1904.] in Relation to the Fluted Spectrum of Titanium. 221 



determined in the usual manner by micrometric measurements of the 

 photographs, using reference lines of titanium and iron, and calculating 

 by the Cornu-Hartmann formula ; though only provisional, they are 

 probably not greatly in error. 



It is instructive first to make a comparison between the more con- 

 spicuous flutings and those recorded visually in the stars by Vogel 

 and Duner. Details of the measurements are given in Table I, but 

 reference should also be made to Plate 6, in which Duner's drawing 

 of the spectrum of cc Herculis, as seen with a spectroscope of small 

 dispersion, is compared with a negative of the titanium flutings, as 

 they appear in the "arc" spectrum of titanium oxide. 



Table I. — Comparison of Titanium Flutings with Visual Observations 

 of the Spectra of Antarian Stars. 



Titanium flutings. 



Antarian flutings (more refrangible 

 edge). 



Wave-length. 



Visual 

 intensity. 



< 



Wave-length.* 



Duner's number. 



7055 



6162-5 



5604-5 

 54470 

 5241-0 

 5167-5 

 4955- 1 

 4761-6 

 4584-3 



10 



10 



8 

 10 

 5 

 10 

 8 

 7 

 5 



6493 

 6164 

 5862 

 5596 

 5453 

 5243 

 5169 

 4960 

 4769 

 4608 



Out of range. 

 1 

 2 

 3 

 4 

 5 

 6 

 7 

 8 

 9 

 10 



It will be seen be seen that eight of the ten bands recorded by 

 Yogel and Duner agree within the possible limits of error with the 

 flutings of titanium, and it is to be noted also that the only one of the 

 principal titanium flutings which is not represented in the stellar 

 spectrum is out of range in the extreme red. The origin of the two 

 outstanding bands at 5862 and 6493 has not yet been ascertained. 

 There are traces of titanium flutings near their positions, but they 

 seem inadequate to account for two such distinct bands as those drawn 



* The wave-lengths given are the means of Yogel's and Duner's measurements, 

 corrected to Bowland's scale (Scheiner's 'Astronomical Spectroscopy, 5 p. 301). 

 For bands 5, 7, 8, 9, 10, the means of the wave-lengths derived from photographs 

 by Lockyer, Pickering, Sidgreaves and Stebbings are respectively 5448, 5165, 4954 

 4761, and 4584 (see Table II). 



