TKOPICS SOLSTICES. 



begins to return to E, are called the TKOPICS from a Greek word 

 rpojrfj (trope), which signifies a return. 



66. It is observed that when the sun arrives at these points 

 T and T', it pauses for some days without changing in any con- 

 siderable degree its distance from E, and under these circumstances 

 the hours of rising and setting continue to be sensibly the same. 

 If, for example, the almanack be examined, it will be found that 

 from the 10th to the 24th June the hour of sunrise does not 



Fig. 4. 



& 



S O N 



change by more than two minutes, and that from the 13th to the 

 21st inclusive it does not change at all. In the same manner the 

 hour of sunset remains the same from the 19th to the 22nd 

 inclusive, and does not vary more than two minutes from the 

 17th to the 28th inclusive. 



The same circumstances will be found to attend the sun when 

 it passes the meridian at T' in December. 



Owing to this stationary position of the sun, and the consequent 

 unchanging length of the days, these epochs are called the SOL- 

 STICES, from a Latin word SOLSTITITJM, which denotes the standing 

 still of the sun. 



The June solstice is called the SUMMER SOLSTICE, and the 

 December solstice the WINTER SOLSTICE. 



They are respectively the days on which the sun attains the 

 greatest and least meridian altitude which in the place for which 

 the almanack is calculated it can attain, since it never can rise 

 higher than T, or descend lower than T' when on the meridian. 



The days of the solstices are also respectively the longest and 

 the shortest days of the year. 



37 



