426 ASSAY OF GOLD AND SILVER COINS. 



In the testing of single pieces it is to be expected that any gold coin, or a cut 

 from any part thereof, will conform faithfully to the bounds prescribed by law. 

 But the silver coins, in addition to the som'ce of error abeady pointed out, (the 

 manner of taking assay samples,) are somewhat liable to show too high a result, 

 from several causes. At certain grades of alloy, and especially the standard of 

 900, the gradual cooling of ingots will draw the better metal to the interior, and 

 the worst towards the exterior and the edges. Hence the fineness of pieces cut 

 off the central part of the ingot is higher than the average fineness of the ingot. 

 Again, in casting ingots from a melting-pot the exposure of the metal to the air 

 during all the time of dipping out, and at the same time the increase of heat 

 towards the bottom of the pot, unavoidably produces a progressive refining, so 

 that the lower ingot is of a higher quality than the average of the whole melt; 

 and, of course, a coin cut from it will be higher still. Yet with the precautions 

 observed, om" silver coins should very rarely exceed the superior limit assigned 

 by law ; and there is no good reason why they should fall below the legal limit, 

 unless it be the taking of an unfair sample for assay. 



A STATEMENT OF FOREIGN GOLD AND SILVER COINS, PRE- 

 PARED BY THE DIRECTOR OF THE MINT, TO ACCOMPANY 

 HIS ANNUAL REPORT, IN PURSUANCE OF THE ACT OF 

 FEBRUARY 21, 1857. 



EXPLANATORY REMARKS. 



The first column embraces the names of the countries where the coins are 

 issued ; the second contains the names of the coin, only the principal denomina- 

 tions being given. The other sizes are proportional ; and when this is not the 

 case, the deviation is stated. 



The third column expresses the weight of a single piece in fractions of the 

 troy ounce canied to the thousandth, and in a few cases to the ten thousandth, 

 of an ounce. The method is preferable to expressing the weight in grains for 

 commercial pm-poses, and coiresponds better with the terms of the mint. It may 

 be readily transferred to weight in grains by the following rules : Remove the 

 decimal point ; from one-half deduct four per cent, of that half, and the remain- 

 der will be grains. 



The fourth column expresses the fineness in thousandths, i. e. the number of 

 parts of pure gold or silver in 1000 parts of the coin. 



The fifth and sixth columns of the first table express the valuation of gold. 

 In the fifth is shown the value as compared with the legal contents, or amount 

 of fine gold in our coin. In the sixth is shown the value as paid in the mint, 

 after the uniform deduction of one-half of one per cent. The fonner is the value 

 for any other purposes than re-coinage, and especially for the purpose of com- 

 parison ; the latter is the value in exchange for our coins at the mint. 



For the silver there is no fixed legal valuation, the law providing for shifting 

 the price according to the condition of demand and supply. The present price 

 of standard silver is 122^ cents per ounce, at which rate the values in the fifth 

 column of the second table are calculated. In a few cases, where the coins could 

 not be procured, the data are assumed from the legal rates, and so stated. 



