Nitrogen Thermometer from Zinc to Palladium. 131 



to the readings in columns 4 and 5, and the eighth column, 

 the mean of these two temperatures. The micrometer read- 

 ings are not given, but in column 9 will be found the expansions 

 reduced to millimeters for that portion of the bar lying between 

 the and 50 cm marks on the ends. Each of these represents 

 the mean of eight settings at each end of the bar. In the 

 last column are given the values of the mean expansion coeffi- 

 cient from 0°, calculated by dividing the expansion b}^ the 

 length at and by the temperature. 



For convenience of comparison, the values of ft at the 

 nearest round temperatures were interpolated linearly between 

 the observations in each series, and the results are- given in 

 Table YI. Yalues interpolated between these values are given 

 in parentheses. 



Table VI. — Values of 10 6 /3 at Hound Temperatures for the 

 alloy 80 Pt, 20 Ph. 



ToYYi-n 



21 Sept. 



25 Sept. 



3 Oct. 



29 Oct. 



13 Oct. 



14 Oct. 



Mean 



i enip. 



190« 



1908 



1908 



1908 



1909 



1909 



250 





9-28 













300 



9-31 



(9-36) 



9-22 





9-24 





9-28 



350 



(9-37) 



9-43 



(9-33) 





(9-33) 





9-36 



400 



9-43 



(9-49) 



9-44 





(9-41) 





9-44 



450 



(9-52) 



9-55 



(9-53) 





(9-50) 





9-52 



500 



9-60 



(9-62) 



9-62 





(9-58) 





9-61 



550 



(9-67) 



9-70 



(9-71) 





(9-67) 





9-69 



600 



9-75 



(9-77) 



9-79 





(9-76) 





9-77 



650 



(9-83) 



9-84' 



(9-86) 





(9-84) 





9-84 



700 



9-90 



(9-92) 



9-94 





9-93 





9-92 



750 



(9-98) 



9-99 



(10-02) 





(10-01) 





10-00 



800 



10-06 



10-06 



10-10 





(10-09) 





10-08 



850 



(10-14) 



10-12 



(10-17) 





(10-16) 





10-15 



900 



10-23 



(10-20) 



10-25 



10-29 



(10-24) 





10-24 



950 



(10-31) 



10-27 



(10-32) 



(10-36) 



(10-32) 





10-32 



1000 



10-40 



(10-36) 



10-40 



10-42 



10-40 



10-37 



10-39 



1050 



(10-47) 



10-44 



(10-48) 



(10-50) 





(10-45) 



10-47 



1100 



10-55 



(10-52) 



10-57 



10-59 





10-54 



10-55 



1150 



(10-60) 



10-60 



(10-64) 



(10-65) 





(10-63) 



10-62 



1200 



10-65 



(10-67) 



10-71 



10-71 





10-73 



10-69 



1250 









(10-81) 





(10-82) 



10-81 



1300 









10-90 





10-92 



10-91 



1350 









(10-99) 





(10-99) 



1099 



1400 













11-07 



11-07 



1450 















(11-15) 



1500 















(11-23) 



The table shows that the percentage error at 300° is greater 

 than that at 1200° and above, probably on account of the 

 larger effect of the hysteresis in the expansion and contraction, 

 already discussed on page 114. The agreement of the results 

 is very satisfactory, particularly in view of the fact that each 



