with the Spectroscope. 73 
The observation of star spectra is of the most difficult and 
delicate description, requiring perfect action in the equatorial 
clock, great patience in the observer and skillful management 
of the scale illumination. Most of the lines and bands, particu- 
larly in the ends of the spectra, are faint and can only be seen 
in a good atmosphere. 
The difficulty of the observations, the imperfection of the 
spectroscope and the want of a sufficient accumulation of obser- 
vations, render it necessary that the places assigned to the 
fainter lines should be received with caution, but I believe that 
no line is represented on the accompanying sketch which does 
not exist. The smallness of the scale and the imperfection of 
the drawing render it necessary that I should increase the 
length of this communication by giving a short note upon each 
ovject. sd 
Sun.—I have inserted the seven principal lettered lines in the 
Solar spectrum at the points seen on the scale and carried them 
through the page as points of comparison. These places are the 
Tesults of several observations, all of which agree absolutely, 
except as to the place of the lines H, for which I have taken the 
mean; at a future time and on a larger scale I propose to locate 
all the solar lines which may be visible with my instrument, and 
thus have further points of comparison with the stellar spectra. 
€ reading for the sun’s lines is as follows: 
B31 C 323 D 30 E27 265 F244 G193 H145 13-9 
Moon —These readings are the means of two observations 
agreeing very closely in most particulars and coincident in all the 
Stronger features, 38-05 broad line generally limiting the spec- 
um; 32°35 sharp dark line; 30°05 well defined; 29:3 faint 
line; 28°7 faint line ; 27-8 faint’ line but stronger than the last; 
27-65 very faint line; 27-4 darker line; 27-25 faint line; 27-05 
Strong line; 26:85 faint line; 26°65 line; 25°55 strong line; 
24-75 line; 24:35 strong line; 21-05 faint band; 19-9 broad line; 
18:09 broad dark line. 
30 piter.—Mean of three observations, 82°1 band; 31:12 band; 
19-4 ites 28 faint line; 27° faint line; 2726 line; 24°7 line, 
ine. oe 
Fy Mars.—Mean of three observations. 32°4 line; 30°25 well 
“efined line; 27-5 well defined line but faint; 27-1 strongest line 
1. the spectrum; 26.55 quite strong line; 24-4 band; 19°1 line. 
Would here remark that the line D is not present, as the ob- 
Me tions made in different nights, one by myself and two by 
=e my assistant, agree in placing a line at 30°2 but 
AM. Jour, Sct.—Szconp Senres, Vou. XXXV, No. 103.—Jan., 1863. 
10 
