est, to 32.60 per cent., the
highest. Under every stratum of coal, and frequently mixed with it, are
these under deposits that are rich in the metal. When exposed to the
atmosphere, these shales yield a small deposit of alum. In the
manufacture of alum near Glasgow the shale and slate clay from the old
coal pits constitute the material used, and in France alum is
manufactured directly from the clay.

Sufficient has been advanced to warrant the additional assertion that we
are here everywhere surrounded by this incomparable mineral, that it is
brought to the surface from its deposits deep in the earth by the
natural process in mining, and is only exceeded in quantity by the coal
itself. Taking a columnar section of our coal field, and computing the
thickness of each shale stratum, we have from twenty-five to sixty feet
in thickness of this metal-bearing substance, which averages over
twenty-five per cent. of the whole in quantity in metal.

It is readily apparent that the only task now before us is the reduction
of the ore and the extraction of the metal. Can this be done? We answer,
it has been done. The egg has stood on end--the new world has been
sighted. All that now remains is to repeat the operation and extend the
process. Cheap aluminum will revolutionize industry, travel, comfort,
and indulgence, transforming the present into an even greater
civilization. Let us see.

We have seen the discovery of the mere chemical existence of the metal,
we have stood by the birth of the first white globule or bead by Wohler,
in 1846, and witnesssed its introduction as a manufactured product in
1855, since which time, by the alteration and cheapening of one process
after another, it has fallen in price from thirty-two dollars per pound
in 1855 to fifteen dollars per pound in 1885. Thirty years of persistent
labor at smelting have increased the quantity over a thousandfold and
reduced the cost upward of fifty per cent.

All these processes involve the application of heat--a mere question of
the appliances. The electric currents of Berzelius and Oersted, the
crucible of Wohler, the closed furnaces and the hydrogen gas of the
French manufacturers and the Bessemer converter apparatus of Thompson,
all indicate one direction. This metal can be made to abandon its bed in
the earth and the rock at the will of man. During the past year, the
Messrs. Cowles, of Cleveland, by their electric smelting process, claim
to have made it possib