SCIENTIFIC SUMMARY. 
549 
Mr. Huggins for observing the lines. He having found that the solar line 
D exactly corresponds with that of the sodium band, makes the latter the 
starting-point of his measures, having both it and the stellar spectrum 
which is to be examined, in the field at the same time. By these observa- 
tions it is to be hoped that not only the chemical constitution but the tem- 
perature of the sun and stars may be determined, as it has been discovered 
that the length of the spectrum depends on the heat of the flame. M. Secchi 
makes use of Janssen’s spectrometer of direct vision, and has been as- 
tonished at the magnificent results which he has obtained by it. In Alpha 
Orionis, he notices a line at F and four between F and G, only one of the 
latter of which is given by the Greenwich observations. The spectrum of 
Aldebaran extends still further, and sixteen lines of various breadths have 
been noticed in it. The spectra of Sirius and Rigel, which are white stars, 
are somewhat longer than those of the red stars, and the prominent lines 
appear in the blue and the violet, but are more rare in the less refrangible 
parts, with the exception of the red. It is remarkable, as Secchi observes, 
that the ray F is found in all the stars prominently as in the sun, and he 
considers its origin may be due to the terrestrial atmosphere. From the 
twenty stars observed at Greenwich, the majority give the same result ; 
which is, however, equally well seen in the line G. There seem to be 
great anomalies in the different observations of spectra, which will doubt- 
less be soon cleared away. 
Companions to Bright Stars . — For some time past, observers have been 
endeavouring to detect faint stars in the immediate neighbourhood of 
bright ones, and have succeeded in many instances. Of those the com- 
panion of Sirius has been seen by the gigantic telescopes of Clark, Lassell, 
and Foucault. Latterly, M. Goldschmidt lias not only succeeded in 
refinding it, but has also discovered five others, all of which are immerged 
in the light of Sirius, and one of them being nearly as close to the prin- 
cipal star as that discovered by Clark. MM. Barclay and Romberg have 
reobserved a small star close to Procyon, seen b3 r Mr. Hind in 1855, and 
two other minute stars are noted, but their places not given. It would 
appear that some faint companions to Procyon have likewise been seen by 
M. Goldschmidt ( vide “Les Mondes” of Feb.) Mr. Dawes says that one 
of the stars seen by hi. Goldschmidt near Sirius is easily detected, but the 
five others could not be observed, and he thinks them atmospheric and not 
telescopic tests. 
Mars. — Mr. Lassell has made a valuable series of drawings of the planet 
Mars, taken during the late opposition, and has arrived at some remark- 
able conclusions in respect to its organism. He finds that whilst the same 
phase occurs every thirty-nine days, and the planet should appear exactly 
the same, the seas and continents can rarely be certainly recognized 
from his drawings, and is thei’efore of opinion that “ if the variously 
coloured portions do generally represent land and water, their aspect must 
be greatly modified by the transit of clouds of great extent, density, and 
variety of form.” The white spot at the North Pole was smaller than that 
of the South Pole. The ruddy portion was more uniform in appearance 
than the blue or green part, the only distinct marking on the red being a 
curved streak near the South Pole. On Nov. 4, it was noticed that the 
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