86 SPECIAL RESULTS IN THE URANOLOGICAL PORTION 



III. 



NUMBER, DISTRIBUTION, AND COLOUR OF THE FIXED STARS 



CLUSTERS OF STARS. MILKY WAY, IN WHICH A FEW 



NEBULA ARE INTERSPERSED. 



I HAVE already alluded, in the first section of this frag- 

 mentary Astrognosy, to a consideration which was first pro- 

 posed by Olbers. ( 167 ) If the whole vault of heaven were 

 covered with a countless succession of starry strata one 

 behind another, forming an unbroken starry canopy, then, sup- 

 posing also their light to be unenfeebled in traversing space, 

 no single constellation could be recognised amidst the uni- 

 versal brightness. The Moon would be seen as a dark disk, 

 and the Sun would be known only by his spots. I have been 

 forcibly reminded of a state of the heavens which, totally op- 

 posite in its cause, would be equally disadvantageous to human 

 knowledge, by what takes place during a portion of the year 

 on thePeruvian plain between the shores of the Pacific and the 

 chain of the Andes. A thick mist covers the sky for several 

 months during the season called " el tiempo de la garua." 

 No planet, not one even of the brightest stars of the Southern 

 Hemisphere, neither Canopus, nor the Southern Cross, nor 

 the two bright stars of the Centaur, are visible. Often one 

 can hardly conjecture the place of the Moon. If, occasion- 



