the Roberts-Austen Recording Pyrometer. 



65 



heating-curves, in investigating the constitution of metals 

 and alloys. The curve representing the melting of the gold 

 is nearly 1° higher on the scale than the curve representing 



I 



o 



O 

 o 



< 

 I 



its solidification, and it would appear that the true melting- 

 point of a pure metal is indicated most nearly by that part 

 of the cooling; record where the curve first becomes approxi- 

 mately horizontal. 



Phil. Mag. S. 5. Vol. 46. No. 278. July 1898. F 



