The Silversmith's Handbook Containing full instructions for the alloying and working of silver
CHAPTER VI.[C
Various Qualities of Silver.
[C] See observations on Depreciation of Cost Price of Silver in Preface to Fourth Edition (pp. vii, viii), and the new Table of Cost Prices of Alloys in this Chapter, following the Preface (p. ix).
The chemical and physical properties of fine silver having been dealt with in a preceding chapter, we shall not refer to them again in detail; but, as we have already observed that it is sometimes employed in _its pure_ state for special purposes, it is desirable that we should point out the uses to which it has been applied, especially those of a mechanical nature. With reference to the latter part of the subject we will now proceed to describe the commercial utility of the metal.
One of the greatest demands for pure silver--if not the greatest of all--is in the manufacture of fine filigree work, a branch of industry extensively practised on the Continent. This kind of silversmith's work was attempted to be revived in this country during the years 1864-5, Birmingham and London being the principal places where the manufacture was carried on; but the success of the undertaking as a staple industry must, at the most, have been only a partial one, for it soon declined, and the trade was thus virtually left, as before, in the hands of our Eastern competitors; most of whom produce splendid specimens of the art of filigree and fine wire-working. In India this work is wonderfully performed, and it is truly marvellous to witness the beautiful handiwork of the natives who practise this craft. Their productions are quite the work of the true artist, almost every article representing Nature in some of her various forms, such as flowers, animals, serpents, &c., and these are so skilfully imitated that no one could possibly dispute either the faithfulness of the representation or the ability of the workman. This is all the more surprising, because in India the natives have not the modern mechanical appliances which we possess in this country. The jeweller there represents to some extent our travelling tinker, only with this difference, that the travelling tinker in this country is generally an inexperienced and unskilful workman, whereas the Indian, if we are to judge him by his work, must be just the reverse.
Filigree wire-work is manufactured in Italy, Germany, Norway, and Sweden, and the secret of these countries maintaining the monopoly in this branch of the silversmith's trade is that labour there is cheap; and not in any sense because English workmen cannot make the articles in question. It is owing to this cheapness of labour and the inexpensiveness of living that our Continental competitors can beat us by underselling us in the market; and to no other cause can the production of the foreign cheap article be assigned.
In India the art of working in silver and gold has long been practised, and so particular are the workmen there about the absolute purity of the metals they use, that they refine them by melting five times, under a very strong blast heat, before commencing the work of manufacture. The principal places where these art-manufactures are carried on are in Southern India and at Trichinopoly; and in these districts the delicacy and intricacy of the workmanship are brought to the greatest possible perfection. The articles produced there are all "hand-made," and wrought entirely with a few simple tools, such as a hammer and an anvil (both of which are highly polished and burnished), a few fine pliers, blow-pipes, burnishers, scrapers, a pair of fine dividers, and some delicate scales and weights; these, with a few perforated steel-plates for drawing the wire through, comprise the chief appliances of the travelling native jewellers. The process of the work is very simple. It is commenced by hammering out the metal upon the anvil, and when it has assumed a certain degree of thinness the dividers are next brought into requisition to mark it into certain widths, which are subsequently cut into strips and drawn into very fine wire through perforated steel-plates, a pair of strong pliers being used for the purpose. The holes in the steel-plates consist of graduated sizes, and by this means the strips of metal are soon considerably reduced; and when the proper thinness has been attained the wire is ready for the exercise of the practical skill and dexterity of the artisan, who produces from it the best filigree work in the world. Most of the native jewellers have books containing a variety of designs, but they more commonly work from memory, without any reference to patterns.
The principal localities where this description of work is produced in the highest perfection are Delhi, Cuttack, and Trichinopoly, in India; and Genoa, Paris, Florence, Malta, Norway, and Sweden. The Indian filigree work is the finest and cheapest in the world. The Maltese manufacture a very good kind, and their crosses are much admired; so also do the Chinese and Japanese, but the manufactures of these latter countries are not so tasteful as those of India, consequently they have not been so highly appreciated. Norway and Sweden produce filigree work of a very light weight; but still their productions in this art will not compare in regard to effect with the finest specimens from India.
We have said that the silver employed by the filigree worker should be in every case absolutely pure; because, when it is quite fine, it is extremely soft and pliable, so that it will remain in almost any form the artist may choose to work it, without that springiness which is found in all alloyed metals. However small might be the amount of alloy contained in the metal, the least admixture of it would produce an elasticity in the wire when pressed into form which would make it unworkable for fine filigree purposes; and in this state it would be the utter bane of the workman, as his progress would be altogether impeded in the production of his work. It is of the greatest importance that the spirals, and all the various forms required in filigree working, should remain steadily in their places when pressed into shape, without that rebounding which happens in the case of metals of an elastic nature, and in consequence of which no really first-class work can be performed in connection with this art. For such reasons as these it will be at once palpable even to the ordinary reader that fine silver should always be used in preference to alloyed in the manufacture of filigree work.
The various ornaments of the filigree kind are commonly enclosed in a rim of plain and somewhat stronger wire, which gives additional strength to each part; and, when put together, tends to compose an article of considerably greater durability. In England these outside rims consist exclusively of sterling or standard silver, whilst all the inner work is of the finer material.
There are several methods of preparing the wire called "filigree." The oldest and the one almost invariably practised in India consists in the first place in drawing down the wire in a circular form until the very lowest possible thinness has been attained, and frequently annealing it during the process, which is done by heating it to a red heat in a muffle placed upon an iron or copper pan. When this process has been effectually performed the wire is taken (if of the proper degree of thinness) and doubled together; these two fine wires are then twisted into one cord, which should be of the fineness desired. The wire requires annealing more than once during the process of twisting, and when it is completed it has a corded appearance, it is then ready for the manufacture of the various articles comprised in this kind of work.
The old plan of twisting was accomplished in the following manner. One end of the doubled wire being firmly secured in a vice or some other suitable instrument, so as to prevent it from turning round and so prevent the progress of the work, the other end of it was also firmly secured in a small hand machine or vice, which was made to revolve by turning a small handle with the right hand, the machine being held and regulated with the left, in order to keep the wire out at its full length so as to avoid knotting in the various parts of it; it was in this manner that fine filigree wire was in the first instance made.
The second plan was somewhat different, and in regard to the last part of the process it was certainly a great advantage, especially in the saving of labour, as a greater quantity could be prepared in a much less time than by the old method, that being slow in its progress. Here the lathe was made to supply the place of the small hand machine, the speed of which soon brought about the object in view.
The flattening of this twisted wire has now commonly come into use, and is effected by passing it through small steel rollers, hardened and polished. The object of this is soon manifest, as the labour-saving process is brought prominently into play: the wire in the first place need not be so finely drawn, and secondly the same filigree surface can be made to appear upon the articles as before, by securing the edges of the wires which show the filigree uppermost; and this is always the case in manipulating with this kind of wire. This method is generally in vogue with most filigree workers.
A third plan of preparing the material for the manufacture of filigree work is, we believe, due to the ingenuity of a celebrated Birmingham firm, who extensively practised this kind of work some years ago. The secret is not now generally known to the trade, therefore a few observations bearing upon it will not be unacceptable to those for whose benefit we are writing. The process is commenced in the same manner as before, in the preparation of the round wire, though this need not be drawn so fine, because by this method we have no twisting. When the round wire has arrived at the proper size it is flattened in the manner already explained; and when this is done it should be annealed, but experience will dictate best when this particular process should be carried out. After this latter operation the wire is submitted to the action of very small rollers, and bearing the pattern required in small grooves of various sizes. The pattern takes effect upon the edges of the wires only, and resembles the milled or serrated edges of our coinage, only of course the latter bears no comparison with regard to fineness. Lastly, the wire is again passed through the flattening rollers, and then it is ready to be worked up into the object desired.
Having gone through the general details of filigree working we shall next direct our attention to the component parts and commercial uses of the English standards, together with those of some other countries. In England there are two silver standards, called respectively the old and the new standards. They are as follows:--
Fine silver per lb. troy.
Old Standard, 11 oz. 2 dwts. = 925 millims. New Standard, 11 oz. 10 dwts. = 959 millims.
The older of these appears to have been always the legally recognised standard for the coinage, and also for the manufacture of plate. By a law passed, however, in the reign of William III. (1697) it was raised to 11 oz. 10 dwts. of fine silver in the pound troy weight. The manufacture of silver articles from this standard was soon found to be not so durable as those made under the older one; consequently the silversmiths were permitted by a law passed in the reign of George III. (1819) to manufacture from the former standard of 11 oz. 2 dwts., the use of the new one being likewise permitted for the benefit of those who chose to avail themselves of it; and to this day it remains an English standard, though hardly ever employed.
By the Silver Coinage Act (10 Geo. 5), the fineness of the British coinage was reduced on account of the increased price of silver bullion; and the silver coinage now consists of one-half silver, one-half alloy, one troy pound of silver being coined into sixty-six shillings. The copper which composes the alloy in the silver coinage hardens the material employed, and it is found to wear better.
In order to make the matter as simple as possible, we purpose giving a few practical alloys, as follows:--
Old standard silver alloy, cost 4_s._ 4_d._ per oz.
oz. dwts. grs. Fine Silver 0 18 12 Shot Copper 0 1 12 ---------------- 1 0 0 ================
If it is intended that the above alloy should be for Hall-marking, it will be advisable to add a little extra silver to the prepared composition, because fine silver purchased from the refiner or bullion dealer is never absolutely pure, consequently the work will not pass the Hall; or better still alloy as follows:--
Old standard silver for Hall marking.
oz. dwts. grs. Fine Silver 0 18 14 Shot Copper 0 1 10 ---------------- 1 0 0 ================
The new standard silver is composed of 38-1/3-40ths of fine silver and 1-2/3-40ths of copper alloy; or millesimal fineness 959 parts of fine silver and 41 parts of copper per 1,000 parts; the remedy being as before 0·004 parts.
New standard silver alloy, cost 4_s._ 6_d._ per oz.
oz. dwts. grs. Fine Silver 0 19 4 Shot Copper 0 0 20 ---------------- 1 0 0 ================
New standard silver for Hall marking.
oz. dwts. grs. Fine Silver 0 19 6 Shot Copper 0 0 18 ---------------- 1 0 0 ================
Quality commonly used in England.
oz. dwts. grs. Fine Silver 0 18 0 Shot Copper 0 2 0 ---------------- 1 0 0 ================
The qualities of the silver employed by the English silversmiths are invariably below the standard, the duties, assay charges, and loss of time in sending the work to the Hall to be marked acting as a great drawback to the trade in the midst of the keen competition of the present day. Silver chains, brooches, buckles, collarets, &c. are for the most part manufactured from inferior metal. In fact, some manufacturers positively refuse to make Hall-marked goods, on account of the great drawbacks attending the marking.
The alloys of silver are not calculated on the carat system, like gold, but by certain numbers, or other distinctive features, well understood by the particular firms which trade in silver wares. For our present purpose it will be sufficient to distinguish them by using the numerals, 1, 2, 3, 4, &c.; the alloy nearest approaching sterling or standard we shall call No. 1, and so on downwards until the lowest quality has been reached. We may state that silver does not lose its whiteness if not alloyed below equal quantities of the two metals; however, the alloys used in manufactures seldom reach so low a limit.
Silver alloy No. 1, cost 4_s._ 2_d._ per oz.
oz. dwts. grs. Fine Silver 0 18 0 Shot Copper 0 2 0 ---------------- 1 0 0 ================
Silver alloy No. 1, same as above.
oz. dwts. grs. Fine Silver 1 0 0 Shot Copper 0 2 6 --------------- 1 2 6 ===============
Silver alloy No. 2, cost 3_s._ 9_d._ per oz.
oz. dwts. grs. Fine Silver 0 16 0 Shot Copper 0 4 0 ---------------- 1 0 0 ================
Silver alloy No. 2, same as above.
oz. dwts. grs. Fine Silver 1 0 0 Shot Copper 0 5 0 ---------------- 1 5 0 ================
Silver alloy No. 3, cost 3_s._ 6_d._ per oz.
oz. dwts. grs. Fine silver 0 15 0 Shot copper 0 5 0 --------------- 1 0 0 ===============
Silver alloy No. 3, same as above.
oz. dwts. grs. Fine silver 1 0 0 Shot copper 0 6 16 --------------- 1 6 16 ===============
Silver alloy No. 4, cost 3_s._ 3_d._ per oz.
oz. dwts. grs. Fine silver 0 14 0 Shot copper 0 6 0 --------------- 1 0 0 ===============
Silver alloy No. 4, same as above.
oz. dwts. grs. Fine silver 1 0 0 Shot copper 0 8 12 ---------------- 1 8 12 ================
Silver alloy No. 5, cost 3_s._ 2_d._ per oz.
oz. dwts. grs. Fine silver 0 13 12 Shot copper 0 6 12 ---------------- 1 0 0 ================
Silver alloy No. 5, same as above.
oz. dwts. grs. Fine silver 1 0 0 Shot copper 0 9 18 ---------------- 1 9 18 ================
Silver alloy No. 6, cost 3_s._ 1_d._ per oz.
oz. dwts. grs. Fine silver 0 13 0 Shot copper 0 7 0 ---------------- 1 0 0 ================
Silver alloy No. 6, same as above.
oz. dwts. grs. Fine silver 1 0 0 Shot copper 0 11 0 ---------------- 1 11 0 ================
Silver alloy No. 7, cost 3_s._ per oz.
oz. dwts. grs. Fine silver 0 12 12 Shot copper 0 7 12 ---------------- 1 0 0 ================
Silver alloy No. 7, same as above.
oz. dwts. grs. Fine silver 1 0 0 Shot copper 0 12 0 ---------------- 1 12 0 ================
Silver alloy No. 8, cost 2_s._ 10_d._ per oz.
oz. dwts. grs. Fine silver 0 12 0 Shot copper 0 8 0 ---------------- 1 0 0 ================
Silver alloy No. 8, same as before.
oz. dwts. grs. Fine silver 1 0 0 Shot copper 0 13 12 ---------------- 1 13 12 ================
The qualities of the silver alloys have been reduced in this list to various values, and the latter ones are as common as it is possible to make them, without a great and perceptible change of colour taking place in the prepared material. But if it be desired to work a still more inferior metal, then another ingredient must enter into its composition, in order to keep up the whiteness of the silver; and this other metal employed is nickel, the alloys with which we shall have occasion to refer to hereafter. Suffice it to say, however, that these inferior alloys of silver, prepared with nickel, are not now much employed by silversmiths in their art-manufactures. It will be observed that we have recommended the employment of _shot_ copper in the manufacture of silver alloys: we do so for two reasons--first, because it can be purchased at a considerably cheaper rate than can the ordinary forms of copper, costing only one shilling per lb., whilst the ordinary prepared copper for alloying will cost double that amount; and, secondly, if proper attention has been given to the melting and casting process, the workable qualities of the metal will be found everything that could be desired. Therefore an excellent material in all respects can be produced by the means suggested at half the cost of alloy. A considerable saving to a large firm might thus be easily effected by its employment.
In France there are three silver standards--two to be employed by silversmiths, and one for the coinage, as follows:--
Fine silver per lb. troy.
Silver ware, 11 oz. 8 dwts. = 950 millims. Coinage, 10 oz. 16 dwts. = 900 millims. Silver ware, 9 oz. 12 dwts. = 800 millims.
It will be seen from the above table that pre-war coinage in France did not represent the highest standard, and also that their principal one was inferior to our highest standard. French coinage contained 36-40ths of fine silver and 4-40ths of copper alloy, or millesimal fineness 900 parts of fine silver and 100 parts of copper per 1,000 parts of metal; the highest standard for silver wares contains 38-40ths of fine silver and 2-40ths of copper alloy, or millesimal fineness 950 parts of fine silver and 50 parts of copper per 1,000 parts of metal; the lowest French standard for silver wares contains 32-40ths of fine silver and 8-40ths of copper alloy, or millesimal fineness 800 parts of fine silver and 200 parts of copper per 1,000 parts of metal. The remedy is millesimal fineness 0·005.
French alloy for coinage, 4_s._ 2_d._ per oz.
oz. dwts. grs. Fine silver 0 18 0 Copper 0 2 0 ----------- 1 0 0 ===========
French alloy for plate, 4_s._ 5_d._ per oz.
oz. dwts. grs. Fine silver 0 19 0 Copper 0 1 0 ----------- 1 0 0 ===========
French alloy, lowest standard, 3_s._ 9_d._ per oz.
oz. dwts. grs. Fine silver 0 16 0 Copper 0 4 0 ----------- 1 0 0 ===========
In the preparation of these alloys with French silver it is undesirable to make any addition of fine silver, in order to enable goods manufactured from them to pass the Hall in safety, because the former is assayed before it leaves the bullion dealers, and the bars of metal are marked with their various standards. Such is not the case in England, and refiners' fine metal is sometimes two or three grams under what it is supposed to be; hence the necessity for the further addition of some fine metal as we have already pointed out, when the object in view is to have goods Hall-marked; without which addition it cannot be effected.
In Germany there are four silver standards--one for the coinage, and three to be employed in the manufacture of silversmiths' wares; and in that country the various standards are severally applied in the production of fine filigree and other artistic work. The fineness of the standards is as follows:--
Fine silver per lb. troy.
Silver ware, 11 oz. 8 dwts. = 950 millims. Coinage, 10 oz. 16 dwts. = 900 millims. Silver ware, 9 oz. 12 dwts. = 800 millims. Silver ware, 9 oz. 0 dwts. = 750 millims.
As regards the alloy to be employed in the manufacture of these various qualities, copper only must be used, all other metals being forbidden. These standards represent all home manufactured articles of silver having reference to the standards of that country, as lately appointed by law.
German pre-war coinage was the same as French and contained 36-40ths of fine silver and 4-40ths of copper, or millesimal fineness 900 parts of fine silver and 100 parts of copper per 1,000 parts of metal. The highest standard of all is used for silver wares, and contains 38-40ths of fine silver and 2-40ths of copper, or millesimal fineness 950 parts of fine silver and 50 parts of copper per 1,000 parts of metal. The next German standard for silver wares contains 32-40ths of fine silver and 8-40ths of copper, or millesimal fineness 800 parts of fine silver and 200 parts of copper per 1,000 parts of metal. The commonest German standard employed by the silversmiths of that country contains 30-40ths of fine silver and 10-40ths of copper, or millesimal fineness 750 parts of fine silver and 250 parts of copper per 1,000 parts of metal indicated. Remedy 0·003.
Silver alloy for the German coinage.
oz. dwts. grs. Fine silver 0 18 0 Copper 0 2 0 --------------- 1 0 0 ===============
Alloy for silver wares of the first standard.
oz. dwts. grs. Fine silver 0 19 0 Copper 0 1 0 ---------------- 1 0 0 ================
Alloy for silver wares of the second standard.
oz. dwts. grs. Fine silver 0 16 0 Copper 0 4 0 ---------------- 1 0 0 ================
Alloy for silver wares of the third standard.
oz. dwts. grs. Fine silver 0 15 0 Copper 0 5 0 ----------------- 1 0 0 =================
Silver goods manufactured according to these standards in Germany, which have recently become law, may be alloyed only with copper, and any foreign substance is not allowed to enter into their composition. The remedy permitted in the actual fineness of the silver must not be under three thousandths of the standard specified. The goods to be stamped with the number of thousandths and the name of the manufacturer of them, and the correctness to be certified by the firm named. Experts are appointed by the Government to test this correctness, and if the provisions of the law have been justly observed a government guarantee mark is applied to them.