in Physics, the act whereby a body is rendered rare; that is, brought to possess more room, or appear under a larger bulk, without accretion of any new matter.—This is very frequently the effect of fire, as has been universally allowed. In many cases, however, philosophers have attributed it to the action of a repulsive principle. However, from the many discoveries concerning the nature and properties of the electric fluid and fire, there is the greatest reason to believe, that this repulsive principle is no other than elementary fire. See REPULSION.

RAS-EL-FEEL, one of the frontier provinces of Abyssinia, of which the late celebrated traveller Mr Bruce was made governor while in that country. It is but of small extent, and in its most prosperous state contained only 39 villages. The climate is extremely hot, in Mr Bruce's opinion one of the hottest in the world. He informs us, that on the first day of March, at three o'clock in the afternoon, the thermometer stood at 114° in the shade, and in the evening at 82°; though at sunrise it had been no higher than 61. Notwithstanding this appearance of extreme heat, however, the sensation was by no means intolerable; they could hunt at midday, and felt the evenings rather cold. The soil is a fat, loofe, black earth, which our author says is the same from 13° to 16° of north latitude; at least till we come to the deserts of Albara, where the tropical rains cease. This country divides that of the Shangalla into two parts, nearly equal. These people inhabit a belt of land about 60 miles broad, all along the northern frontier of Abyssinia, excepting two large gaps or spaces which have been left open for the sake of commerce, and which are inhabited by strangers, to keep the Shangalla in awe. The latter trade in gold, which they pick up in the streams as it is washed down from the mountains; for there are no mines in their country, neither is there any gold in Abyssinia, excepting what is imported from this or some other country. The Shangalla are the natural enemies of the inhabitants of Ras-el-Feel, and much blood has been shed in the various incursions they have made upon one another; though of late those of Ras el-Feel, by the assistance of the emperors, have been enabled to keep the Shangalla at bay.

RAS-SEM, a city of Tripoli in Barbary, concerning which a number of fables were told by the Tripolitans ambassador, all of which were believed in England and other parts of Europe in the beginning of this century. (See PETRIFIED CITY). Mr Bruce informs us, that it is situated about five days journey south from Bengazi; but has no water excepting one fountain, which has a disagreeable taste, and seems to be impregnated with alum. Hence it has obtained the name of Ras-Sem, or the fountain of pelion. The only remains of antiquity in this place consist of the ruins of a tower or fortification, which, in the opinion of Mr Bruce, is as late as the time of the Vandals; but he says he cannot imagine what use they made of the water, and they had no other within two days journey of the place.—Here our traveller saw many of the animals called jerboa, a kind of mice; which, he says, seem to partake as much of the nature of a bird as of a quadruped.

RASY, one of the Hebrides islands, is about 13 miles long and two broad. It contains 700 inhabitants, has plenty of limestone and freestone; feeds great numbers of black cattle; but has neither deers, hares, nor rabbits. The only appearance of a harbour in Rafay is at Clachan bay, where Mr Macleod the proprietor of the island resides. Rafay presents a bold shore, which rises to the height of mountains; and here the natives have, with incredible labour, formed many little corn fields and potato grounds. These heights decrease at the south end, where there are some farms and a good-looking country. Mr Macleod is sole proprietor of this island, and of Roma and Fladda at the north end of it, which are only proper for grazing.

The house of Rafay is pleasantly situated near the south-west end of the island, which is the most level part of it. It has an extensive and excellent garden, and is surrounded with forest trees of considerable magnitude; another proof that trees will grow upon the edge of the sea, though it must be allowed that the channel here is narrow. Immediately behind the house of Rafay are the ruins of an ancient chapel, now used as the family burying-place.