of a solution of Indian-rubber in coal-tar.-(Edin. Phil. Jour. vol. x., p. 185.) Lately, also, they have been seen by Mr. Marsh, at Woolwich, on grinding newly roasted coffee in an iron coffee-mill; they passed between the mill and a tin can placed one-tenth of an inch distant.-(Ann. of Elect. vol. viii. p. 124.) Lastly, a very strong attraction has been noticed in a cotton-mill, in a broad endless band, that passes horizontally over two cylinders of almost 3 feet in diameter, which revolves seventy-two times in a minute.-Cotton-wool was attracted from a distance of two or three feet; and, four feet beneath the band, the hair of the workman stood on end.-(Ann. of Elect. vol. v., p. 397.)-Editor of the Annalen. Mechanics' Mag.

On a new Bleaching Principle produced by the slow combustion of Ether in Atmospheric Air, and by the rapid combustion of Bodies in a jet of Hydrogen Gas. By Prof. SHOENBIEN.

Prof. Shoenbein observing that a peculiar principle, in many respects similar to chlorine, was developed during a slow combustion of phosphorus in the atmosphere, was led to inquire into the product of the slow combustion of the vapor of ether mixed with atmospheric air. He finds that, besides well-known compounds, such as formic and acetic acids, there is evolved a principle hitherto unnoticed, which possesses oxidizing and bleaching properties in an eminent degree.— It decomposes indigo, iodide of potassium, and hydroiodic acid, and also, though more slowly, bromide of potassium. When in contact with water, it converted iodine into iodic acid, and sulphurous into sulphuric acid; changes the yellow ferro-cyanide of potassium into the red, and the white cyanide of iron into the blue; it transforms the salts of prot-oxide of iron into those of the peroxide, and it discharges the colors produced by sulphuret of lead. The author points out the similarity between the action of this substance, in these instances, and that of chlorine and ozone. Analogous results were obtained from the combustion of a jet of hydrogen gas in atmospheric air, and even, under particular circumstances, from the flame of a common candle, and also from various other inflammable bodies when burning under certain conditions. The author is hence led to the conclusion that this peculiar oxidizing and bleaching principle is produced in all cases of rapid combustion taking place in atmospheric air, and that its production is therefore independent of the nature of the substance which is burnt. Proc. Royal Soc.

On the Artificial Formation of a Vegeto-Alkali. By GEORGE FoWNES, Esq.

The substance which is the subject of investigation in this paper is a volatile oil, obtained by distillation from a mixture of bran, sulphuric acid, and water, and is designated by the author by the name of

We may mention that the two cloths are passed between two steam-rollers highly heated; and that the adhesive solution is between the cloths as they enter the rollers.-Ed. Elec. Mag.

15

ness.

Furfurol. Its chemical composition is expressed by the formula, C1, H. O,, and its properties are the following:-When free from water and freshly rectified it is nearly colorless; but after a few hours, it acquires a brownish tint, which eventually deepens almost to blackWhen in contact with water, or when not properly rendered anhydrous, it is less subject to change, and merely assumes a yellow color. Its odour resembles that of a mixture of bitter almond oil and oil of cassia, but has less fragrance. Its specific gravity at 60° Fahr. is 1.168. It boils at 323° Fahr., and distils, at that temperature, without alteration. It dissolves to a large extent in cold water, and also in alcohol. Its solution in concentrated sulphuric acid has a magnifient purple color, and is decomposed by water. Nitric acid, with the aid of heat, attacks the oil with prodigious violence, evolving copious red fumes, and generating oxalic acid, which appears to be the only product. It dissolves in a solution of caustic potass, forming a deep brown liquid, from which acids precipitate a resinous matter.— With a slight heat, it explodes when acted upon by metallic potassium. When placed in contact with five or six times its bulk of liquid ammonia, it is gradually converted into a solid yellowish white and somewhat crystaline mass, which is very bulky, perfectly soluble in cold water, and easily obtained in a state of dryness under a vacuum. The formula expressing the chemical constitution of this substance, or of furfuroamide, is C,, H, NO,, and it is classed by the author with the amides. The oil itself appears to be identical with the substance described by Dr Stenhouse, under the name of artificial oil of ants. Another substance, isomeric with the amides, and of which the formula is C30 H1, N, O,, was obtained by the author, and termed by him furfurine, and found to have the properties of a vegeto-alkali and to form saline compounds with various acids. Proc. Royal Soc.

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TRANSLATIONS FOR THE JOURNAL OF THE FRANKLIN INSTITUTE.

On the Absorption of the Rays of Heat by the Terrestrial Almosphere.-Extract of a letter from M. MELLONI to M. ARAGO.

The only pages of my memoir, which may probably excite interest, are those in which are reported, for the first time, the results deduced from a long series of observations on Solar heat. In numerous repetitions, by means of the same prism of rock salt, of the analysis of these rays, I have proved that the maximum of temperature is not always in the same place in the dark space which is prolonged beyond the red limits of the spectrum, but sometimes more and sometimes less distant from the colored portion, and that under circumstances perfectly similar with regard to radiating force, to the serenity of the sky and the transmission of the air. I conclude from this, that the calorific rays deprived of light, reach us in quantities greater or less according to the condition of certain atmospheric constitutions which exert no influence on the transmission of luminous rays. Now, it appears to me that there is a striking analogy between this phenomenon and that observed by M. Daguerre, relative to the direct action of the chemical

radiations corresponding to equal heights of the sun above the horiIn the latter case, it would be the dark part of that radiation, situated beyond the limit of the violet, which would undergo, on its way, a greater or less absorption, in virtue of a certain modification, which might not alter the transparency of the atmosphere. It is true that, on this hypothesis, we must admit that the permeability of the air for the dark chemical rays, may be different in certain cases from its permeability for luminous rays. But are we not in possession of very many facts which prove that this is actually the case with regard to optical, calorific, phosphogenic and chemical effects produced by the same radiation?

Ann. de Chem., Nov. 1839.

On the force of tension of some condensed gases. By M. BUNSEN. I first measured the resistance of the glass tubes which I intended to use. I filled them completely with water (after introducing a small manometre) and then plunged them into water, which I gradually heated to the boiling temperature-which, by the expansion of the water within the tubes, represented a pressure of 150 atmospheres. When the tubes burst under this pressure there were generally an infinite number of longitudinal parallel fissures and accompanied by a piercing noise.

A tube of 11 millimetres in internal diameter and 14 mill. in thickness, burst under a pressure of 80 atmospheres, and I found tubes of a smaller diameter which resisted 200 atmospheres. But after a while their tenacity became so diminished that some of them which had supported 30 atmospheres, suddenly broke under a pressure of scarcely 4 atmospheres. I attribute this to a diminished elasticity in the glass, like that of all other bodies, in proportion to the length of time in which they have been subjected to great pressure.

I have submitted cyanogen, sulphurous acid, and liquid ammonia to different temperatures, in glass tubes containing a manometre, and the result was the following tensions, calculated in metres of mercury.

Sulphurous acid boils at -10° 5 under a barometric pressure of

0.744 metres.

Cyanogen becomes liquid at -25°c, and begins to solidify at -30°, assuming a radiated texture. Its boiling point is -20.7c.

Ammoniacal gas must be perfectly dried before being liquified. Its boiling point is -330.7.

I have in vain tried to reduce to the liquid state, by a reduction of temperature as far as -50°, the gas which results from the combination of hydrogen with chlorine, brosmine, iodine and phosphorus.

We may obtain sulphuretted hydrogen in a liquid state by subjecting hypersulphuretted hydrogen to decomposition in a tube; but it requires the presence of a little water. If bits of chloride of calcium be introduced into the tube, the hypersulphuret may be preserved intact while the tube remains hermetically sealed.

Annales des Mines, tom. xvii, p. 317.

Chemical constituents of Sugar Beet. By HENRY BRACONNOT. It results from the researches that I have made on the Sugar Beet of Silesia, that this root contains-1, crystalizable sugar; 2, non crystalizable sugar; 3, albumine; 4, pectine; 5, mucilaginous matter; 6, liqueous matter; 7, phosphate of Magnesia; 8, oxalate of potash; 9, niclate of potash; 10, phosphate of lime; 11, oxalate of lime; 12, an acid fat having the constitution of tallow; 13, matter analogous to wax; 14, chloride of potassium; 15, sulphate of potash; 16, nitrate of potash; 17, oxide of iron; 18, animalized matter soluble in water; 19, an unknown odorous and acrid matter; 20, indeterminate sal ammoniac in small quantity; 21, pectic acid. Ann. de Chem. Dec., 1839.

Manufacture of Leaden Bullets, by rolling.

At the Arsenal, at Woolwich, in England, they now manufacture leaden bullets by drawing and compression.

These bullets have the advantage of being without blows or air cavities, and are rolled out of round bars of lead, which are passed between rolls formed like the roulettes used for ornamental work on the lathe.

The rolls are constructed with hemispherical cavities, each one of which forms one half of the ball, whilst the correspondent cavity forms the other half; the bullets are then finished by removing the extra metal, and being rolled together in a barrel.

Journal des Usines.

On the Irregular Movements of the Barometer. By T. HOPKINS.

Mr. Hopkins maintained that the irregular movements of the barometer arise, not from the alterations of surface temperature, but from the condensation of aqueous vapour, and the consequent formations of rain. This (he said) caused local heatings of the atmosphere and considerable reductions of its pressure in the locality, particularly in the colder latitudes. Within the tropics, the barometer does not ordinarily fall as much as in colder latitudes, notwithstanding the abundant rains which take place there, because the conden

sation occurs, and the temperature is increased at a greater height in the atmosphere, and the reduction of the incumbent pressure in the part is spread over a wider area. The condensation takes place too at an elevation, where the air, from being subjected to inferior pressure, is more attenuated, and the heating is consequently more diffused. Rain is formed in certain latitudes, say at an average height of 3,000 feet, where the air has a density proportioned to that height, and where the whole effects of the local heating are confined to an area of moderate extent, thus reducing the pressure of the atmosphere on the barometer in every part of that area in a considerable degree; whilst, in other parts nearer the equator, the condensation which produces rain takes place at an average height of, say 6,000 or 9,000 feet, where the air is rare in proportion to the height; the heating effects are, therefore, diffused to a corresponding extent, whilst the reduction of pressure at the surface is spread over a wider area. It follows, that with equal amounts of rain, the fall of the barometer will be the greatest and confined to the smallest area, in the coldest climates. Mr. Hopkins also represented that the diurnal oscillations of the barometer arise from, first, the condensation of aqueous vapor into cloud, and then from the evaporation of the particles of water that constitute that cloud. He stated, that the morning sun warmed the lower air, and caused it to rise until condensation formed cloud, and liberated heat sufficient to warm a mass of the atmosphere, and thus to cause the barometer in the locality to begin to fall at, say about ten o'clock in the morning, which fall continued until about four o'clock in the afternoon, when condensation ceased. From this time, evaporation of the cloud commenced which cooled the air in part -made it heavier-and caused the barometer to rise until about ten o'clock, P. M., by which time the cloud was evaporated. The cooled and heavier air now descended to the surface, from which it absorbed a portion of heat, and became somewhat warmer. From this second warming of the air, and from a reduction of the quantity of aqueous vapor in the atmosphere, as is evidenced by the fall of the dew point, the barometer again fell, and from the operation of these two causes, continued to fall until four in the morning; from which time, those general cooling influences that operate in the absence of the sun, caused the barometer again to rise till ten in the morning, thus completing the two risings and two fallings in the twenty-four hours.This was shown to be in general accordance with the tables of the Plymouth observations for three years, and with those made at Madras and Poona. The fact, also found in the Plymouth observations, that the dew point rose with the temperature until eleven o'clock, A. M., when, although the temperature continued rising, the dew-point did not rise higher, showed that the vapor formed during the hottest part of the day was expended in supplying that which was condensed in forming the daily cloud. According to these tables, also, the dew point at the surface continued stationary until four o'clock, P. M., when it began to fall, and continued falling with the declining temperature until the great cold resulting from evaporation ceased. The diurnal fluctuations were also shown to be the least, when the irregu