PHYSICAL CONTEMPLATION OF THE UNIVERSE. 1 1 H 



pendulum as a measure of time ; the barometer ; the ther- 

 mometer ; hygrometric and electrometric apparatuses ; and 

 the polariscope, in its appUcation to the phenomena of colored 

 polarization, in the light of the stars, or in luminous regions 

 of the atmosphere. 



The history of the physical contemplation of the universe, 

 which is based, as we have already remarked, on a meditative 

 consideration of natural phenomena, on the connection of great 

 events, and on inventions which enlarge the domain of sens- 

 uous perception, can only be presented in a fragmentary and 

 superficial manner, and only in its leading features. I flatter 

 myself with the hope that the brevity of this mode of treat- 

 ment will enable the reader the more readily to apprehend the 

 spirit in which a picture should be sketched, whose Hmits it is 

 so difficult to define. Here, as in the picture of nature which 

 is given in the former part of this work, it will be my object 

 to treat the subject, not with the completeness of an individ- 

 ualizing enumeration, but merely by the dev^elopment of lead- 

 ing ideas, that indicate some of the paths which must be pur- 

 sued by the physicist in his historical investigations. The 

 knowledofe of the connection of events and their causal rela 

 tions is assumed to be possessed by the reader, and it will con- 

 sequently be sufficient merely to indicate these events, and de- 

 termine the influence which they have exercised on the grad- 

 ual increase of the knowledge of nature as a whole. Com- 

 pleteness, I must again repeat, is neither to be attained, nor 

 is it to be regarded as the object of such an undertaking. In 

 the announcement of the mode in which I propose treating 

 my subject, in order to preserve for the present work its pe- 

 culiar character, I shall, no doubt, expose myself again to the 

 animadversions of those who think less of what a book contains 

 than of that which, according to their individual views, ought 

 to be found in it. I have purposely been much more circum- 

 stantial with reference to the more ancient than the modern 

 portions of history. Where the sources of information are 

 less copious, the difficulty of a proper combination is increased, 

 and the opinions advanced then require to be supported by the 

 testimony of facts less generally known. I would also observe 

 that I have permitted myself to treat my subject with ine- 

 quality, where the enumeration of individual facts afforded the 

 advantage of imparting greater interest to the narrative. 



As the recognition of the unity of the Cosmos began in an 

 intuitive presentiment, and with merely a few actual observa- 

 tions on isolated portions of the domain of nature, it seems in- 



