588 DR J. HALM ON 
the “‘ heads” of an independent Cyanogen-band distinguished from the others by the 
fact that, like the Oxygen-bands, its components shade off towards the red. First we 
must admit that the appearance of the bands does not agree with what we should expect 
if they were “tails.” On the plate accompanying Dr JuneBLuTH’s paper they by no 
means convey the impression of an “infinity” of lines, but appear to be composed of a 
limited number of lines at finite distances from each other. This feature is specially 
noticeable at A = 3603 and 3629, and certainly agrees better with the supposition 
of “heads.” It is also noteworthy that none of the tails of the 1st series computed 
above by means of the RypBerc-THIELE formula agrees with any of the four wave- 
lengths of Mr Kine’s bands. Our experiences with the formula cannot but give us 
now some confidence that the structure of the band should be at least very nearly 
represented by it. On the other hand, however, Dr JuNGBLUTH’s view seems to be 
supported to a certain extent by two noteworthy relations between the wave-lengths of 
the four heads of the series and the supposed tails. He showed that if we form the 
differences between the wave-lengths of corresponding ‘heads and tails, we find 
3884 — 3579 = 305 
3872 — 3603 = 269 
3862 — 3629 = 233 
3855 — 3658 = 197 
36 
36 
36 
It appears, then, that the lengths of the successive series form an arithmetical 
progression. Again, if we form the quotients 
SESS a aes 
3a79 5 ae 0:0105 
Bee 
3603 0 0:0105 
3862 1:0642 
3629 - 
aaee 0:0103 
3658 = 10539 
we notice that these quotients also form approximately an arithmetical progression. 
Hence a somewhat remarkable connection seems indeed to exist between the observed 
heads and the alleged tails. But on a closer view this connection is found to be only 
apparent. or it is seen that the same relations exist, if we combine Mr Krine’s 
“tails” with the successive heads of the other Cyanogen-bands. Thus we find: 
4606 — 3579 = 1027 4216 — 3579 = 637 3590 - 3579 = + 11 
52 ‘ 
4578 3603= 975 4197 — 3603=594 a 3586 -3603=-17 2° 
4553-3629= 924 4181 — 3629 =552 as 3584-3629= -45 28 
4532 —3658= 874 4168-3658=510 ~— 
These figures show therefore that Dr Juyepiuru’s relation indicates not a specific 
connection between Mr Kine’s bands and the band at A=3884 only, but a far more 
general correspondence between the former and all the bands of the Cyanogen-spectrum. 
One might perhaps conclude that Mr Kine’s shadings may represent the common tail of 
