1904.] Lines of Titanium, etc., in Fraunhoferic Spectrum. 



261 



Ti line 4623'28 corresponds to a solar line of intensity 2. It is scarcely likely, 

 then, that the superposition of the Ti and Co lines at 4629'60 would produce a 

 solar line of intensity 6. The proto-iron line at the same wave-length probably 

 supplies the deficiency in intensity. The enhanced line of iron 4515'51, which is 

 of about equal prominence as 4629'60, has an equivalent solar line of intensity 3, 

 and if the p Fe line 4629'60 of itself produces a similar solar line, then the 

 intensity 6 of the solar 4629*60 could be easily accounted for. In faci, it is quite 

 probable that the solar line in question is built up of the lines at the same wave- 

 length belonging to Ti, Co, and^> Fe, and that the proto-iron line has, if anything, 

 the greatest share in its production. 



There is a fairly good corresponding line in the chromospheric spectrum, and, in 

 the publication of eclipse results by various observers, the origin of the line is 

 invariably given as Ti-Co, presumably because they have established its identity 

 with the Fraunhoferic line and accepted Rowland's origin as a correct and 

 sufficient one. In the chromosphere it is probably chiefly due to p Fe, as the 

 ordinary Ti and Co lines are there only weak, while the enhanced iron lines are 

 well marked. There is also a corresponding line in the spectrum of o Cygni. 

 Here, however, the origin is evidently proto-iron only, as the arc lines of cobalt 

 and titanium are entirely missing from the stellar spectrum ; whereas nearly all 

 the proto-iron lines are well seen. 



Chromium. 



