is coming, slowly but surely, a revolution in economic thought similar to the revolution in astronomic thought begun by Copernicus.
Just as we then learned that the sun and moon and stars do not really rise and set—though they move somewhat—but that what so appears is really the revolution of the earth on its axis, so we are now learning that commodities as a whole do not really rise and fall much but that what so appears is really the gyrations of the dollar.
The truth is, that the purchasing power of money has always been unstable. The fundamental reason is that a unit of money, as at present determined, is not, as it should be, a unit of purchasing power, but a unit of weight. It is the only unstable or inconstant unit we have left in civilization—a survival of barbarism. Other units, the yard, pound, bushel, etc., were once as unstable and crude as the dollar still is, but, one after another, they have all been stabilized or standardized.
There was, until recently, ample excuse for an unstable dollar. Up to the present generation no instrument for measuring its aberrations had been devised. In the same way, until the weighing scales were devised, weights could not be standardized, and until instruments for measuring electrical magnitudes were invented, electrical units could not be standardized. But for many years we have now possessed in the "index number" of prices the necessary instrument for measuring the value of the dollar in terms of its power to purchase goods.
One of the most suggestive signs of the times is that this instrument for measuring changes in the purchasing
