e stored and sold. Being sharp, crystalline, and even in
quality, it was a valuable by-product, finding a ready sale for
building purposes, railway sand-boxes, and various industrial uses. The
concentrate, in fine powdery form, was delivered in similar manner to a
stock-house.

As to the next step in the process, we may now quote again from the
article in the Iron Age: "While Mr. Edison and his associates were
working on the problem of cheap concentration of iron ore, an added
difficulty faced them in the preparation of the concentrates for the
market. Furnacemen object to more than a very small proportion of fine
ore in their mixtures, particularly when the ore is magnetic, not easily
reduced. The problem to be solved was to market an agglomerated material
so as to avoid the drawbacks of fine ore. The agglomerated product must
be porous so as to afford access of the furnace-reducing gases to the
ore. It must be hard enough to bear transportation, and to carry the
furnace burden without crumbling to pieces. It must be waterproof, to a
certain extent, because considerations connected with securing low rates
of freight make it necessary to be able to ship the concentrates to
market in open coal cars, exposed to snow and rain. In many respects the
attainment of these somewhat conflicting ends was the most perplexing
of the problems which confronted Mr. Edison. The agglomeration of the
concentrates having been decided upon, two other considerations, not
mentioned above, were of primary importance--first, to find a suitable
cheap binding material; and, second, its nature must be such that
very little would be necessary per ton of concentrates. These severe
requirements were staggering, but Mr. Edison's courage did not falter.
Although it seemed a well-nigh hopeless task, he entered upon the
investigation with his usual optimism and vim. After many months
of unremitting toil and research, and the trial of thousands of
experiments, the goal was reached in the completion of a successful
formula for agglomerating the fine ore and pressing it into briquettes
by special machinery."

This was the final process requisite for the making of a completed
commercial product. Its practice, of course, necessitated the addition
of an entirely new department of the works, which was carried into
effect by the construction and installation of the novel mixing and
briquetting machinery, together with extensions of the conveyors, with
which th