produces in all ranks of people, who on its first commencement run hastily to the sea, exclaiming Morgana, Morgana! He re. marks that he has himself seen this appearance three times, and that he would rather behold it again than the most superb theatrical exhibition in the world.

In the second chapter the author describes the city of Reggio, and the neighbouring coast of Calabria : by which he shews that all the objects which are exhibited in the Fata Morgana are derived from objects on shore.

In his third chapter, consisting of physical and astronomical observations, he affirms that the sea in the straits of Messina has the appearance of a large inclined speculum; that in the alternate cur rent, or tide, which flows and returns in the straits for six hours each way, and is constantly attended by an opposite current along shore to the medium distance of about a mile and a half, there are many eddies and irregularities at the time of its change of direc tion and that the Morgana usually appears at this period. Whence he enters into considerations of the relative situations of the sun and moon, which are necessary to afford high water at the proper time after sun-rise, as before described. It is high water, that is to say, the northern current ceases, at full and change, at nine o'clock. There is probably a small rise and fall, though the annotation to a large chart before me affirms that there is none.

In the fourth chapter and subsequent part of the work, the author collects the opinion and relations of various writers on this subject; namely, Angelucci, Kircher, Scotus, and others; and he afterwards proceeds to account for the effects, by the supposed in. clination of the surface of the sea, and its subdivision into different plains by the contrary eddies. The aerial effects are referred to considerations of saline and other effluvia suspended in the air; which I forbear to abridge, because it seems difficult to make any clear or productive statement either from the narrative or the reasoning.

What I seem to collect upon the whole from the several relations, brought into one point is as follows: 1. That by the situation of the Faro of Messina, the current from the south, at the expiration of which this phenomenon is most likely to appear, is so far impeded by the figure of the land, that a considerable por. tion of the water returns along shore. 2. That it is probable the

same boasts may have a tendency to modify the lower portion of the air in a similar manner, during the southern breeze; or, in other words, that a sort of bason is formed by the land, in which the lower air is more disposed to become motionless and calm than elsewhere. 3. That the Morgana Marina presents inverted images below the real objects, which are multiplied lateraily as well as vertically; and that there are repetitions of the same multiplied objects at more considerable vertical intervals. This I gather from the appearance of the dome and other objects in the plate. 4. That the Aërial Morgana is not inverted, but, as I am disposed to conjecture, is more elevated than the original objects. 5. That the fringes of prismatic colours are produced in falling vapours; similar to many appearances which have been described by authors, but not accurately explained by the general principles of refraction through spheres of water. The ship is referred to by the author as an object surrounded by these fringes: whence it appears that the colours apply to the direct rays from objects, as well as to those of the Marine Morgana. 6. Various other objects in the drawing, at well as in the description, afford matter for question and conjecture, but none perhaps which it may be proper to enlarge upon, until the theory be better known. 7. It seems at all events more probable that these appearances are produced by a calm sea, and one or more strata of superincumbent air, differing in refractive, and consequently reflective power; than from any considerable change in the surface of the water, with the laws of which we are much better acquainted than with those of the atmosphere. 8. By attentive reflection upon the facts and reasonings in Mr. Huddart's paper, we may form a theory to account for the erect and inverted images: the polished surface of the sea may perhaps ac. count for the vertical repetition; but for the lateral multiplication we must have recourse to reflecting or refracting planes in the va. pour, which appear nearly as difficult to deduce or establish, as those which have been supposed on the water.

Swinburne gives the following account of this singular phenomenon, which we quote as affording a stronger proof of the correctness of the hypothesis advanced in the preceding section. Sometimes, but rarely, it (the Faro) exhibits a very curious phenomenon, vul.

garly called La Fata Morgana. The philosophical reader will find its causes and operations learnedly accounted for in Kircher, Minasi, and other authors. I shall only give a description of its appearance, from one that was an eye-witness. Father Angelucci is the first that mentions it with any degree of accuracy, in the fol. lowing terms:

"On the 15th of August, 1643, as I stood at my window, I was surprised with a most wonderful, delectable vision. The sea that washes the Sicilian shore swelled up, and became, for ten miles in length, like a chain of dark mountains; while the waters near our Calabrian coast grew quite smooth, and in an instant appeared as one clear polished mirror, reclining against the aforesaid ridge. On this glass was depicted, in chiara scuro, a string of several thousands of pilasters, all equal in altitude, distance, and degree of light and shade. In a moment they lost half their height, and bent into arcades, like Roman aqueducts. A long cornice was next formed on the top, and above it rose castles innumerable, all per. 'fectly alike. These soon split into towers, which were shortly after lost in colonnades, then windows, and at last ended in pines, cypresses, and other trees, even and similar. This was the Fata Morgana, which, for twenty-six years, I had thought a mere fable."

To produce this pleasing deception, many circumstances must concur, which are not known to exist in any other situation. The spectator must stand with his back to the east, in some elevated place behind the city, that he may command a view of the whole bay; beyond which the mountains of Messina rise like a wall, and darken the back-ground of the picture. The winds must be -hushed, the surface quite smoothed, the tide at its height, and the waters pressed up by currents to great elevation in the middle of the channel. All these events coinciding, as soon as the sun surmounts the eastern hills behind Reggio, and rises high enough to form an angle of forty-five degrees on the water before the city,every object existing or moving at Reggio will be repeated a thou. sand-fold upon this marine looking-glass; which, by its tremulous motion, is, as it were, cut into facets. Each image will pass ra.

* The name is probably derived from an opinion, that the whole spectacle is produced by a fairy, or a magician. The populace are delighted whenever the vision appears, and run about the streets shouting for joy,-calling every body out to partake of the glorious sight.

pidly off in succession, as the day advances, and the stream carries down the wave on which it appeared.

Thus the parts of this moving picture will vanish in the twink. ling of an eye. Sometimes the air is at that time so impregnated with vapours, and undisturbed by winds, as to reflect objects in a kind of aërial screen, rising about thirty feet above the level of the sea. In cloudy, heavy weather, they are drawn on the surface of the water, bordered with fine prismatical colours.

[Nicholson's Journ. 4to. vol. ii. Swinburne.

SECTION III.

Singular Instance of atmospherical Refraction, by which the Coast of Picardy, with its more prominent Objects, was brought apparently close to that of Hastings.

By William Latham, Esq. F.R.S. and A.S.

JULY 26, about five o'clock in the afternoon, while sitting in my dining-room at this place, Hastings, which is situated on the Parade, close to the sea shore, nearly fronting the south, my atten tion was excited by a great number of people running down to the sea side. On inquiring the reason, I was informed that the coast of France was plainly to be distinguished with the naked eye. I immediately went down to the shore, and was surprised to find that, even without the assistance of a telescope, I could very plainly see the cliffs on the opposite coast; which, at the nearest part, are between forty and fifty miles distant, and are not to be discerned, from that low situation, by the aid of the best glasses. They appeared to be only a few miles off, and seemed to extend for some leagues along the coast. I pursued my walk along the shore to the eastward, close to the water's edge, conversing with the sailors and fishermen on the subject. At first they could not be persuaded of the reality of the appearance; but they soon became so tho. roughly convinced, by the cliffs gradually appearing more elevated, and approaching nearer, as it were, that they pointed out, and named to me, the different places they had been accustomed to visit; such as, the Bay, the Old Head or Man, the Windmill, &c. at Boulogne ; St. Vallery, and other places on the coast of Picardy; which they afterwards confirmed, when they viewed them through their telescopes. Their observations were, that the places

appeared as near as if they were sailing, at a small distance, into the harbours.

Having indulged my curiosity on the shore for near an hour, during which the cliffs appeared to be at some times more bright and near, at others more faint and at a greater distance, but never out of sight, I went on the eastern cliff or hill, which is of a very considerable height, when a most beautiful scene presented itself to my view; for I could at once see Dengeness, Dover cliffs, and the French coast, all along from Calais, Boulogne, &c. to St. Vallery; and, as some of the fishermen affirmed, as far to the westward even as Dieppe. By the telescope, the French fishing-boats were plainly to be seen at anchor; and the different colours of the land on the heights, with the buildings, were perfectly discernible. This cu rious phenomenon continued in the highest splendour till past eight o'clock, though a black cloud totally obscured the face of the sun for some time, when it gradually vanished. I was assured, from every inquiry I could make, that so remarkable an instance of atmospherical refraction had never been witnessed by the oldest inhabitant of Hastings, nor by any of the numerous visitors come to the great annual fair. The day was extremely hot. I had no barometer with me, but suppose the mercury must have been high, as that and the three preceding days were remarkably fine and clear. To the best of my recollection, it was high water at Hastings about two o'clock P. M. Not a breath of wind was stirring the whole of the day; but the small pennons at the mast-heads of the fishing-boats in the harbour were in the morning at all points of the compass. I was, a few days afterwards, at Winchelsea, and at several places along the coast, where I was informed the above phenomenon had been equally visible. When I was on the eastern hill, the cape of land called Dengeness, which extends nearly two miles into the sea, and is about sixteen miles distant from Hastings, in a right line, appeared as if quite close to it; as did the fishingboats and other vessels, which were sailing between the two places; they were likewise magnified to a great degree *.

[Phil. Trans. 1798.

In this case, as in that of the desert between Alexandria and Cairo, adverted to in section i. the refractive power of the atmosphere was proba bly produced by a diminution of the density of its lower stratum, in consequence of the increase of heat communicated to it by the rays of the sun