MISCELLANY
.
Spots on the Sun.—Science Review.—We would draw the attention of our scientific readers to a remarkable opinion and theory of Sir John Herschel's with regard to the nature of those curious objects discovered by Mr. Nasmyth on the surface of the sun, and generally called, from their peculiar shape, "willow leaves." We believe Sir John first propounded this theory in an article on the sun, published in Good Words, but it does not seem to have been noticed by many astronomers. However wild the hypothesis may appear, it has just received a further sanction from its eminent author, by its republication in his new book of Familiar Lectures, which we notice elsewhere. Sir John says: "Nothing remains but to consider them (the so-called willow leaves) as separate and independent sheets, flakes, or scales, having some sort of solidity. And these flakes, be they what they may, and whatever may be said about the dashing of meteoric stones into the sun's atmosphere, etc., are evidently the immediate sources of the solar light and heat by whatever mechanism for whatever processes they may be enabled to develop, and, as it were, elaborate these elements from the bosom of the non-luminous fluid in which they appear to float. Looked at in this point of view, we cannot refuse to regard them as organisms of some peculiar and amazing kind; and though it would be too daring to speak of such organization as partaking of the nature of life, yet we do know that vital action is competent to develop both heat, light, and electricity." Strange and startling as is such an explanation, yet scientific men will remember that when we [{571}] knew as little about the cause of the black lines seen in the spectrum of the sun as we now know about these appearances on the sun itself, Sir John Herschel suggested, in 1833, that very explanation which was the foundation of the memorable law announced by the German philosopher, Kirchhoff, in 1859—a law now universally accepted as affording a perfect solution to the long-standing puzzle of Fraunhofer's lines.
Simple Net for the Capture of Oceanic Animals,—Science Review.—In a paper read before the Microscopical Society of London on the fauna of mid-ocean, Major S. R. Owen gives the following directions for the preparation of a simple form of net for the above purpose, and which maybe rigged out at a few hours' notice. A grommet should be made for the mouth, to which three cords may be attached to connect it with the towing-line; that line should be a good stout piece of stuff and capable of bearing a great strain. To the grommet should be attached, first, a bag, the upper part of which may be made of a thin canvas, the lower part of strong jean, ending in a piece of close calico or linen; the bottom must be left open, and tied round with a tape when used; this will be found convenient for taking out the contents, and by leaving it open and towing it so for a short time it can be thoroughly washed. Over the whole an outer covering of the strongest sail-cloth should be put, the upper part, in like manner, attached to the grommet, the lower part left open, and a portion for a foot or eighteen inches of the seam left to be coarsely laced up with a piece of cord, the same being done for the bottom itself. If necessary, a third covering may be put between these of any strong but rather porous material; but this in its turn should be left open at the bottom, and only tied when required for use. Its length should be so adjusted when tied that the inner lining of calico may rest against it, and be relieved from the strain. The outer sail-cloth should, in like manner, be laced up to receive and support the whole.
A New Magnesium Lamp.—An ingenious form of magnesium lamp, the invention of Mr. H. Larkin, and which was first exhibited at the Royal Institution a couple of months since, was shown at the soirées of the British Association at Nottingham. Instead of the ordinary ribbon or wire of the commoner forms of magnesium lamps, magnesium powder is employed. Hence all machinery is dispensed with, the magnesium being contained in a reservoir, from a hole in the bottom of which it falls like sand from an hour-glass. The powder is allowed to fall upon the flame of a small gas-jet, and by this it is inflamed, giving all its usual illumination. In order that a sufficient quantity of powder may be employed, and that the hole in the reservoir may be large enough to allow of a regular flow, without waste of magnesium, the latter is mixed with fine sand. The size of the aperture is regulated by a stopcock. When it is desired to light the lamp, the gas is first turned on, just sufficiently to produce a small jet at the mouth of the tube, which small jet, being once kindled, may be allowed to burn any convenient time, until the moment the magnesium light is required. All that is then needed is to turn on the metallic powder, which instantly descends and becomes ignited as it passes through the burning gas. This action of turning on and off the metallic powder may be repeated without putting out the gas, as often and as quickly as desired; so that, in addition to the ordinary purpose to which lamps are applied, an instant or an intermittent light of great brilliancy, suitable for signals or for light-houses, may be very simply produced with certainty of effect and without the smallest waste of metal. The first evening an objection was made that the blue tone of the light created a cold and somewhat ghastly effect. On the second occasion Mr. Larkin remedied this by mixing with the magnesium a certain quantity of nitrate of strontia.—Journal of the Society of Arts.
An Artificial Eye for restoring Sight.—An apparatus of this kind, whose efficiency we much doubt, has been described by M. Blanchet, in a paper in which he details the operation for its insertion under the title of Helio-prothesis. The operation consists in puncturing the eye in the direction of the antero-posterior axis with a narrow bistoury, and introducing a piece of apparatus to which M. Blanchet gives the name of "phosphore." The operation in most instances produces little pain, and when the globe of the eye has undergone degeneration there is no pain at all, and the "phosphore" apparatus is [{572}] introduced without difficulty. The description of this contrivance is this: "It consists of a shell of enamel, and of a tube closed at both its ends by glasses, whose form varies according to circumstances." M. Blanchet thus describes the operation: "The patient's head being supported by an assistant, the upper eyelid is raised by an elevator, and the lower one is depressed. The operator then punctures the eye with a narrow bistoury, adapting the width of his incision to the diameter of the 'phosphore' tube which he intends to insert. The translucent humor having escaped, the 'phosphore' apparatus is applied, and almost immediately, or after a short time, the patient is partially restored to sight!" Before introducing the apparatus it is necessary to calculate the antero-posterior diameter of the eye, and if the lens has cataract it must be removed. Inasmuch as the range of vision depends on the quantity of the humor left behind, M. Blanchet recommends the employment of spectacles of various kinds.—Popular Science Review.
Action of Different Colored Lights on the Retina.—It is known to physiologists that when a ray of light falls upon the retina, the impression it produces remains for a definite period, according to calculation about the third of a second. It is this fact which is used to explain why a burning brand, when twirled rapidly round, gives the appearance of a ring of light. But till quite recently it had not been shown whether the different colors of light had the same degree of persistence upon the retina. The subject has quite lately been taken up by the Abbé Laborde, who shows that, just as the prism separates the colors at different angles, so the retina absorbs the callers, or the impressions produced thereby, in different times. In conducting his experiment to prove this, the abbé receives the sunlight through an aperture in a shutter into a darkened chamber. The aperture is about three millimetres wide by six high. In the course of the beam and in the middle the chamber there is placed a disk of metal, the circumference of which is pierced by apertures corresponding to the aperture in the shutter. This disk is caused to revolve by clockwork. Behind the disc is placed a plate of ground glass to receive this spot of light. The disk being then caused to revolve rapidly, the spot appears at first white, but as the revolution become more rapid the borders of the spot and the colors which successively appear are in their order of succession as follows: blue, green, red, white, green, blue.—Comptes Rendus.
The Origin of Diamonds.—a curious, and it seems to us very improbable, theory of the origin of diamonds was put foreword by M. Chancourtios in an essay published in the Comptes Rendus for June 25th. The author tries to show in this that diamonds have been produced by and incomplete oxidation of the carbides of hydrogen, in pretty much the same fashion as the sulphur in the Solfatara, described by Professor Ansted in one of our late numbers, results from an incomplete oxidation of sulphuretted hydrogen, all of whose hydrogen is converted into water, while only a part of the sulphur is changed into sulfurous acid. It is by a similar process that petroleum has given rise to bitumen, and this again two graphite. "If, then" says the author, "a mixture of hydrocarbon gases and vapor of water be submitted to slow oxidation, diamonds may possibly be obtained." It is even possible, he observes, that the tubes which convey common coal-gas along the streets of Paris may contain such artificial diamonds in abundance.—Popular Science Review.