High Temperatures. 



201 



Table XXII I. 

 Melting Points of Alloys. 



Alloy. 



t 



Mean. 



Alloy. 



t 



Mean. 













MV 



Degrees. 







MV 



Degrees. 





95 Ag, 5 Au 



8989 



958-7 





95 Au, 5 Pt 



10805 



1115-0 







8990 



958-8 







10799 



1114-5 







8980 



957-9 



958-5 





10826 

 10827 



1116-8 

 1116-8 



1116-0 



90 Ag, 10 Au 



9067 



965.5 















9070 



965-8 





90 Au, 10 Pt 



11551 



1177-2 







9080 



966 7 







11522 



1174-9 







9060 



964 '9 







11533 



1175-7 







9070 



965-8 



965-7 





11495 

 11578 



1173-6 

 1179-7 





40 Ag, 60 Au 



9753 



1025-3 







11482 



1171*5 







9756 



1025-5 







11599 



1181-2 



1176-3 





9730 



1023-3 















9760 



1025-9 





85 Au, 15 Pt 



12285 



1237-4 







9757 



1025-6 



1025-1 





12282 

 12273 



1237-1 

 1236-4 





95 Au, 5 Pt 



10821 



1116-4 







12317 



1240-0 



1237-7 



Thermoelements were first intended only for the measure- 

 ment of temperatures from red heat upwards; afterwards it 

 became evident that lower temperatures could be measured by 

 this means as well. There is no advantage gained by going 

 below 250°, however, as the errors due to the decrease in the 

 sensitiveness at the lower temperatures begin to be more 

 noticeable. 



The accuracy of thermo-electric measurements in the earlier 

 investigation of Holborn and Wien (loc. cit.) was stated to be 

 5°. The present results carry it further. It could fairly be 

 said that, for temperatures up to 1150°, the present error would 

 be about 1° ; that is to say, for any distribution of temperature 

 between the junctions, the temperature of the hot junction is 

 defined by the thermo-electric force to within ±1°. 



This does not in the least mean however, that with constant 

 conditions considerably more accurate relative measurements 

 cannot be made. The determinations of the melting points of 

 the metals contain many examples of this. 



The chief reason for this progress lies in the facilities for 

 electric heating whereby the whole investigation of high tem- 

 peratures gains in accuracy and simplicity. 



For the thermo-elements the change is especially important 

 since the electric oven allows a definite temperature distribu- 

 tion to be exactly reproduced at any time, whence it becomes 



