[SCOTT] ELECTRICAL RESISTANCE THERMOMETERS 157 



and between these the iron thermometer was measured. The corres- 

 ponding platinum resistance was obtained by interpolation from time 

 differences. When comparing the two thermometers, the following 

 rearrangement of the correction formula was employed, the ô for 

 the platinum being 1-5. 



100 



T = 

 3 



FlOl-ô--^ ^ 10302. 25 -6tp^l 



The temperature coefficients of a number of specimens are tabulated 

 below. The purer the specimen, the higher its temperature coefficient. 



Specimen. a x 10^ 



No. 1 Pure 6-32 (two) 6-34 



No. 1 Annealed 6-16 (two) 



No. 2 Pure (hard) 5-11 



No. 3 Annealed 6-14 (two) 



No. 5 4-75 (many) 4-87 (two), 4-88, 4-86. 



No. 5 Annealed 4'75 



Electrolytic 6'6 



Elec. Annealed 6-42 



No. 7 Pure 6-24 



Specimen No. 5. 



T Correction 



10-894 1-038 10-69 



21-03 1-78 10-72 



31-34 2-38 11-06 



40-17 2-72 11-32 



50-62 2-93 11-71 



60-6 2-83 11-85 



70-19 2-58 12-33 



80-56 2-04 13-02 



Specimen No. 1. 



T Correction 5 



10-65 0-925 9-72 



22-66 1-89 10-78 



30-39 2-36 11-15 



40-94 2-78 11-50 



51-85 2-96 11-86 



60-60 2-91 12-19 



72-27 2-58 12-87 



79-83 2-07 12-85 



91-25 1-03 12-90 



