INTRODUCTION. 1 1 



them all by their names. But we have measured the distances and 

 the dimensions of the planets and the periods and the rapidity of 

 their revolutions ; and we have ascertained their absolute and relative 

 weight. We know not where discovery will stop ; the noble science 

 of astronomy is now cultivated with an ardor not surpassed even by 

 that of the age of Newton, and with means far superior. Innumera- 

 ble discoveries of new stars have been made ; and it is ascertained, 

 that a part of the fixed stars have a revolution indicating the move- 

 ments of the members of particular systems. This is true, especial- 

 ly of what are called the double stars, and the sublime conception 

 is entertained, that the whole stellary system, with its myriads of 

 planetary worlds, revolves in the course of ages around a common 

 centre. 



Astronomy is, not without reason, regarded, by mankind, as the 

 sublimest of the natural sciences. Its objects, so frequently visible, 

 and therefore familiar, being always remote and inaccessible, do not 

 lose their dignity. 



Although Newton, a century ago, unfolded the structure of the 

 universe ; Herschel, La Place, La Lande, and other distinguished 

 astronomers have continued to enlarge our knowledge of the heavens* 

 and the Astronomical Society of London diligently collects and com- 

 pares all discoveries, while some of its members are ardently engaged 

 in making new observations. 



The practical applications of astronomy, in determining the latitude 

 and longitude especially at sea, are highly important ; the exact cal- 

 culation and prediction of some of its more striking phenomena have 

 removed the superstitious dread of eclipses, and substituted a rational 

 comprehension of their cause ; while the transits of the planets and 

 the measurement of arcs of great circles of the heavens in different 

 latitudes, have been thought sufficiently important to justify voyages 

 and journeys to the most distant and inhospitable regions. It may be 

 mentioned also, without impropriety, that the observation of the heaven- 

 ly bodies is a rational source of amusement. In a fine night, the teles- 

 cope, although not like that of Herschel, of immoderate size and ex- 

 pense, is an interesting companion, and we contemplate with delight the 

 mild lustre of the evening star, the fiery face of Mars, the silver orb of 

 Jupiter, his belts and his satellites, and the incomprehensible rings of 

 Saturn. f 



* Chalmers, with his own peculiar eloquence, has arrayed astronomy in new at- 

 tractions, by connecting its physical features with our moral instruction. 



t In this connexion we ought not to forget Dollond, Lerebours, Fraunhofer and 

 other distinguished artists without whose aid the science of astronomy must have 

 t>een arrested in its course. 



