144 0« "Encaujlic Vaintwr. 



borrowed from the Egyptians, mixed the wax with air oil tc> 

 make it pliable under the brafh ; but no maitic, alkali or 

 honey, as has been ingenioufly imagined, and which fome 

 have thought might be employed with fuccefs. The difficulty 

 now will be confined to point out in what manner this oil 

 was employed. It does not appear that they ufed thofe fat 

 oils which are commonly called drying oils; becaufe they 

 could have employed thefe as we do, without the addition of 

 wax, which in fuch a cafe would have been entirely fuper- 

 fluous. Fat oils which do not dry would not have been pro- 

 per for that purpofe, as they would have kept the wax conti- 

 nually in the ftate of a foft pomade or falve. Befides, my 

 experiments would without doubt have (hewn me the exiflence 

 of any oily matter. 



With regard to effential or volatile oils, a knowledge of 

 them is not allowed to the ancient?, as the invention of dif- 

 tilling is not older than the eighth or ninth century, and 

 therefore falls in with the period of Geber or Avicenna* 

 But Herodotus fpeaks in a very clear manner of the diftilla- 

 tion of afphaltes, which was made at Sufa ; and I, who dif- 

 tinguifh fo much chemical knowledge among the Egyptians^ 

 cannot fuppofe them ignorant of fo eafy a procefs. In the 

 temple of Vulcan at Memphis they had a fchool of chemiftry, 

 which flourrfhed there for a long time, as we arc told by 

 Zofimus PanopHtanus, Eufcbius, Sinefius, Albufaragius, &c. 

 In order to life wax in their encauftic painting, it is certain 

 that they muft have combined it with an ethereal volatile oil, 

 of which no traces fliould afterwards remain ; becaufe this 

 was required for the folidity of the work, and becaufe I 

 actually found this to be the cafe in the fragment which I 

 examined. But though they might be unacquainted with 

 the art of feparating ethereal oils from the many fubftanres 

 which they contain, they certainly were acquainted with a 

 very volatile thin oil produced by nature, and which in vari- 

 ous places ifilies from the earth, but probably not in Greece, 

 as I found reafon to conjecture from the following obferva* 



tions : 



