of Menury and Platinum Thermometers. 167 



and all of our measurements are given in terms of the mean 

 box unit of Box No. 7 (approximately one mean box unit 

 equals -01 ohm). Griffiths gives as the values of Ri and R 

 the following:— R x = 358*078, R = 258 362 (in mean box 

 units, Box No. 6). From which the fundamental interval 



R 1 -R =99-716, and?- 1 =1*38596. 



To reduce these values to true Board of Trade ohms the factor 

 for this box (No. 6) at 20° 0., as given by Griffiths, is 

 0010003. We are uncertain as to the absolute value of the 

 mean box unit of our box (No. 7), and hence cannot yet com- 

 pare our values in the standardization of our thermometer 

 directly with those of Griffiths. 



The following values of R were obtained : — 



258-471 

 258-472 

 258-469 

 258-471 



258-471 mean box units, 20° C. 



Each of these values is the mean of five or six measure- 

 ments with different combinations of coils and bridge wire. 

 It is interesting to note that the last two determinations 

 suggest the possibility that the effect of radiation is appreciable 

 in a room whose temperature is 20° above the thermometer 

 coil ; the first of these was made in a double-wall vessel with 

 ice in both compartments, the second immediately after in the 

 same mixture of ice and water with the inner polished vessel 

 removed. 



The determination of R x gave the following values : — 



358-228 

 358-229 

 358-235 



358-231 mean box units, 20° C. 



These determinations were made in a hypsometer in which 

 the thermometer was screened on all sides from radiation 

 effects. Each of the above measurements was made on 

 a different day with great differences of barometric height, 

 and is the mean of five or six readings all in close agreement. 



This gives for the value of §- x 1-38597. 



XXq 



