SUMMARY. 



Vols. III. and IV. 



GENERAL SUMMARY OF THE CONTENTS. 



Special Results of Observation in the Domain of Cosmical Phenomena.- 



Introduction. 



Retrospect of the subject. Nature considered under a two-fold as 

 pect : in the pure objectivity of external phenomena, and in their inner 

 reflection in the mind. A significant classification of phenomena leads 

 of itself to their casual connection. Completeness in the enumeration 

 of details is not intended, at least in the representation of the reflected 

 picture of nature under the influence of the creative power of imagina- 

 tion. Besides an actual or external woi'ld, there is produced an ideal 

 or an inner world ; filled with physical symbolic myths, different ac- 

 cording to race and climate, bequeathed for centuries to subsequent 

 generations, and clouding a clear view of nature. Fundamental im- 

 perfectibility of the knowledge of cosmical phenomena. The discovery 

 of empirical laws, the insight into the causal connection of phenomena, 

 description of the universe, and theory of the universe. How, by means 

 of existing things, a small part of their genetic history is laid open. Dif- 

 ferent phases of the theory of the universe, attempts to comprehend the 

 order of nature. Most ancient fundamental conception of the Hellenic 

 mind: physiologic phantasies of the Ionian school, germs of the scien- 

 tific contemplation of nature. Double direction of the explanation of 

 natural phenomena, by the assumption of material principles (elements), 

 and by processes of rarefaction and condensation. Centrifugal revolu- 

 tion. Theories of vortices. The Pythagoreans ; philosophy of meas- 

 ure and harmony, commencement of a mathematical treatment of phys- 

 ical phenomena. The order and government of the universe according 

 to the physical works of Aristotle. The communication of motion con- 

 sidered as the cause of all phenomena ; the tendency of the Aristotelean 

 school but little directed to the opinion of the heterogeneity of matter. 

 This species of natural philosophy bequeathed in fundamental ideas 

 and form to the Middle Ages. Roger Bacon, the Mirror of Nature of 

 Vincentz of Beauvais, Liber Cosmographicus of Albertus Magnus, Imago 

 Mundi of the Cardinal Pierre d'Ailly. Progress through Giordano Bru- 

 no and Telesio. Clearness in the conceptions of gravitation as mass at- 

 traction, by Copernicus. First attempt at a mathematical application 

 of the doctrine of gravitation, by Kepler. The work on the Cosmos by 

 Descartes (Traits du Monde) nobly undertaken, did not appear until 

 long after his death, and only in fragments; the Cosmotheoros of Huy- 

 gens, unworthy of the great name. Newton, and his work Philosophic 

 Naturalis Principia Mathematica. Endeavor toward a knowledge of 

 the universe as a Whole. Is the problem solvable of tracing back to 

 one principle all physical knowledge, from the law of gravitation to the 



