If the might and eminence of a country consist in its surplus of gold, silver, and all other things necessary or convenient for its subsistence, derived, so far as possible, from its own resources (colonies and conquered territories included), without dependence upon other countries, and in the proper fostering, use, and application of these, then it follows that a general national economy . . . should consider how such a surplus, fostering, and enjoyment can be brought about, without dependence upon others, or where this is not feasible in every respect, with as little dependence as possible upon foreign countries, and sparing use of the country's own cash.