702 
PROFESSOR J. N. LOCKYER ON THE PHOTOGRAPHIC 
Comparison of tbe G region of the Spectrum of a Orionis and the Sun. 
The Dark Flutings in these Stars. 
By the use of Edwards’ isocliromatic plates, photographs of the spectra of some of 
the stars under discussion have been obtained which extend as far in the green as 
X 550. These consequently show some of the flutings which have been mapped by 
Duner, Vogel, and others. 
The wavedengths of the flutings have been determined by comparison with the 
spectrum of Arcturus photographed under the sam'e instrumental conditions. These, 
compared with the mean values determined from eye observations by Duner* and 
Vogel, t are as follows :— 
Dun:^r’s 
nnmbei’ of band. 
DuNtn 
(eye observations). 
Vogel 
(eye observations). 
Locktek 
(pbotograpbs). 
10 
4607 
4585 
9 
< 4*770 
4766 
4763 
8 
4958 
4959 
4958 
7 
6168 
5168 
5165 
5 
_ - - 
.5451 
5452 
5455 
The positions given for the bands are for their more refrangible edges, and they are 
the same in all the stars of this group of which the spectra have been photographed 
at Kensington. The positions determined by Vogel and Duner, however, for the 
same band in different stars vary considerably. For band 5, Vogel found the wave¬ 
length 5444 in a Orionis, and 5458 in aHerculis. These differences are, it is possible, 
due to the diflSculties of observation, and in a small degree to the drSeriDg velocities 
in the line of sight. 
* ‘ Sur les fitoiles,’ p. 120. 
t ‘ Bothkamp Beob.,’ Heft 1, 1872. 
