252 



PROCEEDINGS OF THE AMERICAN ACADEMY. 



TABLE II. 

 Calibration of Thermo-electric Junction. 



Sulphur 

 Antimony 

 Aluminum 

 Copper 



Temperature Centi- 

 grade of 

 Melting Point. 



447.7 



630.7 



656.0 



1083.0 



Millivolts. 



3.56 



5.38 



5.59 



10.19 



Log. of 

 Temperature. 



2.6481 

 2.7998 

 2.8169 

 3.0346 



Log. of 

 Millivolts. 



0.5515 

 0.7307 

 0.7474 

 1.0081 



1.0 



0.9 



»^0.8 



0.7 



0.6 



1=111 



V 



2.8 2.9 



Log Temperature 



3.0 



Figure 4. Calibration of thermo-electric couple. 



The logarithms of the temperatures and pressures are seen from Fig- 

 ure 4 to lie on a straight line. 



The pressures given in the following tables are in millimeters of 

 mercury, and the temperatures in centigrade degrees. The numbers 

 of the experiments are those recorded in the laboratory note-book. 

 These tables contain only an abbreviated record of the experiments. 

 Under the heading " Kilowatts " is given the product of current and 

 amperes divided by 1000, not taking into account the power factor of 

 the furnace. 



Experiment 4. 



The following experiment was carried out before the method of 

 standardizing the Wanner pyrometer described above had been adopted. 



