INTRODrCTION. 53 



whether comets transmit light directly or merely by reflec- 

 tion.* 



An equal appreciation of all branches of the mathematical, 

 physical, and natural sciences is a special requirement of the 

 present age, in A\hich the material wealth and the growing 

 prosperity of nations are principally based upon a more en* 

 lightened employment of the products and forces of nature. 

 The most superficial glance at the present condition of Europe 

 shows that a diminution, or even a total annihilation of na- 

 tional prosperity, must be the award cf those states who shrink 

 with slothful indifierence from the great struggle of rival na- 

 tions in the career of the industrial arts. It is with nations 

 as with nature, which, according to a happy expression of 

 Gothe,t " knows no pause in progress and development, and 

 attaches her curse on all inaction." The propagation of an 

 earnest and sound knowledge of science can therefore alone 

 avert the dangers of which I have spoken. Man can not act 

 upon nature, or appropriate her forces to his own use, without 

 comprehending their full extent, and having an intimate ac' 

 quaintance with the laws of the physical world. Bacon has 

 said that, in human societies, knowledge is power. Both must 

 rise and sink together. But the knowledge that results from 

 the free action of thought is at once the delight and the in- 

 destructible prerogative of man ; and in forming part of the 

 wealth of mankind, it not unfrequently serves as a substitute 

 for the natural riches, which are but sparingly scattered ovei 

 the earth. Those states which take no active part in the 

 general industrial movement, in the choice and preparation of 

 natural substances, or in the application of mechanics and 

 chemistry, and among whom this activity is not appreciated 

 by all classes of society, will infallibly see their prosperity di 

 minisli in proportion as neighboring countries become strength- 

 ened and invio-orated under the jrenial influence of arts and 

 sciences. 



As in nobler spheres of thought and sentiment, in philosophy, 

 poetry, and the fine arts, the object at which we aim ought to 

 be an inward one — an ennoblement of the intellect — so ought 

 we likewise, in our pursuit of science, to strive after a knowl- 

 edge of the laws and the principles of unity that pervade the 

 vital forces of the universe ; and it is by such a course that 



* Arago's Discoveries in the year 1811. — Dclambro's Histoire de 

 VA»i., p. 652. (Passage already quoted.) 



t Gotlie, ill Die Aphonsmcn uber Naturwissens€haft.—-Wcr'ke, bJ I. 

 8. 4 



