E N A 



' ' great clearness and brilliancy of colour, in which case 

 they differ from glaw only in softness or easy fusibility. 

 The best enamel that can be had for the purpose of 

 making Urge plates for painting pictures upon, is the 

 Venetian white opaque, with the name of Bertolini 

 stamped upon the cakes, which cakes in general weigh 

 about two pounds each. This article has not been im- 

 ported for some rears past, owing to the exclusion 

 of the British trader from the continent. The writer 

 of this article has however, been informed, that the 

 maker of the best white enamel, whose name we have 

 just mentioned, fell a sacrifice to French tyranny du- 

 ring their struggle for power in I taly and Naples. That 

 this valuable article was the sole production of an indi- 

 vidual, the manufacture of which was unknown to any 

 but himself, may be inferred from the non-importation 

 since the change of government in Italy, although 

 every exertion has been used by those interested in Uie 

 use of it, to obtain it at any price. 



When enamel could be brought to England without 

 restriction, it was generally sold for about six shillings 

 t per pound ; but as it grew scarce, 30 shillings per 

 pound was given, and, at the present time, it is as high 

 as fifty shillings. This high price proved a great sti- 

 mulus to those, who knew any thing about the nature 

 of its ingredients, to exert themselves in their endea- 

 vours to find a substitute, and numerous were the trials 

 of various persons to make an imitation. All attempts, 

 however, were ineffectual, until very lately, when Mr 

 Griffiths, of Round Court, Long Acre, London, suc- 

 ceeded in producing a hard enamel, superior to the best 

 Venetian in whiteness, and much more valuable to the 

 dial-plate makers. But the Venetian is still preferred 

 lor fluxed plates, used for portrait and historical paint- 

 ings ; and, as these plates have always a coat of pure 

 flux laid over the enamel, upon which the colours are 

 laid, it requires a peculiar texture in the enamel, po that 

 when the flux is melted upon it, a partial separation 

 or cracking should not take place, which arises from 

 the unequal expansion of the two substances. We have 

 no doubt that the colouring material used with the flux 

 to produce the white Venetian enamel, is the pure ox- 

 ide of tin, commonly called putty. The manufacturers 

 of putty in London, are in the habit of using 30 per 

 cent, of lead mixed with the tin, which assists the oxi- 

 dation, causing it to proceed much faster than when 

 the tin is used alone ; but the article made in this man- 

 ner has a considerable tinge of yellow, which renders 

 it useless for the purpose of enamel, although it may 

 Miit the lapidary or stone mason equally well as if it 

 was made pure. (T. E.) 



ENAMELLING, the art of covering thin plates of 

 metal with the substance called enamel. As this curi- 

 ous art is carried on to a considerable extent among the 

 manufacturers of watch dial plates, we shall give our 

 readers a general idea of the art of enamelling, by ex- 

 plaining the nature of their manufacture. 



Dial Plate Manufacturing. 



Dial plate Rial plate making is divided into hard enamelling, in 

 nuuiufactu- which the surface of the plate is covered with hard or 

 ting. Venetian enamel ; and into glass or soft enamelling, in 



which the surface of the plate is covered with the Eng- 

 lish soft glass enamel, which is always considered much 

 inferior to hard enamelling. 



The metals that suit this kind of enamelling best, are 



E N A 



fine gold or fine copper ; the former may be had from Enamelling, 

 any goldsmith, the latter at the flatting mills, known by ~~~Y~~~ 

 the name of cnamellers copper. It is necessary to cau- 

 tion persons unacquainted with the art against using ' 

 the copper too thick, as, in that case, the plates would 

 crack in the fire. 



The slips of copper being cut into square pieces, put 

 them into a clear lire, till they have attained a red heat ; 

 when cold they are formed into the intended shape of 

 the dial. Before proceeding, however, to explain this 

 process, we shall here introduce a description of the 

 tools required in the operation. 



1st, The dies aie small circular plates of brass, about 

 Vsth of an inch thick. Their edges should be turned a 

 little conical, and in their centres should be holes near- 

 ly as large as those to be made in the dial plates. An 

 enamcller ought to have at least forty of these, from 

 Jths of an inch, up to 2 inches diameter, observing 

 that the gradation from one size to another should be 

 exceedingly small, having three sizes between every 

 division on die gauge. See Fig. 1. of Plate CCLII. 



2d, A round ended punch made of steel wire, about 

 r^ths of an inch thick and ! ^ long. This should l>c fixed 

 in a convenient handle, and is then lit to punch up the 

 copper into the centre holes of the dies. See Fig. 2. 



Ad, A clock maker's round broach. This should be 

 firmly fixed into a strong handle, being used to bur- 

 nish up an edge to the copper, and likewise to square 

 up the centre holes. See Fig. 3. 



4/A, A die or block, to set the copper of the desired 

 concavity. This should be turned of box or any other 

 hard wood, and should be a little larger in its diameter 

 than the largest brass die. This must have a hole through 

 the centre something wider than the hole in the dial 

 plate. See Fig. 4. 



5th, A large pair of scissars to cut the copper with. 

 Horse scissars are most proper for this purpose. 



CV/;, A setting spatula, which should be made of steel 

 wire, about T'JU'S of an inch in diameter and 5 inches 

 long. One end of this should be be.it flat and diin. The 

 end so prepared is then to be filed a little round, and 

 the flat part bent so as to form a segment of a circle, 

 somewhat smaller than the curve of the setting die. The 

 outer part of the curve should then be smoothed on an 

 oil stone, and the tool is fit to be used. See Fig. 5. 



1th, A smooth needle maker's file, used for filing the 

 plated wire, which will be hereafter explained, and like- 

 wise the edge of the copper, after it has been burnished 

 up to the edge of the brass die. 



Stk, A small steel point, which should be rather 

 stouter than a stocking needle, used for marking the 

 place where the feet of the dial should be put, and other 

 purposes to be described. See Fig. 6. 



9th, A large soldering lamp, wnich should hold at 

 least a quart of oil. This must have a cylindrical spout 

 for the cotton, at least one inch and a quarter in dia- 

 meter, that the oil may have free access to the lighted 

 end of the cotton. See Fig. 7- 



1 Oth, A pair of corn tongs, or tweezers. These are 

 so well known as to need no description. 



\\tli, A blowpipe for soldering the feet upon the 

 coppers, of a convenient length, and the hole a little 

 more open than for other purposes. 



12th, A watclunaker's glass and dial gauge. See 

 Fig. 8. 



1 Stli, A pair of nippers to cut the feet from the plated 

 wire. 



The tools being ready, the workman should proceed 



PLATK 



CCLII. 

 Fig. 1. 



Fig. 2. 



Fig. 3. 



Fig.*. 



Fig. i. 



Fig. 6. 



Fig. 7. 



Fig. 9. 



