258 Sir J. N. Lockyer and Mr. Eaxandall. Enhanced [July 13, 



Notes on p Ti-Solar Lines. 

 (The figures at. the head of each note refer to Rowland's solar lines.) 



r l "I 3900*68 (5), Ti-Fe-Zr. The titanium line involved in the solar line is one 

 of the very strongest in the spark spectrum. The iron line is only a weak one, and, 

 in the light of other adjacent iron lines of equal intensity, would of itself only 

 produce a solar line of intensity 2 or 3. In apportioning the weights to the 

 various elements, which possibly take part in the formation of the solar line, 

 zirconium can be almost ignored. There are many far stronger lines of zirconium 

 than the one in question which are not represented in the sun at all. It would 

 appear, then, that the solar line 3900*68 is really made up of the p Ti and Fe lines 

 in about equal proportions. 



[2.] 3913'61 (5), Ti-Fe. It is very doubtful whether Fe takes any part in the 

 production of this solar line. There is no such iron line recorded by either Kayser 

 and Runge or Exner and Haschek, and there is no trace of a line in any of the 

 Kensington photographs. The titanium line is a very prominent one in the spark 

 spectrum, and quite capable of producing the solar line of itself. 



[3.] 4053-98 (3), Fe-Ti. The iron line is an extremely faint one, while the 

 titanium line is well marked. The solar line is probably a composite one, but 

 more attributable to titanium than iron. 



[4.] 4055'19 (3), Ti-Fe. The iron and titanium lines are coincident, and 

 about equally strong. Solar line probably due to both. 



[5.] 4163-82 (4), Ti-Cr. Both the titanium and chromium lines are well 

 marked in their respective spectra. The former seems to be slightly less refrangible 

 than the other. The solar line is probably a very close double, and due to both 

 Ti and Cr. 



[6.] 4172-07 (2), Ti-Fe. The iron lino is extremely weak, while the p Ti line 

 is one of the strongest in the spectrum. The solar line is probably due chiefly to Ti. 



[7.] 4173'71 (1) ; no origin by Eowland. The mean result of two measure- 

 ments of this enhanced titanium line gives A 4173'7l. Its identity with the solar 

 line is therefore well established. 



[8.] 4184*47 (2) ; no origin by Eowland. The published wave-length of this 

 enhanced titanium line was 4184*40. A re-estimation from a later grating 

 photograph gives as a resulting wave-length 4184'49. There is little doubt of 

 its identity with the solar line 4184'47. 



[9.] 4330-87 (2), Ti-Ni. The nickel line is an exceedingly weak one, and it is 

 doubtful whether the solar line is partially produced by it. Rowland, in a foot- 

 note in his ' Tables of Solar Wave-Lengths,' says : " This is a weak, hazy, nickel 

 line. It is on the red edge of the solar line, and the Ti line is nearer the centre." 



[10.] 4374-98 (0), Zr. The published wave-length of the enhanced titanium 

 line WHS 4374'90. A re-estimation from a better photograph gives 4374'99. It is 

 probably identical with the weak solar line 4374'98, which E-owland ascribes to Zr. 



[11.] 4399-94 (3), Ti-Cr. The chromium line, although apparently coincident 

 with the titanium and solar lines, is a very weak one. On the other hand, the 

 titanium line is quite well marked. The solar line is therefore probably due 

 chiefly to titanium. 



[12.] 4411-24 (1), Cr. Re-measurement of the proto-titanium line gives 

 \ 4411-24. It is apparently coincident both with the chromium and solar lines. 

 The chromium line is a weak one, whereas the titanium line is well marked, and 

 there is little doubt that the solar line is partially, if not chiefly, due to titanium. 



4529-73 (1} J N Ori 8 in bv Rowland. The published wave-length of the 

 enhanced titanium line was 4529 60. Re-measurement from the latest grating 

 photograph gives A 4529'69. It is doubtful which of the two solar lines, 4529'66, 



