National Geographic : 1915 Dec
Photograph byThe Associated Photographers, New Orleans IN THE DEPTHS OF A LOUISIANA SALT MINE "With the exception of one or two minor minerals, the United States produces every mineral thatisneeded inindustry; and this can be said of no other country. . . . We can build a battleship or an automobile (excepting the tires), a railroad or afactory, entirely from the products of American mines and forests" (see text, page 590).