8 ART. 12. — H. HIROBE I ON THE FUSION SURFACES OF THE 



after every observation. The smallest resistance in B was 0.1 

 ohm, and by means of the deflection of the galvanometer one 

 hundredth of one ohm could easily be read. Since the sensibility 

 of the galvanometer depends upon the resistance in the circuit, 

 we calculated the relation between the resistance between b and 

 c and the deflection of the galvanometer for the excess of one 

 ohm between the same points, by means of the following equation : 



Qo 4.70 

 <-/ = 89 X — - — — — , 



where y = the deflection for an excess of one ohm. 

 81) = the resistance of the galvanometer. 

 12.5 = the resistance of the thermo-element. 



X = the resistance between b and c. 

 4.70 = the deflection for an excess of one ohm between b 

 and c without the thermo-junctions. 



The calibration of the thermo-element was done as shown in 

 the " physiko-chemishe Messungen " by Ostwald and Luther (p. 

 445). For fixed temperatures we selected the freezing j)oints of 

 water, benzene and acetic acid, and the boiling points of carbon 

 bisulphide, chloroform and benzene, compared with the temj)erature 

 of the thermostat. AU the temperatures were measured with the 

 normal thermometer itself or the thermometer corrected by the 

 former, and could be relied upon up to 0.02°. The deviations 

 from the linear equation, 



Jt = ß r. 



where Jt = 25.00°— Observed temperature, 

 r = resistance in b and c, 

 ß = coefficient, 



were traced in the carve (Fig. 4). 



