In addition to the above facts, MM. Becquerel and Breschet have ascertained The temperature of the venous, and of the arterial, blood; and The latter experiments exhibit the effect which the pathological state of an organ produces in its temperature. ON THE FATA MORGANA AT GIBRALTAR. May 7th, 1835, 3 P.M., at sea, 20 miles E. of Gibraltar. **** I have just been witnessing an extraordinary phenomenon, so similar to the celebrated Fata Morgana, that I cannot help thinking that it must arise from the same cause, and is perhaps the same thing, though I always before understood that such apparitions were seen only in the straits of Messina. Yesterday, about 2 P.M., the officer of the deck sent for me to look at some spectral ships, which he said he had been for some time observing over the straits of Gibraltar: I went up immediately, but was too late, being able to see nothing unusual, except that a brig just on the edge of a heavy fog that covered the straits, had her upper sails elevated by the refraction, so as to give her an extraordinary height. The officers told me that a few minutes before, another vessel had appeared in the sky, inverted immediately over this one; and one of them described another phenomenon, which he had observed during the forenoon, as follows-a vessel was in the straits, whose royal-sails could only be seen about the thicker part of the fog: immediately above these, and in contact with them, was an inverted vessel, and directly above this was another one, upright; the two keels touching each other; so that he had two spectral vessels, one upright and one inverted, while directly under the latter was the original vessel, only partially seen. The day was pleasant and clear; the breeze was light in the bay of Gibraltar from the east, but in the straits it seemed to be more from the westward; the fog formed a stratum about two hundred feet thick, resting on the water, and with its upper edge horizontal and well defined. I have frequently noticed such fogs stretching from the foot of Apes' hill to the westward, but never before heard of such extraordinary refractions accompanying them. We were then lying in Gibraltar Bay: this morning we weighed anchor, and at meridian were fifteen miles east from the southern end of the Rock, which, you know, goes by the name of Europa Point. Going on deck at this time, I was delighted to find the phenomenon once more exhibiting itself, and from this time until nearly 2 P.M., when it ceased, had ample time for observation. Its first appearance was to the eastward of us. A fog like that of yesterday commenced at Europa Point, and passing along the eastern side of the Rock, stretched along the coast of Spain, then curving across the Mediterranean about twenty miles east of us, returned westward along the African coast, and bending round the promontory of Ceuta, terminated at Apes'-hill, so that we were completely surrounded, except a narrow opening in the direction of the straits. The phenomenon was observable in all this extent, but most striking over the water to the east of us, and at Ceuta and Europa Point. The atmosphere, to a height of about two hundred or two hundred and fifty feet above the water, had an obscured and gray appearance, much like a fog, although I think it looked less dense and material than is the usual appearance of fogs. Near the upper edge it grew darker, and at length terminated in a well-defined dark line, generally horizontal, but sometimes slightly undulating. Along this line, towards the African shore. we had frequently the appearance of islands, sometimes single, sometimes grouped, every two or three minutes changing their shapes. We were steering east. In front of us on either bow, and about eight miles distant, was a small lateen vessel carrying a press of sail: they were very distinct, their white sails glittering in the sun, and it was evident they had not reached the magic circle. A little to the right of the southernmost of these, however, a vessel, apparently of the same kind, was suspended from the upper line of the fog. It was of a dusky colour, and not well defined, but I could only make out that it was a vessel with sails, and in an inverted position. Half-way between it and the African coast was another vessel, a much larger one, for it reached half-way down towards the horizon. It was also dark coloured, but was better defined than the other, and had the tall tapering appearance of a brig, with bow or stern towards us. Both of these vessels were sometimes more distinct than at others, and also varied slightly in their size. While I was looking at them, another appeared between them, of a white colour, and very distinct, but in half a minute it began to fade away, and soon disappeared. To the southward of these vessels, along the upper line, were also numerous islands, sometimes grouped, sometimes single, and constantly changing their form and size. In twelve minutes after I had begun to notice these phenomena, the foggy appearance began to ascend above this dark line, and soon after, another line of the same kind was formed an equal distance above it, but without any of the spectral vessels. These still kept their place on the first line; but three minutes after, the whole began to grow thin and airlike, and four minutes after this the sea before us was perfectly clear. I swept it carefully with the spy glass to find the originals of the inverted ships, but they could not be seen. They must have been so far eastward of us as to be below the horizon. In the mean time the little promontory of Ceuta, the Spanish coast, and the lower part of the Rock of Gibraltar, had been presenting a variety of curious shapes. The first of these slopes gently, on both sides from the water; but now it sometimes presented an iron-bound shore, and for a while its eastern side looked much like the open mouth of a shark or crocodile. The real Europa Point could not be seen, but in its place we had its slopes and offsets inverted, and of a sandy or yellowish colour. The sandy flats stretching north-eastward from Gibraltar, were elevated into yellow perpendicular walls of great height; and further still to the eastward, there was apparently an irregular belt of water as smooth and bright as a mirror, though the sea all around us was agitated by a four-knot breeze. This belt of smooth water was apparently mixed up with the land, so as to form lakes and inlets, and here and there on each side their edge was dotted with white objects, whose character I could not make out: they were probably houses seen through the lower edge of the fog, and refracted also to the upper line. At one spot one of these white objects extended quite across the crystal belt, widening at each end so as to resemble a water-spout. Several fishing-boats were sailing along the coast, their fanciful lateen sails glittering bright in the sun. Suddenly the crystal belt stretched by them, and as suddenly we had their images attached in an inverted position to its upper line: this was the prettiest part of the whole exhibition, the spectre boats being as distinct as the originals, and standing out so clearly from the invisible background. I had scarcely time, however, to direct the attention of some friends to them, when they began to grow indistinct, and in three minutes' time the phantoms could no longer be seen. At 12 o'clock 30 minutes, the atmosphere began to clear up on both sides of us, and I was lamenting the loss of such an unusual and splendid exhibition, when, towards one o'clock, I found it commencing in the straits of Gibraltar, which had heretofore been the only point of our horizon free from it. I noticed, with a watch in my hand, the different changes which the phenomenon underwent in this place, and the following is a copy of notes taken at the time: The same appearance of fog, and of the same height, now stretched in a curved line quite across the straits, beginning at Apes'-hill, and ending at Europa Point. At a, one-third of the way across, was a merchant brig, with lower and top-gallant studding-sails set: it was steering eastward, and was about twenty-five miles distant from us*: over it was an inverted image of itself, the two tops approaching as near as in the above lines. At b, was a two-masted vessel, with its side towards us: its two sets of sails, and also its inverted image above, were very distinct to the naked eye; a, and its image were also clearly seen without the glass. This was the state of things at 1 h. 1 m. P.M. At 1 h. 7 m. the image of b, very distinct, but the original is dim. a, as before. At 1 h. 10 m. the image of b, easily seen, but the original has entirely disappeared. a, as before. With a glass I can now see an inverted vessel at c, but none below it. At 1 h. 13 m. b, very distinct above, and the lower vessel again visible. a, as before. At 1 h. 18 m. At b, both the lower and upper vessels have disappeared; also the upper one at a; and c has grown very dim. At 1 h. 21 m. the inverted vessel above a, has not reappeared, but considerably on its right are three inverted vessels, (probably c, the image of b, and a new image); they are thin and airy-like, but very distinct, and their outline is very well defined; only the images are seen. * I give you the opinion of an old quarter-master as respects the distance, having more confidence in his judgment than my own. At 1 h. 23 m. the inverted vessel over a, has reappeared, and can be seen with the naked eye. The fog is beginning to grow very thin, and its upper line is becoming indistinct, but the four inverted ships are as distinct as before. At 1 h. 27 m. the inverted vessel over a, has again disappeared: the other three remain as before. At 1 h. 29 m. the fog has disappeared; the atmosphere resting on the straits being as transparent as any other: still the three inverted ships on the right continue, but they seem now to be suspended in the clear air: they are rather dim. The one over a, has not reappeared. At 1 h. 31 m. those three are still seen, but are quite in the clear sky: the extremities of the fog at Ceuta and the Europa Point still continue: at the latter it is thin; at the former place it is still thick and gray. At 1 h. 34 m. the three inverted ships still visible, but very dim. At 1 h. 38 m. they have disappeared, and nothing is now left but the brig at a. What has become of the two-masted vessel which, at one o'clock, I saw at b? It has not had time to get behind the land, and its masts were then high above the horizon: was this vessel beyond the horizon, and was it thus elevated by refraction? At all events, of the three inverted vessels which four minutes since we saw elevated two hundred feet or more in the sky, the originals cannot now be seen. The horizon is perfectly clear, and I have got the quarter-master to search it carefully with a good glass, but neither of us can see anything but the brig at b. I ought perhaps to add a few words about the weather and winds. On the 12th ult. it commenced blowing from the east, and, on the 18th, increased to a gale, in which all our squadron, except the schooner, broke from one or both their anchors: it lasted ten days, and then became moderate. About the first of this month the wind changed, and for four days we had strong westerly winds: the last two days have been very pleasant, with moderate breezes from the west and south-west; thermometer at the Rock from 68° to 72°. To-day, at 1 o'clock, 13 minutes P.M., the breeze changed suddenly from west to east-north-east, at which point it still continues. I have since ascertained that the Fata Morgana were seen over the straits also during the forenoon. The mountains in Spain, and also some high ridges in Africa, just south of the straits, are covered with snow. The hot winds from the desert crossing these latter, probably become surcharged with vapour, which settles down in the basin between Cape de Gatt and the straits, and thus forms the radius for the reflection which we have just been witnessing. This will account for at least a part of the phenomena. An officer has just informed me, that four years ago, when lying in the Brandywine, at Algesiras, he saw the same phenomenon around the bay. It lasted about half an hour, and, during this time, the ship's rigging, and the clothing of the persons on deck, were covered with fine cobwebs: the wind was then blowing from the southward, He tells me that he has seen the same while lying in Hampton Roads, Virginia, at a time when the wind had suddenly changed from the north-west to the north-eastward.-(Silliman's Journal, No. 60.) ON ROADS, RAILWAYS, CARRIAGES, AND CANALS. A Treatise upon Elemental Locomotion, and Interior Communication; by ALEX. GORDON, Civil Engineer, &c. 3rd Edit. 1836. THE circulation of two large editions of this work renders it unnecessary for us to do more than to notice the Supplement which is attached to this new edition. It occupies 20 pages. The subjects of it are a further examination of the alleged superiority of Railroads over Common Roads; and the description of an instrument proposed by the author, for ascertaining and recording the amount of traction, &c., required by any given road. This instrument does not appear to have been yet constructed, and the description being merely verbal, and very general, we are not sure that we discover any striking peculiarity in it. We regret that the author has not carried out his notions into practice, because we fully agree in all that he and others have said on the value of a perfect instrument of the kind; and there is another reason why we think he ought to have done so, at least in diagrams, namely, that he may not be accused of pirating, in a greater or less degree, an instrument which has been for some time constructing by the Messrs. Bramah, for his friend Mr. Macneill, at the order of the Commissioners of Woods and Forests. We suspect no improper motive in Mr. Gordon in the publication of his description, but if he will refer to p. 140 of our March number, he will find an extract of a letter from Mr. Macneill, in which the powers of his new instrument are described, and this remarkable statement:- "The spring will act in a different way, its vibrations will not be checked by a piston passing through a fluid, and they will be all registered"! We shall say no more on this part of the supplement, except to observe, that with the accomplishments of draughtsman and lithographer, which Mr. Gordon possesses, it would cost him but very little to give that publicity to his design, which Mr. Macneill has promised for the instrument upon which he is engaged, and by this means remove the doubts which so naturally arise in such cases of coincidence. The other subject of the supplement is, regarding him as a Civil Engineer, peculiarly Mr. Gordon's own. We believe that he now stands, professionally, alone, as the uncompromising advocate of the usual carriage-roads (when made as they ought to be) versus railroads, even of the best construction. One or two reputations, of great eminence in the engineering world, had, till very lately, escaped the railroad-contagion, but the genius of that system has, in the present session of parliament, seduced them; he has enlisted them into his ranks, and names that were quoted as familiarly as Cocker," when the merits of a canal or a road were impeached, and a professional defender thought necessary, are now displayed, not ignominously, perhaps, but certainly triumphantly, by the projectors, at the bottom of prospectuses headed" RAILROAD FROM as "Acting Engineers," "Consulting Engineers," &c., &c. ΤΟ 66 Fallen, fallen, fallen, in the opinion of Mr. Gordon, and all existing canal-companies. That is, from a former one made by Mr. Macneill, and purchased by the Prussian government. |