21 



of the progress of knowledge, that as the field acquires 

 additional extension, the horizon by which it is bounded 

 incessantly recedes before the eyes of the enquirer. Each 

 step that we make in the more intimate knowledge of 

 science leads us to the threshold of new labyrinths. 

 Nature, as it has been defined, and as the word was inter- 

 preted by the Greeks and Romans, is 'Hhat which is ever 

 growing and ever unfolding itself in new forms." The 

 domain of reality thus progressively extending through 

 the perfection of knowledge, is perpetually berdered by a 

 half-transparent, vapor-veiled realm of fancy; a fairy- 

 land where imagination revels and lends a definite out- 

 line to the ever-unfolding manifestations of ideal creation. 

 Thus it is, that every accession to science enriches the 

 fields of fancy, and animates the imaginative faculties 

 by bringing new mysteries within their sphere, and open- 

 ing to them higher and more soul-elevating sources of 

 enjoyment. 



There is no danger that the domains of imagination 

 will ever be obliterated by the progress of exact know- 

 ledge. We shall never succeed in exhausting the im- 

 measurable riches of Nature ; and no generation of men 

 will ever have cause to boast of having comprehended 

 the total aggregation of physical phenomena. In science, 

 as in life, every man, strong or weak, carries his burden 

 but a little way, and then gives place to a younger, who 

 seizes the load joyfully, thinking in his pride, that it is 

 for him to bear it to the end of the journey. But after 

 a short space he is also superseded, for the distance of 

 the goal is infinite ; and when we have all passed away 

 Nature will still be inexhaustible. 



Experimental sciences, based on the observation of the 



