Learn next that silver, gold,
Lead, hardier COPPER, iron, first were trac'd
When o'er the hills, some conflagration dire
Burn'd from its basis the deep-rooted grove;
By lightnings haply kindled, or the craft
Of hosts contending o'er the woodland scenes,
A double fear thus striking through their foes:
Or by the shepherd's wish his bounds t' enlarge
O'er tracts of specious promise; or, perchance,
Wild beasts to slaughter, and their spoils possess ;
For such, with fire and guileful pit, mankind
First caught, ere hounds were marshall'd to the chace,
Or round the copse the mazy net-work drawn.

Whate'er the cause, when now the unctuous flame
Had from their utmost roots, with hideous crash,
Fell'd the tall trees, and, with its torrid heat,
The soil deep-redden'd, rills of liquid gold,
Lead, silver, copper, through its fervid pores

* Quod super est, ES atque aurum, ferrumque repertum est, &c. Lib. V. v. 1240.

The passage is too long for us to quote the original at length; upon the part of it before us the learned translator has the following note:-" The term æs, in the original, is generally interpreted in the different versions brass, which as a generic substantive, it will undoubtedly include, as well as copper. But brass, the appropriate term for which is aurichalcum, being a compound metal, and the invention of subsequent ages, it is obvious the poet here refers to the original metal whence brass was manufactured. Marchetti employs the term rame, which is equally general with as, and may alike be adopted to signify either copper or brass.

The existence of the metals here referred to in the interior of the earth, is thus described by Garth, in his Dispensary:

Here, sullen to the sight, at large is spread

The dull unwieldy mass of lumpish lead:

There, glimmering in their dawning beds, are seen

The more aspiring seeds of sprightly tin.

The copper sparkles next in ruddy streaks,

And in the gloom betrays its glowing cheeks:

The silver then, with bright and burnish'd grace,

Youth, and a blooming lustre in its face,

To th' arms of those more yielding metals flies,

And in the folds of their embraces lies.

On the invention and composition of brass or aurichalcum among the Greeks and Romans, see the same work, Note on Book VI, v. 1113.

Glided amain, and every hollow fill'd.

These when, condens'd, long after men survey'd
Glistening in earth, attracted by the glare,

The splendid mass they dug; and mark'd, surpriz'd,
Each form'd alike, and, to the channell'd bed
Where late it lay, adapted most precise.

Then instant deem'd they, liquified by flame,
The power was theirs each various shape t' assume,
Drawn dextrous out, of point or edge acute;
The power unrivall'd theirs each tool to frame
Art needs to fell the forest, and its trees

Mould into planks or beams; to cleave, or smooth,
Pierce, hollow, scoop, whate'er the plan conceiv'd.
Nor strove they less such instruments t' obtain
From gold, or silver, than stern copper's strength.
Yet vainly for their softer texture fail'd,
Powerless to bear the sturdy toil requir'd.
Whence copper chief they courted, while all gold
Neglected lay, too blunt, and dull for use.
Now triumphs gold, while copper sinks despised.
So rolling years the seasons change of things:
What once was valu'd loses all its worth,

And what was worthless rises in its stead,

Swells into notice daily, every hour

Blooms with new praise, and captive leads the world.

[Editor.

CHAP. III.

OF GUN-METAL; BRONZE, OR STATUARY-METAL; BELL METAL; POT-METAL; AND SPECULUM-METAL, OR METALLIC MIRRORS.

BESIDES brass there are many other metallic mixtures, into which copper enters as the principal ingredient; the most remarkable of these are gun-metal, bell-metal, pot-metal, and speculum-metal.

It has been remarked of Queen Elizabeth, that she left more brass ordnance at her death, than she found of iron on her acces.

sion to the throne. This must not be understood as if gun metal was in her time made chiefly of brass, for the term brass was sometimes used to denote copper; and sometimes a composition of iron, copper, and calamine, was called brass; and we at this day commonly speak of brass cannon, though brass does not enter into the composition used for the casting of cannon. Aldrovandus⭑ informs us, that 100 pounds weight of copper, with twelve of tin, made gun-metal; and that if, instead of twelve, twenty pounds weight of tin was used, the metal became bell-metal. The work. men were accustomed to call this composition metal, or bronze, according as a greater or a less proportion of tin had been used. Some individuals, he says, for the sake of cheapness, used brass or lead instead of tin, and thus formed a kind of bronze for vari. ous works. I do not know whether connoisseurs esteem the metal, of which the ancients cast their statues, to be of a quality superior to our modern bronze; but if we should wish to imitate the Romans in this point, Pliny has enabled us to do it; for he has told us, that the metal for their statues, and for the plates on which they engraved inscriptions, was composed in the following manner. They first melted a quantity of copper; into the melted copper they put a third of its weight of old copper, which had been long in use; to every hundred pounds weight of this mixture they added twelve pounds and a half of a mixture, composed of equal parts of lead and tin t.

In Diego Ufano's Artillery, published in 1614, we have an account of the different metallic mixtures then used for the casting of cannon, by the principal gun-founders in Europe.

Copper
Tin
Brass

160-100-100-100 parts.
10-20- 8- 8
8- 5- 5 0

The best possible metallic mixture cannot be easily ascertained, as various mixtures may answer equally well the rude, purpose to which orduance is applied. Some mixtures, however, are unques tionably better adapted to this purpose than others, in some parti cular points. Of two metallic mixtures, which should be equally strong, the lightest would have the preference: at the last siege of Prague, part of the ordnance of the besiegers was melted by the

* Aldrovandus, p. 108.

+ Hist. Nat. L. XXXIV. S. XX.

frequency of the firing; the mixture of which it was made con. tained a large portion of lead; and it would have been less prone to melt, and consequently preferable, had it contained none.

Woolwich, I believe, is the only place in England, where there is a foundry for the casting of brass cannon. The metallic com. position there used, consists of copper and tin. The proportion in which these two metals are combined, is not always the same, because the copper is not always of equal purity, and the finest copper requires the most tin; they seldom use more than twelve, or less than eight parts of tin to every 100 of copper. This metallic mixture is sold, before casting, for £.75 a ton, and Government pays for casting it £.60 a ton. The guns of the East India Company are less ornamented than those of Govern ment; on that and other accounts they are cast for £. 40 a ton. I have here put down the weights of the brass ordnance, now most generally in use, as cast at Woolwich.

Weight of brass cannon now in use.

These were on board the Royal George in 1780, but had been removed, I believe, before she was lost.

In casting these pieces of cannon, they generally make the thickness of the sides, near the muzzle, half the diameter of the shot, and at the touch-hole, or charging cylinder, three-fourths of the diameter. Brass cannons are dearer than those made of iron; and, which is a disadvantage, they give a louder report at the time of explosion, so as to occasion a tingling in the ears of the persons on shipboard, which takes away for a time the faculty of hearing.

Cannon might be cast of copper alone; but the mixture of tin and copper is harder and denser, and less liable to rust than pure copper is, and upon these accounts it is preferable to copper. Tin melts with a small degree of heat, copper requires a very great heat to melt it; a mixture of copper and tin melts much easier than pure copper, and upon this account also, a mixture of copper and tin is preferred to pure copper, not only for the casting of cannon, but of statues, &c. for pure copper, in running through the various parts of the mould, would lose so much of its heat as to set before it ought to do.

Bell-metal consists also of tin and copper. Authors do not agree in the proportions; some ordering one part of tin to be melted with four parts of copper*; others making the proportion for bell-metal to be the same as that for gun-metal; or one part of tin to about ten parts of copper, to which they order a little brass

Pemb. Chem. p. 32ļ.