20. Assaying. English Assays. The value of bullion depends upon the quantity of pure metal it contains as found in the process of assaying. The value of the alloy is disregarded as a compensation for the expense of refining. 1o. Gold assays were formerly made in carats of 4 carat grains each. 1 carat weighs 4 lb. Troy .. 1 ct. grain 60 grains Troy. = = 10 dwts. = 240 grs., The proportions however are alone essential. British standard gold is 22 carats fine (or 916 in millièmes). The reports were made by comparing the ascertained weights with this standard—the difference being called the "betterness" (B) or worseness" (W) of the metal. The assay report was given in this form :— Russia-ducat (gold) assay B 1.2, weight 54 gr. This means that the Russian ducat is 1 carat 21 ct. grams above the standard, and .. its fineness is 23.21. The full particulars of the assay of a given weight of gold would thus be set out: Given the weight and assay. Fineness standard assay report. = or fine weight of fine weight. Value in sterling = fine weight in oz. × price per oz. fine. Value in sterling = standard weight in oz. × price per oz. standard (the usual method). Value in sterling = full weight in oz. x price per oz. weight (according to purity). CARATS, MILLIÈMES, DWTS. 271 Example. Russian ducat assay B 1.21, weight 54 gr., at £3.178.10 d. per oz. standard. 2°. Gold assays are now expressed in millièmes and thirds-the weights being in oz. and decimals. The fineness is thus expressed directly and the other particulars are set out in the same way. Given the weight and fineness of a quantity of gold bullion. Fine weight = fineness x weight ÷ 1000. oz. fine. = = fine weight of fine weight. fine weight in oz. x price per Value in sterling = standard weight in oz. x price per oz. standard (usual for bars). = Value in sterling - full weight in oz. × price per oz. weight (according to purity). Example. 140.375 oz. gold, 896 fine, at 77s. 6d. per oz. standard. Fine wt. 140·375 × ·896=125.776 oz. fine 140.375 698 112 3000 12 6338 8422 Standard wt.=fine wt. + fine wt.=137.210 oz. st. 125.7760 11.434 137.210 5783 411 6300 Value in sterling standard wt. in oz. × 77s. 6d. = £531.138.9d. 109 7680 9 6047 6861 531.6888 3o. Silver assays are made in ozs., dwts., and dwts.-12 oz. or 240 dwts. being purity. The British standard silver is 11 oz. 2 dwts. fine or 222 dwts. fine (37 or 925 in millièmes). The reports are made from a comparison of the given weights with this standard-the difference as before being called the "betterness" (B) or worseness" (W) of the metal. The assay report is given in this form: France: franc (silver) assay, W 0·7. Weight, 3 dwts. 5 gr. This means that the franc is 7 dwts. below the standard and .. its fineness is 215. Given the weight and assay of silver bullion-the particulars are thus found. Fineness = standard + assay report. = Value in sterling fine weight in oz. x price per oz. fine (cake silver). Value in sterling = standard weight in oz. × price per oz. standard (bars). = Value in sterling full weight in oz. x price per oz. weight (coins). Example. Russian rouble of 13 dwts. 8 grs. W 14 at 5s. per oz. st. Fineness=222-14=208. Value in sterling = 398 × 5s. =1040=34358.=3s. 1·477d. 4°. Silver assays might also very conveniently be expressed in millièmes—with the weights in oz. and decimals. For instance in the above examples, W 14 denotes fineness 8664. .. fine weight = '866666 × 2 1.733333 3 = 3 = 57777 oz. 624624 × 5s. = 3.123123s. In the case of the franc, = 8958 fineness. 43 215 240 = 48 = W 0-7 den 77 x 8958 grains. Standard weight Fine weight = 19 × 771 × 8958 grains. Value in sterling at 5s. per oz. = (480 × 19 × 771 × *8958)s. 21. Continental Assays. These are always expressed in millièmes and tenths for both gold and silver. Their use will be obvious for all from a French example. Given 3.071 kilogrammes gold 917 fine-premium 2 per mille on 3437 fr. per kilog. fine. Fine weight = 3·071 × ·917 = 2.816 kilog. Given 42:117 kilog. silver 925 fine-discount 10 p.c. on 218.89 francs per kilog. fine. = Fine weight 42·117 × 925 = 38.958 kilog. American assays are in millièmes and halves. The Chinese reckon in percentages and call it the touch (toques). The Russians reckon in zolotniks, and .. 96 represents fine metal. 22. Reduction of English Reports to the Decimal Form, and vice versa. 1o. To reduce a decimal gold report to the British standard (22 carats). Multiply the report by 24 ÷ 1000. Find difference of this and 22. Mark B or W accordingly. Example. 900 fine. 21.6 22 = 4-13 ct. grains. W 0 130 1§ nearly. 2o. To bring a British gold report to a decimal form. Add or subtract the report to 22, and divide by 24 to three (or 4) figures. Example. B 1. 11. 23 11. 24 23 375 | 974 raide. 3°. To bring a silver millième report into a British form. Multiply the report by 240, mark off 3 places of decimals. Find difference of result and 222, mark B or W cordingly. |