manufacture of any article which is procured from nature at great
expense. This is the case with marble. It is scarce at best; the
quarries are remote from the centers of population, and the mining and
transportation make it a very costly article. Marble can be manufactured
by imitating nature’s processes--the percolating of water through chalk.
The popular verde antique can be made by an application of an oxide of
copper. The slices of marble are then placed in another bath, where they
are hardened and crystallized, coming out exactly like the real article.
In Italy, a fine black marble is made from common white sandstone. The
manufacture is carried on by the owners of the local gasworks, who thus
reap a double profit from their plant. Here is a hint for American
manufacturers.