DOUBLE STARS. 275 



Christian Mayer, the Manheim astronomer, has the great 

 merit of having first (1778) made the fixed stars a special 

 object of research, by the sure method of actual observations. 

 The unfortunate choice of the term satellites of 'the fixed stars , 

 and the relations which he supposed to exist among the 

 stars between 2 30' and 2 55' distant from Arcturus, exposed 

 him to bitter attacks from his contemporaries, and among 

 these to the censure of the eminent mathematician, Nicolaus 

 Fuss. That dark planetary bodies should become visible by 

 reflected light, at such an immense distance, was certainly 

 improbable. No value was set upon the results of his care- 

 fully conducted observations, because his theory of the phe- 

 nomena was rejected ; and yet Christian Mayer, in his re- 

 joinder to the attack of Father Maximilian Hell, Director 

 of the Imperial Observatory at Vienna, expressly asserts 

 "that the smaller stars, which are so near the larger, are 

 either illuminated, naturally dark planets, or that both of 

 these cosmical bodies the principal star and its companion 

 are self-luminous suns revolving round each other." The 



Annuairepour 1834, p. 308, and Ann. 1842, p. 400.) No great 

 reliance can be placed on the individual numerical results of 

 the calculus of probabilities given by Michell : as the hypotheses 

 that there are 230 stars in the heavens which, in intensity of 

 light, are equal to /3 Capricorni, and 1500 equal to the six 

 greater stars of the Pleiades, are manifestly incorrect. The 

 ingenious cosmological treatise of John Michell ends with a 

 very bold attempt to explain the scintillation of the fixed stars 

 by a kind of '* pulsation in material effluxes of light " an 

 elucidation not more happy than that which Simon Marius, one 

 of the discoverers of Jupiter's satellites (see Cosmos, vol. ii. 

 p. 404,) has given at the end of his Mundus Jovialis (1614) 

 But Michell has the merit of having called attention to the 

 fact (p. 263) that the scintillation of stars is always accom- 

 panied by a change of colour. " Besides their brightness: 

 there is in the scintillation of the fixed stars a change of 

 colour.'* (Vide supra.} 



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