W. A. Miller

On the Spectra of Some of the Fixed Stars.

1. Th e recent discovery by Kirchhoff of the connexion between the dark lines of the solar spectrum and the bright lines of terrestrial flames, so remarkable for the wide range of its application, has placed in the hands of the experimentalist a method of analysis which is not rendered less certain by the distance of the objects the light of which is to be subjected to examination.

On the Spectra of Some of the Nebulae. By William Huggins, F.R.A.S. A Supplement to the Paper "On the Spectra of Some of the Fixed Stars William Huggins F.R.A.S., and W. A. Miller, M.D., LL.D., Treas. and V.P.P.S."

The concluding paragraphs of the preceding paper refer to the similarity of essential constitution which our examination of the spectra of the fixed stars has shown in all cases to exist among the stars, and between them and our sun. It became therefore an object of great importance, in reference to our knowledge of the visible universe, to ascertain whether this similarity of plan observable among the stars, and uniting them with our sun into one great group, extended to the distinct and remarkable class of bodies known as nebulæ. Prismatic analysis, if it could be successfully applied to objects so faint, seemed to be a method of observation specially suitable for determining whether any essential physical distinction separates the nebulæ from the stars, either in the nature of the matter of which they are composed, or in the conditions under which they exist as sources of light. The importance of bringing analysis by the prism to bear upon the nebulae is seen to be greater by the consideration that increase of optical power alone would probably fail to give the desired information; for, as the important researches of Lord Rosse have shown, at the same time that the number of the clusters may be increased by the resolution of supposed nebulae, other nebulous objects are revealed, and fantastic wisps and diffuse patches of light are seen, which it would be assumption to regard as due in all cases to the united glare of suns still more remote.

III. On the spectrum of a new star in Corona Borealis

Yesterday, May the 16th, one of us received a note from Mr. John Birmingham of Tuam, stating that he had observed on the night of May 12 a new star in the constellation of Corona Borealis. He describes the star as “very brilliant, of about the 2nd magnitude.” Also Mr. Baxendell of Manchester wrote to one of us giving the observations which follow of the new star, as seen by him on the night of the 15th instant. “A new star has suddenly burst forth in Corona. It is somewhat less than a degree distant from ε of that constellation in a south-easterly direction, and-last night was fully equal in brilliancy to β Serpentis or v Herculis, both stars of about the 3rd magnitude.”

On the Spectra of Some of the Nebulae. And On the Spectra of Some of the Fixed Stars.

The author commences by showing the importance of bringing analysis by the prism to bear upon the remarkable class of bodies known as nebulæ, especially since the results obtained by the largest telescopes hitherto constructed appear to show that increase of optical power alone would probably fail to determine the question whether all the nebulæ are clusters of stars too remote to be separately visible. The little indication of resolvability, the absence of central condensation, the greenish-blue colour, and the intrinsic brightness characterizing many of the nebulæ classed by Sir W. Herschel as planetary, induced the author to select chiefly nebulæ of this class for prismatic observation.

On the spectra of some of the fixed stars; and on the spectra of some of the nebulae

Mr. HUGGINS and Prof. MILLER presented to the Royal Soci. ety of London, on the 26th of May, 1864, an important paper on the spectra of some of the fixed stars, and Mr. Huggins presented one on the 8th of September on the spectra of some of the neb· uire. By a peculiar adaptation of the spectroscope to a telescope of 10 feet focal length and 8 inches aperture, they were able to make a direct comparison of the spectra of the moon, planets, fixed stars, and nebulre, with the spectra of the several chemical elements. The following are some of the more important points of the two papers. The result of the analysis of the light of the moon is wholly negative as to the existence of any considerable lunar atmos-

II. On the spectra of some of the fixed stars

After a few introductory remarks, the authors describe the apparatu which they employ, and their general method of observing the spectra the fixed stars and planets. The spectroscope contrived for these inqu ries was attached to the eye end of a refracting telescope of 10 feet foe length, with an 8-incli achromatic object-glass, the whole mounted equa torially and carried by a clock-movement. In the construction of th spectroscope, a plano-convex cylindrical lens, of 14 inches focal length, wa employed to convert the image of the star into a narrow line of light which was made to fall upon a very fine slit, behind which was placed an achromatic collimating lens. The dispersing portion of the arrangement consisted of two dense flint-glass prisms; and the spectrum was viewe through a small achromatic telescope with a magnifying power of between 5 and 6 diameters. Angular measures of the different parts of the spectrum were obtained by means of a micrometric screw, by which the position of the small telescope was regulated. A reflecting prism was placed over one half of the slit of the spectroscope, and by means of a mirror, suitably adjusted, the spectra of comparison were viewed simultaneously with the stellar spectra. This light was usually obtained from the induction spark taken between electrodes of different metals. The dispersive power of the apparatus was sufficient to enable the observer to see the line Ni of Kirchhoff between the two solar lines D ; and the three constituents of the magnesium group at b are divided still more evidently*. Minute details of the methods adopted for testing the exact coincidence of the corresponding metallic lines with those of the solar and lunar spectrum, are given, and the authors then proceed to give the results of their observations.

Note on the Lines in the Spectra of Some of the Fixed Stars

The recent detailed examination of the solar spectrum, and the remarkable observations of Kirchhoff upon the connexion of the dark lines of Fraunhofer with the bright lines of artificial flames having imparted new interest to the investigation of spectra, it ha appeared to the authors of the present note that the Royal Society may not consider a brief account of their recent inquiry upon the spectra of some of the self-luminous bodies of the heavens unworthy of attention, although the investigation is as yet far from complete.