SP E
616
S P E
determined by immerging the globe successively in all the fluids, |and observing the weights lost in each, which will be the propor- |tions of the specific gravities of the fluids sought. This same ope-ration determines also the specific gravity of the solid immerged,whether it is a globe, or of any other shape or bulk, supposingthat of the fluklknown. For the specific gravity of the fluid isto that of the solid, as the weight lost is to the whole weight.Hence also may be found the specific gravity of a body that islighter than the fluid, as follows:
IX. To find the specific gravity of a solid that is lighter thanthe fluid, as water in which it is put. —Annex to the lighter bodyanother that is much heavier than the fluid, so that the compoundmass may sink in the fluid. Weigh the heavier body and thecompound mass separately, both in water and out of it; then findhow much each loses in water, by subtracting its weight in waterfrom its weight in air; and subtract the less of these remaindersfrom the greater. Then, As this last remainder, is to the weightof the light body in air, so is the specific gravity of the fluid, tothe specific gravity of that body.
X. The spec ; fie gravities of bodies of ecpial weight, are recipro-cally proportional to the quantities of weight lost in the same fluid.And hence is found the ratio of the specific gravities of solids, byweighing in the same fluid, masses of them that weigh equally inair, and noting the weights lost by each.
XI. A body descends in a fluid specifically lighter, or ascends
in a fluid specifically heavier, with a force equal to the differencebetween its weight, and that of an equal bulk of the fluid.
XII. A body sinks in a fluid specifically heavier, so far as thatthe weight of the body is equal to the weight of a quantity of thefluid of the same bulk as the part immersed. Hence, as thespecific gravity of the fluid is to that of the body, so is the wholemagnitude of the body, to the magnitude of the part immersed.
XIII. The specific gravities of equal solids are as their partsimmerged in the same fluid.
The several theorems here delivered are both demonstrable fromthe principles of mechanics, and are also equally conformable toexperiment, which answers exactly to the calculation. See Hy-drostatics.
Other methods for finding specific gravities, ate likewise used inexperiments with fluids. 'I bus equal bulks of different fluids maybe weighed by filling a small bottle with a ground-stopper witheach respectively, and from their several weights the weights of thebottle and stopper must be deducted. Or otherwise, the instru-ment called the hydrometer may be used. See Hydrometer.This possesses the advantage of portability, speed, and a degreeof accuracy not easily obtained by the use of ordinary balances.The specific gravities of many kinds of bodies, both solid andfluid, have been determined by various authors. The following ,tables contain the specific gravities of some of the most commonbodies which have been determined with the greatest accuracy ;
TABLE I.
t
Shewing the Specific Gravity of Metals and other Bodies to Rain-Water , and the Weight of a Cubic Inch of each inparts of a Pound Avoirdupoise. The Number in the Column, Specific Gravity, shews the Ounces Avoirdupoisein the Cubic Foot of each Body.
Bodies.
Sp. Gray.
VV. lb. Av.
Bodies.
Pure gold cast...
-hammered..
Standard gold cast.
-hammered.......
Pure silver cast.
----hammered..
Standard silver in coin.
Crude platina in grains.
-hammered.
-drawn into wire.
-laminated.
Mercury...
Lead fused.
Copper fused.
‘ - drawn into wire.
Brass cast.
-in wire.
Iron cast..
-bar.
Steel soft, and not hammered
-hardened.
-hammered.
Malacca tin fused..
- -hammered......
Nickel.
Arsenic, the metal.
Cobalt..
Zinc.
Antimony.
Manganese.
Wolfran ..
19258
19362
17486
17589
10474
10511
10391
15602
19500
20377
21042
22069
13568
11352
7788
8878
8396
8544
7207
7788
7840
7816
7291
7299
7296
7306
9823
8660
5763
7812
7191
6702
6850
17600
0.710360.700300.632500.636180.377960.380170 875800.564310.705300.735570.761070.798210.490740.4(119650.281680.321110.303670.309030.260670.281680.283560.282700.263710.264000.263820.264860.355290.313230.208440.282550.260090.242400.247760.63657
Ruby,...
—— Spinell...
Topaz, Oriental.
-■ Brazilian..
-Saxon........................
Emerald...
Adamantine spar.
Rock-crystal from Madagascar...
Quartz.
Muscovy talc...
Common slate.
Calcareous spar.
Alabaster.
White marble...
Limestones, from.
-to..
Ponderous spar.,
Fluor-spar.
Pumice-stone...
Green-glass.,.
Another piece.
White flint-glass for achromatic 1uses J
Glass of S. Gobin.
Brimstone.
Phosphorus.
Yellow amber.
Distilled water.
Diamond
3251
0.11759
Sea-water
Sp. Gray.
IV. lb. Av.
4283
0.15491
3760
0.13600
4011
0.14507
3536
0.11718
3564
0.12891
3994
0.14446
2775
0 10037
4180
0.15118
2653
0.09596
2654
0.09599
2590
0.09368
2376
0.09537
2792
0.10098
2672
0.09664
2715
0.09S20
2730
0.09874
2716
0.09823
1386
0.05113
2390
0.08644 ■
4474
0.16182
3180
0.11502
914
0.03306
2620
0.09476
2520
0.09115
3290
0.11900
3216
0.11632
3437
0.12431
2892
0.10460
2488
0.09000
1990 1
0.07198
1714
0.06199
1078
0.3899
1000
0.03617
1026
0.03711
TABLE