one of the most zealous defenders of Arianism, was born in Syria, and flourished about the year 336. After being servant to a grammarian, of whom he learned grammar and logic, he was ordained deacon, and at length bishop, by Eudoxus patriarch of Constantinople. Actius was banished into Phrygia on account of his religious opinions; but was recalled from exile on the accession of Julian, and was much esteemed by that emperor. He died, it is supposed, at Constantinople, about the year 366. St Epiphanius has preserved 47 of his propositions against the Trinity. His followers were called AEITIANIS.

a famous physician, born at Amida in Mesopotamia, and the author of a work entitled Tetra-biblos, which is a collection from the writings of those physicians who went before him. He lived, according to Dr Freind, at the end of the fifth or the beginning of the sixth century.

governor of Gallia Narbonensis in the reign of Valentinian III., forced the Franks who were passing into Gaul to repass the Rhine. He defeated the Goths; and routed Attila king of the Huns, who invaded Gaul with an army of 700,000 men. But the emperor, jealous of the merit of this great man, killed him in 454, with his own hand, under the pretence that he had permitted the invasion of the Huns, after Attila's defeat.

ÆTNA, (in the Itineraries Æthana, supposed from athu, "to burn;" according to Bochart, from athuna, a furnace, or ætuna, darkness), now Monte Gibello: a volcano or burning mountain of Sicily, situated in N. Lat. 38°. E. Long. 15°.

This mountain, famous from the remotest antiquity, both for its bulk and terrible eruptions, stands in the eastern part of the island, in a very extensive plain, called Val di Demoni, from the notion of its being inhabited by devils, who torment the spirits of the damned in the bowels of this volcano.

Concerning the dimensions of Mount Ætna, we can scarcely extract any thing consistent, even from the accounts of the latest and most ingenious travellers. Pindar, who lived about 435 years before Christ, calls it the Pillar of Heaven, on account of its great height. All modern writers likewise agree, that this mountain is very high, and very large; but differ much both as to its height and magnitude: some making it no less than twelve miles high, others eight, others six, some four; while Mr Brydone, and Sir William Hamilton, who lately ascended to its highest summit, reduce its height to little more than two miles; nay by some it is reduced to 10,036 feet, somewhat less than two miles. No less remarkable are the differences concerning its circumference: some making it only 60 miles round, others 100; and Signior Recupero, from whom Mr Brydone had his information in this respect, affirms it to be no less than 183 miles in circuit.

We are sorry to detract from the merit of Mr Brydone, or to involve in obscurity what he has been at so much pains to elucidate; but every person who compares the account of Mount Ætna's circumference, given by Signior Recupero, and to which Mr Brydone seems to have assented, with its apparent circumference on the map prefixed, to that gentleman's tour through Sicily and Malta, must at once be struck with the prodigious disparity. Indeed, it is plain, that in the map, the geographer has not left room for any such mountain: nor can we help thinking, that, by comparing the distances of some of the Sicilian towns from one another, Signior Recupero's dimensions will be found enormously exaggerated.—Certain it is, that where the geographer has placed Catania, which stands at the foot of Mount Ætna, on one side, there is no more than 28 miles from the most distant point of the river Alcantara, which forms the boundary on the opposite side; so that a circle, whose radius is 14 or 15 miles, must encompass as much space as we can possibly think is occupied by the basis of Mount Ætna. Thus we shall reduce the circumference of this famous mountain to between 80 and 90 miles; and even when we do so, it is perhaps too great.

But if we are embarrassed with the circumference of Ætna, we are much more so with the accounts relating to its height; and one circumstance, particularly, creates almost unsurmountable difficulties. It is agreed upon by all travellers, and among the rest by Sir William Hamilton, that, from Catania, where the ascent first begins, to the summit, is not less than 30 miles. The descent on the other side we have no account of; but whatever supposition we make, the height of the mountain must be prodigious. If we suppose it likewise to be 30 miles, and that Mount Ætna can be represented by an equilateral triangle, each of whose sides is 30 miles, we will have an amazing elevation indeed, no less than 26 miles perpendicular!. Such a height being beyond all credibility, we must contract the sides of our triangle, in proportion to its basis. We shall begin with allowing ten miles for the difference between a straight line from Catania to the summit, and the length of the road, occasioned by the inequalities of the mountain; and supposing the descent on the other side to be somewhat shorter, we may call it 15 miles. Mount Ætna will now be represented by a scalene triangle, whose base is 30 miles, its longest side 20, and its shortest 15; from which proportions we will still find its height to be betwixt eight and nine miles.—This is still incredible: and when all the various relations concerning the height of Ætna are compared, we hope it will not be thought presumptuous in us to give it as our opinion, that the true dimensions of this mountain are as yet unknown. The following measures are given by different authors.

Height above the surface of the sea, 10,036 feet. One hundred and eighty miles circumference at the base.—Faujas de St Fond, in his Volcans du Vivarnis. Height 12,000 feet.—Brydone. Tour to Sicily. Height 2500 toises.—La Platrière, said as from Recupero. Height 1950 toises.—Diameter 30 miles.—Mentelle Geogr. comp. Others make its height only 2000 toises, and its superficies 300 square miles. Concerning the products and general appearance of this volcano, authors are much better agreed.—The journey from Catania to its summit has been lately described by several travellers, M. D'Orville, Mr Brydone, Sir William Hamilton, M. Houel, and the abbé Spallanzani. They all agree, that this single mountain affords an epitome of the different climates throughout the whole world: towards the foot, it is extremely hot; farther up, more temperate; and grows gradually more and more cold the higher we ascend. At the very top, it is perpetually covered with snow: from thence the whole island is supplied with that article, so necessary in a hot climate, and without which the natives say Sicily could not be inhabited. So great is the demand for this commodity, that the bishop's revenues, which are considerable, arise from the sale of Mount Etna's snow; and he is said to draw 100l. a-year from one small portion lying on the north side of the mountain. Great quantities of snow and ice are likewise exported to Malta and Italy, making a considerable branch of commerce. On the north side of this snowy region, Mr Brydone was assured that there are several small lakes which never thaw; and that the snow, mixed with the ashes and salt of the mountain are accumulated to a vast depth. The quantity of salts contained in this mountain, he, with great probability, conjectures to be one reason of the preservation of its snows; for salt increases the coldness of snow to a surprising degree.

In the middle of the snowy region stands the great crater, or mouth of Etna; from which, though contrary to the usual method of travellers, we shall begin our particular account of this mountain. Sir William Hamilton describes the crater as a little mountain, about a quarter of a mile perpendicular, and very steep, situated in the middle of a gently inclining plain, of about nine miles in circumference. It is entirely formed of stones and ashes; and, as he was informed by several people of Catania, had been thrown up about 25 or 30 years before the time (1769) he visited Mount Etna. Before this mountain was thrown up, there was only a prodigious large chasm, or gulf, in the middle of the above-mentioned plain; and it has been remarked, that about once in 100 years the top of Etna falls in; which undoubtedly must be the case at certain periods, or the mountain behaved continually to increase in height. As this little mountain, though emitting smoke from every pore, appeared solid and firm, Sir William Hamilton and his companions went up to the very top. In the middle is a hollow, about two miles and a half in circumference, according to Sir William Hamilton; three miles and a half, according to Mr Brydone; and three or four, according to M. D'Orville. The inside is crusted over with salts and sulphur of different colours. It goes shelving down from the top, like an inverted cone; the depth, in Sir W. Hamilton's opinion, nearly corresponding to the height of the little mountain. From many places of this space issue volumes of sulphurous smoke, which being much heavier than the circumambient air, instead of ascending in it, roll down the side of the mountain, till, coming to a more dense atmosphere, it shoots off horizontally, and forms a large track in the air, according to the direction of the wind; which, happily for our travellers, carried it exactly to the side opposite to which they were placed. In the middle of this funnel is the tremendous and unfathomable gulf, so much celebrated, in all ages, both as the terror of this life, and the place of punishment in the next. From this gulf continually issue terrible and confused noises, which in eruptions are increased to such a degree as to be heard at a prodigious distance. Its diameter is probably very different at different times: for Sir W. Hamilton observed, by the wind clearing away the smoke from time to time, that the inverted hollow cone was contracted almost to a point; while M. D'Orville and Mr Brydone found the opening very large. Both Mr Brydone and Sir W. Hamilton found the crater too hot to descend into it; but M. D'Orville was bolder: and accordingly he and his fellow traveller, fastened to ropes which two or three men held at a distance for fear of accidents, descended as near as possible to the brink of the gulf; but the small flames and smoke which issued from it on every side, and a greenish sulphur, and punice stones, quite black, which covered the margin, would not permit them to come so near as to have a full view. They only saw distinctly, in the middle, a mass of matter which rose in the shape of a cone, to the height of above 60 feet, and which towards the base, as far as their sight could reach, might be 600 or 800 feet. While they were observing this substance, some motion was perceived on the north side, opposite to that whereon they stood; and immediately the mountain began to send forth smoke and ashes. This eruption was preceded by a sensible increase of its internal roarings; which, however, did not continue; but after a moment's dilatation, as if to give it vent, the volcano resumed its former tranquillity; but as it was by no means proper to make a long stay in such a place, our travellers immediately returned to their attendants.

On the summit of Mount Etna, Sir W. Hamilton observes, that he was sensible of a difficulty in respiration from the too great subtilty of the air, independent of what arose from the sulphureous smoke of the mountain. Mr Brydone takes no notice of this: which probably rose from the air being in a more rarefied state at the time of Sir W. Hamilton's observation than of Mr Brydone's; the barometer, as observed by the former, standing at 18 inches and 10 lines, by the latter at 19 inches 6½ lines.

In these high regions there is generally a very violent wind, which, as all our travellers found it constantly blowing from the south, is perhaps most frequently directed from that point. Here Mr Brydone's thermometer fell to 27°.

The top of Etna being above the common region Splendours of vapour, the heavens appear with exceeding great of the stars splendour.—Mr Brydone and his company observed, as seen from they ascended in the night, that the number of stars the top of seemed to be indefinitely increased, and the light of each of them appeared brighter than usual; the whiteness of the milky-way was like a pure flame which shot across the heavens; and, with the naked eye, they could observe clusters of stars that were invisible from below. Had Jupiter been visible, he is of opinion that some of his satellites might have been discovered with the naked eye, or at least with a very small pocket glass. He likewise took notice of several of those meteors called falling stars; which appeared as much elevated as when viewed from the plain; a proof, according to Mr Bry- done, that "these bodies move in regions much beyond the bounds that some philosophers have assigned to our atmosphere."

To have a full and clear prospect from the summit of Mount Ætna, it is necessary to be there before sunrise; as the vapours raised by the sun, in the day time, will obscure every object: accordingly, our travellers took care to arrive there early enough; and all agree, that the beauty of the prospect from thence cannot be expressed.—Here Mr Brydone and Sir W. Hamilton had a view of Calabria in Italy, with the sea beyond it; the Lipari islands, and Stromboli, a volcano, at about 70 miles distance, appeared just under their feet; the whole island of Sicily, with its rivers, towns, harbours, &c. appeared distinct, as if seen on a map. Massa, a Sicilian author, affirms, that the African coast, as well as that of Naples, with many of its islands, have been discovered from the top of Ætna. The visible horizon here is no less than 800 or 900 miles in diameter. The pyramidal shadow of the mountain reaches across the whole island, and far into the sea on the other side, forming a visible track in the air, which as the sun rises above the horizon, is shortened, and at last confined to the neighbourhood of Ætna. The most beautiful part of the scene, however, in Mr Brydone's opinion, is the mountain itself, the island of Sicily, and the numerous islands lying round it. These last seem to be close to the skirts of Ætna; the distances appearing reduced to nothing.

This mountain is divided into three zones, which might properly enough be distinguished by the names of torrid, temperate, and frigid; they are, however, known by the names of the Piedmontese, or Regione culta, the cultivated or fertile region; the sylvosa, woody, or temperate zone; and the Regione deserta, the frigid or desert zone or region. All these are plainly distinguished from the summit. The Regione deserta, is marked out by a circle of snow and ice, which extends on all sides to the distance of about eight miles, beginning at the foot of the crater. Great part of this region is smooth and even. This is immediately succeeded by the sylvosa, or woody region; which forms a circle of the most beautiful green, surrounding the mountain on all sides. This region is variegated with a vast number of mountains of a conical form, thrown up by Ætna in those eruptions which burst out from its sides. Sir W. Hamilton counted 44 on the Catania side, each having its crater; many with large trees flourishing both within and without the crater. All these, except a few of late date, have acquired a wonderful degree of fertility. The circumference of this zone, or great circle, according to Recupero, is not less than 70 or 80 miles. It is everywhere succeeded by the Regione culta; which is much broader than the rest, and extends on all sides to the foot of the mountain. Here terrible devastations are sometimes committed by the eruptions; and the whole region is likewise full of conical mountains thrown up by them. The circumference of this region is, by Recupero, reckoned 183 miles; but we have already given our reasons for rejecting these dimensions.—This region is bounded by the sea to the south and southeast; and on all other sides, by the rivers Semetus and Alcantara, which form the boundaries of Mount Ætna.

The woody region descends eight or nine miles below the Regione deserta, but differs greatly in the temperature of its climate. Sir W. Hamilton observed a gradual decrease of the vegetation as he advanced; the under part being covered with large timber trees, which grew gradually less as he approached the third region, and at last degenerated into the small plants of the northern climates. He also observed quantities of juniper and tansy; and was informed by his guide, that later in the season (he visited Ætna in June 1769) there are a great many curious plants, and in some places rhubarb and saffron in great plenty. In Carrera's history of Catania, there is a list of all the plants and herbs of Ætna.

This region is extolled by Mr Brydone as one of the most delightful spots on earth. He lodged for a night in a large cave near the middle, formed by one of the most ancient lavas. It is called La Spelonca del Capriolo, or the goats cavern; because it is frequented by those animals, which take refuge there in bad weather. Here his rest was disturbed by a mountain thrown up in the eruption 1766. It discharged great quantities of smoke, and made several explosions like heavy cannon fired at a distance; but they could observe no appearance of fire.

This gentleman likewise visited the eastern side of the Regione sylvosa, intending to have ascended that way to the summit, and descended again on the south side to Catania, but found it impracticable. On this Eruptive side, part of the woody region was destroyed in 1755, of boiling water, which issued from the great crater. Its traces were still very visible, about a mile and a half broad, and in some places more. The soil was then only beginning to recover its vegetative power, which it seems this torrent had destroyed for 14 years. Near this place are some beautiful woods of cork, and evergreen oak, growing absolutely out of the lava, the soil having hardly filled the crèvices; and not far off, our traveller observed several little mountains that seemed to have been formed by a late eruption. Each of these had a regular cup, or crater, on the top; and, in some, the middle gulf, or voragine, as the Sicilians call it, was still open. Into these gulfs Mr Brydone tumbled down stones, and heard the noise for a long time after. All the fields round, to a considerable distance, were covered with large burnt stones discharged from these little volcanoes.

The woody region, especially the east side, called Over-Carpinette, abounds with very large chestnut trees; the most remarkable of which has been called, from its size, the Castagno di Cento Cavalli, or chestnut tree of a hundred horse. Mr Brydone was greatly disappointed at the sight of this tree, as it is only a bush of five large ones growing together; but his guides assured him, that all these five were once united into one stem; and Signior Recupero told him, that he himself had been at the expence of carrying up peasants with tools to dig round it, and found all the stems united below ground in one root. The circumference, as measured by Mess. Brydone and Glover who accompanied him, amounted to 204 feet. Here the barometer stood at 26 inches 5 lines and a half, indicating an elevation of near 4000 feet.