OP CHEMISTRY. 5 



have it, filed into a line dust, and thrown into the rirer, of which 

 (Tie children of Israel used to drink : part of the gold would re. 

 main, notwithstanding its greater specific gravity, suspended for a 

 time (as happens in the washingof copper and lead ores), and might 

 be swallowed in drinking the water ; the rest would sink to the bot- 

 tom, or be carried away by the flux of the stream. 



Nevertheless, though nothing satisfactory can be concluded con. 

 cerning the Egyptian chemistry, from what is said of Moses in this 

 instance; yet the structure of the ark, and the fashion of Aaron's 

 garments, clearly indicate to us that the arts of manufacturing me. 

 tals, of dying leather red, and linen blue, purple, and scarlet ; of 

 distinguishing precious stones, and engraving upon them, were at 

 that time practised in a very eminent degree*. The Israelites had 

 unquestionably learned these arts in Egypt, and there is great rea. 

 son to suppose, not only that learning of every kind first flourished 

 in Egypt, but that chemistry in particular, was much cultivated in 

 that country, when other sciences had passed into other parts of 

 the world. Pliny, in speaking of the four periods of learning 

 which had preceded the times in which he lived, reckons the Egyp, 

 tian the first: and Suidas, who is thought to hare lived in the tenth 

 century, informs us, that the Emperor Diocletian ordered all the 

 books of chemistry to be burned, lest the Egyptians learning from 

 them the art of preparing gold and silver, should thence derive re. 

 sources to oppose the Romans. It is worthy of notice, that 

 Suidas uses the word chemistry in a very restricted sense, when he 

 interprets it by the preparation of gold and silver; but all the 

 chemists in the time of Suidas, and for many ages before and after 

 him, were alchemists. The edict of Diocletian in the third century, 

 had little effect in repressing the ardour for that study in any part 

 of the world, since we are told, that not less than five thousand 

 books, to say nothing of manuscripts, have been published upon 

 the subject of alchemy, since his timef. 



At what particular period this branch of chemistry, respecting 

 the transmutation of the baser metals into gold, began to be dis. 

 tinguished by the name of alchemy, cannot be determined. An 

 author of the fourth century, in an astrological work, speaks 

 of the science of alchemy as well understood at that time ; and 



Exod. xxvi. and xxviii* 

 + Chem. Walleri, p. 40. 



f 



