This is the name given to vitrified substances applied chiefly to the surfaces of metals. It is executed in various ways and styles, and is known as Plain enamelling, which is simply the application of opaque or translucent colour in the form of a pattern, etc.

In Champleve enamelling the design is cut out of the solid metal, leaving thin walls of metal to outline the design, and the cells thus formed are filled with the various coloured enamels.

In Basse faille enamelling the same process is gone through as in champleve enamelling, but in addition the bottoms of the cells or divisions are modelled in relief, so giving greater depth and play of light to the enamel the cells are filled with.

In Cloisonne enamelling the design is laid out by means of applying to a smooth groundwork a piece or pieces of rectangular or triangular wire forming or outlining the design, which are silver soldered down on to the groundwork and then the hollows are filled with enamel; in some instances the cloisons are held in position by the enamel only. This is really a modification, or an easier method, of obtaining a result similar to champleve enamelling.

Plique a jour enamelling is enamelling or enamelled work that can be seen through, simply a network comprising the design and the spaces filled in with various coloured enamels which are translucent. When the spaces in the design are small the object can be fired without a support to hold the enamel in its place, but where this is not possible the object has to be laid on a back or support made of some material such as platinum that will not stick or fuse at the temperature at which the enamel melts. Enamelled work can be done on gold, silver, copper, and gilding metal, but the best results are obtained on gold or silver, though often the colours have to be toned down to prevent them looking harsh and raw. When enamelling on other metals which are not so brilliant, paillons are often used to lighten up the design; these are simply pieces of gold or silver foil laid on the enamel, fired, and then covered with more enamel. By this means a reflected light is obtained which can be toned down to suit the design. Enamel in the sense in which it is used here means coloured glass that is fused on the metal, and there is nothing to compare with it for brilliant and beautiful effects. It is one of the decorative arts seen at its best in association with metal work. Hinges, handles, bell pushes, switch covers, finger plates, brackets, fenders, jardinieres, grilles, altar rails, candlesticks, etc., could all be made most decorative by the right use of good enamelled work.

To obtain the best results an enamelling furnace must be used, that is a furnace constructed specially for this purpose and heated either by gas or benzo-lene according to the system that is desired.

The enamel which is supplied in the lump or ground to a certain fineness as required must be thoroughly washed (this is one of the most important processes) and the metal base, which must also be scrupulously clean (scraped for preference), is slightly domed, and the enamel in form of a powder which has been wetted with some thin gum tragacanth if necessary, to make it adhere to the metal, is applied to the back and front of the work with a spatula and well pressed down to form a firm and even coating. This is thoroughly dried and then placed in the muffle of the furnace when the furnace is at the right heat, and baked until the enamel has fused. It is then taken out and left to cool. This process is repeated until the operator is satisfied.