228 



PROCEEDINGS OF THE AMERICAN ACADEMY. 



sensible systematic error ; 2d, that the exponential equation simi- 

 larly fitted the Holborn and Wien comparison of the rhodo-platinum 

 couple with the air thermometer within the same limits ; 3d, that the 

 exponential equation diverged systematically, although slightly, from 

 the Barus data, and the logarithmic from the Holborn and Wien data, 

 by about equal and opposite amounts both inside and outside these 

 limits, but much more markedly between 0° and 400° than at higher 

 points. 



TABLE I. ' 



Melting Points. 



Aven. 2o e= {t^ - h) j 9.7335 + 0.00 484 49 {t^ + h) {. 

 Exp. 2oc = 0.3901 t1-*88 -1645. 

 Log. 2oe = 2.49655 /1-2563. 



