Bullion usually means uncoined gold and silver in bars or other masses, though occasionally it is used as practically synonymous with the precious metals, coined and uncoined. The origin of the word bullion in its present sense, as well as that of the French Billon (q.v.), and the corresponding Spanish vellon, seems to be as follows: Bullion originally meant the mint, where the alloy for the coinage was prepared and the coin stamped (either from the Lat. bulla, a round boss or stud, or stamp; or from the verb bullare, to boil or bubble); and hence it came in England to signify the standard metal of which the coins are made. In France, where the kings debased the currency much more than ever took place in England, billon, the mint, came to signify the base mixture issued therefrom.
It is difficult to obtain trustworthy statistics regarding the production and consumption of the precious metals even at the present time, and still more so at remote periods. For ancient and medieval times the reader may consult Jacob's Historical Inquiry into the Production and Consumption of the Precious Metals, published 1831, which was long regarded as the standard work on the whole subject. Recently, however, Dr Adolph Soetboer has made much more thorough investigations for the period 1493-1885, and his Materials for the Study of the Precious Metals is now the work most generally relied upon.
As regards the production of the precious metals, two great revolutions are to be observed in the 16th and 19th centuries. Between 1493-1520 the total production of gold and silver was in the proportion of about 57 per cent. of gold to 43 per cent. of silver (the value being reckoned at the actual value of the time), whilst between 1581-1600 the proportion became (in value) 17.2 gold to 82.8 silver. This change was principally due to the discovery of the silver mines of Potosi (1545). Between 1831-40 the production (in value) was 34.9 gold to 65.1 silver, and for the period 1851-55 the proportion had become 77.6 gold to 22.4 silver. This change was caused by the discovery of the great gold mines in Australia and California. The magnitude of these discoveries may be estimated from the fact that between 1493-1850 (358 years) the total production of gold is given at 4,752,070 kilograms, whilst between 1851-85 (35 years) it is given at 6,383,388 kilograms. The value of a kilogram of gold is £139, 10s. Since 1855 the relative production of gold to silver has gradually declined, the figures for 1881-85 being 49.3 gold to 50.7 silver. The total production of gold (in value) was (1493-1850) about £663,000,000, and from 1851-85 about £890,000,000; the total production of silver (estimated at its actual gold value at different times) was (1493-1850) about £1,472,000,000, and from 1851-85 about £480,000,000.
The most remarkable circumstance in these changes in the relative amounts of gold and silver produced is the slight effect on the ratio between gold and silver. Before the discovery of the rich silver mines of Potosi the ratio was (1521-40) about , and from 1601-20 it was only . Again, just before the great gold discoveries in this century (1841-50) the ratio was 15.83 : 1, and between 1851-55, in spite of the enormous increase in gold, it fell only to 15.41 : 1. See BIMETALLISM.
The production of the precious metals must of course be compared with their consumption or use. The principal uses are for coinage, including keeping up the coins to their full weight, for the arts, and for hoards. The statistics are largely conjectural, and are given by Dr Soetboer with due reserve. The most interesting conclusion is the large increase in the use of gold for the arts and for exportation to the East, more than five-sixths of the annual supply being used for these purposes.