u6 THE POPULAR SCIENCE MONTHLY. 



in a few lines an experiment performed by order of Caligula for 

 fabricating gold with sulphuret of arsenic (or orpiment). There 

 was thus a whole special chemistry, now abandoned, which was 

 conspicuous in the practices and pretensions of the alchemists. 

 A patent has been obtained in our own times for an alloy of cop- 

 per and antimony, containing six hundredths of the latter metal, 

 which presents most of the apparent properties of gold and is 

 worked in the same manner. Alchemic gold belonged to a family 

 of similar alloys. Those who made it fancied besides that some 

 agents played the part of ferments to multiply gold and silver. 

 Before deceiving other people they deluded themselves. Some- 

 times the artisan was satisfied to use a cement or superficial 

 action, painting the surface of silver in gold or the surface of 

 copper in silver, without modifying the metals in their thickness. 

 This is what goldsmiths still call giving color. They would even 

 do no more^than apply to the surface of the metal a gold-colored 

 varnish, prepared with the bile of animals or with certain resins, 

 as is still done. From these colorings the operator, led by a 

 mystic analogy, passed to the idea of transmutation, in the false 

 Democritus and in the Key to Painting. The author of the last 

 work concluded, for example, with the words, " You will thus ob- 

 tain excellent gold and fit for the test." The author added, fur- 

 ther, " Hide this sacred secret, which should be delivered to no 

 one, nor to any prophet." The word prophet betrays the Egyp- 

 tian origin of the recipe. It refers to the Egyptian priests, who, 

 according to a passage in Clement of Alexandria on the Hermetic 

 books that were borne with great pomp in the processions, were 

 called prophets. 



In further proof of the Greco-Egyptain origin of goldsmiths' 

 recipes contained in the Key to Painting is the existence in the 

 Latin collection of ten recipes some of the elaborate ones which 

 are phrased in precisely the same terms in the Greek papyrus 

 in Leyden ; the former text being translated from the latter, even 

 to the detail of certain technical expressions, which are still per- 

 petuated in the goldsmiths' manuals of the present. This does not 

 mean that the text transcribed in the Key to Painting was origi- 

 nally translated from the very papyrus that we possess, which 

 was not found till the nineteenth century at Thebes, Egypt ; but 

 the coincidence of the text proves that there existed books of 

 secret goldsmiths' recipes transmitted from hand to hand of the 

 tradesmen, which continued through the middle ages, and of 

 which the Key is an example. It was firmly believed in the time 

 of Diocletian that the Egyptians had the secret of enriching them- 

 selves by making gold and silver; and in consequence of this 

 belief, after a revolt, the emperor ordered all their books burned. 

 Nevertheless, as we have seen, the formulas did not disappear. 



