= 
C. A. Young—Spectroscopic Notes. 335 
as compared with the number of such lines in the higher re- 
_ gions. Of course the resolution of the spot-spectrum into lines 
tends to indicate that the absorption which darkens the center 
of a sun-spot is produced, not by granules of solid or liquid 
matter, but by matter in the gaseous form, and it becomes in- 
teresting to inquire what substances are capable of producing 
such a spectrum, and under what conditions. As to the fine- 
ness and number of the lines, it may be noted that in the region 
included between 5, and 0, the single lines appear to be eac 
about half as wide as the components of b,. and are separated 
by an interval about one-third as great. The whole number 
between 6, and 6, must be over a hundred, though they are of 
8 0 
Which is also noticeable enough in the ordinary solar spectrum. 
Attention has indeed been frequently called to it long since by 
other observers. Below E,these bright lines are rare. Higher 
Up in the spectrum, between F and G, they become very nu- 
merous. 
have also made a considerable number of observations upon 
prominences with the nine and one-half inch equatorial and its 
‘Own spectroscope. ‘There have been lately numerous very fine 
exhibitions, especially in connection with the spots. The num- 
ber of lines reversed in the spectrum of the chromosphere has at 
times been very great, far exceeding the number observed and 
catalogued in 1872, but I have not been able to detect a single 
new one below C, though the two mentioned in my catalogue 
have been seen almost continuously. On two occasions—July 
31st and August 1st—a new line above H (A 3884-2) was con- 
Spicuously visible for an hour or two each time, during a spe- 
cially vigorous eruption of the prominences associated with the 
great spot which was then just passing off the limb. This line 
was seen easily without the aid of any fluorescent eye-piece, 
and I am satisfied that on a photographic plate it would have 
its position within one or two units on account of the difficulty 
of identifying the numberless fine lines around it. 
