Spe-cif′ic Grav′i-ty.
The relative weight of a ponderable substance compared with another which is taken as a standard.
For solids and liquids,
water, and, for gases,
air, are universally adopted as the standards.
It took a long time to find out that air really was a ponderable substance.
The specific gravity of a body is ascertained by weighing the body in air, and then in water.
Subtract the weight in water from the weight in air, and divide the weight in air by the difference The quotient is the specific gravity required.
The bulk of the object must agree with that of the standard of comparison if the result is to be stated in relative terms.
See specific-gravity balance.
In obtaining the specific gravity of fluids, a bottle is obtained, whose capacity is 1,000 grains of distilled water.
This is filled with water, and balanced on the scales.
The water is then removed and the fluid substituted, and the bottle and contents again weighed.
The weight of the fluid divided by the weight of the water gives the specific gravity required.
Archimedes invented the plan for determining specific gravity by displacement of water.
He also enunciated the doctrine of the “center of gravity.”
Alhazen the Saracen, A. D. 1100, improved upon the hydrometer, which had been in use in
Alexandria 600 years previously.
See hydrometer.
Abu-r-Raihan of Kharizim, about A. D. 1000, compiled a table of specific gravities, which is quoted by Al-Khazini in his “Book of the balance of wisdom,” translated from the Arabic by Chev.
Khanikoff,
consul-general of
Russia, at
Tabriz, Persia It was in reference to this table that Al Khazini uttered his pious hope that, “in the day of judgment, the
All Merciful will take pity on the soul of Abu-r-Raihan, because he was the first of the race of men to construct a table of specific gravities.”
The table is recorded in connection with the modern data on pages 84, 85 of the “Journal of the American Oriental Society,” Vol.
VI., New Haven, 1860.
See also page 212, article balance.
Al-Khazini states that when a body is weighed in air and afterward in the water-bowl, the beam of the balance rises in proportion to the weight of the water which is displaced, which is equal to the entire weight of the body weighed.
The “Balance of wisdom,” as the instrument is called by its describer, in the fanciful style common in the literature of that day, was a turned brass tube with closed ends, and so weighted as to float upright in a liquid.
Graduations on the side were marked above and below a line that was termed the equator of equilibrium, to which line the instrument sank when plunged in the liquid—water of a certain description—which formed the unit of calculation.
It is, as to this feature, a hydrometer, such as described by
Synesius, and is credited by Al Khazini to
Archimedes.
The conical instrument of Abu-r-Raihan is described by Al Khazini, and has a conical body, a narrow vertical neck, and a curved spout leading from the latter, by which the water dis-
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placed by a solid body was conducted to the bowl of a balance, by which it was weighed.
Al Khazini says in his book, of the eminent teacher “Abu — Hatim ” al-Muzaffar Bin “Ismail of ” Isfazar, who was adapting the specific-gravity balance to the determination of the specific gravity of metal by graduations on the beam calculated for liquids of immersion of different densities: “He passed away, to meet the mercy of the
Supreme God, before perfecting it, and reducing all his views on the subject to writing.”
The first person
in Europe to make a tabular statement of computations in this line was
Athanasius Kircher, 1602-80; after him Galileo, 1657;
Boyle (born in 1627). The calculations of the latter of the specific gravity of mercury—13.76 and 13.357 —are both less exact than those of the scientific
Arab in the retinue of Mahmoud of Ghuzna, A. D. 1000; he made it 13.56.
The modern figure is 13.557.
The following table gives the
specific gravity of a number of gaseous, liquid, and solid substances.
See also
Clark's “Constants of nature,” Smithsonian Institution Collections, December, 1873.
Gases, Air = 1.
| Hydrogen | 0.069 |
| Marsh gas | 0.559 |
| Steam | 0.623 |
| Carbonic oxide | 0.968 |
| Nitrogen | 0.971 |
| O'efiant gas | 0.978 |
| Nitric oxide | 1.939 |
| Oxygen | 1.106 |
| Sulphuretted hydrogen | 1.191 |
| Nitrous oxide | 1.527 |
| Carbonic acid | 1.529 |
| Sulphurous acid | 2.247 |
| Chlorine | 2.47 |
Non-Metallic, Solid, Elementary Substances, Water = 1.
| Boron | 2.68 |
| Bromine | 2.98-2.99 |
| Carbon, diamond | 3 529-3.550 |
| Carbon, graphite | 2.105-2.585 |
| Carbon, from gas-works | 1.885 |
| Carbon, charcoal, variable from 0.280 for that from soft wood freshly burned in the stick, to 1.57.
for oak charcoal, pulverized and compressed. |
| Iodine | 4.948 |
| Phosphorus, common | 4.826 |
| Selenium | 4.760-4.808 |
| Silicon | 2.004-2.493 |
| Sulphur, roll | 1 868-2.000 |
| Sulphur, flowers | 1.913-2.086 |
Metals, etc.
| Aluminium, cast | 2.50 |
| Aluminium, hammered | 2.67 |
| Arsenic | 5.763 |
| Barium | 4.00 |
| Bismuth | 9.67-9.83 |
| Cadmium | 8.54-8.67 |
| Calcium | 1.55-1.8 |
| Cerium | 5.5 |
| Cobalt | 8.48-8.95 |
| Columbium or Niobium | 6.0-7.37 |
| Copper, cast | 8.78-8.83 |
| Copper, rolled | 8.88-8.95 |
| Copper wire | 8.93-8.95 |
| Glucinium | 2.1 |
| Gold | 19.2-19.4 |
| Indium | 7.362 |
| Iridium | 21.78-21.83 |
| Iron, pure | 7.83 |
| Iron, cast | 6.928-7.330 |
| Iron, bar | 7.658-7.760 |
| Iron, rolled plate | 7.570-7.732 |
| Iron, hammered | 7.868 |
| Iron wire | 7.6-7.83 |
| Lead | 11.07-11.445 |
| Magnesium | 1.69-2.04 |
| Manganese | 8.01 |
| Mercury | 13.568 |
| Molybdenum | 8.49-8.60 |
| Nickel | 7.807-9.261 |
| Nickel wire | 8.88 |
| Osmium | 21.40 |
| Palladium | 10.923-12.148 |
| Platinum, cast | 19.5 |
| Platinum, hammered | 20.3 |
| Platinum wire | 21.0-21.7 |
| Platinum sponge | 21.47 |
| Potassium | 0.865 |
| Rhodium | 11.0-11.2 |
| Rubidium | 1.52 |
| Ruthenium | 11.0-11.4 |
| Silver | 10.362-10.575 |
| Sodium | 0.972 |
| Steel, cast | 7.802-7.825 |
| Steel, blister | 7.720 |
| Steel, puddled | 7.640-7.707 |
| Strontium | 2.4-2.58 |
| Tantalum | 10.08-10.78 |
| Tellurium | 6.115-6.343 |
| Thallium | 11.777-11.900 |
| Thorium | 7.657-7.795 |
| Tin | 7.278-7.304 |
| Tungsten | 17.6-19.261 |
| Uranium | 18.33-18.40 |
| Vanadium | 5.5 |
| Zinc | 6.861-7.21 |
Alloys.
| Brass |
| Copper, 84; zinc, 16. | 8.832 |
| Copper, 67; zinc, 33. | 7.820 |
| Brass plate | 8.380 |
| Brass wire | 8.214 |
| Bronze gun-metal | 8.700 |
| Gold, English standard, 22 carats fine | 18.888 |
Ores.
| Copper, compact vitreous | 4.129 |
| Copper, Cornish | 5.452 |
| Copper, pyrites | 4.080-4.344 |
| Iron, chromate | 4.057 |
| Iron, pyrites | 4.789 |
| Iron, magnetic | 4.2-4.9 |
| Iron, red hematite | 4.740-5.005 |
| Iron, brown hematite | 3.789-4.029 |
| Iron, specular | 4.934-5.218 |
| Iron, sparry | 3.64-3.81 |
| Iron, ironstone | 2.952-3.863 |
| Lead, carbonate | 6.00-7.20 |
| Lead, sulphide (Galena） | 7.22 |
| Tin, Cornish | 5.8-6.45 |
| Zinc, calamine | 3.525 |
Stones and Mineral Substances.
| Agate | 2.348-2.637 |
| Alabaster | 2.611-2.876 |
| Amethyst | 2.750 |
| Asbestus | 0.680-0.993 |
| Asbestus, starry | 3.073 |
| Barytes | 4.00-4.865 |
| Basalt | 2.421-3.000 |
| Beryl | 2.723-3.549 |
| Brick | 1.367-1.900 |
| Brick, fire | 2.201 |
| Brick-work in mortar | 1.600-2.000 |
| Brick-work in cement | 1.800 |
| Carnelian | 2.597-2.630 |
| Cement, Portland | 1.300 |
| Cement, Roman | 1.560 |
| Chalcedony | 2.586-2.664 |
| Chalk | 1.520-2.784 |
| Chrysolite | 2.782-3.489 |
| Clay | 1.93-2.16 |
| Coal, anthracite | 1.436-1.640 |
| Coal, cannel | 1.238-1.318 |
| Coal, Cumberland, Md. | 1.355 |
| Coal, Newcastle | 1.270 |
| Coal, Welsh | 1.315 |
| Coke | 1.000 |
| Corundum | 3.710-3.981 |
| Cryolite | 2.692-3.077 |
| Diamond, Oriental | 3.521-3.550 |
| Diamond, Brazilian | 3.444 |
| Dolomite | 2.800 |
| Earth | 2.194 |
| Earth, loose | 1.500 |
| Earth, rammed | 1.600 |
| Earth, moist sand | 2.050 |
| Emerald | 2.600 |
| Emerald, Brazilian | 3.155 |
| Flint | 2.586-2.664 |
| Garnet, common | 3.576-3.688 |
| Garnet, precious | 4.000-4.352 |
| Granite | 2.613-2.956 |
| Gypsum | 1.872-3.310 |
| Gypsum, ordinary, about | 2.3 |
| Hornblende, common | 3.600-3.830 |
| Hyacinth | 4.000-4.620 |
| Jade | 2.959-3.389 |
| Jasper | 2.566-2.816 |
| Jet | 1.259-1.300 |
| Limestone | 2.700-2.837 |
| Limestone, green | 3.182 |
| Marl | 1.700-2.944 |
| Malachite | 3.572-3.994 |
| Marble | 2.516-2.858 |
| Mica | 2.546-2.934 |
| Millstone | 2.484 |
| Mortar | 1.384-1.750 |
| Mud, about | 1.630 |
| Opal | 1.958-2.144 |
| Peat | 0.600-1.329 |
| Pitchstone | 1.970-2.720 |
| Plaster of Paris | 1.176 |
| Plumbago | 1.987-2.267 |
| Porphyry | 2.670-2.790 |
| Pumice-stone | 0.915 |
| Quartz | 2.64-2.66 |
| Rock crystal | 2.605-2.888 |
| Ruby, Oriental | 4.283 |
| Ruby, Brazilian | 3.531 |
| Sand | 1.392-1.800 |
| Sandstone | 2.08-2.52 |
| Sapphire | 3.991-4.283 |
| Sardonyx | 2.594-2.628 |
| Serpentine | 2.429-2.999 |
| Shale | 2.600 |
| Slate | 2.672-2.955 |
| Spar, calc. | 2.715 |
| Spar, feld | 2.693-2.704 |
| Spar, fluor | 3.138-3.183 |
| Spar, other varieties | 2.43-3.873 |
| Steatite | 2.61 |
| Stone, building varieties | 1.386-2.945 |
| Stone, building, common | 2.520 |
| Stone, building, Bath, England | 1.961 |
| Stone, building, Bristol, England | 2.510 |
| Stone, building, Norfolk, England (Parliament House） | 2.304 |
| Stone, building, Portland | 2.368 |
| Stone, building, Caen, Fr | 2.076 |
| Stone, building, Notre Dame Cathedral | 2.378 |
| Stone, building, Breakneck, N. Y. | 2.704 |
| Stone, building, Kip's Bay, N. Y. | 2.759 |
| Stone, building, Staten Island, N. Y. | 2.976 |
| Stone, building, Sullivan Co., N. Y. | 2.688 |
| Tale | 2.08-2.90 |
| Trap | 2.72 |
| Topaz | 3.155-4.061 |
Woods, Dry.
| Alder | .800 |
| Apple | .793 |
| Ash | .800 |
| Ash, American | .514–.736 |
| Bass | .482–.502 |
| Bay, Spanish | .822 |
| Beech | .852 |
| Beech, American | .672–.735 |
| Birch | .567 |
| Box | .900-1.030 |
| Brazil-wood | 1.031 |
| Campeachy (logwood) | .913 |
| Cedar, American | .560 |
| Cedar, Indian | 1.315 |
| Cherry | .715 |
| Cherry, American | .579 |
| Chestnut, Amer | .469–.545 |
| Cocoa | 1.040 |
| Cork | .240 |
| Cypress, Spanish | .644 |
| Cypress, American | .553 |
| Dogwood | .756–.852 |
| Ebony, Indian | 1.209 |
| Ebony, American | 1.331 |
| Elder | .695 |
| Elm | .671 |
| Elm, American | .723–.775 |
| Fir, Norway | .512 |
| Fir, Oregon, yellow | .559–.630 |
| Fir, Oregon, red | .462 |
| Fir, Oregon, white | .468 |
| Gum, black | .615 |
| Gum, blue | .843 |
| Gum, water | 1.000 |
| Hackmatack | .590 |
| Hawthorn | .910 |
| Hazel | .606–.860 |
| Hemlock | .368–.453 |
| Hickory | .826–.992 |
| Holly | .760 |
| Holly, American | .641 |
| Juniper | .556 |
| Lancewood | .720 |
| Larch | .544–.560 |
| Lemon | .703 |
| Lignum-vitae | 1.257-1.333 |
| Lime | .804 |
| Linden | .604 |
| Locust | .728–.826 |
| Logwood | .913 |
| Mahogany | .720-1.063 |
| Mahogany, San Domingo | .727 |
| Mahogany, Honduras | .560 |
| Maple | .681–.755 |
| Maple, bird's-eye | .576 |
| Maple, Oregon | .491 |
| Mulberry | .897 |
| Oak, African | .823 |
| Oak, Canadian | .872 |
| Oak, Dantzic | .759 |
| Oak, English | .932 |
| Oak, white | .632–.882 |
| Oak, live | 1.021-1.103 |
| Olive | .927 |
| Orange | .705 |
| Pear | .661 |
| Persimmon | .710 |
| Pine, pitch | 1.080 |
| Pine, red | .590 |
| Pine, white | .360–.461 |
| Pine, yellow | .528–.672 |
| Plum | .785 |
| Poplar | .432–.498 |
| Poplar, white Spanish | .529 |
| Quince | .705 |
| Redwood, Cal | .387 |
| Rosewood | .728 |
| Sassafras | .482 |
| Satin-wood | .885 |
| Spruce | .436–.444 |
| Sycamore | .623 |
| Tamarack | .383 |
| Teak | .961 |
| Walnut, black | .529–.649 |
| Willow | .486–.585 |
| Yew | .788–.807 |
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Miscellaneous Solids.
| Amber | 1.078-1.085 |
| Ambergris | .866 |
| Beeswax | .965 |
| Bone | 1.66 |
| Butter | .942 |
| Camphor | .988 |
| Caoutchouc | .903 |
| Fat, beef, mutton | .923 |
| Fat, hog | .936 |
| Flesh | .890 |
| Gum-arabic | 1.452 |
| Gunpowder, loose | .900 |
| Gunpowder, shaken | 1.000 |
| Gunpowder, solid | 1.550-1.800 |
| Gutta-percha | .980 |
| Horn | 1.689 |
| Ice | .918 |
| Indigo | 1.009 |
| Isinglass | 1.111 |
| Ivory | 1.825-1.920 |
| Lard | .947 |
| Mastic | 1.074 |
| Myrrh | 1.360 |
| Opium | 1.071 |
| Spermaceti | 0.943 |
| Starch | 1.505-1.560 |
| Sugar, Cane | 1.593-1.606 |
| Tallow | .941 |
Liquids.
| Acids:— |
| Acetic | 1.063 |
| Carbolic | 1.065 |
| Fluoric | 1.036 |
| Hydrochloric | 1.270 |
| Hydrocyanic | .700 |
| Nitric | 1.554 |
| Sulphuric | 1.970 |
| Aqua regia | 1.23 |
| Blood | 1.040-1.954 |
| Honey | 1.45 |
| Milk | 1.032 |
| Sea-water | 1.026-1.027 |
| Sea-water (Dead Sea） | 1.240 |
| Tar | 1.015 |
| Vinegar | 1.080 |
Alcohol:—
| Absolute | .749 |
| 95 per cent | .816 |
| 80 per cent | .863 |
| 50 per cent (proof) | .934 |
| 40 per cent | .951 |
| 25 per cent | .970 |
| 10 per cent | .986 |
Oils:—
| Codfish | .923 |
| Linseed | .940 |
| Olive | .915 |
| Palm | .969 |
| Petroleum | .830–.890 |
| Rapeseed | .914 |
| Sunflower | .926 |
| Turpentine | .870 |
| Whale | .923 |
