732 



SCIENCE 



[N. S. Vol. XXX. No. 777 



star to the magnitude 9.0 in the Bonn Durohmus- 

 terung from the north pole to declination 22° 

 south, with the object of securing data for a 

 statistical study of double stars. Since 1905, 

 when Professor Hussey left the observatory, the 

 work has been carried on by the author alone. 

 It should be completed in two years' time, pro- 

 vided that the observing conditions between De- 

 cember and June are reasonably good. At present 

 about 85 per cent, of the area has been examined; 

 3,375 close double stars have been added to those 

 previously known and of these 1,327 are to Pro- 

 fessor Hussey's credit. One star in eighteen of 

 those examined has proved to be a double with a 

 separation under 5". It appears that double stars 

 with a separation under 2" are far more numerous 

 than those between 2" and 5". The discussion of 

 the material thus far collected is under way, but 

 definitive results will not be forthcoming until 

 the survey has been extended to the south pole. 

 It is hoped that an expedition suitably equipped 

 to carry out this program may be sent to South 

 America by the Lick Observatory immediately 

 upon the conclusion of the present survey. 



Speofrographio and Photographio Observations of 

 Comet 1908 (Morehouse) : Heber D. Cuetis. 

 Between the dates February 23 and March 23, 

 1909, one slit spectrogram and seventeen objective- 

 prism spectrograms were secured at the observa- 

 tory of the D. 0. Mills expedition. With the slit 

 spectrograph it was found possible to obtain only 

 the strongest of the pairs of lines of unknown 

 origin which characterized this comet. The wave- 

 lengths of this pair as derived from the slit spec- 

 trogram are X 4254.2 and X 4275.4. 



The following are the wave-lengths as derived 

 from the objective-prism plates: X3914.1, X4002.1, 

 X4021.3, X4254.0, (X4276.0), X4526.0±, X4545.9, 

 X4570.2, X4690.7, X4716.3. Collecting the differ- 

 ences for the three strongest pairs of lines, 

 X 4002-21, X 4254-76, X 4546-70, together with the 

 corresponding angles at the comet between the 

 radius vector and the line connecting the comet 

 with the earth, we have: 



The objections to interpreting the doubling of 

 these lines as a Doppler-Fizeau efTect have already 

 been stated by Campbell and Albrecht (cf. Lick 



Observatory Bulletin, No. 147 ) . Assuming the 

 actual velocities along the tail or transverse to 

 the tail to have been the same when Deslandres 

 and Bosler observed on November 1 and when the 

 author observed on March 21, the mean of the 

 intervals for the three principal pairs of lines 

 should have been about four tenth-meters greater, 

 or less, respectively, on March 21 than on No- 

 vember 1, whereas the observed intervals were not 

 quite one tenth-meter greater on the latter date. 



The various spectral images are replicas of the 

 tail, as shown by the direct photographs taken 

 at the same dates, as far as can be made out on 

 the small scale of the plates. In this respect the 

 plate of March 20 is of especial interest. The 

 direct photograph on this night shows a marked 

 curve in the tail about half a degree from the 

 head, a curve which is duplicated in each of the 

 spectral images. 



Twenty-eight direct photographs of the comet 

 were also made during this period, the majority 

 of them with a 6 J inch portrait lens; many of 

 these plates show interesting evidences of the 

 extraordinary activity which characterized this 

 comet both before and after perihelion. 



Three Stars of Oreat Radial Velocity: Hebeb D. 



Cuetis. 



A number of stars with proper motions of I".0 

 per year or greater have been investigated with 

 the spectrographs of the D. 0. Mills expedition 

 to the southern hemisphere, and in the course of 

 this work three stars have been found with radial 

 velocities of unusual magnitude. Of these the 

 most interesting is the star Cordoba Zones 5''243 

 {a^5"7'".4, S=: — 44° 56') who.se proper motion 

 of 8.7 seconds of arc per year is the greatest thus 

 far observed. Its magnitude is 9.2, and its photo- 

 graphic magnitude about 10.5, so that a satis- 

 factory plate was secured only by prolonging the 

 exposure time to twenty-nine hours on four con- 

 secutive nights. The mean of two plates shows 

 that the star is receding from the sun at a rate 

 of 242 km. per second. Using the Cape value of 

 the parallax of this star, 0".312, with Kapteyn's 

 values for the proper motion in right ascension 

 and declination, and eliminating the motion of 

 the solar system in accordance with Campbell's 

 value, the resulting space velocity of this star is 

 about 261 km. per second, directed toward a point 

 whose coordinates are a = 122°, 5=: — -60°. This 

 enormous space velocity seems to be exceeded only 

 by the star 1830 Groombridge, which is traveling 

 at a rate of about 278 km. per second toward an 

 apex in a ^250°, S^ — 52°. From five plates 



