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riatic acid is saturated with ether. The natural chlorophyll which may be extracted from leaves by means of alcohol, may be easily decomposed into its constituents by shaking it with this mixture of muriatic acid and ether. The liquid first takes a brown color, after which the aqueous muriatic acid takes a beautiful blue, while the ether separates, holding the yellow coloring matter in solution. Frémy calls the blue substance phyllocyanin, and the yellow phylloxanthin. When alcohol is added, so that the two liquids mix, a green is again produced, of the color of the natural chlorophyll. * Young leaves exposed to the vapors of muriatic acid, quickly assume a beautiful green color. The yellow autumn leaves, on the other hand, contain only phylloxanthin. Under certain circumstances, phyllocyanin is capable of yielding another yellow substance, to which the author gives the name of phylloxanthein ; from this substance phyllocyanin may be again obtained. The blue coloring matter of chlorophyll is more easily altered than the other. The author promises a further investigation of this very interesting subject; his results are of equal interest to naturalists and chemists.-Compt. Rendus, l, p. 405. 2. On the Separation and Estimation of Phosphoric Acid.—CHANCEL has given a method of estimating phosphoric acid, which depends upon the entire insolubility of phosphate of bismuth in liquids containing free nitric acid. When a solution of acid nitrate of bismuth, so dilute as not to be rendered turbid by water, is added to a liquid containing a phosphate dissolved in nitric acid, a very dense, white precipitate is immediately formed, which has the formula BiO3, PO5, and the constitution of which, according to Chancel, is perfectly constant. The neutral phosphate of bismuth is perfectly insoluble in water, and dilute nitric acid, whether cold or hot; it dissolves sensibly in solutions containing a large proportion of salts of ammonia. The filtration and washing is very easy and rapid; the dried salt may be ignited in a platinum crucible, and does not fuse at a red heat. Pyrophosphoric acid is also precipitated completely by the acid nitrate of bismuth; a white precipitate is formed which is much more voluminous than the tribasic phosphate. This precipitate has the formula 2BiQ3.3ppO5: it is easily and completely transformed into the tribasic phosphate by simply boiling it in the presence of an excess of the acid nitrate of bismuth. The metaphosphates behave in the same manner, but the precipitate requires a longer boiling to be completely transformed into the ordinary phosphate. Chancel asserts that he has been able to detect the presence of one milligram of phosphoric acid when mixed with 120mm. of alumina in a dilute solution containing more than a gramme of free nitric acid. As the precipitation is very rapid in a hot solution, and as the liquid becomes almost instantly clear, it would be easy to estimate phosphoric acid by a titrated solution of acid nitrate of bismuth. Chancel prepares the acid nitrate by dissolving, with the aid of heat, one part of pure crystalline subnitrate of bismuth in four parts of nitric acid of specific gravity 1-36, adding to the solution 30 parts of distilled water, and filtering if necessary. In using this solution, the phosphate,

if not soluble in water, is to be dissolved in nitric acid, avoiding a large excess. The solution is to be diluted with water, the nitrate of bismuth added as long as a precipitate is produced, and the whole brought to boil, filtered and washed with boiling water. After drying, the filter must be separated as completely as possible from the precipitate, burned by itself, and the ashes added to the precipitate, which may be heated to redness in a platinum crucible. The bases are easily estimated in the filtrate, af. ter removing the excess of bismuth by sulphuretted hydrogen. This process requires that the liquid should be free from chlorids and sulphates, which, when present, are easily removed by nitrate of silver and chlorid of barium.—Comptes Rendus, l, p. 416. 3. On a New Mode of Preparing Calcium.—CARoN has succeeded in preparing large quantities of calcium by the following process: A mixture of 300 parts of fused and pulverized chlorid of calcium with 400 parts of granulated distilled zinc and 100 parts of sodium in pieces is to be heated to redness in a crucible. The reaction is feeble, and after some time flames of zinc appear. The heat is then to be moderated, the temperature remaining as high as possible without volatilizing the zinc ; af. ter a quarter of an hour the crucible may be withdrawn from the fire. It contains a well fused metallic mass, which is highly crystalline, and which contains from 10 to 15 per cent. of calcium. The alloy is then to be placed in a crucible of gas-retort carbon and the zinc expelled by heat: in this manner Caron obtained masses of 40 grammes at a single operation, and containing only the impurities of the zinc employed. As thus obtained calcium has a brass-yellow color and a density of from I-6 to 1-8, it is not sensibly volatile, but filings of the metal burn with red sparks of remarkable beauty without formation of vapor, which seems to show that the metal is not volatile at the temperature of its combustion. The author promises to communicate the results of similar experiments in the preparation of barium, strontium, &c.—Compt. Rendus, l, p. 547. 4. On a Wew Metallic Element.—Won KobelL has discovered in euxenite, aeschynite, and samarskite, and a tantalite from Tammela, a new metallic acid belonging to the same group with tantalic and niobic acids. To the new metal contained in this acid, the author has given the (not very well selected) name of Dianium. When dianic acid, as precipitated by ammonia from its solution in chlorhydric acid, is boiled with chlorhydric acid and metallic tin, a beautiful deep sapphire blue solution is produced, which remains blue after filtration. When tantalic acid, from the tantalite of Kimeto, or niobic acid from Bodenmais, are treated in the same way, the solution becomes bluish; and on adding water, the color quickly vanishes, and the solution, on filtering, passes through colorless. - g When dianic acid is boiled with chlorhydric acid and zinc, instead of with tin, the blue solution does not appear, the precipitated acid becomes blue, but filters colorless, and is decolorized by water without being sensibly dissolved. When equal quantities of dianic, tantalic, and hyponiobic acid are boiled with concentrated chlorhydric acid, upon a funnel of platinum-foil for three minutes, all three give yellowish milky liquids; if water be then added, the solution of dianic acid becomes perfectly clear, while the tantalic and hyponiobic acids remain undissolved.

When freshly precipitated dianic acid is heated to boiling with dilute sulphuric acid, the milky liquid poured into a glass, and grains of distilled zinc thrown in, the dianic acid in a few moments becomes smalt blue, even dark blue, and retains this color for some time on addition of water; but the liquid passes through the filter colorless. In this respect, dianic acid resembles hyponiobic acid, while tantalic acid, under the same circumstances, becomes pale blue, and immediately loses this color on addition of water. In this manner, tantalic may be distinguished from dianic and hyponiobic acids. The relations of the three acids to chlorhydric acid and tin, and to sulphuric acid and zinc, are thus sufficient to distinguish them from each other. Dianic acid appears to exist, though in a less pure state, in the tantalite from Greenland, in pyrochlore from the Ilmengebirg, and in the brown Wöhlerite—though the author had but small quantities of these minerals at his disposal. A small piece of black yttrotantalite, believed to be from Ytterby, gave the reaction of dianic acid. A second specimen, however, the specific gravity of which was found to be 5'55, contained tantalic acid. Titanic acid is easily distinguished from the other acids of the same group, by boiling it with muriatic acid and tin, and diluting the solution with water. The blue color then passes to rose red, and the solution retains this color several days. When dianic acid is present, the blue color predominates, but after standing some hours the rose color of titanic acid appears. The tantalite from Tammela, which Von Kobell terms dianite, has a specific gravity of 5.5—while the other tantalites vary in density from 7:06 to 7.5. The streak of dianite is dark grey, while that of the tantalites from Tammela is dark brown red. Before the blowpipe, dianite exhibits no sensible difference from the tantalite of Kimeto. * H. Rose, to whom Von Kobell sent a specimen of dianic acid for examination, considered it probable that the peculiar reactions of this substance might be due to the presence of tungstic acid. Von Kobell has, however, shown by special experiments, that this is not the case. In conclusion, the author recommends those who desire to répeat his experiments, to employ the same proportions of water, acid, etc., of which he himself made use, and for the details of which we must refer to the original paper—Bull. der Acad. der Wissenschaften, March 10th, 1860, (Munich). TVW. G. 5. Note on the extent to which Mercury volatilizes along with the vapor of water at 100° C.; by J. W. MALLET.”—In Berzelius' Traité de Chimie it is stated that Stromeyer drew attention to the fact of the evaporation of mercury in considerable quantity at 60° to 80°C. with the vapor of water, the more volatile substance carrying with it the less volatile, as in the case of a solution of boracic acid when heated. This fact does not seem to have been very generally noticed by the compilers of chemical text-books in treating of the history of mercury, though it is always stated that the metal is capable of volatilizing to a very slight extent, even when alone, at the common temperature of the atmosphere. Some doubt too would seem to have been thrown upon Stromeyer's observation by the experiments made, under peculiar condi

* Communicated by the author.

tions, by Fresenius, and reported by him in the appendix to his treatise on quantitative analysis. It was found that 6:4402 grim. of mercury, covered with a considerable quantity of water, and heated to the boiling point of the latter for a quarter of an hour, lost but 0004 grim., while exposure to the air at summer heat for six days produced a further loss of .0005 grim.

I have lately observed the tolerably rapid evaporation of the metal with steam, produced not from a mass of water covering the quicksilver, but from a porous and highly absorptive clay which was dry to the touch, but gave off some eight or ten per cent of water when heated to 100° C. A specimen of this soil had been in contact with mercury, and several grams of the metal in small globules had become mixed up with the mass. It was placed in the common copper box with double sides which serves as a steam-bath, and exposed to the temperature of boiling water. In half an hour I was surprized to see that the little piece of glass tube through which the heated air and vapor from the inside of the steambath escapes was coated with a bright specular deposit of metallic mercury. This was brushed off, and the tube replaced, when again it became in a short time similarly coated. The steam-bath was kept in constant use in drying this and other specimens of soil for twenty or thirty hours, and in this time between four and five grains of mercury was collected from the glass tube. Doubtless the condensation of the mercury vapor on the latter must have been far from complete—a large proportion of mercury probably escaped into the atmosphere. At any rate it seems clear that the metal can volatilize in very considerable amount when surrounded by vapor of water at 100° C., and not at the same time pressed upon or affected by the cohesion of a mass of liquid water. Hence an obvious necessity for thoroughly effective condensation when mercury is to be determined in its compounds by ignition with soda-lime. TECHNICAL CHEMISTRY.

6. Disinfectants.-The use of a mixture of coal-tar and plaster-ofParis for purposes of disinfection and for dressing wounds, as proposed by CoRNE and DEMEAUx (Comptes Rendus, xlix, 127; see this Journal, xxviii, 425), has been recently reported upon in the French Academy by a committee—Chevreul, J. Cloquet, and Velpeau (rapporteur)—to which the subject was referred in July, 1859.

The great interest, which this method, so favorably commented upon by the distinguished surgeon Velpeau soon after its publication,-excited among the medical men of France gave rise to the publication of numerous other systems of disinfection, which being submitted to the Academy for its approval were also referred to the committee in question. The labors of its members have thus been materially increased, and their report swelled to the dimensions of a general treatise upon disinfectants— especially those applicable to wounds.

In numerous experiments made at the Hospital de la Charité the mixed coal-tar and plaster of Corne was exployed, both in the state of powder and as a poultice made by mixing it with oil. When applied as a thick layer, three or four times a day, upon putrid, gangrenous and sanious wounds, the powder destroyed their odor without giving rise to any special pain. Upon indolent sores, however, or upon recent burns, the contact of the powder produced considerable Smarting upon some patients, though well borne by others. Wounds of the first class were of. ten found to be cleaned as well as disinfected; while those of the second class generally acquired a dirty, pale, gray tint, their circatrization being hindered. • The poultices were found to be more advantageous than the powder in the treatment of cavernous wounds, purulent or fetid, and sinuous foci, open suppurating abscesses, anthracoidal suppurations, etc. Applied directly to the sore, the poultices destroyed the putrid odors, allayed the inflammation without augmenting the pain, leaving beneath them a healthier pus, and the surfaces in better condition. In a word, the mixed coal-tar and plaster, when properly applied, disinfects wounds and putrid suppurations. As for the absorbent and detergent qualities which its inventors also claim for it, these are less clearly evident. The powder absorbs better than the poultices, the latter, it is true, take up a portion of the morbid exudations, but unless the dressing is carefully renewed, five or six times a day, pus will nevertheless collect beneath it. From this it follows that after having been somewhat cleansed the wound ceases, at the end of a few days, to clean itself, or to heal more rapidly than it would with the usual topical applications. Upon ulcerated cancers, the mixture, either as powder or poultice, disinfects them partially, but neither dries up the suppuration nor alleviates the pain. *" It is in the dissecting-room, upon organic matter in a state of putrefaction, that the mixed coal-tar and plaster is all powerful. The most infectious masses, when imbued with the powder, or simply rolled about in it, lose at once their disagreeable odor. According to Velpeau, his autopsy room was as approachable towards the close of last summer as it had formally been repulsive. It was freed from flies and other insects, as well as from putrid odors. Although it would have been out of the province of the committee to experiment upon the application of this mixture in disinfecting filth upon the great scale, they have nevertheless proved that it can be advantageously used in hospitals for deodorizing urine or fecal matters. The following inconveniences, to which the use of the mixture in surgery would give rise, are enumerated: It not only soils the clothes of the patient, but hardens them and causes them to weigh more heavily upon or about the wound; it imparts to the bandages, with which the poultices are covered, a very tenacious rusty or yellow color; it must be frequently renewed, and although it destroys putrid smells, it retains a bituminous odor by no means agreeable to many persons. These inconveniences are of comparatively slight importance, it is true, and may possibly admit of being remedied. Of the other disinfectants submitted to the committee, several were only modifications of that of Corne and Demeaux:-Vegetable tar, as shown by Renault, may be substituted for coal-tar.—A mixture.composed of hydraulic lime and tar did not disinfect wounds to which it was applied, nor could it be supported by the patients. . With regard to the assertions of some practitioners, that common earth, tale, flour, or other

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