a steel mold. The
base metals oxydize and are absorbed with the lead into the pores of the
cupel. A button or globule of perfectly pure gold and silver is left
behind, and by weighing it and noting the loss, the assayer knows the
proportion of base metal the brick contains. He has to separate the gold
from the silver now. The button is hammered out flat and thin, put in
the furnace and kept some time at a red heat; after cooling it off it is
rolled up like a quill and heated in a glass vessel containing nitric
acid; the acid dissolves the silver and leaves the gold pure and ready to
be weighed on its own merits. Then salt water is poured into the vessel
containing the dissolved silver and the silver returns to palpable form
again and sinks to the bottom. Nothing now remains but to weigh it; then
the proportions of the several metals contained in the brick are known,
and the assayer stamps the value of the brick upon its surface.

The sagacious reader will know now, without being told, that the
speculative miner, in getting a "fire-assay" made of a piece of rock from
his mine (to help him sell the same), was not in the habit of picking out
the least valuable fragment of rock on his dump-pile, but quite the
contrary. I have seen men hunt over a pile of nearly worthless quartz
for an hour, and at last find a little piece as large as a filbert, which
was rich in gold and silver--and this was reserved for a fire-assay! Of
course the fire-assay would demonstrate that a ton of such rock would
yield hundreds of dollars--and on such assays many an utterly worthless
mine was sold.

Assaying was a good business, and so some men engaged in it,
occasionally, who were not strictly scientific and capable. One assayer
got such rich results out of all specimens brought to him that in time he
acquired almost a monopoly of the business. But like all men who achieve
success, he became an object of envy and suspicion. The other assayers
entered into a conspiracy against him, and let some prominent citizens
into the secret in order to show that they meant fairly. Then they broke
a little fragment off a carpenter's grindstone and got a stranger to take
it to the popular scientist and get it assayed. In the course of an hour
the result came--whereby it appeared that a ton of that rock would yield
$1,184.40 in silver and $366.36 in gold!

Due publication of the whole matter was made in the paper, and the
popular assayer left tow