WEIGHT, in physics, is a quality in natural bodies, by which they tend to wards the centre of the earth. See Gan MATION. Weight may be distinguish ed into absolute, specific, and relative. It is demonstrated by Sir Isaac Newton ; 1. That the weights of all bodies, at equal distances from the centre of the earth, are proportional to the quantities of matter that each contains. 2. On dif ferent parts at the earth's surface, the weight of the same body is different ; owing to the spheroidal figure of the earth, which causes the bodies on the surface to be nearer the centre in going from the equator towards the poles ; and the increase of weight is nearly in pro portion to the square of the sine of the latitude : the weight at the equator to that at the pole being as 229 230; or i the whole increase of weight from the equator to the pole is the 229th part of the former. 3. That the weights of the same body, at different distances above the earth, are inversely as the squares of the distances from the centre. So that a body at the distance of the moon, which is 60 semi-diameters from the earth's cen tre, would weigh only part of what it weighs at the surface of the earth. 4. That at different distances within the earth, or below the surface, the weights of the same body are directly as the dis tances from the earth's centre ; so that at half way toward the centre a body would weigh but half as much, and at the centre it would weigh nothing at all. 5. A bo dy immersed in a fluid, which is specifi cally lighter than itself, loses so much of its weight as is equal to the weight of a quantity of the fluid of the same bulk with itself. Hence a body loses more of its weight in a heavier fluid than in a lighta.e one, and therefore it weighs more in a lighter fluid than in a heavier one.
The weight of a cubic foot of water is 1000 ounces, o. 62316. avoirdupois ; this, multiplied by 32, g-ves 200016. the weight of a ton : hence eight -,uhic feet formerly made a hogshead, and raw hogsheads a ton, in capacity as well as in weight.
Measures for corn, coals, and other dry articles, were constructed on the same principle. A bushel of wheat, assumed as a general standard for all sorts of grain, weighed 6211b. eigat of these make a quarter, and four quartet.. or 32 bush els, a ton weight. Coals were by the chaldron, and supposed to wetrii a ton, in reality it weighs moe,. more. 'Hence a ton weight is the common ard for liquids, wheat, and coals. r.o this analogy been adhered to, the con fusion which is occasioned by different local weights would have been avoided.
To regulate the weights and measures of a country is a branch of the sovereign's prerogative. For the public conveni ence, these ought to be universally the same throughout the nation, the better to reduce the prices of articles to equiva lent values. But as weight and measure are things in their nature arbitrary and uncertain, it is necessary that they be reduced to some fixed rule or standard.
It is, however, impossible to fix such a standard by any written law or oral clamation, as no person can, by words i only, give to another an adequate idea of a pound weight, or foot rule. It is there five expedient to have recourse to some visible, palpable, material standard, by forming a comparison with which all weights and measures may be reduced to one uniform size. Such a standard was anciently kept at Winchester; and we find in the laws of King Edgar, nearly a century before the conquest, an injunc tion that this measure should be observ ed throughout the realm.
Most nations have regulated the stand ard of measures of length from some parts of the human body : as the palm, the hand, the span, the foot, the cubit, the ell, (ulna, or arm) the pace, and the fa thom. But as these are of different dimen sions in men of different proportions, an cient historians inform us, that a new standard of length was fixed by our king Henry the First ; who commanded that the ulna, or ancient ell, which answers to the modern yard, should be made of the '• exact length of his own arm. See MEA