SBCT. xxxvii.] CONSTITUTION OF NEBULJE. 445 



permanent. The places where these appearances occurred 

 are given in order that those who wish to verify them may 

 have it in their power. 



Such is a brief account of a very few of the discoveries 

 contained in Sir John Herschel's great work on the Nebulae 

 and other Phenomena of the Southern Hemisphere, a work 

 which will rise in estimation with the lapse of years. Its 

 date may be regarded as the epoch of nebular time, whence 

 all the changes that take place in the most distant regions 

 of the universe will be estimated for ages to come. To 

 him and to his father we owe almost all that is known of 

 nebular, and the greater part of sidereal astronomy ; and in 

 the inimitable writings of the highly gifted father and son 

 the -reader will find these subjects treated of in a style 

 worthy of it and of them. Of late years the excellence of 

 the instruments, and still more of the astronomers in the 

 foreign observatories, have aided the progress of sidereal 

 astronomy immensely. Nor has it been cultivated with less 

 success in our home and colonial establishments : certainly 

 one of the most remarkable features of the times is the 

 number of private observatories, built and furnished with 

 the best instruments by private gentlemen, whose zeal has 

 been rewarded by eminent success in all departments of the 

 science. 



So numerous are the objects which meet our view in the 

 heavens, that we cannot imagine a point of space where 

 some light would not strike the eye ; innumerable stars, 

 thousands of double and multiple systems, clusters in one 

 blaze with their tens of thousands of stars, and the nebulae 

 amazing us by the strangeness of their forms and the in- 

 comprehensibility of their nature, till at last, from the limit 

 of our senses, even these thin and airy phantoms vanish in 

 the distance. If such remote bodies shone by reflected 

 light, we should be unconscious of their existence. Each 

 star must then be a sun, and may be presumed to have its 

 system of planets, satellites, and comets, like our own ; and, 



