414 Account of certain Colours dug tip at Pompeia. 



•which is of a different colour I'rom that of the red coating 

 vhich covers the surface. 



Perhaps the Romans even made use of saline fluxes to 

 fiicilitatc the baking of the coverings of their earthen-ware. 



M. d'Arcet has completely imitated the vwhite covering 

 of the Etruscan vases by employing a shining white argil, 

 with which he mixes a twenlicth part of borax. 



It should seem that the Romans were not acquainted, in 

 the first century of the Christian oera, with the metallic 

 fluxes for fixing and vitrifying the coverings of their earth- 

 en-ware: at least the analysis of the coverings of Etruscan 

 vases, and of red, white, or brown earthen -ware, gave na 

 indications of metal either to M.. d'Arcet or mystlf. It 

 was only in later periods that the sulpharets of copper and 

 of lead, as 'a.-o11 as the o.'jidc'jof this last metal, were em- 

 ployed. V/e som£tin>.;s !nJi;cd find these metallic cover- 

 ma;? on some vases that have been dug up, but their inanu- 

 factuic does not seem to me to have been postevior to the 

 sera when ihe Romans occupied Gaul : for ail those v;hich 

 I examined, and the origin of which is evidernly prior tor 

 tiiesc first periods'^ presented, no trace of copper or lead on 

 analysis. 



Sometimes the black colour alone presents characters of 

 ■vitrification. I have seen several specimens of ancient 

 earlhen-ware, in which this is indubitable; and I have 

 always thought that the vitreous lava formed the basis of 

 these coverings, the fusion of Vv'hich, naturally easy, was 

 aided by the mixture of saline fluxes. .1 published my 

 work on this subject twenty-five years ago: M. Fourniy 

 has made a successful applic-ation of my discoveries in hi* 

 manufacture at Paris, and M. d'Arcet has added his expe- 

 rience to mine. '" 



To conclude : the earthen-ware of the Romans, particH- 

 larly their Etruscan vases, have been baked in a much lower 

 heat than that uhich we now ernploy : we may estimate 

 the former at the seventh or eighth degree of Wedgwood's 

 pvrometcr: and at this- degree of heat, as provtd by M. 

 d'Arcet, we cannot employ the oxides of lead, which pe- 

 netrate the clay, and leave th» colour on the surface with- 

 out any brilliancy. 



We are, without doubt, far superior to the ancients in 

 the art of the potter. The numerous metallic oxides suc- 

 cessively discovered, have furnished us with the mear.s of 

 enriching our potteries with a variety of colours as brilhant 

 as they arc durable, at the same tin^e that a better assorted 

 mixture of the earths has admitted of our adding,the greatest 



hardness 





