We have already observed that the prolongation of the cupelling process increases the richness of the remaining alloy, and this very rich silver-lead alloy is again subjected to a second operation in cupelling.
The process of cupelling is conducted in the furnace of the assayer, an apparatus of peculiar construction, the most important part of which, however, is the muffle (Fig.
Suppose we have an alloy of silver and lead in unknown proportions and that by cupelling two lots of 10 grams each there is got from I.
Karsten got by actual experiment on cupelling copper and lead in equal proportions, a loss of 21.
The silver is incorporated with the gold, and at the same time the copper is eliminated, by cupelling with sheet lead.
It is easy to determine what allowance must be made for the loss in cupellation by cupelling side by side with the assay piece an alloy of similar and known composition.
If the button left on cupelling the lead from an assay of an ore appears white, it is best to assume that it already contains at least a sufficiency of silver, in the absence of any knowledge to the contrary.
For small buttons of gold as little lead as may be relied on to start cupelling may be taken; the lead may conveniently be in the form of little cups made by folding lead foil on a piece of glass rod.
Refer to the table on page 105 to find what weight of lead is required for cupelling 1 gram of alloy.
The button of gold obtained by cupelling is loosened from the cupel by gently touching with the moistened point of a knife; it generally adheres to the knife, and is then transferred to a glass slide.
During the whole process of cupelling a silver lead alloy a more or less abundant fume may be observed rising from the cupel.
That it does not do so in the ordinary way of working is shown by the fact that a button of silver equal in weight to the silver lost in cupelling may be got by smelting the cupel and cupelling the resulting button of lead.
The base metals are generally determined by cupelling .
Gold, obtained by cupelling and "parting," is for most purposes sufficiently pure.
The determination may also be made by cupelling the button of lead got in the dry lead assay.
The intervening kettles contain leads with silver contents ranging from above market to belowcupelling lead.
The latest cupelling furnaces have the general form of a reverberatory copper-smelting furnace.
The same is done with the kettle one-third filled with liquid lead, and so on until the first kettle contains market lead, the last cupelling lead.
Put your Copper in filings into a test, and set it under the muffle of a cupelling furnace; light the fire, and keep up such a degree of heat as may make the whole quite red, but not enough to melt the Copper.
The Cupelling Furnace is much larger than it should be, with respect to the Melting Furnace.
The Cupelling furnace is that in which gold and silver are purified, by the means of lead, from all alloy of other metallic substances.
Place the test thus loaded under the further end of the muffle in a cupelling furnace.
Break into small bits the Black Copper you intend to purify; mix therewith a third part in weight of granulated Lead, and put the whole into a cupel set under the muffle in a cupelling furnace, and previously heated quite red.
Chaudet has made some experiments on the means of detecting the metals of alloys by the cupelling furnace, and they promise useful applications.
In such small work as cannot be assayed by scraping off a part and cupelling it, the assayers endeavour to ascertain its fineness or quality by the touch.
When copper is to be separated from gold by cupellation, a higher temperature is requisite than in cupelling silver coin.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "cupelling" in a variety of sentences. We hope that you will now be able to make sentences using this word.
