5 | 4.7 | 4.9 | 5.1 | 5.4 | 5.7
27 | 4.3 | 4.5 | 4.7 | 4.9 | 5.1 | 5.4
28 | 4.1 | 4.3 | 4.5 | 4.7 | 4.9 | 5.1
29 | 3.9 | 4.1 | 4.3 | 4.5 | 4.7 | 4.9
30 | 3.8 | 3.9 | 4.1 | 4.3 | 4.5 | 4.7
===========================================================================

Table III. This table is calculated by inversion of the factors
in Table I, and is the most useful of all such tables, as it is
a direct calculation of the number of years that a given rate of
income on the investment must continue in order to amortize the
capital (the annual sinking fund being placed at compound interest
at 4%) and to repay various rates of interest on the investment. The
application of this method in testing the value of dividend-paying
shares is very helpful, especially in weighing the risks involved in
the portion of the purchase or investment unsecured by the profit
in sight. Given the annual percentage income on the investment from
the dividends of the mine (or on a non-producing mine assuming a
given rate of production and profit from the factors exposed), by
reference to the table the number of years can be seen in which
this percentage must continue in order to amortize the investment
and pay various rates of interest on it. As said before, the ore
in sight at a given rate of exhaustion can be reduced to terms of
life in sight. This certain period deducted from the total term
of years required gives the life which must be provided by further
discovery of ore, and this can be reduced to tons or feet of extension
of given ore-bodies and a tangible position arrived at. The test
can be applied in this manner to the various prices which must
be realized from the base metal in sight to warrant the price.

Taking the last example and assuming that the mine is equipped,
and that the price is $2,000,000, the yearly return on the price is
10%. If it is desired besides amortizing or redeeming the capital to
secure a return of 7% on the investment, it will be seen by reference
to the table that there will be required a life of 21.6 years. As the
life visible in the ore in sight is ten years, then the extensions
in depth must produce ore for 11.6 years longer--1,160,000 tons. If
the ore-body is 1,000 feet long and 13 feet wide, it will furnish
of gold ore 1,000 tons per foot of depth; hen