If Copper be mixed with any other base metall or semi-metall it will not endure the hammer when red hot but fly in pieces. So soon as it is refined by the Copper-workers dto that degree as to be purged from all other base metalls, it begins to endure the hammer hen red hot & to be worth about 98 or 100li per Tunn; & such copper they call fine copper. For making Copper Vessels they refine it a little higher, & for drawing into wyer they refine it still higher. But for money it suffices to refine it till it begins to beare the hammer when red hot. They that work in copper can readily judge of the fineness also by breaking off a little piece & observing the grain & colour where it breaks. There is also a way of assaying copper by separating the other base metalls from it, but the assay by the hammer I reccon sufficient for the Mint. For it will be proper for the Master & Worker not to receive course copper & put it out to refine as is done in gold & silver, but only to receive it when refined to the degree above mentioned.

In the reign of King Charles II a pound weight of Swedish copper was cut into 20d. The copper & making the blanks cost 18d the stamping 1d, & a penny remained for other charges.

A pound weight of fine English copper such as will endure the assay above mentioned will cost 10$\frac{1}{2}$d or 10$\frac{3}{4}$d, & the coynage will cost 5$\frac{1}{2}$ or 5$\frac{3}{4}$ including the work of the Smith & Graver: so that the whosle charge of copper & coynage will scarce exceed 16$\frac{1}{2}$d per pound weight averdupoise. And if the same be edged the edging will cost a penny more. And if a pound weight not edged be cut into 19d, or a pound weight edged be cut into 20d, there will remain 2$\frac{1}{2}$d per pound weight for purchasing Mills & Presses & setting up a copper Mint, & paying Clerks & incident charges of assaying, weighing, telling, porterage, putting off, &c