216 THEORY OF THE EARTH. 



Construction and Use of the Table. 



" The longitudes of the stars,for 1800, have been 

 taken from the Berlin Tables, and are those of 

 Lacaille, Bradley, or Flam stead. The first and the 

 last of each constellation have been taken, as well 

 as some of the brightest of the intermediate stars. 

 The third column indicates the year in which the 

 longitude of the star was 0', that is to say, that 

 in which the star was in the equinoxial colure of 

 spring. The last column indicates the year when 

 the star was in the solstitial colure, whether of 

 winter or of summer. 



" For Aries, Taurus, and Gemini, the winter 

 solstice has been chosen ; for the other constella- 

 tions the summer solstice has been chosen, for 

 the sake of not receding into too remote anti- 

 quity, and of not approaching too near modern 

 times. It will be easy to find the opposite sol- 

 stice, by adding the semiperiod of 12,960 years. 

 The same rule will serve for finding the time 

 when the star has been, or will be, at the autum- 

 nal equinox. 



" The sign indicates the years before our era, 

 the sign 4- the year of our era ; and the last line, 

 at the end of each sign under the title of dura- 

 tion) gives the extent of the constellation in de- 

 grees, and the time which the equinox, or the 

 solstice, occupies in traversing the constellation 

 from one end to the other. 



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