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The spectrum of the planet Uranus
84:
Editorial.
Browne, Mr. E. Moelling, Mr. O. H. Kendall, Mr. James Cremer, Philadelphia, Pa. This will constitute the photographic portion of ~ e party, allowing five operators in all to each instrument. Professor J. H. C. Coffin, of the Nautical Almanac Office, will meet this party at Burlington, with an Astronomical Corps, and Professor E. C. Picker. ing, of the Massachusetts Institute of Technology, will go with them to make physical observations. Also Professor James McClune, the astronomer of the High School, will accompany the Philadelphia party, with instruments for astronomical work. The various telescopes have been fitted with eye-pieces of special construction and instantaneous expos.ure slides by Mr. Zentmayer, and with light cameras furnished by the American Optical Company~ Near York. There will also be taken a Chronograph from the Washington Observatory (which has been put in excellent order ) by Messrs. Chester & Patrick of this city, by means of which the dates of exposure of the various partial-phase pictures may be actually recorded and thus rendered of infinite value as astronomical observations. 3_ temporary observatory has been constructed in West Philadelphia, on a very convenient location, kindly placed at the disposal of the party by Mr. John Sellers, and regular drilling in the various manipulations required is being carried on there, and will continue until the time fQr starting arrives, which will be on the 2d of August. The Spectrl~ of the Planet U r a n u s . - - T Q his astonishing discovery of vapor of water in the vicinity of sun-spots, noticed in our last number, Father Secchi has added" another spectroscopic discovery fully as remarkable, namely, that the light which comes to us from Uranus differs very much from that refleete~t by the other planets. In a number of the Comytes Rendus just received, (Vol. L X V I I I , page 761,) we find an account to this effect. Having turned the spectroscope by chance upon this planet, then appearing as a star of the sixth magnitude, he obtained in place of the normal solar spectrum which he expected, one whose principal characteristics are indicated by the accompanying diagram, where the intensity of light in various parts is indicated by the height of the curve. The red end of this spectrum is at the left, the violet to the right. The position of the normal sun lines 9 and b is indicated by those letters ~ and N were two very strong ab-
Ite~ns and Novelties.
85
sorption bands located, as here shown, and corresponding to no strong solar lines. The yellow part of the spectrum was entirely wanting, as is indicated between/~ and q. From this we would conclude that this planet has an atmosphere of considerable extent, and generally transparent, but absorptive of certain rays and of all yellow tints, to a considerable degree, and that the rays from the sun are not chiefly reflected to us from clouds or mists in the upper region of such an atmosphere, but penetrate it to a notable depth before they are turned back by reflection. The material of this atmogphere remains to be determined. The Spectrum of R. G e m i n i . - - T h i s variable star with a spectrum like that of • Coronm Borialis, showing bright superposed lines indicative of a surrounding luminous envelope of gas, has been further studied by Father Secchi, who, in the paper quoted above, gives a diagram of its spectrum, which we subjoin. The intensity of the general spectrum is here, as before, shown by the curve, while the positions of the bright bands, is indicated.by that of the vertical lines. Two of these, c and F, it will be seen, indicate hydrogen, one, b, magnesium, and the double line, D, sodium. The first, c and F, are found likewise in the spectrum of Coronm Borialis, but the others are confined to this star. A New Regulator for the Electric L~mp.--Cari6, the inventor of the ice machine which bears his name, has communicated to the Soc. d'Encouragement, a new form of battery, regulator and carbons for the electric light. Of these the most notable is the regulator, whose chief feature is the means by which the varying current gives motion to the carbons. Between the poles of an Electro magnet is an armature, shaped somewhat like the letter 5, the spiral curves being so adjusted that the power of the magnet is almost equally efficient in all positions, but tends to bring the central part in line -#ith the poles. This is resisted by the torsion of a steel wire, attached at right angles~ to the armature N ~ 8 at its centre. Thus, as the current increases in strength, (1 ~ !) the armature, A B, is drawn into line with ~ s, the resistance of the spring increasing with the degree of motion. This, by simple connecting machinery, separates the points. I f the current diminisheS in strength, then the springs conquer, and the motions are all reversed.
Editorial.
Browne, Mr. E. Moelling, Mr. O. H. Kendall, Mr. James Cremer, Philadelphia, Pa. This will constitute the photographic portion of ~ e party, allowing five operators in all to each instrument. Professor J. H. C. Coffin, of the Nautical Almanac Office, will meet this party at Burlington, with an Astronomical Corps, and Professor E. C. Picker. ing, of the Massachusetts Institute of Technology, will go with them to make physical observations. Also Professor James McClune, the astronomer of the High School, will accompany the Philadelphia party, with instruments for astronomical work. The various telescopes have been fitted with eye-pieces of special construction and instantaneous expos.ure slides by Mr. Zentmayer, and with light cameras furnished by the American Optical Company~ Near York. There will also be taken a Chronograph from the Washington Observatory (which has been put in excellent order ) by Messrs. Chester & Patrick of this city, by means of which the dates of exposure of the various partial-phase pictures may be actually recorded and thus rendered of infinite value as astronomical observations. 3_ temporary observatory has been constructed in West Philadelphia, on a very convenient location, kindly placed at the disposal of the party by Mr. John Sellers, and regular drilling in the various manipulations required is being carried on there, and will continue until the time fQr starting arrives, which will be on the 2d of August. The Spectrl~ of the Planet U r a n u s . - - T Q his astonishing discovery of vapor of water in the vicinity of sun-spots, noticed in our last number, Father Secchi has added" another spectroscopic discovery fully as remarkable, namely, that the light which comes to us from Uranus differs very much from that refleete~t by the other planets. In a number of the Comytes Rendus just received, (Vol. L X V I I I , page 761,) we find an account to this effect. Having turned the spectroscope by chance upon this planet, then appearing as a star of the sixth magnitude, he obtained in place of the normal solar spectrum which he expected, one whose principal characteristics are indicated by the accompanying diagram, where the intensity of light in various parts is indicated by the height of the curve. The red end of this spectrum is at the left, the violet to the right. The position of the normal sun lines 9 and b is indicated by those letters ~ and N were two very strong ab-
Ite~ns and Novelties.
85
sorption bands located, as here shown, and corresponding to no strong solar lines. The yellow part of the spectrum was entirely wanting, as is indicated between/~ and q. From this we would conclude that this planet has an atmosphere of considerable extent, and generally transparent, but absorptive of certain rays and of all yellow tints, to a considerable degree, and that the rays from the sun are not chiefly reflected to us from clouds or mists in the upper region of such an atmosphere, but penetrate it to a notable depth before they are turned back by reflection. The material of this atmogphere remains to be determined. The Spectrum of R. G e m i n i . - - T h i s variable star with a spectrum like that of • Coronm Borialis, showing bright superposed lines indicative of a surrounding luminous envelope of gas, has been further studied by Father Secchi, who, in the paper quoted above, gives a diagram of its spectrum, which we subjoin. The intensity of the general spectrum is here, as before, shown by the curve, while the positions of the bright bands, is indicated.by that of the vertical lines. Two of these, c and F, it will be seen, indicate hydrogen, one, b, magnesium, and the double line, D, sodium. The first, c and F, are found likewise in the spectrum of Coronm Borialis, but the others are confined to this star. A New Regulator for the Electric L~mp.--Cari6, the inventor of the ice machine which bears his name, has communicated to the Soc. d'Encouragement, a new form of battery, regulator and carbons for the electric light. Of these the most notable is the regulator, whose chief feature is the means by which the varying current gives motion to the carbons. Between the poles of an Electro magnet is an armature, shaped somewhat like the letter 5, the spiral curves being so adjusted that the power of the magnet is almost equally efficient in all positions, but tends to bring the central part in line -#ith the poles. This is resisted by the torsion of a steel wire, attached at right angles~ to the armature N ~ 8 at its centre. Thus, as the current increases in strength, (1 ~ !) the armature, A B, is drawn into line with ~ s, the resistance of the spring increasing with the degree of motion. This, by simple connecting machinery, separates the points. I f the current diminisheS in strength, then the springs conquer, and the motions are all reversed.