INVASION OF THE ARABS. INTEL1 ECTUAL APTITUDE Of 



THIS BRANCH OF THE SEMITIC RACES. INFLUENCE 



OF FOREIGN ELEMENTS ON THE DEVELOPMENT OP 



EUROPEAN CULTURE. THE INDIVIDUALITY OF THE 



NATIONAL CHARACTER OF THE ARABS. TENDENCY TO 



A COMMUNION WITH NATURE AND PHYSICAL FORCES. 

 MEDICINE AND CHEMISTRY. EXTENSION OF PHY- 

 SICAL GEOGRAPHY. ASTRONOMY AND MATHEMATICAL 



SCIENCES IN THE INTERIOR OF CONTINENTS. 



IN the preceding sketch of the history of the physical contem- 

 plation of the universe we have already considered four 

 principal momenta in the gradual development of the recog- 

 nition of the unity of nature, viz. : 



1 . The attempts made to penetrate from the basin of the 

 Mediterranean, eastward, to the Euxine and Phasi's; south- 

 ward, to Ophir and the tropical gold-lands; and westward, 

 through the Pillars of Hercules, into the " all encircling 

 ocean." 



2. The Macedonian campaign, under Alexander the Great. 



3. The age of the Ptolemies. 



4. The universal dominion of the Romans. 



We now, therefore, proceed to consider the important 

 influence exercised on the general advancement of the 

 physical and mathematical sciences, first, by the admixture 

 of the foreign elements of Arabian culture with European 

 sivilisation, and, six or seven centuries later, by the mari- 

 time discoveries of the Portuguese and Spaniards ; and like- 

 wise their influence on the knowledge of the earth and the 

 regions of space, with respect to form and measurement, and 

 to the heterogeneous nature of matter, and the forces inherent 

 in it. The discovery and exploration of the New Continent, 

 through the range of its volcanic Cordilleras and its elevated 

 plateaux, where climates are ranged in strata, as it were, above 

 one another, and the development of vegetation within 120 

 degrees of latitude, undoubtedly indicates the period which 

 has presented, in the shortest period of time, the greatest 

 abundance of new physical observations to the human mind. 



From this period the extension of Cosmical knowledge 



