108 COSMOS. 



either vague, or blended with the most Tinfounaed h}TDotheses, 

 has, at a subsequent epoch, been confirmed by sure experience, 

 and then been recognized as a scientific truth I The preseii- 

 tient fancy and the vivid activity of spirit which animated 

 Plato, Columbus, and Kepler, must not be disregarded, as if 

 they had effected nothing in the domain of science, or as if 

 they tended, of necessity, to draw the mind from the investi- 

 gation of the actual. 



As we have defined the history of the physical contempla- 

 tion of the universe to be the history of the recognition of 

 nature in the unity of its phenomena, and of the connection 

 of the forces of the universe, our mode of proceeding must 

 consist in the enumeration of those subjects by which the idea 

 of the unity of the phenomena has been gradually developed. 

 We would here distinguish : 



1. The independent efforts of reason to acquire a knowledge 

 of natural laws, by a meditative consideration of the phenom- 

 ena of nature. 



2. Events in the history of the world which have suddenly 

 enlarged the horizon of observation. 



3. The discovery of new means of sensuous perception, as 

 well as the discovery of new organs by which men have been 

 brought into closer connection, both with terrestrial objects 

 and with remote regions of space. 



This three-fold view serves as a guide in defining the prin 

 cipal epochs that characterize the history of the science of the 

 Cosmos. For the purpose of further illustration, I would 

 again adduce some examples indicative of the diversity of the 

 means by which mankind attained to the intellectual posses- 

 sion of a great portion of the universe. Under this head I 

 include examples of an enlarged field of natural knowledge, 

 great historical events, and the discovery of new organs. 



The knowledge of nature, as it existed among the Hellenic 

 nations under the most ancient forms of physics, was derived 

 more from the depth of mental contemplation than from the* 

 sensuous consideration of phenomena. Thus the natural phi- 

 losophy of the Ionian physiologists was directed to the funda- 

 mental ground of origin, and to the metamorphoses of one sole 

 element, while the mathematical symbolicism of the Pythago- 

 reans, and their consideration of numbers and forms, disclose 

 a philosophy of measure and harmony. The Doric-Italian 

 school, by its constant search for numerical elements, and by 

 a certain predilection for the numerical relations of space and 

 time, laid the foundation, as it were, of the subsequent de>e/- 



