24 COSMOS. 



the tides, from, molecular attraction, which acts at infinitely 

 small distances and in the closest contact. 



Thus we see that among the various attempts which have been 

 made to refer whatever is unstable in the sensuous world to 

 a single fundamental principle, the theory of gravitation is the 

 most comprehensive and the richest in cosmical results. It 

 is indeed true, that notwithstanding the brilliant progress that 

 has been made in recent times in stoechiometry (the art of 

 calculating with chemical elements and in the relations of 

 volume of mixed gases) all the physical theories of matter have 

 not yet been referred to mathematically-determinable prin- 

 ciples of explanation. Empirical laws have been recognized, 

 and by means of the extensively diffused views of the atomic 

 or corpuscular philosophy, many points have been rendered 

 more accessible to mathematical investigation ; but owing to the 

 unbounded heterogeneousness of matter and the manifold con- 

 ditions of aggregation of particles, the proofs of these empirical 

 laws cannot as yet by any means be developed from the theory 

 of contact-attraction, with that certainty which characterizes 

 the establishment of Kepler's three great empirical laws derived 

 from the theory of the attraction of masses or gravitation. 



At the time, however, that Newton recognized all move- 

 ments of the cosmical bodies to be the results of one and 

 the same force, he did not, like Kant, regard gravitation as an 

 essential property of bodies ; * but considered it either as the 



40 Hactenus phenomena ccelorum et maris nostri per vim 

 gravitatis exposui, sed causam gravitatis nondum assignavi. 

 Oritur utique haec vis a causa aliqua, quaB penetrat ad usque 

 centra solis et planetarum, sine virtutis diminutione ; quaeque 

 agit non pro quantitate superficierum particularum, in quas 

 agit (ut solent causse mechanics), sed pro quantitate material 

 solida3. Rationem harum gravitatis proprietatum ex phae- 

 nomenis nondum potui deducere et hypotheses non fingo. 

 Satis esc quod gravitas revera existat et agat secundum leges 

 a nobis expositas. Newton, Principia Phil. Nat., p. 676. 



