522 



SCIENCE. 



[N. S. Vol. V. No. 117. 



The Modern Spectroscope XX. On a New Fluid 

 Prism Without Solid Walls and its Use in an 

 Objective Spectroscope: By F. L. O. Wads- 

 "WORTH. The writer suggests that a plane 

 mirror slanting downward at the proper angle 

 be introduced into the dispersing fluid, and 

 that the level surface be made to form the face 

 of the prism. The arrangement is similar to 

 that in the Lettrow form of spectroscope. 



Preliminary Table of Solar Spectrum Wave- 

 lengths : By Henry A. Rowland. One of 

 the regular series of tables. 



Researches on the Arc Spectra of the Metals 

 III. Cobalt and Nickel I. One of the regular 

 series of papers by B. Hasselberg. The 

 measurements of the wave-length are discussed 

 and probable impurity lines eliminated. 



Minor Contributions and Notes — Recent Astro- 

 physical Publications. 



DECEMBER, 1896. 



Oxygen in the Sun: By C. Runge and F. 

 Paschen. In the oxgen vacuum tube there 

 exists a triplet: 1 7772.26, 74.30, 75.97, which 

 is also found in the solar spectum. As the solar 

 spectrum is comparatively weak in lines in this 

 region (which is on the outside edge of the red) 

 the chance of coincidence with lines of foreign 

 origin is less than elsewhere. It is therefore 

 suggested by the writers that observations upon 

 these lines be made, to determine their solar or 

 telluric origin, whichever it may be. If the 

 origin be solar the writers believe the existence 

 of oxygen in the sun will be proved.* 



The Algol Variable + 17° 4Z67 ; W. Delphini: 

 By Edward C. Pickering. An ephemeris and 

 light curve for the star. 



The Determination of the Various Quantities of 

 Aqueous Vapor in the Atmosphere by Means of the 

 Absorption Lines of the Spectrum: By L. E. 

 Jewell. An investigation of the relative in- 

 tensities of the water vapor lines on the red 

 side of the D lines, in connection with meteoro- 

 logical readings. 



* Recent observations by Mr. L. E. Jewell at Johns 

 Hopkins University shovr that the triplet varies in 

 intensity upon different days in the same manner in 

 ■which the water vapor lines do, thereby indicating 

 that it is due to that substance in the earth's atmos- 

 phere and not to oxygen either here or in the sun. 



Researches on the Arc Spectra of the Metals III. 

 Cobalt and Nickel II: By B. Hasselberg. A 

 continuation of the details of comparison by 

 which impurity lines are eliminated from the 

 spectra of these elements. 



Minor Contributions and Notes. Including H. 

 C. O. circulars No. 12, 13 and 14. No. 13 con- 

 tains a description of the spectrum of Pup- 

 pis. This spectrum in addition to dark hydro- 

 gen lines and the line K contains a series of 

 dark lines that are satisfied by Balmer's formula 

 less a constant term.* 



JANUARY, 1897. 



On the Spectroscopic Binary aiQeminorum : By 

 A. Belopolsky. Containing an account of the 

 detection of the binary character of the princi- 

 pal component of castor. A general discussion 

 of the elements is also included. 



On an Automatic Arrangement for Giving 

 Breadth to Stellar Spectra on a Photographic Plate : 

 By William Huggins. Dr. Huggins suggests 

 in this article that an eccentric gear wheel be 

 put in the clock mechanism so as to produce an. 

 oscillation of the telescope during exposure. 

 This will cause the stellar image to move back 

 and forth over the desired length of slit. The 

 advantage claimed for this method, over the one 

 ordinarily in use (that of changing the rate of 

 the clock, which was also due to the writer), is 

 the saving of time ordinarily wasted in the re- 

 setting, and in general convenience. 



On the Application of Interference Methods to 

 the Determination of the Effective Wavelength of 

 Starlight : By Geo. C. Comstock. An investi- 

 gation taken up in connection with the effect 

 of refraction upon the apparent places of 

 stars. The author claims that for physiological 

 reasons the effective wave-length can not be de- 

 termined by matching the apparent color of the- 

 stars with the spectrum. The following device 

 was adopted. The objective of the equatorial 

 was covered by a diaphragm having two paral- 

 lel slits cut out of it. When the telescope was- 

 pointed at a star there resulted the usual dif- 



* More recent investigations by Professor Picker- 

 ing, and Professor Kayser, indicate that this second 

 series is also due to hydrogen under physical condi- 

 tions different from those under which it has heett 

 previously observed. 



