COMMON THINGS THE ALMANACK. 



and its meridional altitude will continually decrease, and conse- 

 quently its southern declination will continually increase until 

 the December solstice, when it will be 23 degrees 28 minutes, 

 just what it was at the June solstice, only that it is now that 

 distance south of its meridional altitude at the equinoxes, whereas 

 in June it was north of that altitude. 



After the December solstice the meridional altitude will gra- 

 dually increase, and consequently the southern declination will 

 gradually decrease until the March equinox, when the declination 

 will become nothing. 



. All these periodical changes in the declination may be seen by 

 referring to the column of the almanac appropriated to it. 



65. Now there are certain circumstances connected with these 

 changes which require especial notice. 



It will be observed that the northern declination of the sun con- 

 tinually increasing after the March equinox until the June solstice, 

 then ceases to increase, begins to decrease, and continues to de- 

 crease until it becomes nothing at the September equinox. The 

 sun, therefore, continually moves from its position in March, and 

 crosses the meridian at points more and more distant from that at 

 which it crossed it in March, until at length at the June solstice 

 it crosses it at a distance of 23 degrees 28 minutes from the point 

 where it crossed it in March. After that the point where, it 

 crosses the meridian begins to go back towards the point where 

 it crossed in March, and continues to go back until it returns at 

 the September equinox, to the point where it crossed in March. 



The same observations will be applicable to the points where it 

 crosses the meridian from September to March, these points 

 gradually receding southwards until the December solstice, and 

 then returning back and resuming their position in March. 



This will be more clearly understood by reference to fig. 4, 

 where s N represents the horizon, s being the south, N the north, 

 o the observer ; s z N the celestial meridian, E the point where 

 the sun passes it at noon on the day of the equinox. Let us 

 suppose that the equinoxes fall on the 21st March and 23rd 

 September, and the solstices on the 2 1st June and 22nd December. 

 After the 21st March the sun passes the meridian at points farther 

 and farther above E until the 21st June, when it passes at T. 

 After the 21st June it passes at points nearer and nearer to E until, 

 on the 23rd September, it passes at E. After the 23rd September 

 it passes below E lower and lower until, on the 22nd December, it 

 passes at T'. After the 22nd December it passes at points higher 

 and higher until the 21st March, when it passes at E. 



The points T and T' at which the sun attains its greatest 

 distance from E, and at which, after having departed from E, it 

 36 



