276 COSMOS. 



importance of Christian Mayer's labours has, long after Lis 

 death, been thankfully and publicly acknowledged by Struve 

 and Madler. In his two treatises, Vertheidigung neuer Beo- 

 bachtungen von Fixstern-trabanten (1778), and Dissertatio de 

 novis in Coelo sidereo Phcenomenis (1779), eighty double stars 

 are described as observed by him, of which sixty-seven are 

 less than 32" distant from each other. Most of these were 

 first discovered by Christian Mayer himself, by means of the 

 excellent eight-feet telescope of the Manheim Mural Quad- 

 rant; "many even now constitute very difficult objects of 

 observation, which none but very powerful instruments are 

 capable of representing, such as and 71 Herculis, Lyrae, 

 and a Piscium." Mayer, it is true, (as was the practice long 

 after his time,) only measured distances in right ascension 

 and declination by meridian instruments, and pointed out, 

 from his own observations, as well as from those of earlier 

 astronomers, changes of position; but from the numerical 

 value of these he omitted to deduct what (in particular cases) 

 was due to the proper motion of the stars. 8 



These feeble, but praiseworthy beginnings were followed 

 by Sir William Herschel's colossal work on the multiple 

 stars, which comprises a period of more than twenty-five 

 years. For although Herschel's first catalogue of double 

 stars was published four years after Christian Mayer's treatise 

 on the same subject, yet the observations of the former go 

 back as far as 1779 indeed, even to 1776, if we take into 

 consideration the investigations on the trapezium in the 

 great nebula of Orion. Almost all we at present know of 

 the manifold formation of the double stars has its origin 

 in Sir William Herschel's work. In the catalogues of 1782, 



Struve, m the Recueil des Actes de la Seance publique de 

 r Acad. Imp. des Sciences de St. Peter sbourg, le 29 Dec 

 } 832, pp. 48-50. Madler, Astr., s. 478. 



