114 PLINT' 3 NATURAL HISTORY. [Book XXXIII. 



Hence it is, too, that when copper has to be gilded,^^ a coat of 

 quicksilver is laid beneath the gold leaf, which it retains in its 

 place with the greatest tenacity : in cases, however, where the 

 leaf is single, or very thin, the presence of the quicksilver is 

 detected by the paleness of the colour.^* For this reason, per- 

 sons, when meditating a piece of fraud, have been in the habit 

 of substituting glair of egg for quicksilver, and then laying 

 upon it a coat of hydrargyros, a substance of which we shall 

 make further mention in the appropriate place.-' Generally 

 speaking, quicksilver has not been found in any large quantities. 



appears from Pliny, that the ancients were acquainted with amalgam and 

 its use, not only for separating gold and silver from earthy particles, but 

 also for gilding." — Beckmann, Hist. Inv., Vol. I. p. 15. Bohns Edition. 



23 See the description of the mode of gilding, given in Chapter 20 of 

 this Book. Beckmann has the following remarks on the present passage : 

 *' That gold-leaf was affixed to metals by means. of quicksilver, with the as- 

 sistance of heat, in the time of Pliny, we are told by himself in more passages 

 than one. The metal to be gilded was prepared by salts of every kind, 

 and rubbed with pumice-stone in order to clean it thoroughly (see Cliapter 

 20), and to render the surface a little rough. This process is similar to 

 that used at present for gilding with amalgam, by means of heat, especially 

 as amalgamation was known to the ancients. But, to speak the truth, 

 Pliny says nothing of heating the metal after the gold is applied, or of 

 evaporating the quicksilver, but of drying the cleaned metal before the 

 gold is laid on. Had he not mentioned quicksilver, his gilding might 

 have been considered as that with gold leaf by means of heat, dorure en 

 feuille dfeii^ in which the gold is laid upon the metal after it has been 

 cleaned and heated, and strongly rubbed with blood-stone, or polished steel. 

 Felibien {Principes de I' Architecture. Paris, 1676, p. 280) was undoubt- 

 edly right when he regretted that the process of the ancients, the excellence 

 of which is proved by remains of antiquity, has been lost." — Hist. Inv. 

 Vol. II. pp. 294, 29-5. £okn's Edition. 



2* Beckmann finds considerable difficulties in this description — "I ac- 

 knowledge that this passage I do not fully comprehend. It seems to say 

 that the quicksilver, when the gold was laid on too thin, appeared through 

 it, but that this might be prevented by mixing with the quicksilver the 

 white of an egg. The quicksilver then remained under the gold : a thing 

 which is impossible. When the smallest drop of quicksilver falls upon 

 gilding, it corrodes the noble metal, and produces an empty spot. It is, 

 therefore, incomprehensible to me how this could be prevented by using 

 the white of an egg. Did Pliny himself completely understand gilding ." 

 Perhaps he only meant to say that many artists gave out the cold-gilding, 

 where the gold-leaf was laid on with the white of an egg, as gilding by 

 means of heat." — Hist. Inv. Vol. II. p. 295. 



25 Chapter 42 of this Book. See also Chapter 20, in Note 20, to which 

 it has been mentioned as artificial quicksilver. 



