Platinum Temperatures. 453 



Their researches (Table III.) are given in ohms and Centi- 

 grade degrees down to o- 60, below this point the temperatures 

 are only indicated. From these I have chosen two as being 

 perhaps the best known, — for (a) which was " taken in solid 

 carbonic acid and ether" I use — 78°'2 C, and for (b) which 

 was "taken in liquid oxygen boiling at 760 millim." I use 

 -182°-5 0. 



Table III. 



E., in ohms. 



Temp. C. 

 Observed. 



Temp. O. 

 Calculated. 



v. 



V 2 . 





O 



O 







5-2171 



1952 



1959 



-•7 



•49 



4-6345 



1410 



1402 



+•8 



•64 



4-1876 



98-5 



98-4 



+•1 



•01 



4-1813 



98 05 









39982 



80-90 



80-9 







•00 



37695 



600 



59-9 



+ •1 



01 



3-5440 



3960 



39-4 



+•2 



•04 



33108 



1845 



18-46 



-•01 



•00 



33043 



1790 









3-2991 



17-20 









32739 



1490 









2-2487 



12-80 









3-2450 



1260 









31136 



60 



0-9 



-•3 



•09 



2-2085 



(a)- 78°-2 



- 77-9 



-•3 



•09 



0-9473 



(6)-182°-5 



-182-6 



+•] 



•01 



Of the observations given in Table III. I have employed 

 the ten indicated in the 3rd column from which to calculate, 

 by the method of least squares, the formula 



(R + 20-529023) 2 = -53270015(£+ 1048-4396). . . (11) 



By means of this formula I have calculated the temperatures 

 in the 3rd column, whence the 4th and 5th columns give (as 

 before) the divergences, and their squares, leading to the 

 probable value of the divergence between a calculated and an 

 observed temperature being 



•6745 



V 1 



= •26, 



or about a quarter of a degree over a range of nearly 400°, — 

 a result within the acknowledged errors of observation. The 

 absolute zero given by this formula (R=0) is — 257 0- 3 C. 



Observations of Messrs. Holborn and Wien* . — Messrs. Hol- 

 born and Wien give five (or six) series of observations of 



* Wied. Ann. vol. lix. (1896). 



