118 THE MILKY WAY. j 



The magnitudes of the fixed stars appear to be different ' 

 from one anotlier, which difference may arise either from a j 

 diversity in their real magnitudes, or distances; or from 

 both these causes acting together. The difference in the 

 apparent magnitude of the stars is such as to admit of their i 

 being divided into six classes, the largest being called stars I 

 of the first magnitude, and the least which are visible to the ^ 

 naked eye, stars of the sixth magnitude. Stars that cannot '\ 

 be seen without the help of glasses are called telescopic '■ 

 stars. The number of stars, visible at any one time to the 

 naked eye, is about one thousand ; but Dr. Herschel, by his i 

 skilful improvements of the reflecting telescope, has disco- | 

 vered that the whole number is great beyond all conception. J 

 Upon viewing the heavens during a clear night, we discover % 

 a pale irregular light, and a number of stars whose mingled 

 rays form the luminous tract called the milky-way. The j 

 stars themselves are at too great a distance to be perceived ] 

 by the naked eye ; and among those which are visible with  

 a telescope there are spaces apparently filled with others in 

 immense numbers. Many whitish spots or tracts (called 

 nehuloi) are visible in different parts of the heavens, which ^. 

 are supposed to be milky-ways at an inconceivable distance. ] 



The distance of these remoter bodies is so vast and mea- i 

 sureless, that we can hardly speak of it except in relation to i 

 the inconceivable swiftness of light. The rays by which ^^ 

 they are now made visible to the eye of the astronomer, k 

 the rapid motion of which might circle the earth while on« \ 

 is pronouncing a syllable, have been darting forward for 1 

 thousands and ten thousands of years to reach us. All the I 

 events and revolutions, which history records, have taken 

 place during their progress. They commenced their career, 

 it has been computed, at a period of such remote antiquity, 

 that, compared with it, the date of that time, when God 

 gave the earth to man for a habitation, is but of yesterday. 



Dr. Herschel has calculated that the distance of the re- 

 motest nebulae, exceeds that of the nearest fixed star at least 

 three hundred thousand times. Upon this fact, he thus re- 

 marks ; a telescope with a power of penetrating into space, 

 like my forty feet one, has also, as it may be called, a 

 power of penetrating into time past. To explain this we 

 must consider that from the known velocity of light, it may 

 be proved that when we look at the star called Sirius, the 



