ENAMELS 269 



a mystery of the means that succeeded best with him, and thus a multitude of curious 

 processes have been buried with their authors. 



The enamel was applied to the metallic ground in several distinct ways, giving rise 

 to very different kinds of enamel-work, which it is desirable to distinguish. In the 

 process called cloisonne enamelling, the plan was to braze on to a plain surface of 

 metal, the bars or cloisons which were intended to hold the coloured paste which was 

 to be vitrified in the enamel furnace. The vases from China, probably some 500 or 

 600 years old, are enamelled by the true cloisonne process. After the sacking of the 

 Summer Palace at Peking, large numbers of Chinese cloisonne enamels were brought 

 to Europe, and the English market thus becoming glutted, they sold at prices very 

 much lower than what they would have realised in the East. The cloisonne method 

 was also much used in Mediaeval Greek and Byzantine art, and fine examples are to 

 be seen in the celebrated Pala d' Oro, or Altar-front, of the Church of St. Mark at 

 Venice, in the crown of Charlemagne at Vienna, and in the shrine of the Magi at 

 Cologne. Theophilus, who described the cloisonne process in the twelfth century, 

 applied the term ekctrum to these enamels. 



A similar yet distinct method is that known as champ lev enamelling. Here, in- 

 stead of fillets of metal being soldered on to the metal ground, the field or ground 

 itself is incised or hollowed out so as to leave the outline of the design in slender 

 elevated bands of metal ; the parts which are sunk, or in intaglio, are then filled in 

 with enamel powder, which is vitrified in the furnace, and the surface is finally 

 .smoothed down by grinding and polishing. The difference, therefore, between the 

 two processes is this : in the champ leve enamels the metallic fillets, or cloisons, form- 

 ing the partitions between one colour and another, are part of the metallic plate itself, 

 whilst in the cloisonne enamels they are separate bands of metal soldered on to the 

 metallic plate. Champ leve enamels are generally executed in copper ; the cloisonne 

 often on gold. The art of champ leve enamelling was extensively practised at Limoges, 

 in France, from the eleventh to the fourteenth century, especially for the decoration 

 of ecclesiastical objects.' 



Beautiful enamels of modern French workmanship are now produced, in which the 

 enamel colours are surrounded by filigree work obtained by the electrotype process, 

 and many pleasing designs result from the facilities thus afforded of producing this 

 beautiful mixture of metal and enamel the ' emaux cloisonnes a champ leve.' 



After the champ leve enamelling had long flourished at Limoges, a different and 

 simpler method became popular. This was a method in which the subject was exe- 

 cuted in slight relief, by a process of engraving or chasing, and the surface was then 

 encrusted with translucid enamels of brilliant colours, through which the design on 

 the subjacent metal was visible. The technicalities of this process were carefully 

 described by Benvenuto Cellini in his ' Trattato dell' Oreficeria.' 



Finally, the school of Limoges introduced the method of painting on an enamelled 

 surface. The plate of metal, usually copper, is coated with an opaque white enamel 

 ground, which is fired, and on this ground the design is then painted in enamel 

 colours. All the later Limoges enamels are of this character. The old English 

 enamels made at Battersea and at Bilston in Staffordshire were also produced by 

 this process ; snuff-boxes, patch-boxes, tea-caddies, candlesticks, &c., were made of 

 enamelled copper, in the last century, and are now much prized. Modern enamel 

 paintings are also examples of superficial enamelling, but are less popular now than 

 they were some few years ago ; the family of Bones for three generations were cele- 

 brated as enamel-painters, and Mr. Essex has also obtained reputation in this art. 

 The kind of enamel used as a ground by the artist is known as ' Venetian white hard 

 enamel,' and is composed of silica, borax, and binoxide of tin. 



The Venetians are still in possession of the best enamel processes, and they sup- 

 ply the French and other nations with the best kinds of enamel, of every coloured 

 shade. 



Enamels are either transparent or opaque; in the former all the elements have 

 experienced an equal degree of liquefaction and are thus run into crystal glass, 

 whilst in the latter, some of their elements have resisted the action of heat, so that 

 their particles prevent the transmission of light. This effect of opacity is produced 

 particularly by the oxide of tin. 



The simplest enamel, and the one which serves as a basis to most of the others, is 

 obtained by calcining, first of all, a mixture of lead and tin, in proportions varying 

 from 15 to 50 parts of tin for 100 of lead. The middle term appears to be the most 

 suitable for the greater number of enamels ; and this alloy has such an affinity for 



1 For the history of Enamelling, the reader may refer to Jules Labarte's ' Recherches sur !a 

 Peinture en Email dans 1'Antiquite et an Moyen Age/ Paris, 1S5G. 



