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conception of the progress that chymistry had made 

 among the Egyptians, though their history affords a 

 thousand others of the kind, not to be wondered at 

 among a people so very active and industrious,where 

 even the lame, the blind, and the maimed, were in 

 constant employment, and so little subject to envy, 

 that they inscribed their discoveries in the arts and 

 sciences, upon pillars reared in holy places, in order 

 to omit nothing that might contribute to the public 

 utility. The Emperor Adrian attests this first part 

 of their character, in a letter written to the Consul 

 Servianus, upon presenting him with three very curious 

 cups of glass, which like a pigeon's neck, reflected 

 en whatever side they were viewed, a variety of co- 

 lours, representing those of the precious stone called 

 obsidian nm, which some commentators have ima- 

 gined to be the cat's-eye, and others the opal. 



6. This art of imitating precious stones, was not 

 peculiar to the Egyptians; the Greeks, who indeed 

 derived their knowledge from those great masters, 

 were also very skilful in this branch of chymistry. 

 They could give to a composition of chrystal, ail 

 the different tints of any precious stone they want- 

 ed to imitate. Pliny, Theophrastus, and many others, 

 give instances of this, but they most remarkably ex- 

 celled in an exact imitation of the ruby, the hya- 

 cinth, the emerald, and the sapphire. 



7. Chymistry being a principal branch of medi- 

 cine, it will not be amiss to mention some particulars 

 wherein the Egyptians have contributed to the per- 

 fection of that science. I set aside the history of 

 Esculapius, who was instructed by Mercury orllermes. 

 Their pharmacy depended much upon chymistry ; 

 witness their manner of extracting oil, and preparing 

 opium, for alleviating of acute pains, or relieving the 

 mind from melancholy thoughts. Homer seems to 

 have had this last in view, when he introduces llelou 



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