50 



Prof. J. A. Fleming. 



Majoris. Whereas Lockyer"^ in his most recent paper " On the 

 Chemical Classification of the Stars " (April, 1899), regards the so-called 



Crucian " stars, as at a higher temperature than the " Eigelian " and 

 " Cygnian," and indeed he regards Bellatrix " as a type of the hottest 

 stars, exception being made of ( Puppis." 



Of the other lines recorded by Eder and Valentaf as due to silicon, 

 39054, 3862-5 and 3855-7 are present both in the spectra of the 

 dissociated glass and in the high temperature spectrum of silicon 

 obtained from the silicon tetrafiuoride tube. 



They are enhanced lines in the latter case, occurring together with 

 Lockyer's enhanced lines in the absence of the three new silicon lines, 

 but they lie outside the region measured by Scheiner in a Cygni, 

 Sirius, and Eigel. 



In the Harvard " Spectra of Bright Stars "| the two latter lines 

 are however, specially noted in Eigel as 3863*2 and 3856-2 as " con- 

 spicuously strong in the ultra-violet," whilst all three are recorded 

 (3905-6, 3863-2, 3856-2) in stars of Groops VI to VIII (Harvard), 

 comprising a Cygni, Sirius, and Eigel. They would thus appear in 

 these stars to accompany the enhanced silicon lines, specially noted 

 by Lockyer, viz. 4128-6 and 4131-4. 



The lines 3834*4 and 3836-7 recorded by Eder and Valenta are not 

 present in any of the photographs of silicon spectra, and may possibly 

 be due to impurities. 



The lines 3795-9 and 3791-1 recorded by Eder and Valenta are 

 present in all the silicon photographs, but do not become enhanced at 

 high temperatures. There is, however, a third line, approximately 

 X 3807, not recorded by them, but which appears in all the photo- 

 graphs of silicon spectra. It is stronger than 3795-9 and 3791*1, and 

 does not become enhanced with high temperature. All three lines 

 accompany the three new silicon lines in e Canis Majoris. 



'•A l^ote on the Electrical Eesistivity of Electrolytic Mckel." 

 By J. A. Fleming, M.A., D.Sc, F.E.S., Professor of Electrical 

 Engineering, University College, London. Eeceived Novem- 

 ber 21,— Eead December 14, 1899. 



The numerical values assigned by various experimentalists for the 

 mass or volume electrical resistivity of certain metals differ very con- 

 siderably. Some metals are without much difiiculty prepared as often 



* ' Koy. Soc. Proc.,' vol. 65, No. 416, p. 189. 



t Wa'.ts's ' Index of Spectra.' 



X ' Harvard Annals,' vol. 28, Part I, Table 7, p. 23. 



