THE EARLY DAYS OF CHEMISTRY 9 



The conquest of Egypt by the Arabians in the seventh 

 century put an end for a time to the school of learning 

 of Alexandria, where citizens of all nations met and dis- 

 cussed problems of all kinds. But the spirit of the Grseco- 

 Egyptians was too strong even for the fanaticism of the 

 Arabians ; the conquered became the conqueror ; and an 

 Arabian school of philosophy arose, which carried on the 

 traditions acquired from the Greeks. It has been be- 

 lieved, until M. Berthelot showed the belief to be erro- 

 neous, that Latin works which professed to be translations 

 from the Arabic of the eighth and succeeding centuries 

 were really renderings of the ancient Arabian authors. 

 It appears, however, that they are for the most part 

 forgeries, having little if any resemblance to the originals. 

 Thus Geber, said to have been translated into Latin in 

 1529, is entirely different from the Arabic writings of the 

 real Geber. The historical Geber lived in the ninth cen- 

 tury. His comment on alchemy is characterised by 

 strong common sense. It is : 'I saw that persons em- 

 ployed in attempts to fabricate gold and silver were 

 working in ignorance, and by false methods ; I then per- 

 ceived that they belonged to two classes, the dupers and 

 the duped. I pitied both of them.' 



About this time, however, an addition to Aristotle's 

 classification of elements was made ; and it endured until 

 within the last two hundred years. It evidently arose 

 from attempts to account for the properties of the metals, 

 and the changes which they undergo by heat. These 

 additional 'principles,' as they were termed, were salt, 

 sulphur, and mercury. We read that the noble metals 

 contain 'a very pure mercury/ the meaning being, pro- 

 bably, that they possess a high metallic lustre ; while the 

 common metals, such as copper and iron, contain ' a base 

 sulphur,' implying that these metals are easily altered by 

 fire, losing their metallic appearance and changing into 



