a 1823.] Capt. Franklin's Narrative of a Journey, &c. 389 “ The bearings of the terminations of the arches are to be " It is to be noticed, that the bearings given by Dr. Richardson and Lieut. Hood are true, and not magnetic. “On the Aurora Borealis, Cumberland House. Extracted from the Journal of Lieut. Robert Hood, RN.—The most material information we had obtained at this period regarded the height of the Aurora from the earth. The following is the result of the observations that were made at the Basquiau Hill, and at the same time by Dr. Richardson at Cumberland House. The instruments used for the purpose were two small wooden quadrants, revolving on pivots, and furnished with plummets. Our chronometers were previously regulated, though great accuracy was not necessary in this particular, as the arches of the Aurora are sometimes stationary for many minutes. On the 2d of April, the altitude of a brilliant beam was 10° 0' 0", at 101 1m 0$, p.m. at Cumberland House. Fifty-five miles SSW it was not visible. As the trees at the latter station rose about 5° above the horizon, it may be estimated that the beam was not more than seven miles from the earth, and twenty-seven from Cumberland House. On the 6th of April, the Aurora was, for some hours, in the zenith at that place, forming a confused mass of flashes and beams; and in lat. 63° 22' 48" N, long. 103° 7' . », it appeared in the form of an arch,"stationary about 9o high, and bearing N by E. It was, therefore, seven miles from the earth. On the 7th of April, the Aurora was again in the zenith before 10, p. m. at Cumberland House, and in lat. 53° 36' 40" N, and long. 102° 31'41"; the altitude of the highest of two concentric arches at 9hs p. m. was 9°; at 9lis 30m, it was 11° 30'; and at 10h Om 0$, p. m, 15° 0' 0", its centre always bearing N by E. During this time, it was between six and seven miles from the earth. After 106, p. m. it covered the sky at Cumberland House, and passed the zenith at the other place." « These observations are opposed to the general opinion of th their eing Cel 息 meteorologists ; they are nevertheless facts. We have sometimes seen an attenuated Aurora flashing across 100° of the sky in a single second; a quickness of motion inconsistent with the height of sixty or seventy miles, the least of which has hitherto been ascribed to it. This kind of Aurora is not brighter than the milky way, and resembles sheet-lightning in its motions." “For the sake of perspicuity, I shall describe the several parts of the Aurora, which I term beams, flashes, and arches. The beams are little conical pencils of light, ranged in parallel lines, with their pointed extremities towards the earth, generally in the direction of the dipping needle. The flashes seem to bé scattered beams approaching nearer to the earth, because they are similarly shaped, and infinitely larger. I have called them flashes, because their appearance is sudden, and seldom continues long. When the Aurora first becomes visible, it is formed like a rainbow, the light of which is faint, and the motion of the beams undistinguishable. It is then in the horizon. As it approaches the zenith, it resolves itself at intervals, into beams, which, by a .quick undulating motion, project themselves into wreaths, afterwards fading away, and again brightening, without any visible expansion or concentration of matter. Númerous flashes attend in different parts of the sky. That this mass, from its short distance above the earth, would appear like an arch to a person situated at the horizon, may be demonstrated by the rules of perspective, supposing its parts to be nearly equidistant from the earth, An undeniable proof of it, however, is afforded by the observations of the 6th and 7th of April, when the Aurora which filled the sky at Cumberland House, from the northern horizon to the zenith, with wreaths and flashes, assumed the shape of arches at some distance to the southward." “But the Aurora does not always make its first appearance as an arch. It sometimes rises from a confused mass of light in the east or west, and crosses the sky towards the opposite point, exhibiting wreaths of beams, or coronæ boreales in its way, An arch, also, which is pale and uniform at the horizon, passes the zenith without displaying any irregularity or additional brilliancy; and we have seen three arches together, very near northern horizon, one of which exhibited beams and even colours, but the other two were faint and uniform." “On the 7th of April, an arch was visible to the southward, exactly similar to that in the north, and it disappeared in fifteen minutes. It had probably passed the zenith before sunset. The motion of the whole body of Aurora is from the northward to the southward, at angles not more than 200 from the magnetic meridian. · The centres of the arches were as often in the magnetic as in the true meridian.' "The colours do not seem to depend on the presence of any luminary, but to be generated by the motion of the beams, and then only when that motion is rapid, and the light brilliant. a The lower extremities quiver with a fiery red colour, and the upper with orange. We once saw violet in the former. The number of Auroræ visible in September was two; in October, three ; in November, three; in December, five; in January, five; in February, seven; in March, sixteen ; in April, fifteen ; and in May, eleven. Calm and clear weather was the most favourable for observation ; but it is discernible in cloudy weather, and through mists. We could not perceive that it affected the weather. The magnetic needle, in the open air, was disturbed by the Aurora, whenever it approached the zenith. Its motion was not vibratory, as observed by Mr. Dalton; and this was, perhaps, owing to the weight of the card attached to it. It moved slowly to the E or W of the magnetic meridian, and geldom recovered its original direction in less than eight or nine hours. The greatest extent of its aberration was 45°.” "A delicate electrometer, suspended at the height of fifty feet from the ground, was never perceptibly affected by the Aurora, nor could we distinguish its rustlíng noise, of which, however, such strong testimony has been given to us, that no doubt can remain of the fact. The conclusions to be drawn from the above will be found in the observations for the winter of 1820." (To be continued.) ARTICLE XV. Proceedings of Philosophical Societies. umed ROYAL SOCIETY.' * We endeavoured, last month, to give a full report of the important paper communicated by the President to the Royal Society, on the 5th of March; but writing only from memory, we have made two errors, one with respect to the rotation of the mercury not being stopped, but produced, by the approximation of the magnet; the other in the historical paragraph in the conclusion, which, as we have stated it, is unjust to Mr. Faraday, and does not at all convey the sense of the author. We wish, therefore, to refer our readers forward to the original paper, when it shall be published, for the correction of these mistakes.--Edit. March 20.-At this meeting the reading of the following paper, which had been commenced on the 13th, was resumed and concluded. Of the Motions of the Eye, in Illustration of the Uses of the Muscles of the Orbit. By Charles Bell, Esq. (Communicated by the President.) In this paper the author enters upon an examination of the motions of the eye, and the classification of the muscles accordling to their offices. This is done for the purpose of explaining the 'uses of the six nerves which enter into the orbit, and in pursuance of his former papers on the nervous system. His 'object in this paper is to show, in the first place, that there are motions performed by the eye not hitherto noticed, Every time the eyelids descend to cover the transparent part of the eye, the eyeball ascends, or suffers a revolving motion. If this were not the case, the surface of the eye. would not be moistened, nor freed from offensive particles. He proves, in the next place, that when we fall asleep, the eyeball is turned up, and the cornea lodges secure and moistened by the tears, under cover of the upper eyelid. "He shows that these motions are rapid and insensible, and that they are provided for the safeguard of the eye. The other motions are voluntary, and for the purpose of directing the eye to objects. He then proceeds to the examination of the muscles of the eyeball, distinguishing them, 'as usual, into the straight and oblique muscles. It has been supposed, hitherto, that both these classes of muscles were voluntary ; some describing the oblique muscles as coadjutors of the recti, and others as opponents to the recti; but Mr. Bell maintains that the obliqui are provided for the insensible motions of the eyeball, and the recti for those motions, which are directed by the will, and of which we are conscious. He proceeds to show, that the consciousness of the action of ma the recti muscles, gives us the conception of the place or relation of objects. He then proves by observation and experiment, that the actions of the straight muscles are inseparably connected with the activity of the retina; that is, with the enjoyment of the sense of vision: but that the moment the vision is unexercised, the eyeball is given up to the operation of the oblique muscles, and the pupil is consequently drawn up. under the eyelid. Hence, the eyes are elevated in sleep, in faintness, and on the approach of death; and that distortion which we compassionate .; as“ the expression of agony, is the consequence merely of a approaching insensibility: "Having examined the different motions of the eye and eyelids, and the muscles which are appropriated to them, the author pror mises, in the second part of the paper, to explain on this foundation, the distinction in the uses of the nerves of the orbit., The Society then adjourned, in consequence of the approach- 1 ing fast and festival, to meet again on April 10, when the following paper was read: An Account of an Apparatus on'a peculiar Construction, for the Exhibition of : Electromagnetic Experiments. By W. H. Pepys, Esq. FRS. This apparatus, constructed at the London Institution, unders, the direction of the author, consists of two plates, the one of copper, and the other of zinc, each two feet wide, and 50 feet ! a 1828) 393 long, giving a total surface of 200 square feet. These plates are wrapped or coiled round a common centre, and are prevented from contact with each other by the interposition of three cords of hair line, and also of notched slips of wood placed at intervals. Two conductors of copper wire, nearly three-fourths of an inch in diameter, are attached, one to the zinc, and the other to the copper plate. In order that so large a mass may be readily employed for experiment, the apparatus is suspended by means of pulleys and a counterpoise, and so let down into a tub of acid, or, when not in use, into one of water. It requires 55 gallons of fluid. , "This instrument' exhibits very powerful magnetic effects : when the contact was made, a change in the direction of compass needles was produced, at the distance of five feet; steel bars enclosed in cylinders of glass, with a spiral of wire round them, were rendered magnetic, and several were suspended together; when the contact was broken, the bars fell, but one of them was immediately taken up again on restoring the contact, though it weighed above 270 grains. The electric intensity of the apparatus is very slight; it has not any decomposing action, and will not make a spark with charcoal, nor will it deflagrate the metals. A paper was also read, On the Condensation of several Gases into Liquids. By M. Faraday, Chemical Assistant in the Royal Institution. (Communicated by the President.) In this paper, Mr. Faraday described the results obtained by the application of the mode of condensation by which he had succeeded in liquefying chlorine, and Sir H. Davy muriatic acid gas, to several other aeriform bodies. A portion of sulphuric acid being heated with mercury at one end of a sealed glass tube, while the other was kept cool by moistened bibulous paper, the sulphurous acid gas, which was evolved, condensed into a liquid in the cool end: the same result was obtained by forcing the dry gas into an exhausted tube with a condensing syringe, until its pressure became equal to three or four atmospheres. When the sealed tube was broken, the liquid expanded into pure sulphurous acid gas. The refractive power of liquid sulphurous acid is nearly that of water; the prese sure exerted by its vapour in the tube was determined, by means of a mercurial guage, to be equal to two atmospheres. Liquid sulphuretted hydrogen was produced in the following manner: The small and closed leg of a bent tube was filled with muriatie acid; a piece of platinum foil, crumpled up, was next introduced; and then some fragments of sulphuret of iron; the platinum foil being interposed in order to prevent the two substances from contact until the tube was 'sealed, which operation would otherwise have been rendered ineffectual by the pressure of the evolved gas. When this had been done, the acid was made to rected S. under de of feet |