Note 2 — Chapter VI · Gold, and How they Came to Use It.

In 1862 Mr. Eckfelt, then principal assayer at the mint in Philadelphia, communicated to the American Philosophical Society the result of some exceedingly curious examinations demonstrating the very wide distribution of gold. The city of Philadelphia, he stated, was underlaid by a bed of clay having an area of about ten square miles, with an average depth of about fifteen feet. Specimens of this clay—all natural deposits—taken from such localities as might furnish a fair assay of the whole—the cellar of the market on Market Street, near Eleventh, and from a brick-yard in the suburbs of the city—all yielded, on careful analysis, small amounts of gold; the average amount indicated being seven-tenths of a grain—or about three cents’ worth—of gold for every cubit foot of clay. Assuming these data to be correct, the value of the gold, according to Mr. Eckfelt, which lies securely buried underneath the streets and houses of Philadelphia must therefore be equivalent to $128,000,000; or if we include all the clay contained in the corporate limits, the amount of gold contained in it must be equal to all that has yet been obtained from California and Australia.

“It is also apparent,” says Mr. Eckfelt, “that every time a cart-load of clay is hauled out of a cellar in Philadelphia, enough gold goes with it to pay for the carting; and if the bricks which front our houses could have brought to their surface, in the form of gold-leaf, the amount of gold which they contain, we should have the glittering show of two square inches on every brick.”