538 



Sir N. Lockyer and Mr. F. E. Baxaudall. [Jan. 3, 



or taking Chappuis and Barker's value for the boiling point, which is 

 0'74 higher, we obtain for T54. 



Conclusion. As might be expected, it is possible to apply the parabolic 

 formula of Callendar and Griffiths to the recalculation of the differences 

 between the platinum scale of temperature and the scale of the gas 

 thermometer, though the range through which it is applicable, and the 

 value of the constant 9, precludes the possibility of employing it except for 

 interpolation. A standard scale of temperature, based on Callendar's 

 three fixed points, using standard wire, and taking 1 '5 for the value of 9, 

 would obviously lead to absurd results at low temperatures ; and the 

 converse may be said of our own observations. To sum the matter up, 

 we will tabulate the results that have been referred to in this paper. 



Nature of gas thermometer. 

 Constant pressure air (0 to 444) .... 

 Constant volume nitrogen ( 23 to 445) 

 Constant volume nitrogen standardised 



by constant pressure air at 444 



(500 to 1000) 

 Constant volume hydrogen ( 190 to 



34 C ) 



Observer. CT. 



Callendar and Griffiths 1 '5O 

 Chappuis and Harker 1 *54 



Barker ., 1 "51 1 '49 



Travers and Gwyer 1 '9tt 



" The Arc Spectrum of Scandium and its Eelation to Celestial 1 

 Spectra." By Sir NORMAN LOCKYER, K.C.B., LL.D., Sc.D. 

 F.B.S., and F. E. BAXANDALL, A.E.C.Sc. Beceived January 3 r 

 Bead February 9, 1905. 



Very little has been published regarding the spectrum of this rare 

 element. The records of Thalen,* and Exner and Haschek,f are the 

 only ones previously given, the former observer confining his atten- 

 tion to the spark spectrum, whereas Exner and Haschek have recorded 

 the lines under both arc and spark conditions. In the latter lists,, 

 however, no lines are given in the region less refrangible than 

 X 4744-0. Bowland, in his " Tables of Solar Wave-lengths," certainly 

 ascribes a small number of solar lines to scandium, but, of course, no 

 indication is there given as to the relation of these lines to others 

 which occur in the scandium spectrum, either in regard to number or 

 intensity. In connection with the work at Kensington on stellar and 

 other celestial spectra, it has been found that in some types of spectra 

 scandium is conspicuously represented by some of its lines, in fact, 



* ' Ofvereigt af Kongl. Vetensk. Akad. Forhandl.,' vol. 38, No. 6, p. 13. 



t ' Wellonlangen-Tabellen fur Spektralanalytische Untersuohungen uuf Grrund 

 der Ultraviolettcn Funkenspektren und Bogenspektren der Elemente,' Leipzig und 

 Wien, Franz-Deuticke, 1902. 



