though the more eminent instances should be enumerated; as the ductility of gold, &c.

XIII. Contraction by the emission, or discharge, of a body received.

Having thus prosecuted the business of dilatations, rarifactions, and relaxations of bodies; the contrary actions thereto must also be enquired into; viz. the contractions, condensations, and shuttings up of bodies. And as contraction is correlative to dilatation; that must be thoroughly examined.

XIV. Contractions by the shrinking of the grosser parts, after the discharge of the spirits.

Here again, the instances are to be carefully collected.

XV. The contraction of bodies by actual, external cold.

This is the reciprocal action to that of dilatation by external heat; and the most genuine and proper kind of contraction. Here, therefore, the enquiry should be more largely and fully prosecuted; so far as the degrees of cold, upon the earth's surface, can be made to reach.

XVI. The contraction of bodies by potential cold. Let this article be prosecuted as the correlative to article VI.

XVII. The contractions of bodies by flight, and antiperistasis.

This is the opposite to dilatation by union and embrace. See article IX.

XVIII. The contraction of bodies by assimilation or conversion, into a denser state.

This is the correlative to article X.

XIX. The contractions of bodies by external violence.

This corresponds to article XI. *

SECT. II.

A

TABLE EXPRESSING THE DENSITY AND RARITY, OR SPECIFIC GRAVITIES, OF DIFFERENT TANGIBLE

BODIES, IN PROPORTION TO GOLD;

WITH THE EXPLANATION,

AND USES THEREOF.

The bodies in the following tables were all taken of the same bulk, or dimensions.

THE TABLE, IN ALPHABETICAL ORDER.t

Pure gold weighed an ounce, or twenty penny-weight.

*Fuller directions, admonitions, and precepts, are occasionally interspersed in the enquiry itself.

+ For the sake of convenience, and ready use, this table is ranged in alphabetical order; though there are considerable ends answered also by disposing it in the natural order, so as to shew how bodies run down, in a descending scale, from the most ponderous substance, gold; to the lightest

the author tried, which was fir. Whence, we judge, that both forms ought to be preserved; at least till a complete table of the specific gravities of all bodies is procured; though on many occasions, even then, it would be proper to have two; one in the order of nature, and the other in that of the alphabet, according to the present example.