CHAPTER XXXVII. 

 THE EARTH. 



FORM OF THE EARTH MOTION OF THE GLOBE RATE AND MANNER 



OF PROGRESSION LATITUDE AND LONGITUDE THE SEASONS. 



WE have learnt from our books on Geography that the earth is shaped 

 like an orange, that is, our globe is round and flattened slightly at the 

 " poles," and we can easily see that the earth curves away, if we only try 

 the experiment mentioned in a foregoing chapter viz., how far a person 

 standing (or lying) on the ground can see on a level. Our power of eye- 

 sight is not limited to three or four miles, but a man of ordinary height 

 standing on the plain cannot see more than three miles, because the earth is 

 curving away from him. 



We know that at the seaside we can see ships gradually appear and 

 disappear. When approaching us the masts and top-sails appear first, then 

 the main-sails, and then the ship itself. A sailor climbing up the mast can 

 see farther than the captain on deck, because he can see over the curve, as it 

 were. When the vessel is at a considerable distance we see her "hull 

 down " as it is termed, that is, only her sails are visible to us, and at last 

 they disappear also. If we want any other proof that the earth is round 

 we can see when an eclipse takes place that the shadow on the moon is 

 circular. So we may be certain of one fact; the earth is round, it is a globe, 

 So much for the rotundity of the earth. 



But the earth appears to us, except in very mountainous districts, as 

 being almost a plane. This is because of its extent ; and even from very high 

 mountains we can only see a very small portion of the earth, and so, on a globe 

 sixteen inches in diameter, the highest hills would be only about T JQ- of an 

 inch, like a grain of sand. 



The motion of the earth is known to most people, though as every- 

 thing upon the globe passes with it, and a relative fixity is apparent, this is, of 

 course, not real rest. The earth is moving from west to east at a tremendous 

 rate, viz., nearly nineteen miles a second ! We think a train at sixty miles 

 an hour a fast train ; but what should we think of an express going more 

 than 68,000 miles an hour ! Yet this is about the rate at which our globe 

 whirls around the sun. Her fastest pace is really 18-5 miles a second ; the 

 least about one mile per second less. 



That is one motion of the earth ; the other is its motion on its axis. 



