Alloys having a density greater than the Mean of their Constituents.

Gold and zinc.

Silver & antimony.

Gold and tin.

Copper and zinc.

Gold and bismuth.

Copper and un.[um

Gold and antimony.

Copper and palladi-

Gold and cobalt.

Copper & bismuth.

Silver and zinc.

Lead and antimony

Silver and lead.

Platinum & molybdenum, [muth.

Silver and tin.

Silverand bismuth.

Palladium and bis-

Alloys having a density less than the Mean of their Constituents.

Gold and silver.

Iron and bismuth.

Gold and iron.

Iron and antimony.

Gold and lead.

Iron and lead.

Gold and copper.

Tin and lead.

Gold and iridium.

Tin and palladium.

Gold and nickel.

Tin and antimony.

Silver and copper.

Nickel and arsenic.

Silver and lead.

Zinc and antimony.

ALLOYS OF COPPER AM) ZINC. AND OF COPPER AND TIN.

Composition by Weight per cent.

Specific Gravity.

Colour.

Ultimate

Strength of an.In. square. Bar. in Tons.

Characteristic Properties, etc.

Copper

8667

Tile red.

24.6

Malleable.

100 00 Zinc

689S

Bluish grey.

15.2

Brittle

83.02+l6.98

8415

Yellowish red.

13.7

Bath metal.

79.05+20.35

-44-

do. do.

14.7

Dutch brass.

74.58+25.42

Pale yellow.

13.1

Rolled sheet brass.

66.18+33.82

S299

Full yellow.

12.5

British brass.

49.47+50.53

8230

do. do.

9.2

German brass.

32.85+67.15

8283

Deep yellow.

19.3

Watchmakers' brass.

30.30+69.70

7836

Silver while.

2.2

Very brittle.

24.50+75.50

7449

Ash grey.

3.1

Brittle.

19.05+80.35

7371

do.

1.9

While button metal.

Tin

7291

White.

2.7

84.29+15.71

8561

Reddish yellow.

16.1

Gun metal.

S1.10+1S.90

8459

Yellowish red.

17.7

Gun metal and bronze.

78.97+21.03

8728

do. do.

13.6

Hard, mill brasses.

34.92+65.08

8065

White.

1.4

Small bells.

15.17+84.83

7447

Very white.

3.1

Speculum metal.

11.82+88.18

7472

do. do.

3.1

Files, tough

Note. - No simple binary' alloy of copper and zinc, or of copper and tin. works as pleasantly in turning, planing, or filing, as if combined with a small proportion of a third fusible metal; generally lead is added to copper and zinc, and zinc to copper and tin.

To Polish Brass. - When the Brass is made smooth by turning or filing with a very fine file, it may be rubbed with a smooth fine grained stone, or with charcoal and water. When it is made quite smooth and free from scratches it may be polished with rotten stone and oil, alcohol or spirits 0f turpentine.

To Clean Brass. - If there is any oily substance on the Brass boil it in a solution of potash, or strong lye. Mix equal quantities of Nitric and Sulphuric Acids in a stone or earthern vessel, let it stand a few hours, stirring it occasionally with a stick, then dip the Brass in the solution, but take it out immediately and rinse it in soft water, and wipe it in saw dust till it is dry.

Glue. - Powdered Chalk added to common Glue strengthens it. A Glue which will resist the action of water is made by boiling 1 pound of Glue in 2 quarts of skimmed Milk.