ASTRONOMY. ;]71 



II itude (K. A. =23'' 58«, Decl. = — 37° 58'). It appears to liave a proper 

 motion of + 0^-482 and — 2"'45, or G"*21 in the arc of a great circle. 

 This motion is only less than that of Groombridge 1830 (7"-03), and that 

 of Lacaille 0352 (6"-06), which precedes the star in question by 1*^ and is 

 npon nearly the same parallel. The star is numbered 1584 in Hour xxiii 

 of the Cordoba Zone-Catalogue. 



Proper motion of Lalande 16616. — Professor Frisby has found* a ])roi)er 

 motion of — 0''-00020 ± 0^-0013, in right ascension and — 0"-3610 ± 0"-004S 

 in declination for this star, from observations of Lalande, Argelander, 

 Robinson, and Washington transit-circle observations in the years 18S1 

 and 1882. 



A large proper motion has been detected by Herr Berberich in the 

 star Weisse X 1021 ; and Professor Porter has called attention to proi)er 

 motions in the stars Lalande 20959 and 24423. 



Proper motions in the Pleiades. — Professor Pritchard has publishetl in 

 the forty eighth volume of the Memoirs of the Royal Astronomical So- 

 ciety a paper of some 50 pages, " On the relative proper motions of 

 forty stars in the Pleiades, determined from micrometric and merid- 

 ional observations." 



Motions of stars in the line of sight. — " For the past ten years the Royal 

 Observatory of Greenwich has been assiduously observing the spectra 

 of more than 50 of the brightest stars, for the purpose of determin 

 ing the velocity of their motions toward or from the earth in the ' line 

 of sight' — the line joining the earth and star. The reports of tbc 

 astronomer royal have given the annual results, but no general exhibi- 

 tion of the present state of the question has been made until lately, 

 when Mr. Maunder, the, observer, has collected them in an interesting- 

 paper in the Observatory. Mr. Maunder points out, in the first place, 

 that the conclusions which are drawn are worthy of confidence in spite 

 of the extremely small displacements of the spectral lines upon which 

 they depend. The entirely independent researches at Greenwich and 

 those of Dr. ITuggins and Dr. Vogel mutually confirm each other; and, 

 moreover, if the method is applied to the measurement of the difference 

 between the velocity of approach of the two limbs (edges) of the sun or 

 Ju[)iter, the results are consistent with what we know of the rotation- 

 times of these two bodies. We can compute exactly how fast one limb 

 of the sun is approaching us, and how fast the opposit*' limb is moving 

 away; and these same quantities can be determined by the spectro 

 scopic methods with substantially the same results. Hence the spec- 

 troscopic determinations of the velocity of a body in the line of sight 

 may be fairly said to belong to exact astronomy. The directions and 

 the velocities for some fifty stars have been thus determined at Groen- 

 wich by measures extending over several years. Velocities of thirty 

 to forty miles per second are not uncommon. A velocity of less than 

 ten miles corresponds to such a small displacement that its determina- 



* Asiron Xachr..2Ci33. 



