(anc. geog.), an island between the borders of Phoenicia and Seleucia, at the distance of 20 stadia from a dangerous coast; all of it a rock surrounded by the sea, in compass seven stadia; and forming a very powerful city and republic. It is now called Ronad; but not a single wall is remaining of all that multitude of houses which, according to Strabo, were built with more stories than even those of Rome. The liberty enjoyed by the inhabitants had rendered it very populous; and it subsisted by naval commerce, manufactures, and arts. At present the island is deserted; nor has tradition even retained the memory of a spring of fresh water in its environs, which the people of Aradus discovered at the bottom of the sea, and from which they drew water in time of war by means of a leaden bell and a leather pipe fitted to its bottom.

ARÆ PHILANON, or PHILENORUM (Strabo); to the south of the Syrtis Major; but in Peutinger; more westerly, to the south almost of the Syrtis Minor. In Strabo's time, the altars were not extant, but a village of the same name stood on the spot. On a dispute about limits, between the Cyreneans and Carthaginians, it was agreed that two of each people should set out on the same day, and that where they should happen to meet, there the limits of both should be fixed. The Phileni, two brothers, Carthaginians, undertook it for Carthage; these, after having advanced a great many miles into the territory of the Cyreneans, were met by their antagonists; who, enraged at their being beforehand with them so far, gave them the option of either returning back, or of being buried alive on the spot. Like zealous patriots, they chose the latter; and there the Carthaginians raised two altars in honour of the Phileni. (Sallust, Valerius Maximus.)

ARÆOMETER, an instrument wherewith to measure the density or gravity of fluids.

The aræometer, or water-poise, is usually made of glass; consisting of a round hollow ball, which terminates in a long slender neck hermetically sealed at top; there being first as much running mercury put into it as will serve to balance or keep it swimming in an erect position.

The stem is divided into degrees (as represented Plate XXXI. fig. 23.); and by the depth of its descent into any liquor, the lightness of that liquor is concluded; for that fluid in which it sinks least must be heaviest; and that in which it sinks lowest, lightest.

M. Homberg has invented a new aræometer, described in Phil. Transact. No. 262. thus: A is a glass bottle or matraf, with so slender a neck that a drop of water takes up in it about five or six lines, or half of an inch. Near that neck is a small capillary tube D, about six inches long, and parallel to the neck.—To fill the vessel, the liquor is poured in at the mouth B, (which is widened to receive a funnel), till it run out at D, that is, till it rise in the neck to the mark C, by which means you have always the same bulk or quantity of liquor; and consequently, by means of the balance, can easily tell, when different liquors fill it, which weighs most, or is most intensely heavy.

Some regard, however, is to be had in these trials to the season of the year and degree of heat and cold, in the weather; because some liquors rarely with heat and condense with cold more than others, and accordingly take up more or less room.

By means of this instrument, the ingenious author has made a table to show the different weights of the same bulk of the most considerable chemical liquors both in summer and winter, as follows:

| Weighed in summer | In winter | |-------------------|----------| | oz. dr. gr. | oz. dr. gr. | | Quicksilver | 11 00 06 | 11 00 32 | | Oil of tartar | 01 03 08 | 01 03 31 | | Spirit of urine | 01 00 32 | 01 00 43 | | Oil of vitriol | 01 03 58 | 01 04 03 | | Spirit of nitre | 01 01 40 | 01 01 70 | | Spirit of salt | 01 00 39 | 01 00 47 | | Aquafortis | 01 01 38 | 01 01 55 | | Vinegar | 00 07 55 | 00 07 60 | | Spirit of wine | 00 06 47 | 00 06 61 | | River water | 00 07 53 | 00 07 57 | | Distilled water | 00 07 50 | 00 07 54 |

The instrument itself weighed, when empty, one dram twenty-eight grains. See HYDROMETER.

ARÆOPAGUS. See AREOPAGUS.

ARÆOSTYLE, in architecture, a term used by Vitruvius, to signify the greatest interval which can be made between columns.

ARÆOTICS, in medicine, remedies which rarefy the humours, and render them easy to be carried off by the pores of the skin.