SINGEING 



835 



placing the sliver-leaves on the heated piece, und fixing them to its surface by 

 burnishers of steel, of various forms. The workman begins by applying the leaves 

 double. Should any part darken in the heating, it must be cleared up by the scratch- 

 brush. 



The silverer always works two pieces at once ; so that he may heat the one, while 

 burnishing the other. After applying two silver-leaves, he must heat up the piece 

 to the same degree, as at first, and he then fixes on with the burnisher four addi- 

 tional leaves of silver ; and he goes on charging in the same way, 4 or 6 leaves at a 

 time, till he has applied, one over another, 30, 40, 50, or 60 leaves, according to the 

 desired solidity of the silvering. He then burnishes down with great pressure and 

 address, till he has given the surface a uniform silvery aspect. 



Silvering by the precipitated, chloride of silver. The white curd obtained by adding 

 a solution of common salt to one of nitrate of silver is to be well washed and dried. 

 One part of this powder is to be mixed with 3 parts of good pearlash, 1 of washed 

 whiting, and one and a half of sea-salt. After cleaning the surface of the brass, it is 

 to be rubbed with a bit of soft leather, or cork moistened with water, and dipped in 

 the above powder. After the silvering, it should be thoroughly washed with water, 

 dried, and immediately varnished. Some use a mixture of 1 part of the silver pre- 

 cipitate, with 10 of cream of tartar, and this mixture also answers very well. 



Others give a coating of silver by applying with friction, in the moistened state, a 

 mixture of 1 part of silver-powder precipitated by copper, 2 parts of cream of tartar, 

 and as much common salt. The piece must be immediately washed in tepid water 

 very faintly alkalised, then in slightly warm pure water, and finally wiped dry before 

 the fire. 



The inferior kinds of plated buttons get their silver coating in the following way : 



Two ounces of chloride of silver are mixed lip with 1 ounce of corrosive sublimate, 

 3 pounds of common salt, and 3 pounds of sulphate of zinc, with water, into a paste. 

 The buttons being cleaned, are smeared over with that mixture, and exposed to a 

 moderate degree of heat, which is eventually raised nearly to redness, so as to expel 

 the mercury from, the amalgam formed by the reaction of the horn-silver and the 

 corrosive sublimate. The copper button thus acquires a silvery surface, which is 

 brightened by cleaning and burnishing. See ELECTKO-METALLUKGY. 



SILVERING OF GLASS. See MIERORS. 



SIlYIXIiOR. A name given to a rich-coloured brass, composed of 3 oz. of zinc to 

 1 Ib. of copper. See ALLOY and BRASS. 



SINGEING. In the article BLEACHING, the modern and most approved singeing 

 apparatus is described. The old furnace for singeing cotton goods is represented in 

 longitudinal section, Jig. 1850, and in a transverse one in fig, 1851. a is the fire- 

 door : b, the grate ; c, the ashpit ; d, a flue, 6 inches broad and 2 high, over which 

 a hollow semi-cylindrical mass of cast iron e, is laid, 1 inch thick at the sides, and 

 2| thick at the top curvature. The flame passes along the fire-flue d, into a side 

 opening/, in the chimney. The goods are swept swiftly over this ignited piece of 

 iron, with considerable friction, by means of a wooden roller, and a swing frame for 

 raising them at any moment out of contact. 



1851 



1850 



In some shops, semi-cylinders of copper, three-quarters of an inch thick, have been 

 substituted for those of iron, in singeing goods prior to bleaching them. The former 

 last three months, and do 1,500 pieces with one ton of coal ; while the latter, which 

 are an inch and a half thick, wear out in a week, and do no more than from 500 to 

 600 pieces with the same weight of fuel. 



, In the early part of the year 1818, Mr. Samuel Hall introduced the plan for 

 removing the downy fibres of the cotton thread from the interstices of bobbinet 

 lace, or muslins, by singeing the lace with the flame of a gas-burner. And in 1823 

 he modified this process by causing a strong current of air to draw the flame of the 



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