still more subtle values of mental effort, and the intervention of erratic taxation, are impossible to measure.
Even if this method is attempted there is no accurate index of the retail price of finished commodities, such as cakes, shoes, clothes and sausages, and the services of the retailer which go with them.
What we can call to our assistance, in calculating population by Fisher’s method, is an estimate of the absorbing power of rent: an optimistic or pessimistic approximation of the time value of labor in all its varied forms: a surmise in regard to the incidence of taxation; and finally the index numbers of those unfinished commodities which lie behind the cake, the shoes, the clothes and the sausages, namely, wheat, hides, wool and hogs. But the index numbers of these commodities, useful as they may be, are simply industry’s guess at the total quantity of these goods and the probable future appetite of the population, measured in terms of a fluctuating unit. To use the product of an estimate, an approximation, a surmise and a compound forward guess, and record its belated consequences by a fluctuating weight of gold, is intensely interesting, but it is not scientific. To comment seriously on this plan calls for the same patience that the engineer must exercise when some enthusiast proposes to measure steam pressure by weighing the water and the coal which are needed for the boiler, keeping cheerful tally by dropping washers into a bucket. The enthusiast would be firmly led to the front of the boiler where there was a pressure gauge.
Yet Fisher has done enormous service in laying bare the practical defects of our currency, and may be wiser than he seems. His project has two merits: it seeks to approximate population justly by its physical appetites and it makes a gentle concession to those who think there is some sanctity in gold. Poor Galileo was not so tactful, and he had a much harder time of it.
We are wise to respect prejudice if we desire to accomplish anything; and there are still very capable engineers who pretend to express the value of expanding gas against the walls of a