LINE OF APSIDKS. 103 



nearest those places in summer. And those signs, which are 

 winter signs to us, who live in the northern hemisphere, are 

 summer signs to the inhabitants of the southern. All varieties of 

 seasons are thus, at all times, upon our globe. When one portion 

 is covered with the white mantle of winter, another is producing 

 beautiful flowers. At one place spring is commencing, at another 

 the autumn, and around the equatorial regions of the earth per- 

 petual summer reigns. Perhaps there is nothing that seems more 

 strange to the traveler, than this variety of seasons from change 

 of latitude. The names of the winter months, which so long 

 have been associated with ideas of cold, and frost, and storm, seem 

 strangely misplaced, when he beholds flowers blooming around 

 him in December, and hears the songs of birds wafted on the 

 light breeze. Christmas and New Years, which in our northern 

 country, are wont to be associated with the cheerful blaze, the 

 merry sleigh-ride, or the drifting snow, bring no such associations 

 to the inhabitant of the southern hemisphere ; there, mid-summer 

 reigns, and the cool breezes, which blow over the Indian seas, 

 laden with perfume, dispel the sultry heat. The cause by which 

 all this variety is produced, is not the less interesting because it is 

 simple, and because we see in it a guaranty that long as time shall 

 last, or the present race inhabit the globe, so long the seed- 

 time and harvest must return with undeviating certainty. 



We have mentioned formerly that the earth's orbit is an ellipse, 

 and that the longer or major axis of the ellipse is called the line 

 of the apsides. We might have shown that between the limits of 

 an ellipse, viz: a perfect circle on the one hand and a straight 

 line on the other, this orbit might vary, but still the periodic 

 time of a revolution remain unchanged. But these are theoreti- 

 cal investigations upon which we cannot enter. We will, how- 

 ever, observe that the line of the apsides, or major axis of the 

 earth's orbit, is its most important element, for when this is de- 

 termined the periodic time of a revolution, and the mean distance 

 from the sun are also determined. The orbit itself, under the 

 influence of various forces, may change its ellipticity, expanding 

 towards a circle on the one hand, or diminishing towards a 

 straight line on the other, or the ellipse may swing round upon 



