( 427 ) 



The probable error of an adjustment to the resistance thermo- 

 meter appears to be equal to that of a reading on the hydrogen 

 thermometer (conip. Comni. N^ 95« § 7)^). 



The following observations related to the delining of a temperature 

 o\er a longer recording period. 



Ptni i^nd Ptv were calibrated immediately after each other witii 

 Ptj, thence we derived the temperature reading according to Pti 

 on Ptui iind Ptv- Afterwards and adjusted to the same temperature 

 we have compared the gold thermometer .1?^,, with Ptm and Ptv 

 immediately after each other. The readings were 



temp. Pti on Ptm, temp. Pti on Ptv, Aii^, resistance') 



If we disregard the large deviation in braci^ets which indicate 

 that it must be ascribed to an irregnlaiity, it appears that the 

 detinition of a temperature by means of a single determination on 

 a resistance thermometer has al)Out the same probable erroi' as a 

 single determination with the hydrogen thermometer and is generall v 

 I'eliable to an amount which remains below 0^.02. 



For the present the accuracy of the determinal ion of a temperature 

 Avhich is kept constant during a long time by means of the hydrogen 

 thermometer may be considered equal to the accuracy of the detinition 

 of a temperature b}' means of the resistance thermometer, where 

 however the necessary i-eadings, even when they are repeated require 

 less time. 



§ 5. xlccording to § 3 the observations of June 30 and July 6, '06 

 must be rejected. They have been used for the calibration of the 

 thermo-eiement and the resistance thermometer of Comms. jSI"^ 95", 

 95« and 95/ (Nov. J 906) and hence the values — 217°.411 and 

 — 182°. 75 of the tables VIII of Comm. N". 95^ 1, II of Comm. 

 N". 95" and IX of Comm. N". 94^' must be modified. 



The determination of June 30, '06 at — 183° shows a perceptible 

 difference with that of March 25, '07, the ojdy one of the required 



hi Comm. N^. 95e § 7 we for the time being took as a starting point tliat 

 the error in the adjustment of the liydrogen thermometer was negligible. 



~) These values deviate a little from the values given in table III of Comm. 

 N". O.'j ' owing to corrections which were afterwards determined. 



