PHYSICAL CONTEMPLATION OF THE UNIVERSE. 113 



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

 mometer ; hyirrometric and electrometric apparatuses ; and 

 the polariscope, in its application to the phenomena of colored 

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

 of the atmosphere. 



The liistory of the pliysieal eontemplation of tho univer>e. 

 which is based, as \ve have already remarked, on a meditative 

 consideration of natural phenomena, on the connection of Tcat 

 events, and on inventions which enlarge the domain ot' sen>- 

 nons pereeption, can only IK- presented in a fragmentary and 

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

 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 limits it is 

 so dulicult to define. Here, as in the picture of nature \\ Inch 

 i> given in the tbnuer part of this work, it will bo my object 

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

 uali/ing enumeration, but merely by the development of lead- 

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

 sued by the physicist in his historical investigations. The 

 knowledge of the connection of events and their causal rela 

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

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

 termine the influence which they have exercised on the i_ r rad- 

 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 proent work its pe- 

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

 animadversions of those who think less of what a book contains 

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

 to be tbund in it. 1 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 

 le>s copious, the difficulty of a proper combination is increased, 

 and the opinions advanced then require to be supported by tho 

 testimony of tacts le>s generally known. 1 would also observe 

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

 quality, where the enumeration of individual facts ailorded the 

 advantage of imparting greater interest to the narrative. 



lion of the unity of the Cosmos began in an 

 intuitive presentiment, and with merely a tew actual ob.-.-rva- 

 tions on isolated portions of the domain of nature, it .M.VIUS in- 



