YET A YEAR LATER. JJ 



these bodies assume particular positions ; but that he 

 would also like to know a little about the causes of 

 their becoming so placed, as well as of the laws accord- 

 ing to which the sequence of such events is deter- 

 mined. 



We are thus led to a mode of considering the 

 subject which is very generally useful in the study of 

 astronomy. I cannot, indeed, too earnestly recommend 

 the student of the science to employ this method at 

 every opportunity. It consists in imagining oneself 

 pfaced at some suitable standpoint whence all the 

 movements of such and such celestial bodies may be 

 watched. 



In this case, the proper standpoint is the sun 

 himself, and the bodies to be watched in imagination 

 are the earth and moon. The student must picture to 

 himself this earth on which we live, as a small globe 

 circling around his standpoint once in a year. He 

 must conceive this globe as no larger in appearance 

 than any one of the planets as seen from the earth. 

 He would, indeed, require a good telescope to see the 

 earth (from his place on the sun) actually as a globe. 

 Now let him further conceive that around this small 

 globe a much smaller orb is circling once in rather 

 more than four weeks ; but that the direction in which 

 he looks at the circular path of the smaller orb is 

 always such that this orb seems to travel backwards 

 and forwards across or close past the larger one. To 

 show exactly how long this path would look as seen 

 from the sun, as well as to illustrate other points of 



