economic problem. Compare in the present connection this figure with
Figure 3, in Chapter 6, Section 4, showing changes in index numbers of
prices.

[Illustration: FIG. 1. GOLD PRODUCTION OF THE WORLD. 1493-1710.
AVERAGES FOR PERIODS BEFORE 1870]]

[Footnote 6: This formula is presented by E.W. Kemmerer in "Money and
Prices" (2d ed., 1909), p. 15 ff.]

[Footnote 7: See above, ch. 3, sec. 6, table.]

[Footnote 8:

PER CAPITA CIRCULATION OF MONEY (ESTIMATED) IN THE UNITED
STATES IN VARIOUS YEARS.

1800......$4.99 1850......$12.02 1890......$22.82
1810...... 7.60 1860...... 13.85 1900...... 26.93
1820...... 6.96 1870...... 17.51 1910...... 34.33
1830...... 6.78 1880...... 19.41 1915...... 35.44
1840......10.91
]

[Footnote 9: On the function of deposits, see below, ch. 7, sec. 11.]

[Footnote 10: Consult Figure 1 in ch. 4 and Figure 2 in ch. 6 for the
graphic presentation of these and related facts.]