6 COSMOS. 



procal molecular attraction as a cause of unceasing motion on 

 the surface, and very probably also in the interior of the 

 earth's body, exerts upon the attraction of gravitation, by 

 which the planets as well as their central body are main- 

 tained in constant motion. Even the partial solution of this 

 purely physical problem would yield the highest and most 

 splendid results that can be attained in these paths of inquiry, 

 by the aid of experimental and intellectual research. I pur- 

 posely abstain in these sentences from associating (as is qom- 

 monly done) the name of Newton with that law of attraction, 

 which rules the celestial bodies in space at boundless dis- 

 tances, and which is inversely as the square of the distance. 

 Such an association implies almost an injustice towards the 

 memory of this great man, who had recognised both these 

 manifestations of force, although he did not separate them 

 with sufficient distinctness, for we find as if in the felicitous 

 presentiment of future discoveries that he attempted in the 

 Queries to his Optics to refer capillarity and the little that 

 was then known of chemical affinity to universal gravita- 

 tion (Laplace, Expos, du Syst. du Monde, p. 384. Cosmos, 

 vol. iii, p. 23). 



As in the physical world, more especially on the borders 

 of the sea, delusive images often appear which seem for a 

 time to promise to the expectant discoverer the possession of 

 some new and unknown land ; so, on the ideal horizon of the 

 remotest regions of the world of thought, the earnest inves- 

 tigator is often cheered by many sanguine hopes, which 

 vanish almost as quickly as they have been formed. Some 

 of the splendid discoveries of modern times have undoubtedly 

 been of a nature to heighten this expectation. Among these 

 we may instance contact-electricity magnetism of rotation, 

 which may even be excited by fluids, either in their aqueous 

 form or consolidated into ice the felicitous attempt of con- 

 sidering all chemical affinity as the consequence of the elec- 

 trical relations of atoms with a predominating poiar force 

 the theory of isomorphous substances in its application to the 

 formation of crystals many phenomena of the electrical 

 condition of living muscular fibre and lastly, the knowledge 

 which we have obtained of the influence exerted by the sun's 

 position, that is to say, the thermic force of the solar rays, 

 upon the greater or lesser magnetic capacity and conducting 



