738 



RETROSPECT OF THE EPOCHS THAT HATE BEEN SUC- 



SESSIVELY CONSIDERED. INFLUENCE OF EXTERNAL 



OCCURRENCES ON THE DEVELOPMENT OF THE RECOG- 

 NITION OF THE UNIVERSE AS ONE WHOLE. MULTI- 

 PLICITY AND INTIMATE CONNECTION OF THE SCIEN- 

 TIFIC EFFORTS OF RECENT TIMES. THE HISTORY OF 



THE PHYSICAL SCIENCES BECOMES GRADUALLY ASSO- 

 CIATED WITH THE HISTORY OF THE COSMOS. 



I APPROACH the termination of my bold and difficult under- 

 taking. Upwards of two thousand years have been passed in 

 review before us, from the early stages of civilisation amongst 

 the nations \vho dwelt around the basin of the Mediterranean 

 and the fruitful river valleys of Western Asia, to the begin- 

 ning of the last century, to a period, therefore, at which 

 general views and feelings were already beginning to blend 

 with those of our own age. I have endeavoured, in seven 

 sharply- defined sections, forming, as it were, a series of as 

 many separate pictures, to present a history of the physical 

 contemplation of the universe, or in other words, the history 

 of the gradual development of the knowledge of the universe 

 as a w r hole. To what extent success may have attended the 

 attempt to apprehend the mass of accumulated matter, to 

 seize on the character of the principal epochs, and to indicate 

 the paths on which ideas and civilisation have been advanced, 

 cannot be determined by him, who with a just mistrust of 

 his remaining powers, is alone conscious that the image of so 

 great an undertaking has been present to his mind in clear 

 though general outlines. 



At the commencement of our consideration of the period of 

 the Arabs, and in beginning to describe the powerful influ- 

 ence exercised by the admixture of a foreign element in 

 European civilisation, I indicated the limits beyond which 

 the history of the Cosmos coincides with that of the physical 

 sciences. According to my idea, the historical recognition of 

 the gradual extension of natural science in the tw r o spheres of 

 terrestrial and celestial knowledge (geography and astro- 

 nomy), is associated with certain periods and certain active 



