Gold and silver, like every other commodity, vary in their value. The discovery of the abundant mines of America reduced in the sixteenth century the value of gold and silver in Europe to about a third of what it had been before. This revolution in their value, though perhaps the greatest, is by no means the only one of which history gives some account. And again: Increase the scarcity of gold to a certain degree and the smallest bit of it may be more precious than a diamond. John Locke, "Considerations, etc., in relation to money" (published in 1691), says: The greater scarcity of money enhances its price and increases the scramble; there being nothing that does supply the want of it; the lessening of its quantity, therefore, always increases its price and makes an equal portion of it exchange for a greater of any other thing. Prof. Francis A. Walker, "Money," etc., page 210, says: Gold and silver do, over long periods, undergo great changes of value and become in a high degree deceptive as a measure of the obligation of the debtor of the claim of the creditor. Thus Professor Jevons estimates that the value of gold fell between 1789 and 1809, 46 per cent., that from 1809 to 1849 it rose 145 per cent., while in twenty years after 1849 it fell again at least 20 per cent. Jevons, "Money and Exchange," chapter 6, says: In respect to steadiness of value the metals are probably less satisfactory, regarded as a standard of value, than many other commodities, such as corn. And again, in chapter 24 of the same work, he says: We are too much accustomed to look upon the value of gold as a fixed datum line in commerce; but in reality it is a very variable thing. Sir Archibald Alison (England, in 1815 and 1845), says: The coining of gold and silver, which is universal in all civilised nations, and affixing to them one definite and permanent value by authority of law, has no effect whatever in preventing the fluctuations in the real value of the current coin of the realm. Professor Laughlin, of Harvard, in his work on Political Economy (page 72), says: It is quite evident that the name dollar does not always have the same value, although people often think it does. We get into the habit of using names without thinking what they really mean. The 23.22 grains in a gold dollar may be exchanged sometimes for more, sometimes for less, of other commodities. When it is exchanged for less, its value has fallen relatively to all other commodities, and, even if the name dollar remains the same, its value has fallen. One must then offer more dollars than before for the same commodities. That is, when money falls in value, prices rise; when money rises in value, prices fall.