Labour, therefore, it appears evidently, is the only universal, as well as the only accurate measure of value, or the only standard by which we can compare the values of different commodities at all times, and at all places.We cannot estimate, it is allowed, the real value of different commodities from century to century by the quantities of silver which were given for them.We cannot estimate it from year to year by the quantities of corn.By the quantities of labour we can, with the greatest accuracy, estimate it both from century to century and from year to year.From century to century, corn is a better measure than silver, because, from century to century, equal quantities of corn will command the same quantity of labour more nearly than equal quantities of silver.From year to year, on the contrary, silver is a better measure than corn, because equal quantities of it will more nearly command the same quantity of labour.
But though in establishing perpetual rents, or even in letting very long leases, it may be of use to distinguish between real and nominal price; it is of none in buying and selling, the more common and ordinary transactions of human life.
At the same time and place the real and the nominal price of all commodities are exactly in proportion to one another.The more or less money you get for any commodity, in the London market for example, the more or less labour it will at that time and place enable you to purchase or command.At the same time and place, therefore, money is the exact measure of the real exchangeable value of all commodities.It is so, however, at the same time and place only.
Though at distant places, there is no regular proportion between the real and the money price of commodities, yet the merchant who carries goods from the one to the other has nothing to consider but their money price, or the difference between the quantity of silver for which he buys them, and that for which he is likely to sell them.Half an ounce of silver at Canton in China may command a greater quantity both of labour and of the necessaries and conveniences of life than an ounce at London.Acommodity, therefore, which sells for half an ounce of silver at Canton may there be really dearer, of more real importance to the man who possesses it there, than a commodity which sells for an ounce at London is to the man who possesses it at London.If a London merchant, however, can buy at Canton for half an ounce of silver, a commodity which he can afterwards sell at London for an ounce, he gains a hundred per cent by the bargain, just as much as if an ounce of silver was at London exactly of the same value as at Canton.It is of no importance to him that half an ounce of silver at Canton would have given him the command of more labour and of a greater quantity of the necessaries and conveniences of life than an ounce can do at London.An ounce at London will always give him the command of double the quantity of all these which half an ounce could have done there, and this is precisely what he wants.
As it is the nominal or money price of goods, therefore, which finally determines the prudence or imprudence of all purchases and sales, and thereby regulates almost the whole business of common life in which price is concerned, we cannot wonder that it should have been so much more attended to than the real price.
In such a work as this, however, it may sometimes be of use to compare the different real values of a particular commodity at different times and places, or the different degrees of power over the labour of other people which it may, upon different occasions, have given to those who possessed it.We must in this case compare, not so much the different quantities of silver for which it was commonly sold, as the different quantities of labour which those different quantities of silver could have purchased.
But the current prices of labour at distant times and places can scarce ever be known with any degree of exactness.Those of corn, though they have in few places been regularly recorded, are in general better known and have been more frequently taken notice of by historians and other writers.We must generally, therefore, content ourselves with them, not as being always exactly in the same proportion as the current prices of labour, but as being the nearest approximation which can commonly be had to that proportion.I shall hereafter have occasion to make several comparisons of this kind.
In the progress of industry, commercial nations have found it convenient to coin several different metals into money; gold for larger payments, silver for purchases of moderate value, and copper, or some other coarse metal, for those of still smaller consideration.They have always, however, considered one of those metals as more peculiarly the measure of value than any of the other two; and this preference seems generally to have been given to the metal which they happened first to make use of as the instrument of commerce.Having once begun to use it as their standard, which they must have done when they had no other money, they have generally continued to do so even when the necessity was not the same.
The Romans are said to have had nothing but copper money till within five years before the first Punic war, when they first began to coin silver.Copper, therefore, appears to have continued always the measure of value in that republic.At Rome all accounts appear to have been kept, and the value of all estates to have been computed either in asses or in sestertii.
The as was always the denomination of a copper coin.The word sestertius signifies two asses and a half.Though the sestertius, therefore, was originally a silver coin, its value was estimated in copper.At Rome, one who owed a great deal of money was said to have a great deal of other people's copper.
