62 LIGHT SCIENCE FOR LEISURE HOURS. 



changes we have been considering will become effec- 

 tive, the subject appears to us to have an interest apart 

 from the mere speculative consideration of the future 

 physical condition of our globe. Instead of the recur- 

 rence of ever-varying, closely-intermingled cycles of 

 fluctuation, we see, now for the first time, the evidence 

 of cosmical decay a decay which, in its slow progress, 

 may be but the preparation for renewed genesis but 

 still, a decay which, so far as the races at present sub- 

 sisting upon the earth are concerned, must be looked 

 upon as finally and completely destructive.* 



(From Chambers' s Journal, October 12, 1867.) 



ENCKE THE ASTRONOMER. 



FOUK years have passed since Encke died. Even 

 those four years have witnessed notable changes in the 

 aspect of the science lie loved so well. But we must 

 look back over more than fifty years, if we would form 

 an estimate of the position of astronomy when Encke's 

 most notable work was achieved. At Seeberge, under 

 Lindenau, Encke had been perfecting himself in the 



* In the Quarterly Journal of Science for October, 1866, a more 

 detailed but somewhat less popular account of the subject of the above 

 paper is presented. A few months earlier, a charmingly-written paper 

 on the same subject, from the pen of Mr. J. M. Wilson, of Rugby, had 

 appeared in the Eagle, a magazine written by and for members of St. 

 John's College, Cambridge. Although my paper in the Quarterly Journal 

 of Science was written quite independently of Mr. Wilson's (which, 

 however, I had read), yet it chanced that in dessribing the same mathe- 



