52 



ASTRONOMICAL PHENOMENA AND PROGRESS. 



space, similar to that inferred from theoretical 

 considerations by Cheseaux and afterward sup- 

 ported, on other grounds, by Olbers and the 

 elder Struve. The author concludes that, at 

 the time of his observation, the nebula of 

 Orion was not receding from the earth with a 

 velocity greater than ten miles per second ; for 

 this motion, added to the earth's orbital ve- 

 locity, would have caused a want of coincidence 

 of the lines of the spectrum that could have 

 been observed. 



Suspected Change in a Nebula. The Rev. 

 H. Cooper Key, of England, has been making 

 observations on the nebula, 45 Herschel, 

 iv G-erminorurn, with a silvered glass spec- 

 ulum of eighteen-inch aperture, and ten feet 

 focal length, using an eye-piece giving a power 

 of 510. This nebula presented to the Her- 

 schels a uniform nebulous disk, with a stellar 

 centre ; Lord Rosse saw one ring only ; in Mr. 

 Key's telescope, two rings were distinctly vis- 

 ible. Mr. Huggins considers the observation 

 important, as showing a definite change in 

 these objects ; the central star of the nebula 

 gives a continuous spectrum, and possibly the 

 luminous haze surrounding it also ; but of 

 that Mr. Huggins is not so certain, the difficulty 

 of getting spectrum observations of such faint 

 objects is so great. 



Stellar Spectra. Father Secchi has com- 

 municated to the French Academy of Sciences 

 some further observations on stellar spectra, 

 made by means of a new spectroscope, with 

 a cylindrical achromatic eye-piece. He con- 

 cludes that, 1st, red stars have generally spectra 

 of the third type ; when the color is pale, it 

 may be referred to an intermediate place be- 

 tween the second and third ; 2d, a great num- 

 ber of these stars have their spectra perfectly 

 resolvable into columns which are afterward 

 themselves resolvable into finer lines. There 

 are many others that cannot be resolved into 

 secondary lines, on account of the faintness, 

 but of which the principal lines indicate the 

 type ; 3d, the stars which cannot be referred 

 to the three established types are very rare. 

 Some of the author's speculations and sugges- 

 tions are interesting. He says : 



We have, therefore, without doubt, in the heavens 

 a grand fact, which is the fundamental distinction of 

 the stars in a small number of types', which opens 

 the field to very many cosmological important spec- 

 ulations. 



Secondly, another grand fact, which was brought 

 out from "those researches, was, that the stars of the 

 same type are crowded occasionally in the same space 

 of the heavens, so the white stars are thickly gath- 

 ered in the Leo, in the Ursa Major, in Lyra, Pleiades, 

 etc., while the yellow ones are very frequent in Ce- 

 tus, in Eridanus, Hydra, etc. The region of Orion 

 is verv remarkable for having all through, and in the 

 neighborhood, green stars of the first type, but with 

 very narrow lines and with scarcely any red color. It 

 seems that this particular kind of star is seen through 

 the great mass which constitutes the great nebulae of 

 Orion, whose spectrum may contrast with the primi- 

 tive spectrum of the stars. Sirius is perhaps too near 

 us to be affected by this influence. The distribution 

 of stars seems to indicate in space a particular distri- 



bution of matter or of temperature in the different 

 regions. 



Thirdly, all the spectra of the third and fourth 

 type belong to variable stars. The representative 

 of these is the wonderful (Mira) Ceti. This has been 

 carefully examined and found that, even when it is 

 only of the seventh magnitude, it has the same spec- 

 trum as the typical, but only reduced to its few 

 bright lines ; & Orion is in the same condition, a 

 Tauri or Aldebaran, and Antares, this year appeared to 

 be smaller and of a more red hue than in the past year, 

 and in the first appeared traces of columns which 

 were not seen the year before ; so that it is evident 

 that the change of these stars depends on a periodi- 

 cal change which happens in their atmosphere. It is 

 not so, however, with Algol, which has the very same 

 spectrum of the first class or type in every stage of 

 greatness ; which induces me to believe that there 

 the variation is produced by the passage of an op_aque 

 body passing between us and the central star, giving 

 thus an example of eclipse of a fixed star, by his 

 own obscure planet. 



Finally, a very delicate question I propose to my- 

 self to be resolved by spectral analysis ; this consists 

 in ascertaining whether the star has a proper motion 

 from the displacement of the lines, which ought to 

 take place in the spectrum by the combined motion of 

 the star and the propagation of light. From this new 

 kind of aberration it would be easy to ascertain if a 

 star has a motion whose velocity should be five times 

 that of our earth around the sun. The star a of 

 Lyraa, examined in this manner, has not given any- 

 such displacement, so that it appears not to have such 

 a motion. In some other stars I have found that 

 there is a little displacement, as in Ursee Majoris, but 

 this seems especially due to the different breadth of 

 the hydrogen line in the star and in the compared 

 spectrum. I have employed for this study the com- 

 parison of the direct image of the stars with its own 

 spectrum, but I have found no such quantity of dis- 

 placement. 



A New Comet. A new comet (II. 1868) was 

 discovered June 13th, by Dr. Winnecke, at 

 Carlsruhe. It was also independently discov- 

 ered, the same night, at the Marseilles obser- 

 vatory. The next night, several astronomers, 

 to whom the discovery had been communicated, 

 observed the comet, and described it as very 

 bright and having a tail. On the 20th, the tail 

 was more than 3 in length. About that time 

 the comet was just visible to the naked eye, 

 and, when brightest, was comparable to a star 

 of the fifth magnitude. It passed its perihe- 

 lion, June 26th ; its distance from the sun being 

 then about six-tenths of that of the earth. It 

 was nearest the earth, June 30th, and was then 

 within about 56,000,000 miles of us. Early 

 in July it gradually ceased to be visible. 



The Spectrum of Comet II., 1868. Mr. 

 Huggins, the industrious and skilful observer 

 of the spectra of astronomical bodies, made a 

 careful study of the spectrum of comet II., of 

 the past year. The results he . communicajbed 

 to the Royal Society in July. He describes the 

 appearance of the comet in the telescope, June 

 22d, as a nearly circular corona, which became 

 rather suddenly brighter toward the centre, 

 where there was a nearly round spot of light. 

 A tail was traced for almost a degree. The 

 light of the comet, examined with a spectro- 

 scope, furnished with two prisms of 60, was 

 resolved into three broad bright bands. In 

 the two more refrangible of these bands, the 



