employed, would doubtless prove instructive, and might partly 

 remove or account for some of the apparent discrepancies, — 

 a task which will perhaps be undertaken later. 



Table IY. 



Authority. 



Date. 



Method. 



Metals. 



Al. 



Ag- 



Au. 



Cu. 



Pt, 



H. L., and B 



1895 



1879 

 1884 



1894 

 1892 



Th.-el. 

 Sp. Ht. 

 Sp. Ht. 

 Th.-el. 



Th.-el. 

 Th.-el. 



o 

 660 



635 



641 



970 

 954 

 960 



[945] 

 954 

 985 

 986 

 968 



[1072] 

 1035 



[1035] 

 1037 

 1075 

 1090 

 1091 

 1072 



1095 

 1054 

 1100 



1095 

 1096 

 1082 



1760 

 1775 



1783 

 1757 



Violle 







Callendir 



Erhard and Schertel... 

 Baru9, by Log. Eq.*... 



byEq 3 



Holborn and Wien . . . 



Mean of independent absolute measure- 

 ments, i.e. excluding H., L. & B., 

 Le C, and C. 



641 



964 



1068 



1083 



1779 



N.B. — Values in brackets [ ] are those assumed by the 

 observers, and upon them their other values depend to a 

 greater or less extent. 



Rogers Laboratory of Physics, 

 Massachusetts Institute of Technology, 

 Boston, October 1895. 



* See discussion by Holnian, Phil. Mag. xli. p. 465. 

 E 2 



