AND DISTANCEFROM THE EARTH 



US, and then as we move on the same trees appear to come 

 together again from behind. Whichever way w^e turn our 

 steps the same effects are invariably observed among the 

 trees. So too with all other objects as we approach and 

 recede from them. The same effect has often been 

 strikingly exemplified in our own experience at sea by 

 night. In making port two harbour lights are usually 

 placed on the pier. At a considerable distance out these 

 lights have apparently almost touched one another, but as 

 the good ship ploughed her way through the deep and came 

 nearer shore, the welcome beams spread further and 

 further apart until they appeared at last on our port and 

 starboard sides. Then, as the vessel proceeded up the 

 harbour, the same lights appeared to gradually close up 

 again. 



In order to determine the course of the sun's voyage 

 through space, it will now be apparent that no evidence of 

 this motion cau ever be obtained b}^ observations of the 

 sun itself, nor, in fact, of any movement of the earth, 

 moon or planets, as tliey all travel together in a body. It 

 is only by endeavoring to find out if any such effect as we 

 noticed in the forest or on sea is observable when we look 

 right out into space at the far off stars, which do not 

 partake of any motion attributable to our sun, that we 

 can ever hope to find the secret of our destination, or what, 

 in technical language, is known as the "apex." of the 

 sun's wa3^ 



It was the genius of Sir Wm. Herschel. which first 

 applied this reasoning to determine the point. By classify- 

 ing the proper motion of all the stars as known to him in 

 1783, he found conclusive evidence of the direction of the 

 sun's path as well as its velocity. The principle involved 

 is thus defined by Prof. Young : " On the v/hole, the 

 stars appear to drift bodily in a direction opposite to the 

 sun's real motion. Those in that quarter of the sky which 

 we are approaching open out from each other, and those 



