*So Obfcrvaticns on Naples Yellozv, 



explanation. But, however this may be, it is certain that no 

 writer ever yet knew properly what the nature of this 

 paint really is. Mod of them have confidered it as origi- 

 nating from fire, and as a volcanic production of Mount Ve- 

 fuvius or Mount /Etna * ; others have pronounced it to be a 

 natural ochre f. Guettard thought it rather a kind of bole J '■> 

 but Pott approached neareft the truth, by afferting it to be 

 an artificial preparation §. Fougeroux is entitled to the me- 

 rit of having proved this, and of having ihewn the poffibi- 

 lity of preparing it. According to his experiments, Naples 

 yellow will be obtained, ii you boil for feven or eight hours, 

 firft over a flow and then over a ftrong fire, a mixture finely 

 pulverifed of twelve parts of pure white lead, one part of 

 alum, one part offal ammoniac, and three parts of diapho- 

 retic antimony || {white oxyd of antimony by nitre). But 

 before Fougeroux, who may have obtained an account of the 

 procefs during his Travels through Italy, a more certain 

 procefs was publiflied in the year 1758, by Giambattifta 

 PalTeri, in his interefting work on the painting of earthen- 

 ware^. The articles to be employed, according to this au- 

 thor, are, " one pound of antimony, a pound and a half of 

 lead, one ounce of allume di Jeccia, and the fame quantity 



.* Amon^ thefe are Pomct, two writers in ihe firft edition of the Ency- 

 clopedic, Montamy in Abbandlung von den Vaiben xum Porze/lan, Leip- 

 zig. 1 7 ^ 7 > 8 v Oj p 266, and the editor of Didiennuire port at if de peinture, 

 fculptureetgravure, 1757, p. 363. 



t For example, Hill in his lltfiory of Foffils, vol. i. p. 55, 66. Gadd 

 a'fo in Inledning til Stcn-Rikets Kacnning. Abo, 1787, 8vo, p. 49, mentions 

 Naples yellow among the calcareous earths mixed with metallic calces. 



+ In Memoir? fur lei ocres, to be found in the Memoirs of the Academy 

 of Sciences for the year 1762. 



§ Lithogcognofie. II. p. 15. 



|| In the Memoirs of the Academy of Sciences for the year 1766. p. 303. 



% This paper may be found in Nuova rarcolta if opufcoli fcientifiei . t. iv. 

 t^R. p. 103. Jl giallolino, ocolor d'oro, fi fa con una libra di antimonio, 

 una e mezza di piombo, cd un'oncia d'allume di feccia. ed un'altra di lal 

 commune. 



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