THE SPECTEA OE SOME OF THE FIXED STAES. 
423 
Jupiter is for the most part reflected from clouds floating in its atmosphere at an eleva- 
tion above the planetary surface. The solar light, therefore, would not traverse the lower 
and denser portions of Jupiter’s atmosphere, corresponding to those of our own atmo- 
sphere in which the vapours, which probably produce these lines, appear to be chiefly 
present. The band about C, and that a little more refrangible at 838 of the scale, 
appear quite as strong in Jupiter as in the light from the sky. It may therefore be 
supposed that these bands are in part due to absorption at Jupiter, since the light from 
Jupiter suffers less absorption from our atmosphere than does the solar light reflected 
from the sky under the circumstances in which the observations were made. 
With the exception of these bands in the orange and the red, the spectrum of 
Jupiter appeared to correspond exactly with that of the sky. — August 31, 1864.] 
Saturn was observed on April 12, 1862, April 14, 1863, and April 12, 1864. Several 
solar lines were seen, but the spectrum was too faint to permit of any satisfactory deter- 
mination as to the presence or absence of atmospheric lines. 
[The spectrum of Saturn was observed with the apparatus and in the manner described 
when speaking of Jupiter, on June 13, 16, and 20. The spectrum was more difficult of 
observation, on account of the feebler brilliancy of Saturn, and its less favourable posi- 
tion. Bands in the red and orange were seen similar to those in the spectrum of Jupi- 
ter, and by measurement these bands were found to occupy positions in the spectrum 
corresponding to those of the bands of Jupiter. — August 31, 1864.] 
The spectrum of Mars was observed on November 6, 1862, and April 17, 1863. The 
principal solar lines were seen, and no other strong lines were noticed. 
[On August 10 and 29, 1864, we re-examined Mars, using the new spectrum apparatus. 
No lines in the red, similar to those of Jupiter and Saturn, were observed; but in the 
extreme red, probably about B and a , two or three strong lines were seen. With the 
exception of these, no lines were detected in the red, orange, yellow, and green portions 
of the spectrum, other than those of the solar spectrum. At about F the brilliancy of 
the spectrum diminishes in a remarkable manner, in consequence of a series of strong 
and nearly equidistant bands, which commences at F and continues towards the more 
refrangible end as far as the spectrum can be traced. The absorption of these bands is 
evidently the cause of the predominance of the red rays in the light of this planet. 
The spectrum apparatus of greater power resolves these bands in the blue into groups 
of lines. — August 31, 1864.] 
The light of Venus gives a spectrum of great beauty. The observations were chiefly 
made on April 17, 22, and 26, 1863. The line D was seen double. B, C, and nume- 
rous solar lines to a little distance beyond G, were distinctly visible ; and the principal of 
these were measured and found to agree with corresponding lines in the solar spectrum. 
Lines other than these, and in the position in which the stronger atmospheric lines pre- 
sent themselves, were carefully looked for, but no satisfactory evidence of any such lines 
has been obtained. Venus was observed as early in the evening as possible, and while 
a considerable amount of daylight still remained. 
mdccclxiv. 3 L 
