removed; and, when this was effected, the internal surface of the mould appeared corroded in some parts, and, as it were, inlaid by the mixed metal.

Upon weighing the bar, it was found that only 15 pennyweights of the antimony remained combined with the gold; so that three pennyweights and twenty-one grains had been dissipated.

This metal was of a dull pale colour, not very unlike tutenague; it was excessively brittle, and in the fracture appeared of an ash colour, with a fine close grain, somewhat resembling that of porcelain.

Experiment 11.

To eighteen pennyweights and ten grains of the fine gold, in fusion, nineteen grains of copper were added, which being melted and well mixed, nineteen grains of antimony were also added; after which, the metal was poured into a mould.

The external colour of the button was like gold made standard by copper; it was very brittle, and, in the colour and grain of the fracture, resembled the result of the preceding experiment.

Experiment 111.

Eighteen pennyweights and ten grains of the fine gold, were alloyed with one pennyweight and six grains of copper, and afterwards eight grains of antimony were added, to complete the standard proportion of alloy; the mixture was then poured, as expeditiously as possible, into a mould.

The ingot resembled that of the former experiment, in every particular, excepting that the grain of the fracture was more coarse, although it was still devoid of metallic lustre.

Experiment iv.

Eighteen pennyweights and ten grains of the fine gold, were alloyed with one pennyweight and ten grains of copper, and, when in perfect fusjon, four grains of antimony were added.

The external colour of the ingot was like that of Experiments II. and III. It was very brittle, and the grain of the fracture was similar to Exper. III. excepting that it shewed a small degree of metallic lustre.

Experiment v.

To one ounce sixteen pennyweights and twenty grains of the fine gold, alloyed with three pennyweights and three grains of copper, one grain of antimony was added, and the mixture was treated as before.

The antimony, in this mass, was in the proportion of only half a grain in each ounce; but the ingot was completely brittle, and the fracture still shewed a close grain, although the metallic lustre now began to be more apparent.

Experiment vi.

The two ounces of the metal formed by the preceding experiment, were added to two ounces of gold made standard by fine copper.

The proportion of antimony, in this experiment, could at most be estimated only at of a grain in the ounce; but, as it may be supposed that, by the repeated meltings, some of the antimony had been volatilized, it probably was in a less proportion.

The ingot formed by this experiment was, in colour, and in other properties, very like that of Exper. v. It was, however, in a

slight degree less brittle, as it did not so immediately break under the hammer.

I

The foregoing experiments prove, that of a grain of antimony in the ounce, or part of the mass, can destroy the ductility of gold.

I 9

The following experiments were made to ascertain the effects of the vapour or fumes of antimony upon gold, when close and when open vessels were employed.

Experiment VII.

480 grains of fine gold were exposed, in close vessels, to the fumes of about 480 grains of antimony, under circumstances similar to those described in the third experiment upon arsenic.

When the crucibles were unluted, the chief part of the antimony was found, unchanged, at the bottom of the inferior large crucible.

The button of gold in the small crucible was not altered in the external colour, but proved to be extremely brittle, for it immediately split under the hammer, and exhibited a close grained earthy fracture, of an ash colour.

After the experiment, the button weighed 483,9 grs.; so that it had acquired 3,9 grs. of antimony.

Experiment VIII.

A small four-inch crucible, containing 480 grains of fine gold, was placed within another, of 12 inches; and four ounces of antimony were put into the large outer crucible, as soon as the gold appeared to be perfectly melted.

When half an hour had elapsed, the small crucible was

removed, and the gold was poured into a mould. The button was externally of a dull brownish colour, and was very brittle.

From the two last experiments, it may be inferred, that gold, when melted in close, and even in open vessels, attracts and combines with antimony in the state of vapour.*

GOLD ALLOYED WITH ZINC.

Experiment 1.

Eleven ounces one pennyweight and three grains of gold, 23 car. 31 grs. fine, were melted, after which, eighteen pennyweights and twenty-one grains of zinc were added, and, being quickly stirred, the whole was poured into a mould of iron.

Upon the addition of the zinc, a bright flame immediately arose; and, although as little time as possible was lost, yet, upon weighing the bar, it appeared, that in this short period, five pennyweights and twenty-one grains of zinc had been volatilized, and that only thirteen pennyweights remained combined with the gold.

The bar was of a pale greenish yellow, like brass, and was totally devoid of ductility.

Experiment 11.

Eighteen pennyweights and ten grains of the fine gold, were alloyed with 19 grains of copper, to which, when completely melted, 19 grains of zinc were added, and, being expeditiously mixed, the metal was poured into a mould.

The external colour of the ingot was pale yellow; it was

It has been proved, that arsenic will not combine readily with gold in open vessels; but the reverse was observed when antimony, zinc, and some other metals, were reduced to vapour in the vicinity of melted gold. This effect appears to depend on the relative affinities of the different metals with gold and with caloric.

very brittle, and, like the former bar, exhibited a coarse grain in the fracture.

Experiment III.

Eighteen pennyweights and ten grains of the fine gold, were alloyed with one pennyweight and six grains of copper, and, when in fusion, eight grains of zinc were added.

This experiment was conducted as quickly as possible; but nevertheless, upon weighing the ingot, it appeared that the whole of the zinc had been volatilized; and this was farther proved, by the colour, and by the perfect ductility of the metal.

Experiment IV.

To eleven ounces one pennyweight and three grains of the fine gold, in fusion, eighteen pennyweights and twenty-one grains of fine brass wire were added, and mixed as before.

The external and internal colour was of a fine pale yellow; but the metal was very brittle, and the grain of the fracture was

coarse.

Experiment v.

To eighteen pennyweights and ten grains of gold, alloyed with 19 grains of copper, in fusion, were added 19 grains of fine brass.

This ingot did not, in general properties, differ from the former.

The following experiment was made, to ascertain the effects of zinc upon gold, when the two metals were melted in open vessels, near each other, without being in absolute contact.

Experiment vi.

One ounce of fine gold was melted in a four-inch crucible, which had been previously placed within another, of 12 inches.