cupellations

In ten cupellations with the same quantities of gold and lead, but at an ordinary temperature, the gold recovered from the cupels varied from 1.37 to 1.92 milligrams, and gave an average of 1.59 milligrams.

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

In judging these results, it must be borne in mind that it is difficult to regulate the temperature, &c., in consecutive experiments so as to get exactly similar results, so that the range in consecutive cupellations is greater than that in a batch cupelled side by side.

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

The furnace should then be stoked and made ready for the next cupellations; by the time the furnace is ready the cupels will be ready also.

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

A determination of the actual silver in the buttons got in the series of cupellations quoted on pages 102, 103, gave an average percentage of

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

Three lots of 1 gram of gold cupelled each with 20 grams of lead repeatedly, so as to make 13 cupellations in all, lost in actual weight 35.72 milligrams.

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

The best plan is to do all the cupellations in batches.

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

In three cupellations of 1 gram of gold with 20 grams of lead made purposely at a very high temperature the cupel absorbed 6.04, 6.20, and

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