Masterpieces of Science 



sented by the sun's mysterious corona if, in- 

 deed, some new mode of observation does not 

 soon remove the restrictions which now confine 

 our observations to such rare and precarious 

 opportunities. 



Turning to the planetary system, we see a 

 wide field for the increase of our knowledge, and 

 an encouraging probability of progress, both 

 through the patient use of our present means 

 of investigation, and still more by the aid of the 

 expected improvements in instruments and 

 methods. 



Mere persistence in the old ways is certain to 

 give us ultimately a much exacter knowledge of 

 the dimensions and motions of the system, and 

 may very likely be able to throw light upon cer- 

 tain perplexing problems presented by some 

 slight apparent anomalies which as yet seem to 

 be inexplicable on the existing theories of gravi- 

 tation. Possibly the power of the new mathe- 

 matics may show them to be merely apparent 

 and perfectly reconcilable with that theory (as 

 has often before happened in similar cases) ; but 

 it may well be, and in fact is rather likely, that our 

 "law of gravitation," as at present formulated 

 is only an approximation to a complete and 

 perfect statement an approximation so near 

 the truth, indeed, that its representation of the 

 facts is about as exact as our present means of 

 observation and computation. When anomal- 

 ies crop out, we are as yet doubtful whether to 



