356 PHYSICAL SCIENCE IN THE MIDDLE AGES. 



sipated at once by the application of the maxim 

 above stated. What analysis of theirs tended 

 to establish any received principle of chemistry? 

 What true doctrine concerning the differences and 

 affinities of acids and alkalis did they teach ? We 

 need not wonder if Gibbon, whose views of the 

 boundaries of scientific chemistry were probably 

 very wide and indistinct, could include the arts of 

 the Arabians within its domain; but they cannot 

 pass the frontier of science if philosophically defined, 

 and steadily guarded. 



The judgment which we are thus led to form 

 respecting the chemical knowledge of the middle 

 ages, and of the Arabians in particular, may serve 

 to measure the condition of science in other depart- 

 ments; for chemistry has justly been considered 

 one of their strongest points. In botany, anatomy, 

 zoology, optics, acoustics, we have still the same 

 observation to make, that the steps in science 

 which, in the order of progress, next followed what 

 the Greeks had done, were left for the Europeans 

 of the sixteenth and seventeenth centuries. The 

 merits and advances of the Arabian philosophers in 

 astronomy and pure mathematics, we have already 

 described. 



3. Experimental Philosophy of the Arabians. 

 The estimate to which we have thus been led, of 

 the scientific merits of the learned men of the 

 middle ages, is much less exalted than that which 

 has been formed by many writers ; and, among the 



