( 307 ) 



time will ho doA'cloped as an iiislaiice I'oi' tlio calciilatioii. ll refers 

 to a iiieasiirenieiil willi llie uold wire in o.nvu'ch hoiliiiu;- iiiider 

 i-ediiced i)re8siii-e. 



The values ot" the rullowiii^- lahh' ([». .'i()<S) were read directly. 



Ill this iiieasui-eiueiit the leiiiperaliire was kept eonstant by means 

 of the thermoelement so that the detenninatioii of temperatnre need 

 not be repeated. 



For the derivation of the resnlts from the observations see table 

 II, whieh does not require further explanation. 



§ 10. Results. Tlie determinations of the zero yielded the following 

 resnlts. 



Date. 



Resistance Method of tlie measurement 

 gold wire. of resistance. 



April 23, 1902 31.5506 Wheatstone's bridge. 



May 23, „ 31.556 



,, „ ,, 31.565 Differential galvanometer. 



May 26, ,, 31.555 Wueatstone's bridge. 



Our chief object of the determination with the differential galvano- 

 meter was to ascertain that the two methods gave the same residts, 

 so that the latter could also be employ eti for a detei-niination of 

 temperature. During this measurement A\'e did not stir and so it is 

 possible that the temperature has increased a little. In connection 

 with the following results the agreement is suliticient. 



After the measurements at low temperatures, winch are made 

 between June 17 and July 12, tlie zero was redetermined in October 

 and then a deviating \alue was found, \ iz. 31.043. T have searched 

 in vain for the reason of this deviation. It does not probably lie in 

 the measurement of i*esistance. A known resistance determined in 

 the same w^ay gave the true xalue. While I searched for possible 

 causes the gold wire bi-oke so that I have not attained any cei'tainty 

 on this subject. It may be that during the interval between the two 

 determinations a short circuit has been formed between the two 

 ends of the gold wire, in consecpience of wdiich the I'esistance is 

 ap[)arently so much diminished. A change in the gold wire itself 

 would probably always have produced an increase of resistance. 



The values for the furfhei- determinations of llie ratio between 

 the |)latinuni resistance and the gold resistance will be snllicientlv 

 cleai' IVom the following table (p. 310). 



I'he measni-eiuenls show thai this method lo delernn'ne the I'atio 

 between the resistances is certaiuly a ,u()o<l one and jireferable to 

 that of measuring the resistance of each wire separately. It will 



