IV. 



An Account of the Nebula in Andromeda. 

 By GEORGE P. BOND, 



ASSISTANT XT THE CAMBRIDGE OBSERTATORY. 



(Read before the .Academy, March 7th, 1848.) 



Of the four thousand nebulae which have been recognized, that 

 which forms the subject of the present account is the only one the 

 discovery of which preceded the invention of the telescope. The 

 evidence which history affords of its having been noticed prior to 

 the year 1612 is derived through Ismael Bouillaud, a writer of the 

 seventeenth century, author of the Philolaica Astronomica, and, 

 among other astronomical treatises, of one entitled, De Nebulosd in 

 Andromeda Cinguli Parte Bored ante Biennium iterum Ortu ; con- 

 taining an ancient catalogue of stars, with charts of the constella- 

 tions, on which the nebula is represented of an oval form, and ac- 

 cording to Le Gentil, " fait un angle avec le circle de longitude." 

 By comparing the positions of the stars in this catalogue with mod- 

 ern determinations, the latter found that the date of its construction 

 was towards the close of the tenth century. As there seems to be 

 no reason for doubting the authenticity of this production, it is 

 probable that the great nebula in Andromeda was recognized at 

 least six hundred years before the invention of the telescope. 



Its appearance in 1612 is described with some care by Simon 



