The weight of any body, or substance, compared with the weight of some other body which is assumed to be a standard. The standard of comparison, by common consent and practice, is rain water, on account of its being less subject to variation, in different circumstances of time and place, than any other body, whether fluid or solid. A cubic foot of rain water weighs 1000 ounces avoirdupois; therefore, assuming this to be the specific gravity of rain-water, and comparing all other bodies with it, the same numbers which express the specific gravities of bodies, denote, at the same time, their weight per cubic foot, in avoirdupois ounces. Hence, by reference to the tables, we are enabled to find the magnitude of any solid which is too irregular to admit of the common rules of mensuration, and also the weight of any body of known magnitude which is too ponderous to be submitted to the operation of the steel-yard or balance.

Example

Required the quantity of material in an irregular shaped block of marble, weighing 4 1/2 tons.

Reduce the weight to ounces, and divide by the specific gravity of marble. Hence 4 1/2 tons X 16 oz.÷ 2.838 = 56.8 cubic feet.

Required the quantity of material in a statue of white Parian marble, weighing 800 pounds.

800 X 16 = 12800÷ 2.838 = 4 1/2 cubic feet. Again. - Required the weight of a block of Aberdeen granite, measuring 43 feet in length, 8 feet in breadth and thickness.

43 X 8 X 8 = 2752. Then, as 1:: 2752:: 2.625: 7224000 = 201 tons 11 cwt. 1 qr. The properties of specific gravity are as follows:-

1. A body immersed in a fluid will sink if its specific gravity be greater than that of the fluid; if it be less, the body will rise to the top, and be only partly immersed; and if the specific gravity of the solid and fluid be equal, it will remain at rest in any part of the fluid in which it may be placed.

2. When a body is heavier than a fluid, it loses as much of its weight, when immersed, as is equal to a quantity of fluid of the same magnitude.

3. If the specific gravity of the fluid be greater than that of the body, then the quantity of fluid displaced by the part immersed is equal to the weight of the whole body. Hence, as the specific gravity of the fluid is to that of the body, so is the whole magnitude of the body to the part immersed.

Specific Gravities of Metals.

Sp. Grav.

Antimony, in a metallic state, fused . . . . . . . . . . .

6.624

Bismuth, cast . . . . . . . . . .

9.823

native . . . . . . . . . .

9.822

Brass, common cast . . . . . . . . . .

7.824

cast, not hammered

8.396

wire-drawn . . . . . . . . . .

8.544

Copper, cast . . . . . . . . . . . . . .

8.788

wire-drawn . . . . . . . . . .

8.878

Gold, pure, cast . . . . . . . . . .

19.258

the same hammered

19.362

22 carats, fine, standard

17.486

Iron, cast . . . . . . . . . . . . . . . . .

7207

bars . . . . . . . . . . . . . . . . .

7.788

Lead, cast . . . . . . . . . . . . . . . . .

11.352

litharge . . . . . . . . . .

6.300

Mercury, solid, 40° below 0

Fahr . . . . . . . . . .

15.632

at 32° of heat . .

13.619

at 60o . . . . . . . . . .

13.580

at 212o . . . . . . . . . .

13.375

Nickel, cast . . . . . . . . . . . . . . .

7.807

Sp. Grav.

Platina, crude, in grains . . . . . . .

15.602

purified . . . . . . . . . . .

19.502

the same hammered .

20.337

„ rolled . . .

22.069

„ wire-drawn .

21.042

Silver, cast, pure . . . .

10.474

„ „ hammered .

10.511

French coin . . . . . . . . . .

10.048

shilling (George III.) .

10 534

Steel, soft . . . . . . . . . . . . . . . . . .

7.833

hardened, but not tempered . . . . . . . . . . .

7.840

tempered, but not hardened . . . . . . . . . . .

7.816

tempered and hardened

7.818

Tin, pure Cornish . . . . . . . . . . .

7.291

Malacca, fused . . . . . . . . . .

7.296

Tungsten . . . . . . . . . . . . . . . . . .

6.066

Uranium . . . . . . . . . . . . . . . . . .

6.440

Wolfram . . . . . . . . . . . . . . . . . .

7.119

Zinc, in its usual state . . .

6.862

pure and compressed . . . .

7.191

Specific Gravities of Woods.

Sp. Grav.

Alder . . . . . . . . . . . . . . . . . . . .

.800

Beech . . . . . . . . . . . . . . . . . . . .

.845

Box, Dutch . . . . . . . . . . . . . . . .

.852

Campechy . . . . . . . . . . . . . . . .

.912

Cedar, American . . . . . . . . . .

.913

Indian . . . . . . . . . .

.561

Palestine . . . . . . . . . .

1.315

Cherry-tree . . . . . . . . . . . . . . .

.613

Citron . . . . . . . . . . . . . . . . . . . .

.715

Cork . . . . . . . . . . . . . . . . . . . .

.726

Cypress . . . . . . . . . . . . . . . . . . .

.240

Ebony, Indian . . . . . . . . . . . . .

.644

Elder . . . . . . . . . . . . . . . . . . . .

1.209

Elm . . . . . . . . . . . . . . . . . . . .

.695

Elm.........

.671

Filbert . . . . . . . . . . . . . . . . . . . .

.600

Fir, Yellow . . . . . . . . . . . . . . .

.657

white . . . . . . . . . . . . . . . . .

.569

Hazel . . . . . . . . . . . . . . . . . . . .

.600

Juniper . . . . . . . . . . . . . . . . . . .

.556

Lemon-tree . . . . . . . . . . . . . . .

.703

Sp. Grav.

Lignum-vitae . . . . . . . . . . . . . .

1.333

Lime-tree . . . . . . . . . . . . . . . . . .

.604

Logwood . . . . . . . . . . . . . . . . .

.913

Mahogany . . . . . . . . . . . . . . . .

1.063

Maple . . . . . . . . . . . . . . . . . . . .

.750

Mulberry . . . . . . . . . . . . . . . . . .

.897

Oak, heart of, 60 years old

1.170

Olive-tree . . . . . . . . . . . . . . . . . .

.927

Orange-tree . . . . . . . . . . . . . . . .

.705

Pear-tree . . . . . . . . . . . . . . . . . .

.661

Pomegranate-tree . . . . . . . . . . .

1.354

Poplar . . . . . . . . . . . . . . . . .

.383

Plum-tree . . . . . . . . . . . . . . . . .

.755

Quince-tree . . . . . . . . . . . . . . . .

.705

Sassafras . . . . . . . . . . . . . . . . .

.482

Vine . . . . . . . . . . . . . . . . .. . .

1.327

Walnut . . . . . . . . . . . . . . . . .

.671

Willow . . . . . . . . . . . . . . . . .

.585

Yew, Spanish . . . . . . . . . . . . . .

.807

Dutch . . . . . . . . . . . . . . .

.788

Specific Gravities of Stones, Earths, etc.

Alabaster, Yellow . . . . . . . . . . .

2.699

Ambergris . . . . . . . . . . . . . . . . .

.926

Amianthus, long . . . . . . . . . . . . .

.909

short . . . . . . . . . . . . .

2.313

Asbestos, ripe . . . . . . . . . . . . .

2.578

starry . . . . . . . . . . . . .

3.073

Borax . . . . . . . . . . . . . . . . .

1.714

Brick . . . . . . . . . . . . . . . . .

2.000

Chalk, British . . . . . . . . . . . . . .

2.784

Coal, Cannel . . . . . . . . . . . . . . .

1.270

Newcastle . . . . . . . . . . . .

1.270

Staffordshire . . . . . . . . . .

1.240

Scotch . . . . . . . . . . . . . . .

1.300

Cutler's stone . . . . . . . . . . . . . . .

2.111

Emery . . . . . . . . . . . . . . . . .

4.000

Flint, black . . . . . . . . . . . . . . . .

2.582

white . . . . . . . . . . . . . . . . .

2.594

Glass, flint . . . . . . . . . . . . . . .

2.933

bottle . . . . . . . . . . . . . . . .

2.732

green . . . . . . . . . . . . . . . . .

2.642

Leith, crystal . . . . . . . . . . . . . . .

3.189

Granite, Aberdeen, blue kind . . .

2.625

Cornish . . . . . . . . . . .

2.662

Egyptian, red . . . . . . . .

2.654

beautiful red . . . . . . . .

2.761

Girardinor . . . . . . .

2.716

violet, of Gyromagny . .

2.685

Daupbiny, red . . . . . . .

2.643

" green ... . . .

2.684

" radiated . .

2.668

Semur, red . . . . . . .

2.638

Bretagne, grey . . . .. .

2.788

Granite, Bretagne, yellowish . . . .

2.619

Grindston . . . . . . . . . . . . . .

2.143

Gypsum, opaque . . . . . . . . .

2.168

semi-transparent . . .

2.306

Hone, white, razor . . . . . . .

2.876

Jet, a bituminous substance . . . .

1.259

Lime-stone, green . . . . . . .

3.182

white fluor . . .. . . .

3.156

compact . . . . . . .

2.720

Manganese . . . .. . . . . . . . . . . . .

7.000

Marble, Biscay an, black . . . .

2.695

Brocatelle . . . . . . . . .

2 650

Carrara, white . . . . . . .

2.717

Egyptian, green . . . . .

2.668

Italian, violet . . . . . . . .

2.858

red . . . . . . . . . . . . . .

2.724

Porcelain, China . . . . . . . . . . . . .

2.385

Porphyry, red . . . . . . . . . . . . . . .

2.765

green . . . . . . . . .

2.676

Salt . . . . . . . . . . . . . . . . . . . . . . .

2.130

Serpentine, opaque, green,

Italian . . . . . . . . . . . . . . . . . .

2.430

Italian . . . . . . . . . . .

2.672

Stalactite, opaque . . . . . . . .

2 478

Stone, Bristol . . . . . . . . . . . . . . . .

2.510

Portland . . . . . . . . .

2.570

Pumice . . . . . . . . . .

.915

Purbeck . . . . . . . . .

2.601

rag . . . . . . . . . . .

2.470

Sulphur, native . . . . . . . . . .

2.033

melted . . . . . . . . . .

1.991

Talc, Muscovy . . . . . . . . .

2.792

Specific Gravities of Liquids.

Sp. Grav.

Acetic acid . . . . . . . . . . . . . . . . .

1.007

Alcohol, commercial . . . . . . . .

.837

highly rectified . . . . .

.829

Ammonia, liquid . . . . . . . . . . . .

.897

muriate of. . . . . . . .

1.453

Beer, pale . . . . . . . . . . . .. . . . .

1.023

Cyder . . . . . . . . . . . .. . . . . . . . . .

1.034

Ether, acetic . . . . . . . . . . . .. . . .

1.018

muriatic . . . . . . . . . . . .

1.018

nitric . . . . . . . . . . . .

.866

sulphuric . . . . . . . . . . . .

.730

Fluoric acid . . . . . . . . . . . .. . . . .

.909

Formic acid . . . . . . . . . . . .. . . . .

.739

Milk of Cows . . . . . . . . . . . .

.909

Muriatic acid . . . . . . . . . . . .

.994

Milk of Cows. . . . . . . . . . .. . . . .

1.032

Muriatic acid . . . . . . . . . . .. . . . .

1.194

Nitric acid . . . . . . . . . . .. . . . .

1.271

highly concentrated

1.583

Oil of almonds, sweet . . . . . . . . .

.917

cloves, essential . . . .

1.036

cinnamon, essential

1.044

filberts . . . . . . . . . .. . .

.916

hemp-seed . . . . . . . .

.926

lavender, essential .

.894

Sp. Grav.

Oil of linseed . . . . . . . . . .. . . . .

.940

olives . . . . . . . . . .. . . . .

.915

Poppies . . . . . . . . . .. . . .

.924

rape-seed . . . . . . . . . .

.919

turpentine, essential . . .

.870

whales . . . . . . . . . .. . . . .

.923

Spirits of wine, commercial . . .

.837

highly rectified

.829

Sulphuric acid . . . . . . . . . .. . . .

1.841

highly concentrated . . . . .

2.125

Turpentine, liquid . . . . . . . . . ..

.991

Vinegar, distilled . . . . . . . . . .. .

1.010

Water, rain . . . . . . . . . .. . . . .

1.000

distilled . . . . . . . . . .. . . .

1.000

sea . . . . . . . . . .. . . . .

1.026

Wine, Burgundy . . . . . . . . . ..

.992

Bordeaux . . . . . . . . . .. .

.994

Champaigne, white . . . .

.998

Canary . . . . . . . . . .. . . .

1.033

Constance . . . . . . . . . ..

1.082

Madeira . . . . . . . . . .. . .

1.038

Malaga . . . . . . . . . .. . . .

1.022

Port . . . . . . . . . .. . . . .

.997

Tokay . . . . . . . . . .. . . . .

1.054

Specif c Gravities of Resins, Gums, Animal Substatices, fyc.

Aloes, socotrine . . . . . . . . . .. . .

1.380

Ambergris . . . . . . . . . .. . . . .

.926

Assafoetida . . . . . . . . . .. . . . .

1.328

Bark, Peruvian . . . . . . . . . .. . . . .

.785

Butter . . . . . . . . . .. . . . . . . . . . .

.942

Camphor . . . . . . . . . .. . . . . . . .

.989

Copal, Chinese . . . . . . . . . .. . . . .

1.063

Fat, beef . . . . . . . . . .. . . . . . . . . .

.923

mutton . . . . . . . . . .. . . . .

.924

veal . . . . . . . . . .. . . . . . . . .

.934

hog's . . . . . . . . . .. . . . . . . .

.967

Galbanum . . . . . . . . . .. . . . . . . .

1.212

Gamboge . . . . . . . . . .. . . . . . . .

1.222

Gum Ammoniac . . . . . . . . . .. . . .

1.207

Arabic . . . . . . . . . .. . . . .

1.452

Scammony of Aleppo . . . .

1.235

„ of Smyrna .

1.274

tragacanth . . . . . . . . . .. . .

1.316

Gunpowder, in a loose heap . . . .

.836

shaken . . . . . . . . ..

.932

solid . . . . . . . . .. . .

1.745

Honey . . . . . . . . .. . . . . . . . . . . .

1.450

Indigo . . . . . . . . .. . . . . . . . . . . .

.769

Ivory . . . . . . . . .. . . . . . . . . . . .. .

1.826

Lard . . . . . . . . .. . . . . . . . . . . .. .

.948

Madder-root . . . . . . . . .. . . . . . . .

.765

Mastic . . . . . . . . .. . . . . . . . . . . .

1.074

Myrrh . . . . . . . . .. . . . . . . . . . . .

1.360

Olibanum . . . . . . . . .. . . . . . . . . .

1.173

Opium . . . . . . . . .. . . . . . . . . . .

1.336

spermaceti . . . . . . . . .. . . . . . . . .

.943

Sugar, white . . . . . . . . .. . . . . . .

1.606

Tallow . . . . . . . . .. . . . . . . . . . . .

.942

Wax of bees, white . . . . . . . . .. . .

.969

yellow . . . . . . .

.965

Shoemakers' . . .

.897

Gases.

In the following Table, the specific gravities of the principal gases will be given as they correspond with the specific gravity of atmospheric air, which is supposed to be about 1.000.

Atmospheric, or common air .. . . . .

1.000

Ammoniacal gas . . . . . . . .. . . . . . .

.500

Arsenical hydrogen gas . . . . . . . .. .

.529

Azote . . . . . . .. . . . . . . . . . . . . . . .

.969

Corbonic acid . .. . . . . . . . . . . . . .

1.520

oxide . . . . . . . . . . . . . .

.960

Carburetted hydrogen . . . . . . . . .

.491

Chlorine . . . . . . . . . . . . . . .. . . ..

.470

Sp. Grav.

Chloro-carbonic gas . . . . . . . . .

3.389

Chloro-cyanic vapour. .. . . .

2.111

Cydrogen . . . . . . . . . . . . . . . . . .

1.806

Euchlorine . . . . . . . . . . . . . . . . .

2.409

Fluoboracic . . . . . . . . . . . . . . . .

2.371

Fluosilicic acid gas . . . . . . . . .

3.574

Hydrogen . . . . . . . . . . . . . . . . . .

.074

Hydriodic acid gas . . . . . . . . .

4.443

Hydrocyanic vapour . . . . . . . .

.948

Muriatic acid gas . . . . . . . .

1.278

Nitrous gas . . . . . . . . . . . . . . . .

1.094

acid gas . . . . . . . . . . . .

2.427

oxide . . . . . . . . . . . . . .

1.614

Sp. Crav.

Oxygen, mean . . . . . . . . . . . . . .

1.044

Phosphuretted hydrogen . . . . . .

.870

Steam . . . . . . . . . . . . . . . . . . . . .

.690

Sulphuretted hydrogen . . . . . . .

1.777

Sulphurous acid . . . . . . . . . . . . . .

2.193

Vapour of Alcohol . . . . . . . . . . .

2.100

absolute alcohol . . . .

1.613

hydriotic ether

5.475

iodine . . . . . . . . . . .

8.620

muriatic ether . . . . .

2.219

oil of turpentine . . . .

5.013

sulphuret of carbon . .

2.645

sulphuric ether . .. .

2.586

In concluding, it may be necessary to remark, that all bodies expand by heat and contract by cooling; but the contraction and expansion, by the same change of temperature, is very different in different bodies. Water, when heated from 60 to 100 degrees, increases its volume nearly one sixty-seventh of its bulk; mercury, one two-hundred and forty-third part; and many substances much less. It is therefore proper, in ascertaining the specific gravities of bodies, to note particularly the temperature.