THE ALCHEMICAL STUDIES OF SCOT 73 



tradition which pronounced the transmutation of 

 metals possible. The unwearied but still unavailing 

 experiments which had now been carried on through 

 several ages, produced at last their inevitable effect 

 in the shape of philosophic doubt, eagerly urged on 

 the one part and as eagerly repelled on the other. 

 The chemical school was now divided according to 

 these opposite opinions, and each party in their 

 writings sought to give weight to what they taught 

 by borrowing in support of their arguments the 

 names of the mighty dead. In this conflict it was 

 left to the followers of Kases to sustain the affirma- 

 tive and to assert the possibility of transmutation. 

 These were the apologists for the past, and the 

 advocates, in the name of their great master, of 

 that hope which had inspired previous research and 

 borne fruit in so many important discoveries. 



The defence of the new doubt belonged on the 

 other hand to the school of Al Kindi. This chemist 

 lived and died during the ninth century. He was 

 probably the earliest Arabian commentator on 

 Aristotle, and seems to have paid special attention 

 to the Meteora of that author. The treatise De 

 Mineralibus, so often appended to the Meteora as 

 a supplement, is ascribed to Al Kindi in the Paris 

 manuscript.^ It represents the alchemy of the 

 time. 



Between these two contendiug parties stood the 

 school of Avicenna, which now occupied an inter- 

 mediate position and doubted of the doubt. That 

 this had not always been the opinion of Avicenna 

 himself is plain, however, from a passage which 

 occurs in his Sermo de generatione lapidum, where 



1 6514. 



