( 205 ) 



In table II (p. 204:) the temperatures are used wliicli are found 

 with the thermo-element. A control-measurement with the thermo- 

 element placed in the same vacuum tui)e without rod gave for the 

 temperature in nitrous oxide — 87^,3 instead of — 86^,32. 



The mean value of the two deterininations is used for the calculation. 



Another reason for the measurement of the temperature of the 

 bath with a thermo-element as a control was the large difference 

 between the mean temperature found by us and the boiling point of 

 nitrous oxide — 89^ given by Ramsay and Shields ^). 



As we are going to press we find that Hunter *) has given 

 — 86^.2 for that temperature. 



§ 3. Results. 



Jena glass 16 III a 835 b 117 



k, 2505 k, 353 



Platinum a 905,3 b 49,4 



k, 2716 k, 148,4. 



' 1905 



As regards platinum: 



Bexoit finds from 0^ to 80° a 890,1 b 12,1 



Scheel from 20' to 100' a 880,6 h 19,5 



HoLBORN and Day from 0' to 1000^ a 886,8 b 13,24 



As to the differences between the values obtained now and those 

 of Comm. K". 85 (comp. § 1), we must remark that these are almost 

 entirely due to the differences in the determinations of temperature. 

 The uncertainties of the latter, however, do not influence in the 

 least the conclusion about b and the necessity of a cubic formula. 



There is every reason to try to combine our determinations on 

 Jena glass above and below 0"" in such a cubic formula. Taking into 

 account also the previous determination 242.10-*^ as the mean cubic 

 coefficient from 0' to 100' (Comm. N". 60, Se|)t. 1900, § 20) we 

 find in the formula for the linear expansion below 0^ and in the 

 corresponding one for the cubic expansion 



ii = K 



1 + !«' ^ + ^' (Aj^^ ^' r^LY! 10-0 



100 ' viooy viooy 



Jena glass 16 III a 789,4 k'^ 2368,1 



b' 39,5 k', 120,2 



c' — 28,8 k'. 86,2 



1) With this measurement in N2O we have not obtained a temperature deter- 

 mination with the thermo-element. This determination is not included in the 

 calculation. It is mentioned here on account of the agreement with the determi- 

 nation of 20 Dec, which for the rest has been made under the same circum- 

 stances. 



2) Journ. Phys. Chem. May 1906, p. 356. 



