GER′MAN SILVER

Syn. Albata , Argent an , Electrum , Nickel Silver , Tutenag , Virgin i an Plate , White Copper. A well-known alloy, the finer varieties of which nearly equal silver in whitene and susceptibility of receiving a high polish, whilst they surpa it in hardne and durability. The following formulæ are from the highest authorities, or are the results of actual analysis of the finest commercial samples:— Prep. 1. Copper, 50 parts; nickel, 20 parts; zinc, 30 parts. Very malleable, and takes a high polish. 2. Copper, 50 parts; nickel, 26 parts; zinc, 24 parts. Closely resembles silver; an excellent sample. 3. Copper and zinc, of each 41 parts; nickel, 18 parts. Rather brittle. 4. (M. Gersdorff.) Copper, 50 parts; nickel and zinc, of each 25 parts. Very white and malleable, and takes a high polish. Recommended as a general substitute for silver. 5. (Gersdorff.) Copper, 60 parts; nickel and zinc, of each 20 parts. For castings, as bells, candlesticks, . 6. (Gersdorff.) Copper, 60 parts; nickel, 25 parts; zinc, 20 parts. For rolling and wire. Very tough and malleable. 7. (Sample made from the ore of Hilburghausen.) Copper, 40 1 ⁄ 2 parts; nickel, 31 1 ⁄ 2 parts; iron, 2 1 ⁄ 2 parts; zinc, 25 1 ⁄ 2 parts. Equal to the best Chinese sample. 8. (Pelouze.) Copper and nickel, equal parts. Recommended by M. Pelouze as superior to any of the alloys containing zinc. 9. (Pelouze.) Copper, 2 parts; nickel, 1 part. Not so white as the last, but more malleable. 10. (White Copper from China.)— a. Copper, 30 parts; nickel, 36 parts; zinc, 34 parts. b. (Said to be prepared from native ore.) Copper, 41 parts; nickel, 32 parts; iron, 2 1 ⁄ 2 parts; zinc, 24 1 ⁄ 2 parts. Silvery white, takes a high polish, very sonorous, malleable both cold and at a dull-red heat, and may be rolled into leaves or formed into wire. 11. (White metal spoon, sold as ‘German Plate.’) Copper, 55 parts; nickel, 24 parts; zinc, 16 parts; tin, 3 parts; iron, 2 parts. Anal. This may be briefly described as follows:— a. 100 gr. of the alloy is digested in nitric acid q. s., diluted with a little water. If the sample is unequally attacked by the acid, and a white external shell is observed which di olves more slowly than the internal portion, it is ‘plated’ on those parts with silver. If this silver shell or casing has a polished surface on both sides, the article has been ‘electro-plated,’ if the contrary is the case, it has most probably been plated in the usual way. b. The solution being completed, heat is applied to expel the exce of acid, and the remainder is largely diluted with distilled water; dilute hydrochloric acid is now dropped in as long as it occasions a precipitate, and the whole, after being moderately heated for a short time, and cooled, is thrown upon a small paper filter; the precipitate on the filter is next washed with distilled water, carefully dried, and ignited in a small porcelain crucible, the filter itself being separately burnt on the cover of the crucible, and the ashes added to its contents prior to ignition. Every 143 1 ⁄ 2 gr. of the resulting fused chloride is equal to 108 gr. of metallic silver. c. The filtered liquid (see b ) is next treated with a stream of sulphuretted hydrogen, and the black precipitate is collected, washed, and digested in strong nitric acid; when the solution is complete sulphuric acid is dropped in to precipitate the lead (if any is present); if a precipitate is formed, the whole is evaporated to dryne , and the exce of sulphuric acid expelled by a rather strong heat applied towards the end; the dry ma is now collected on a filter, washed with a mixture of water and alcohol, dried, and exposed to slight ignition in a porcelain crucible. Every 152 gr. of the resulting dry sulphate is equal to 104 gr. of lead. d. The liquor filtered from the sulphate of lead, or (in its absence) hydrogen (see c ), is next treated with pota a, ., as described under the analysis of bra . Every 40 gr. of the dry protoxide thus obtained represents 32 gr. of pure copper. sulphuretted hydrogen (see c ) is boiled until it loses its offensive odour, and is then precipitated with carbonate of soda, in slight exce , and again boiled for a few minutes; the precipitate (mixed oxides of nickel and zinc) is collected, washed, and redi olved in dilute acetic or nitric acid, in exce ; a current of sulphuretted hydrogen is next pa ed through the solution, the precipitate collected on a filter, washed, redi olved in hydrochloric acid, and the solution again treated with carbonate of soda; the last precipitate (oxide of zinc) is washed, dried, and gently ignited. Every 40 gr. of this oxide is equivalent to 32 gr. of metallic zinc. f. The washings of the precipitated oxides and the liquid filtered from the precipitate occasioned by the sulphuretted hydrogen (see e ) are mixed together, pure solution of ammonia added in considerable exce , and the mixture agitated for some time; the undi olved portion of the precipitate is then collected on a filter, washed with distilled water, redi olved in dilute nitric acid, again precipitated with solution of pota a, and this last precipitate (ferric oxide) washed, dried, ignited, and weighed. Every 80 gr. represents 50 gr. of metallic iron. g. The ammoniacal solution filtered from the precipitate of sesquioxide of iron (see f ) is precipitated with pure solution of pota a, boiled for a few minutes, and, when cold, thrown on a filter; the precipitate is, lastly, washed with hot water, dried, ignited, and weighed. Every 37 1 ⁄ 2 gr. of the oxide thus obtained is equal to 29 1 ⁄ 2 gr. of metallic nickel. Obs. The manufacture of nickel or German silver has of late acquired an importance which is second only to that of silver plate itself. The superior quality of this alloy, and the graceful patterns which it is often made to a ume in the hands of the accomplished artist cannot fail to have attracted the admiration of the majority of our readers. The value of correct information regarding the preparation of this alloy, and of a ready method of determining the composition of the most improved commercial samples will, therefore, be fully appreciated by every metallurgist who wishes to throw his wares into the arena of public competition. Much that is vended under the name of German silver is little better than the Britannia metal or PLATE PEWTER formerly so plentiful in every establishment in this country. German silver has quite superseded copper as the basis of ‘electro-plated goods.’ [332] See Electrotype . The union of the metals in the above formulæ is effected by heat with the usual precautions. When iron is ordered, it is generally added under the form of ‘tin plate.’ See Alloy , Bra , Britannia Metal , Bronze , .