INTRODUCTION. 37 



among the most savage nations (as my own travels enable me 

 to attest) a certain vague, terror-stricken sense of the all-pow- 

 erful unity of natural forces, and of the existence of an invisi- 

 ble, spiritual essence manifested in these forces, whether in 

 unfolding the flower and maturing the fruit of the nutrient 

 tree, in upheaving the soil of the forest, or in rending the clouds 

 with the might of the storm. We may here trace the revela- 

 tion of a bond of union, linking together the visible world and 

 that higher spiritual world which escapes the grasp of the 

 senses. The two become unconsciously blended together, de- 

 veloping in the mind of man, as a simple product of ideal con- 

 ception, and independently of the aid of observation, the first 

 germ of a Fhiloioiohy of Nature. 



Among nations least advanced in civilization, the imagina- 

 tion revels in strange and fantastic creations, and, by its pre- 

 dilection for symbols, alike influences ideas and language. In- 

 stead of examining, men are led to conjecture, dogmatize, and 

 interpret supposed facts that have never been observed. The 

 inner world of thought and of feelins: does not reflect the imajje 

 of the external world in its primitive purity. That which in 

 some regions of the earth manifested itself as the rudiments 

 of natural philosophy, only to a small number of persons en- 

 dowed with superior inteUigence, appears in other regions, and 

 among entire races of men, to be the result of mystic tenden- 

 cies and instinctive intuitions. An intimate communion with 

 nature, and the vivid and deep emotions thus awakened, are 

 likewise the source from which have sprung the first impulses 

 toward the worship and deification of the destroying and pre- 

 serving forces of the universe. But by degrees, as man, after 

 having passed through the different gradations of intellectual 

 development, arrives at the free enjo}rment of the regulating 

 power of reflection, and learns by gradual progress, as it were, 

 to separate the world of ideas from that of sensations, he no 

 longer rests satisfied merely with a vague presentiment of the 

 harmonious unity of natural forces ; thought begins to fulfill 

 its noble mission ; and observation, aided by reason, endeav- 

 ors to trace phenomena to the causes from which they spring 



The history of science teaches us the difficulties that have 

 opposed the progress of this active spirit of inquiry. Inaccu 

 rate and imperfect observations have led, by false inductions, 

 to the great number of physical views that have been perpet- 

 uated as popular prejudices among all classes of society. Thus 

 by the side of a solid and scientific knowledge of natural phe- 

 nomena there has been preserved a system of the pretended 



