THE ARABS. 201 



gions of space, and the delicate tissues of anirnal and vege 

 table structures, which serve as the very substratum of life. 

 Thus the whole of the seventeenth century, whose commence- 

 ment was brilliantly signalized by the great discovery of the 

 telescope, together with the immediate results by which it was 

 attended — from Galileo's observation of Jupiter's satellites, 

 of the crescentic form of the disk of Venus, and the spots on 

 the sun, to the theory of gravitation discovered by Newton — 

 ranks as the most important epoch of a newly-created physical 

 astronomy. This period constitutes, therefore, from the unity 

 of the efforts made toward the observation of the heavenly 

 bodies, and in mathematical investigations, a sharply-defin- 

 ed section in the great process of intellectual development, 

 which, since then, has been characterized by an uninterrupt- 

 ed progress. 



In more recent times, the difficulty of signalizing separate 

 momenta increases in proportion as human activity becomes 

 more variously directed, and as the new order of social and 

 political relations binds all the various branches of science in 

 one closer bond of union. In some few sciences, whose devel- 

 opment has been considered in the history of the physical con- 

 templation of the universe, as, for instance, in chemistry and 

 descriptive botany, individual periods may be instanced, even 

 in the most recent time, in which great advancement has been 

 rapidly made, or new views suddenly opened ; but, in the his- 

 tory of the contemplation of the universe, which, from its very 

 nature, must be limited to the consideration of those facts re- 

 garding separate branches of science which most directly relate 

 to the extension of the idea of the Cosmos considered as one 

 natural whole, the connection of definite epochs becomes im- 

 practicable, since that which we have named the process of 

 intellectual development presupposes an uninterrupted simul- 

 taneous advance in all spheres of cosmical knowledge. At 

 this important point of separation between the downfall of the 

 universal dominion of the Romans and the introduction of a 

 new and foreign element of civilization by means of the first 

 direct contact of our continent with the land of the tropics, it 

 appears desirable that we should throw a general glance over 

 the path on which we arc about to enter. 



The Arabs, a people of Semitic origin, partially dispelled 

 the barbarism which had shrouded Europe lor upward of two 

 hundred years after the storms by which it had been shaken, 

 from the aggressions of hostile nations. The Arabs lead ua 

 back to the imperishable sources of Greek philosophy ; and 



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