Hydrostatics.
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with the Body suspended in the Air, theEquilibrium will be destroyed when the
Solid
and an Ounce Troy contains 480 Grains, therefore theAverdupois Ounce is to the Troy Ounce as 437s to 480,or, as 51 to 56 nearly. The Averdupois Pound is tothe Troy Pound as 437s X 16 = 7000, to 480 X 12 =5760, that is, as 17 to 14 nearly ; so that a cuhic Footof Water weighs 62 \lb. Averdupois, and nearly 76 Ib.
Troy. And hence it is that such a Table becomes souseful in the Solution of various physical and mathema-tical Problems, and Science of Geometry, extended byHydrostatic Principles.
8. From what has been said, nothing can be easierto be understood, than the Method or Praxis of theHydrostatic Balance, for finding the specific Gravitiesof all such Solids as are heavier than Fluids, and willfink in them ; but for those which are lighter, as Wood,Cork, fsV. and will not be totally immersed, a diffe-rent Method must be taken, viz. the lighter is to beconnected to an heavier, and so both together to beimmersed into the Fluid, as one compound Body, andits specific Gravity thus determined ; then having thespecific Gravity of the heavier Body, and of the com-pound, that of the lighter Body will be easily found.
9. For suppose to a Piece of Copper, weighing 18Grains, be tied a Piece of Elm Wood, weighing 15Grains, then will the Compound weigh 33 Grains :Again, suppose the Copper alone in Water weighed 16Grains, and the Compound only 6 Grains ; the Lossof Weight in the Compound will be 27 ( — 33— 6)which is the Weight of an equal Bulk of Water: Iffrom this we subtract 2 (the Loss of Weight in theCopper, and Weight of an equal Bulk of Water) theRemainder 25 will be the Weight of a Bulk of Water,equal to that of the Elm. But the Weight of the Elm was15 Grains: The specific Gravity therefore of Wateris to that of Elm-Wood, as 25 to 15, or, as 1 to 0,6.
10. Another Way more simple to find the specific pjGravities of light Bodies (without tying them to heavy p.'ones) is as follows, A BCD is a Veflel of Water, ®‘
in