1904.] Spectra of Antarian Stars in Relation to Titanium. 219 



As the results of these experiments seem to justify very completely 

 the use of Callendar's parabolic formula over a wide range, a table has 

 been calculated by which the value of T may be obtained directly 

 from the value of Vt for a range of temperature extending from 

 - 200 to + 1100° C, and for the value 1*5 of the constant 8. 



A second short table extends this to all values of 8 usually met with. 

 It is hoped that this table may be of general use to others who are 

 employing platinum thermometers. 



The experiments were carried out at the National Physical Laboratory, 

 and, in conclusion, I wish to thank those members of the staff who have 

 assisted in it. 



'•' The Spectra of Antarian Stars in Eelation to the Fluted 

 Spectrum of Titanium." By A. Fowler, A.E.G.S., F.E.A.S., 

 Assistant Professor of Physics at the Eoyal College of 

 Science, South Kensington. Communicated by Professor 

 H. L. Callendab, F.E.S. Received February 18, — Eead 

 March 3, 1904. 



[Plate 6.] 



The distinguishing feature of the spectra of the Antarian Stars* is 

 the system of apparently dark flutings, sharp towards the violet and 

 fading off towards the red end of the spectrum. The principal flutings 

 are well seen in An tares, but they are more strongly developed in 

 the spectra of x Herculis and o Ceti, in which stars additional details 

 are also seen. These flutings have not hitherto received a definite 

 chemical interpretation, and it has been uncertain, owing to the 

 possibly misleading effects of contrast, whether the spectrum was to 

 be regarded as one consisting wholly of absorption flutings fading 

 "towards the red, or as one partly consisting of emission flutings fading 

 in the opposite direction. 



The purpose of the present communication is to state the nature of 

 the evidence which indicates that the spectrum is essentially an 

 absorption spectrum, and that the chief substance concerned in the 

 production of the flutings is titanium, or possibly a compound of that 

 -element with oxygen. 



The first indication of this result was the striking general resem- 

 blance of the titanium flutings, as seen in photographs recently 

 obtained, with the stellar flutings, both as to relative intensity and 

 apparent position (Plate 6). The interspaces between the flutings, 

 -as they appear on a negative, in some cases also strongly recall the 

 corresponding bright spaces in the stellar spectra. 



* Secclu's Type 111 ; Yogel's Class Ilia. 



