every emigrant, $150 per head for the average value of personal property brought, as I have shown, by each, we find that immigration increased the national wealth, in the stated period, by more than five billions of dollars, or more than twice as much as the present amount of the national debt. The total immigration into the United States being now at the rate of 300,000 souls per year, the country gains nearly four hundred millions of dollars annually, or more than one million per day.
My friend, Mr. Charles L. Brace, in a very able communication Mr. Brace theorywhich, on November 3, 1869, he addressed to the New York daily Tribune, has taken exceptions to these statements and estimates, which were contained in a paper read by me before the American Social Science Association.
"Mr. Kapp," he says, "deserves high commendation for the ingenuity and industry he has shown in thus analyzing our emigration statistics, and proving the economical value of this current of population.
"But, in the light of science, we are compelled to point out what seem to us omissions in these economical reasonings, which will somewhat modify the results. The capital value of an object is not determined merely by the cost of its production, but also by another element—the demand for it. Thus, if a hundred new sewing-machines are produced, they are worth to the community not merely what they cost to make, but what the demand for them will bring. If there has been an overproduction of sewing-machines, or they are of poor quality, their worth sinks, and their money value to the community may fall below the cost of manufacture. The same is true of all articles which are parts of the capital of a country. Their money value or price is conditioned by cost of production and the relation of demand to supply. It is true also of animals. A cow or a horse is worth not alone what it costs to produce it, but what the demand will bring. Some, from adventitious circumstances, will fall below the cost of production; some will rise above it. Many fine horses, which cost no more to raise than poor ones, are worth far more to the country, because the demand for them is greater, while many poor ones sink below their cost, because the demand is unreasonably small. So with human beings, if we look at them purely as
