of the latter will be immediately destroyed, and an effect, in part analogous to that of a positive discharge of electricity, will be produced. Some of the most serious accidents which occur from lightning are supposed to be produced in this way, not by the mere disturbance of electricity in a person only, but of the electricity of those bodies with which the person may be in contact, and to which he accidentally serves as a conductor. On the 24th of Sept. 1826, at the moment when the lightning struck the ground, at the farm of Gali, near Versailles, M. Bwas violently affected by a returning stroke, at the distance of half a league from the place. The following are the circumstances of the case-A violent storm occurred at Versailles and the neighbouring parts, at half past nine o'clock. M. B., aged seventy-two years, was passing the Rue Dauphine, at a little distance from the church of Notre Dame, when one of those whirlwinds so common in the neighbourhood of large buildings, obliged him to turn round. He was then close to the party-wall of the houses 13 and 14, his right side being at a small distance from it. A metal water-pipe was fixed up the front of the house in this place, bringing the rain from the roof to the level of the pavement. In this position M. B. felt a commotion, which he describes as if all the right side of his body was roughly thrown towards the left, feeling, at the same time, much oppression, and vertigo, resembling that of drunkenness. The immediate effects were, difficulty of motion in all the left side, and a disturbed respiration; and it was with much difficulty, and only by resting frequently, that M. B. could reach the house of a neighbouring friend. It was there observed, that the tongue was embarrassed in its motions as well as the left side, but by the aid of attention the agitation of the mind was calmed; the night passed moderately, and the next morning all was nearly in its ordinary state. In the evening, however, at the hour when the circumstance occurred, all the symptoms returned, and the same results occurred daily until the end of the week, when a physician was consulted. He immediately recognised the symptoms of compression on the brain and spinal-marrow, from which had resulted an incomplete paralysis of the tongue and the left arm and leg. This speedily gave way under the hands of the physician, but the periodical returns occurred until the cure was completed. It would be difficult to prove the identity of the electric discharge which fired the farm of Gali, and struck M. B., but the latter cannot be attributed to a direct stroke; for at the moment when it happened, the intervals between the lightning and thunder were such as to shew that the storm was not over Versailles. By a coincidence of circumstances, M. Demonferrand, who describes the case, was in the house No. 15, the whole of the evening, in an apartment contiguous to the metal-pipe which appears to have served as a conductor for the electricity, but neither he nor any other person in the house felt the slightest disturbance. In the opposite house was a person in a bad state of health, and therefore, perhaps, more sensible to electric changes, but neither did he experience any change in his feelings at the moment.-Annales de Chimie, xxxiii. 417. 7. Phosphorescence of Fluate of Lime.-Fluate of lime, though a highly phosphorescent substance, requires either to be heated or rubbed, for the emission of the light. A fluate of lime obtained from Odonschelon, in Daourie, was, however, found to be luminous without this preparation, the light being of such intensity as to render the piece visible without being placed in perfect obscurity. Its luminous state has continued ever since, and nothing indicates that it will cease. The intensity of the light is not always the same, and appears to be changed by changes in the atmosphere; it is greatest in wet and stormy weather. The contact of air appears to exert an influence on the light, for pieces of the fluor closed in a drawer for eight days, were found scarcely luminous, but being exposed to air became equally brilliant as at first. When plunged into water the degree of phosphorescence appeared to be much more constant. The light was of a feeble yellowish-green colour; a piece of the substance two inches in diameter gave light sufficient to permit words to be read at some lines distance. According to the observations of M. Becquerel, heat has great influence over the phosphorescence: at zero the light is scarcely visible; plunged into boiling water, it became very luminous; upon mercury heated to 300° C. (572°F.), the light was so strong as to allow printed characters to be read at seven inches and a half distance. This high temperature injured the phosphorescent power of the substance at common temperatures for a short time; but it was restored to its full intensity by exposure for a few hours to solar light finally, it appeared that atmospheric causes, not as yet understood, exert a great influence upon the substance. The object of the note is to point out the curious property possessed by this fluate of lime, of remaining permanently luminous. It is found in a primitive granitic rock, in company with beryl, topaz, wolfram, &c., and differs, in appearance, from the ordinary varities of fluor spar, by its peculiar waxy or resinous lustre. It is found massive, having a structure more interlaced than the ordinary varieties, and sometimes crystallised; it then has very complicated forms.-Bull. Philomat. 1826, 104. S. Chemical Compounds produced by physical Powers." Sitting of the Royal Academy of Sciences at Paris, 11th December, 1826. M. Becquerel announced, that he had succeeded in producing new compounds, by means of physical powers only. Each of the new compounds has a peculiar crystalline system, and most of them have the property of being decomposed by water."-Annales de Chimie, xxxiii. 439. 9. Table of the Density of Vapours and Gases, examined by M. Dumas. This table gives the specific gravity of vapours and gases, as compared to air, and also the density, as calculated from the weights of their elements, and from certain experiments. There is likewise in the table a column indicating the weight of a litre of each gas, or vapour, at the temperature of 32° F., and barometric pressure of 29.92 inches, the weight being expressed in grammes. Annales de Chimie, xxxiii. 391. Boron The litre is equal to 61.02525 cubic inches; the gramme to 15.44 grains. 10. On the Existence and Nature of Bromine.-Professor Liebig has repeated the experiments of M. Balard, relative to the production of this peculiar body upon the mother waters of the salt-works of Theodorshalle, near Kreutznach, and has obtained as much as 20 grammes (308.8 grains) of bromine from 30 pounds of the fluid. The process adopted was that of M. Balard. After repeating most of the experiments of M. Balard, with consistent and satisfactory results, M. Liebeg proceeded to some which he considers as supporting the simple view of the nature of the substance. Iron was heated to redness in a glass tube, and the vapour of bromine dried by chloride of calcium, passed over it; on coming into contact with the metal, the latter became incandescent, without any disengagement of gaseous matter; the mass fused into a body of a clear yellow colour, having, when cold, a lamellar structure, and dissolving readily in water. It was proto-bromide of iron, and yielded bromine on the action of chlorine. Platina and lamp-black did not act on the vapours of bromine: 2.521 parts of the bromide of potassium being decomposed by nitrate of silver, gave 4.041 parts of bromide of silver, which, by calculation, gives 94.11 as the atom of bromine oxygen being 10.—Annales de Chimie, xxxiii. 331, Royal Academy of Sciences at Paris, Oct. 2.-M. Chevruel announced to the academy that M. Dumas had discovered a chloride of iodine, having all the properties of the bromine recently described as a simple body by M. Balard.-Bull. Univ., c. ix. 277. 11. Preparation of Chloride of Boron.-M. Dumas obtains chloride of boron by passing dry chlorine over an incandescent mixture of charcoal and boracic acid. It is a gaseous body, which may be collected over mercury, and corresponds in its composition with fluo-boric acid. The apparatus used consisted of a porcelain tube, containing the mixture. The dry chlorine was introduced at one extremity, the other was attached to an adopter, and that to a bent tube, plunged into mercury. The tube was first heated for some time, to expel all humidity, then the gas introduced, and when it had continued to pass for about a quarter of an hour, the adopter and bent tube were attached, and the gas collected. When the small tube became obstructed by flocculi resulting from the action of water, it was replaced by another.-Ann. de Chimie, xxxiii. 378. 12. Chloride of Boron.-M. Despretz lays claim to the discovery of the chloride of boron, which, according to a letter to the Editor of the Annales de Chimie, he announced to the Société Philomatique, some years ago. He obtained this compound by passing dry chlorine, at a high temperature, either over boruret of iron or a mixture of charcoal with boracic acid or borax. In the first case, the chloride of boron is mixed with a certain quantity of chlorine, which may, however, be absorbed by mercury: in the second case, the gas collected contains oxide of carbon, carbonic acid, and muriatic acid. The apparatus consists of a balloon, in which the chlorine is to be generated; a porcelain tube, containing the mixture; an adopter destined for the condensation of the chloride of iron or boracic acid disengaged during the operation; and finally, a tube, the end of which dips into mercury. The gas collected by either of the processes is colourless, denser than the air, decomposable by water, fuming in contact with air, resisting a high temperature, &c.—Ann. de Chimie, xxxiii. 442. 13. Preparation of Chloride of Arsenic.-One part of arsenious acid, with ten parts of concentrated sulphuric acid, is to be put into a tubulated retort, and the temperature raised to nearly 212° F. Fragments of fused common salt are then to be thrown in by the tubular. By continuing the heat, and successively adding common salt, proto-chloride of arsenic is obtained; it falls drop by drop from the beak of the retort, and may be collected in cooled vessels. Little, if any, muriatic acid is disengaged; but towards the end of the operation a portion of hydrated chloride of arsenic is frequently produced, which collects in the vessel, above the pure chloride. The two bodies do not mix; the hydrate is liquid, transparent, and colourless, and more viscid than the dry chloride. The hydrate may be decomposed, and a pure chloride obtained, by distilling the mixture from a sufficient quantity of concentrated sulphuric acid.—Dumas, Ann. de Chimie, xxxiii. 360. 14. Preparation of Oxide of Chrome, as a Pigment.-M. Nasse recommends that a chromate of mercury should be formed, according to the usual process, by precipitation from a chromate of potash and a nitrate of mercury, as neutral and concentrated as possible. The oxide of chrome, obtained by heating the chromate of mercury, will have the greatest perfection of colour, if it be put into an unglazed porcelain crucible, and exposed to the heat of the furnace during the time required for baking the porcelain. The oxide produced will have a fine grass-green colour. The following directions are given for the preparation of the blue oxide the concentrated alkaline solution of chrome is to be saturated with weak sulphuric acid, and then to every 8lbs. is to be added 1lb. of common salt and half a pound of concentrated sulphuric acid; the liquid will then acquire a green colour. To be certain that the yellow colour is totally destroyed, a small quantity of the liquor is to have potash added to it, and filtered; if the fluid is still yellow, a fresh portion of salt and of sulphuric acid is to be added: the fluid is then to be evaporated to dryness, re-dissolved and filtered; the oxide of chrome is then to be precipitated by caustic potash. It will be of a greenish-blue colour, and being washed, must be collected upon a filter.Bull. Univ. E., vi. 275. 15. Separation of Iron from Manganese.-The novelty of situation in which the chemical analyst is frequently placed, in pursuing his intricate experimental inquiries, often renders one process for the separation of substances useful, when another of a generally superior character is inadmissible. It is for this reason that we insert at present a mode of separating iron from manganese, proposed by M. Quesnevile, jun. :-Dissolve both oxides in muriatic acid, and boil the solution for some time, to expel all excess of acid, in order to render the solution as neutral as possible. Dilute the solution with a large quantity of water, and pass chlorine gas through it, to peroxidize the iron entirely; then precipitate the liquor by arseniate of potash: the precipitate is of a greenish-white colour, and consists entirely of arseniate of iron. After some hours, filter the liquor, and wash the precipitate with a large quantity of boiling water; dry it, and calcine it strongly, to obtain the oxide of iron; evaporate the solution, which con · tains the arseniate of manganese, almost to dryness, and add water to it; if there remain by accident any traces of arseniate of iron, it separates: then filter and decompose the solution by caustic potash, and the oxide of manganese, when well washed, is then perfectly pure.-Jour. de Phar., Sept., 1826. |