NOVEMBEB 19, 1009] 



SCIENCE 



733 



a velocity of recession of 100 km. per second was 

 found for the star Lacaille 2957, and a velocity 

 of approach of 132 km. per second in the case of 

 the star Lacaille 8362, derived from three plates. 



Thirteen Stars having Variable Radial Velocities: 



Hebee D. Cubtis. 



This paper gave a list of thirteen new spectro- 

 scopic binaries discovered during the past two 

 years in the course of the work of the D. O. Mills 

 expedition to the southern hemisphere. Eight of 

 the number were discovered by Dr. Curtis, and 

 five by Mr. George F. Paddock. In two cases the 

 spectra of both components of the system are 

 visible. 

 7\ote on the Apparent Wave-lengilis of Lines in 



the Different Spectral Types and in Certain 



Variable Stars: SEBASTIA^f Albeecht. 



In 1900 the author made an investigation of 

 the individual spectrum lines in certain spectro- 

 grams, with a view of determining whether there 

 is a shift of any of the lines which is progressive 

 from spectral type to type. A preliminary list of 

 lines which undergo such a change, as indicated 

 by the radial velocities obtained from them, was 

 published in November, 1900. This investigation 

 has been continued intermittently during the last 

 two years, and a number of additional lines have 

 been found whose positions also change progres- 

 sively. 



In the paper referred to, a comparison was 

 made with Mr. Adams's list of sunspot lines 

 {Aph. Jour., 24, 1906). The principal result 

 of the comparison was the strong indication that 

 the physical conditions in the stars as we pass 

 from the F to the Mb type vary roughly in the 

 same direction as from the sun to the sunspots. 

 The results for the additional lines are in har- 

 mony with the above conclusion. 



In his first paper the author expressed the 

 opinion that for variable stars of large light 

 changes similar changes of apparent wave-lengths 

 of line might be found, corresponding to changes 

 in spectral type from maximum to minimum. 

 Measures of the available spectrograms of the 

 fourth class variables r; Aquilw and 1 Carinw were 

 tabulated according to phase of light variation 

 and some lines in the case of each star were 

 found to show a variation dependent upon the 

 phase of the light curve. In general, the direction 

 of variation is such as to indicate a later spectral 

 type at minimum than at maximum, though the 

 variation does not in each case take place in the 

 same part of the light curve. The change in the 

 spectrum of the variable star is probably such 



that the spectrum always has some characteristics 



of more than one spectral type. 



Unpublished Work of the Harvard Observatory: 



Edwabd C. Pickering. 



Discussion of the Revised Harvard Photometry, 

 H. A., 04, 4, pp. 50; ready for distribution. 



Observations on J. D. 3182 with the Four-inch 

 Meridian Photometer, H. A., 64, 5, pp. 12; ready 

 lor printing. 



Magnitudes of Components of Double Stars, 

 H. A., 64, 0, pp. 34; in type. 



A Discussion of the Eclipses of Jupiter's Satel- 

 lites, 1878-1903, by Ralph A. Sampson, /7. A., 

 52, 2, pp. 190; in type. 



Durchmusterung Zones Observed with 12-inch 

 Meridian Photometer, 190 pages; in type. 



Maxima and Minima of Variable Stars of Long 

 Period, 130 pages; in type. 



Photometric Measurements made with the East 

 Equatorial, by Oliver C. Wendell, pp. 50; in type. 



Photographic Magnitudes of Seventy-two Bright 

 Stars, Photographic Observations of Occultations, 

 Eclipses of Jupiter's Satellites, Transformation of 

 Prismatic to Normal Spectra, Miscellaneous, by 

 Edward S. King; nearly ready for printing. 



Statistical Investigations of Planetary Orbits, 

 by W. H. Pickering; nearly ready for printing. 



The Zone of Stars, in declination — 9° 50' to 

 — 14° 10', observed by Professor Searle with the 

 eight-inch meridian circle, is now nearly com- 

 pleted. It will occupy three volumes of the Har- 

 vard Annuls. It will be sent to the printer this 

 autumn, unless unforeseen delays arise. 

 The Photographic Search for Planet 0: W. H. 



PiCKEEING. 



The search for this planet was prosecuted on 

 plates taken by the Rev. Joel IT. Metealf with his 

 12-incli doublet. Two plates of each region were 

 taken at intervals of a few days apart. A posi- 

 tive was printed from one of these, and the other 

 negative superposed upon it. It was expected to 

 detect the planet by its motion during the interval 

 elapsed. The planet has not as yet been found. 

 This may be due to one or more of three causes: 

 (a) The planet may be unexpectedly faint, or 

 reddish in color. Its computed magnitude is 13.5. 

 (6) The orbit may be highly eccentric, the com- 

 putation being based on an approximately cir- 

 cular orbit, (c) The orbit may lie highly inclined 

 to the ecliptic, and the planet at present situated 

 far from its node. For various reasons the first 

 two causes are not thought sufficiently effective 

 to interfere with the discovery of the planet. We 

 might, by analogy, compare planet on account 



