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will not answer. The great brittleness has been generallyimputed to the lead, of which the common forts of zincare supposed to partake in a greater or less degree; andhence it has been supposed necessary to previously purifythe zinc, by cementation and fusion with sulphur, whichabsorbs and scorifies the lead without acting upon thezinc; some forts of zinc may doubtless require a treatmentof this kind, but such, as has been usually brought fromthe East Indies, does not seem, when prepared in thismanner, to give less brittleness than when unprepared.

It is certain, however, that copper impregnated withzinc, by cementation and fusion with calamine, provesmore malleable, than when melted directly with as muchof common zinc'itself as it imbibes from the calamine; onaccount, perhaps, of the commixture being in the firstcafe more equal and perfect. By the process withcalamine, copper cannot easily be made to receive thefull quantity of zinc necessary for producing a good goldcolour: by combining the two processes together, thatis by making the copper first into brass, and then meltingit with a suitable quantity of zinc, a metal may beobtained of better quality than by either method singly.A very ingenious artist, who now prepares a gold-colouredmetal in great perfection, has a fine kind of brass madeon purpose for this use. An enquiry into the preparationand improvement of brass will make a separate article inone of the future numbers of this work.

A good deal of address is requisite in melting the copperand zinc together; for the heat necessary for the fusion ofcopper occasions the zinc to burn and flame, and a con-siderable part of it to be dissipated, so that the remainingcopper is defrauded of its due proportion. If the twometals are put into the crucible at first, and the firegradually raised, greatest part of the zinc will be burnt oss

before