509 



then at a iimiiber of other tetiipcmtiires, vvitli the differeiilial-galvano- 

 inetei' according to Kohlralsch's method. 



The result of these determinations was as shown in the table (7' = 

 temperature on the Kelvin scale, with ,7(|oe'. =i 273°.(H)) 



In the third colnmn are given the values, which would have been 

 obtained, if the resistance diminisheil linearly from the melting point 

 down to the absolute zero. 



T T 



treaic = — ^^, = 



• 234.1(3 



■Jti.SOO z= 0.11445 T. 



Cohunn 4 gives the deviations 

 of the real values of the resistance 

 from those, calculated bv means 

 of the linear formula. These devia- 

 tions are also plotted in the figure. 

 The relation between electrical 

 i-esistance and temperature seems 

 to be of a very complicated 

 character. 



§ 2. Direct deter I lunation o f the 

 ckamje in resistance at the meUlmj- 

 polnt. 

 cT ju;.uv.» Of two resistances, which were 



Fig. 1. frozen without auxiliary bath, the 



change in resistance in melting was determined dii-ectly. The first 

 consisted of a narrow capillary tilled with mercury, section + 0,0015 

 mm'. At — 49°. 88 the resistance was 25.095 ii, immediately above 

 the melting point '115.0 52, 



the ratio — = 4.bb. 



The second capillary had a section of 0.43 mm'. With this resis- 

 tance the ratio 4.50 was found. 



As a preliminary value of the melting point — 38°. 93 C. was found.') 



§ 3. Indirect determination of the chamje In resistance at the 

 meltlmj point. 



Daring the numerous determinations of mercury resistances in 

 liquid helium (Comm. N°. 133), we always measured the resistance at 

 ordinary temperature too. By means of the resistances of solid mercury of 



1) Our measurements dale of 19l!2. In the meantime was published the paper 

 of F. HeniNing Ann. d. Ph. (4) 43 p. 282, 1914 who finds — 38°.89 C. 



