Abbildungen der Seite

His first chapter contains a description of the phenomenon, ** When the rising sun shines from that point whence its incident ray forms an angle of about forty-five degrees on the sea of Reggio, and the bright surface of the water in the bay is not disturbed either by the wind or the current, the spectator being placed on an eminence of the city, with his back to the sun and his face to the sea ;-on a sudden there appear in the water, as in a catoptric theatre, various multiplied objects ; that is to say, numberless series of pilasters, arches, castles well delineated, regular columns, lofty towers, superb palaces, with balconies and windows, extended alleys of trees, delightful plains with herds and flocks, armies of meu on foot and horseback, and many other strange images, in their natural colours and proper actions, passing rapidly in suc. cession along the surface of the sea, during the whole of the short period of time while the above-mentioned causes remain.

“ But if, in addition to the circumstances before described, the atmosphere be highly impregnated with vapour, and dense exhala. tions, not previously dispersed by the action of the wind or wares, or rarefied by the sun, it then happens that in this vapour, as in a curtain extended along the channel to the height of about thirty palms, and nearly down to the sea, the observer will behold the scene of the same objects not only reflected from the surface of the sea, but likewise in the air, though not so distinct or well defined as the former objects from the sea.

“ Lastly, if the air be slightly hazy and opake, and at the same time dewy and adapted to form the iris, then the above-mentioned objects will appear only at the surface of the sea, as in the first case, but all vividly coloured or fringed with red, green, blue, and other prismatic colours.”

The author therefore distinguishes three sorts of Fata Morgana : that is to say, the first at the surface of the sea, which he calls the Marine Morgana ; the second in the air, called the Aërial Morgana : and the third only at the surface of the sea, which he calls the Morgana fringed with prismatic colours.

In a note in this chapter P. Minasi enquires into the etymology of Morgana. After various remarks, he thinks the opinion of those who derive this word, which is so foreign to the Roman idiom, from juwpoo tristis and yarów lætitia afficio, is not far from the truth; considering the great exultation and joy this appearance 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 ob. servations, 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 an. notation to a large chart before me affirms that there is none.

In the fourth chapter and subsequent part of the work, the au. thor 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 re. lations, 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 pora 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 laterally as wellas vertically; and that there are repetitions of the same multi. plied 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 conjec. ture, 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 pheno. menon, 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 terins:

« On the 15th of August, 1643, as I stood at my window, I was surprised with a most wonderful, detectable 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 ruse castles jooumerable, 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 sur. mounts 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, hy 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 speetacle 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. VOL. IV.

2 L

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

In cloudy, heavy weather, they are drawn on the surface of the water, bordered with fine prismatical colours.

(Nicholson's Journ. 4to. vol. i. Swinburne.


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 sailon 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

« ZurückWeiter »