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 0Fahr . . . . . . . . . . 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 . . . . . . . . . . . . . . . . . 0.926 Amianthus, long . . . . . . . . . . . . . 0.909 short . . . . . . . . . . . . . 2.313 Asbestos, ripe . . . . . . . . . . . . . 2.578 starry . . . . . . . . . . . . . 3.073 Borax . . . . . . . . . . . . . . . . . 1.714 Brick . . . . . . . . . . . . . . . . . 2 Chalk, British . . . . . . . . . . . . . . 2.784 Coal, Cannel . . . . . . . . . . . . . . . 1.27 Newcastle . . . . . . . . . . . . 1.27 Staffordshire . . . . . . . . . . 1.24 Scotch . . . . . . . . . . . . . . . 1.3 Cutler's stone . . . . . . . . . . . . . . . 2.111 Emery . . . . . . . . . . . . . . . . . 4 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 . . . . . . . . . .. . . 1.38 Ambergris . . . . . . . . . .. . . . . 0.926 Assafoetida . . . . . . . . . .. . . . . 1.328 Bark, Peruvian . . . . . . . . . .. . . . . 0.785 Butter . . . . . . . . . .. . . . . . . . . . . 0.942 Camphor . . . . . . . . . .. . . . . . . . 0.989 Copal, Chinese . . . . . . . . . .. . . . . 1.063 Fat, beef . . . . . . . . . .. . . . . . . . . . 0.923 mutton . . . . . . . . . .. . . . . 0.924 veal . . . . . . . . . .. . . . . . . . . 0.934 hog's . . . . . . . . . .. . . . . . . . 0.967 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 . . . . 0.836 shaken . . . . . . . . .. 0.932 solid . . . . . . . . .. . . 1.745 Honey . . . . . . . . .. . . . . . . . . . . . 1.45 Indigo . . . . . . . . .. . . . . . . . . . . . 0.769 Ivory . . . . . . . . .. . . . . . . . . . . .. . 1.826 Lard . . . . . . . . .. . . . . . . . . . . .. . 0.948 Madder-root . . . . . . . . .. . . . . . . . 0.765 Mastic . . . . . . . . .. . . . . . . . . . . . 1.074 Myrrh . . . . . . . . .. . . . . . . . . . . . 1.36 Olibanum . . . . . . . . .. . . . . . . . . . 1.173 Opium . . . . . . . . .. . . . . . . . . . . 1.336 spermaceti . . . . . . . . .. . . . . . . . . 0.943 Sugar, white . . . . . . . . .. . . . . . . 1.606 Tallow . . . . . . . . .. . . . . . . . . . . . 0.942 Wax of bees, white . . . . . . . . .. . . 0.969 yellow . . . . . . . 0.965 Shoemakers' . . . 0.897

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 Ammoniacal gas . . . . . . . .. . . . . . . 0.5 Arsenical hydrogen gas . . . . . . . .. . 0.529 Azote . . . . . . .. . . . . . . . . . . . . . . . 0.969
 Corbonic acid . .. . . . . . . . . . . . . . 1.52 oxide . . . . . . . . . . . . . . 0.96 Carburetted hydrogen . . . . . . . . . 0.491 Chlorine . . . . . . . . . . . . . . .. . . .. 0.47
 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.