THE SEASONS. 109 



cold surface, or beneath the colder waves. The Polar Bear, and 

 the huge Walrus, and the Seal, sport among the floating fields of 

 ice; and the great Auk, or Penguin, seems to choose, by instinct, 

 this desolate and almost forsaken region of the earth, 



As the earth moves on in its orbit, the sun now rises higher 

 and higher in the heavens, at noon, each day, and finally arrives 

 at the point of vernal equinox and enters the constellation Pisces. 

 Again the nights and days are equal all over the globe, the earth 

 being illuminated from pole to pole. As the sun proceeds still far- 

 ther north of the equator, the north pole becomes more and more 

 illuminated, until finally it arrives at the point of greatest differ- 

 ence between the equator and ecliptic marked XVIII, see figure on 

 page 91, which is the point of the summer solstice. The sun is 

 now vertical in the northern hemisphere, at noon, at all places 

 situated on the parallel a b t which is called the tropic of Cancer. As 

 the sun is now entering the sign Cancer, and since the north pole 



of the earth is now wholly illuminated, as in the above diagram, 

 it is evident that the north pole, or rather the axis of the earthy is 

 inclined towards the sign Cancer. The days are still equal to the 

 nights, at the equator, but at all places north of the equator, as for 

 example on the parallel A B, the days are now longer than the 

 nights, the half illuminated portion I B. being greater than the 

 half unilluminated A I. It is now mid-summer, the beginning 

 of July, in the northern hemisphere, while at the same time it is 

 mid-winter in the southern. The arctic circle is now wholly illu- 

 minated, but the antarctic is in complete shade. At this season 

 the sun mounts highest in the heavens to all north of the equator, 

 and lowest to all south of it. The rays of the sun falling almost 

 direct, or perpendicular, upon the earth* in our northern latitude 



