cupels

How many of all these old folios round me are like so many old cupels!

The Atlantic Monthly, Volume 04, No. 23, September, 1859 Various

With four assay pieces, the cupels should be placed close together in two rows of three across the muffle; the two check pieces are put in the middle cupels.

A Text-book of Assaying: For the Use of Those Connected with Mines. Cornelius Beringer 1886

Another is to cover the cupel with another cupel previously heated to redness; in this case the silver cools between two hot cupels, and, of course, cools slowly.

A Text-book of Assaying: For the Use of Those Connected with Mines. Cornelius Beringer 1886

These cupels are square blocks, a little less than 2 inches across, and a little more than three quarters of an inch deep.

A Text-book of Assaying: For the Use of Those Connected with Mines. Cornelius Beringer 1886

One plan is to allow the cupels to cool in the muffle itself, the mouth being closed with hot charcoal.

A Text-book of Assaying: For the Use of Those Connected with Mines. Cornelius Beringer 1886

[13] Still the precautions of having cupels well made from bone ash in fine powder, and of working the cupellation at as low a temperature as possible are very proper ones, provided they are not carried to an absurd excess.

A Text-book of Assaying: For the Use of Those Connected with Mines. Cornelius Beringer 1886

There should be no unnecessary handling of the cupels once they have been placed in the muffle.

A Text-book of Assaying: For the Use of Those Connected with Mines. Cornelius Beringer 1886

The process is as follows: -- The cupels, which should have been made some time before and stored in a dry place, are first cleaned by gentle rubbing with the finger and blowing off the loose dust; and then placed in a hot muffle and heated to redness for from 5 to 10 minutes before the alloy to be cupelled is placed on them.

A Text-book of Assaying: For the Use of Those Connected with Mines. Cornelius Beringer 1886

On such cupels a small speck of gold (less than .01 milligram) will be left in a good shape and easily visible; but the cupel must be withdrawn from the muffle as soon as the cupellation is finished to make sure of always getting the button in good condition.

A Text-book of Assaying: For the Use of Those Connected with Mines. Cornelius Beringer 1886

These small cupels are best made by grinding the unsaturated portion of a used cupel to a fine powder, and compressing the dry powder into a small Berlin crucible or scorifier; the face should be made quite smooth by pressure from a pestle.

A Text-book of Assaying: For the Use of Those Connected with Mines. Cornelius Beringer 1886