Page images

Gases in Plants.—Messrs. Faivre and Dupré have experimented on this subject and submitted their results to the Edinburgh Botanical Society. They examined more especially the mulberry and the vine, and have arrived at the following conclusions :-1. The presence of gases in the interior of the root, stem, and branches in the mulberry and vine is a normal and constant fact. 2. The composition of these gases changes with the epochs of vegetation. 3. During the period of inactivity, carbonic acid is in very small proportion, and is scarcely appreciable. Oxygen is present to the same extent as in atmospheric air. During the phase of activity the contrary takes place, and the changes are more marked in proportion as the vegetation is more energetic; with the progress of vegetation, the proportion of oxygen diminishes. 4. In the roots during the epoch of vegetation, the quantity of oxygen is not so great, while that of carbonic acid is greater than in the branches examined under the same circumstances. 5. In the branches, as well as in the roots, there is an inverse relation between the oxygen and the carbonic acid; by adding to the normal oxygen that disengaged under the form of carbonic acid, we obtain a number which is scarcely above the proportion of oxygen in the air. 6. In the mulberry and vine, injections do not penetrate the pith or the bark, whether in the branches or roots. The ligneous layers are alone permeable to mercury. The more the formation of the vessels increases, the easier and more complete are the injections. The injections are fuller in the roots than in the branches; they are also more in the branches than in the young herbaceous shoots. In the old stems of the mulberry, the central layers cease to be permeable. 7. Microscopic examination proves that the injection specially penetrates the pitted and reticulated vessels, and also the spiral vessels in the young herbaceous shoots. 8. The pitted vessels show distinctly the mercury in the areolæ, as if in so many little pouches formed by thin portions of the wall; the same observations have been made in regard to the reticulated vessels.

FRANCE.—Absorption by the Roots of Plants. It is still a vexed question as to how far the roots, of plants absorb certain elements of their food, such as carbonic acid. M. Corenwinder has applied himself to the solution of this problem, believing that very rash statements as to the functions of the roots have been lately made by M. Boussingault and others. He states it as his conviction that plants have not the power of absorbing carbonic acid from the soil by their roots, or that at least the quantity which permeates the tissues from this source represents but a very small proportion of the total amount of carbon their tissues contain. Boussingault stated that in the air contained in an ordinary soil he found no less than ten per cent. of carbonic acid. M. Corenwinder asks what is the source of this large quantity of gas, and replies that it arises from the mass of decom

posing organic matter, leaves, &c., which in the processes of agriculture and by the influence of the earth-worm, &c., become embedded in the soil. M. Corenwinder, however, does not say what becomes of this carbonic acid. Liebig and other chemists answer the question better in showing that the carbonic acid is taken up by water which percolates through the soil, and that it is then used in eroding rocks and dissolving up otherwise insoluble mineral matters.

Aëriferous Vesicles of the Utricularia.-S. B. Schnetzler publishes an account in the 'Annals of Natural History,' of these curious appendages to the leaves. The genus Utricularia consists of aquatic plants which are found in the stagnant waters of ditches, marshes, &c. The leaves are submerged and divided into fine lacinæ furnished with the remarkable utricles. De Candolle states that when the plant is young these vesicles are filled with a mucilage which is heavier than water, and the plant held down by this ballast remains at the bottom. Towards the period of flowering, the leaves secrete a gas which makes its way into the utricles and drives out the mucilage by raising an operculum or lid with which the utricles are furnished. The plant thus becomes furnished with a multitude of air-bladders, and rises slowly and at last floats at the surface. After flowering in the air, the mucilage is again secreted and the plant sinks again to ripen its seeds below water. M. Schnetzler has carefully investigated the morphology and history of these organs, and concludes that they play the part at once of organs of respiration and of a hydrostatic apparatus. The organs do not appear at a given moment and for a particular purpose, but as a natural consequence of the anatomical structure of the plant and the action of the surrounding medium. After some philosophical generalizations the author observes, “The totality of the forms in which life manifests itself upon the earth, during a given epoch, appears to us like a magnificent mosaic, of which the different pieces brought together mutually determine their nature.”

The Fall of Leaves.-Dr. Maxwell Masters has recently discussed this subject in a very seasonable article in the ‘Popular Science Review. It appears from the researches of M. Trécul (published in the Comptes Rendus') and others, that in many plants a phenomenon occurs just before the fall of the leaf, which is not unlike the process which accompanies the shedding of horns in animals. It consists in the obstruction of the proper vessels at the base of the petiole or leaf-stalk. This obstruction is caused by the multiplication of cells, which first occurs in the parietes of the vessels. The cells increase and multiply, till at last the vessels are completely choked up in the neighbourhood of the insertion of the leaf, and thus a differentiated plane is formed, across which the leafstalk breaks, and the leaf accordingly falls.

Movements of the Sensitive Plant.- M. Bert and M. de Blon

deau have published accounts of some investigations into this highly interesting matter in the Comptes Rendus.' It is to be regretted that more critical examinations of the phenomena of movement in the higher plants have not been made. M. Bert shows that the natural and regular movement of the leaves, which takes place in the Sensitive plant, is produced by a different cause from that to which the sudden contraction is due when the plant is touched by the fingers. M. Blondeau's observations are exceedingly curious, and are well worth further examination. He submitted three plants to the influence of an electric current from a Ruhmkorff's coil. The first he acted on for five minutes; when left to itself, the plant seemed prostrated, but after a quarter-of-an-hour, the leaves opened, and it seemed to recover itself. The second specimen was acted on for ten minutes. The specimen was prostrate for an hour, after which it slowly recovered. The third specimen was galvanized for twenty-five minutes, but it never recovered, and in twenty-four hours it had the appearance of a plant struck by lightning. A fourth plant was etherized and then exposed to the current. Strange to say, the latter had not any effect, the leaves remained straight and open ; thus proving, says M. Blondeau, that the mode of the contraction of the leaves of the Sensitive plant is in some way allied to the muscular contraction of animals.

5. CHEMISTRY. (Including the Proceedings of the Chemical Society.) Among the papers calling for special mention this quarter are those by Dr. A. W. Hofmann, “ On the Production of Formic Aldehyde.” The method by which the author has succeeded in forming this hitherto unknown body was shown at a meeting of the Chemical Society, and will be described in our Report of the Proceedings. Other papers of great scientific value have been communicated by the same author to the Royal Society, “On the Homologues of Prussic Acid."* These also were briefly referred to at the meeting of the Chemical Society.

Dr. E. Schunck has also contributed to the Royal Society a valuable series of papers “On the Chemistry of Urine.” These, as well as the paper by Dr. Hofmann, do not admit of abridgment, and we must refer our readers interested in the subjects to the Proceedings of the Royal Society.t

The past quarter has not been marked by any specially interesting discovery, and but few facts call for notice. M. E. Duclauxt '* Proceedings of the Royal Society,' vol. xvi., p. 144. † Vol. xvi., p. 73. 1 Comptes Rendus,'t. Ixv., p. 1099.

has noticed the formation of what he believes to be a Hydrate of Sulphide of Carbon. If a little water is placed on a glass plate, and a watch-glass full of the bisulphide is set in the midst and then blown upon, the water soon congeals, and the watch-glass is filled with snow-white flakes of the supposed hydrate. A lighted coal brought to the snowy mass sets fire to the bisulphide, which burns away, leaving the water with which it had united. The author has several times determined the amount of the water, and finds it to be constant, and just the quantity required by the formula 2 C SQ, H, O.

The formation of this substance, we may add, is easily shown in another way. If a stream of the bisulphide is made to trickle down a piece of loose twine, the twine quickly becomes covered with a thick crust resembling hoar-frost. The substance, whatever it may be, rapidly evaporates, leaving the twine perfectly dry.

A new process for the production of sulphuric acid has been patented in France, and probably in England, by MM. Tardani and De Susini. Its great recommendation is that it dispenses with the large leaden chambers necessary to the English process. We must refer our readers to the source indicated below* for full particulars, and need only say that the Sulphur or Pyrites is burned in compressed air, and the sulphurous acid is first washed to free it from arsenic and other contaminations, and is then brought in contact with the nitric vapours in a small leaden chamber of peculiar construction. The reactions are precisely the same as in the old mode: the apparatus, however, it is said, occupies forty times less space, and an acid is obtained free from the ordinary impurities.

A new process for the manufacture of Soda has also been patented in France by M. Kessler. As in Leblanc's process, the inventor starts with common salt. This is intimately mixed with sesquioxide of chromium, either alone or with peroxide of manganese, and then roasted in a current of steam. The result is the evolution of hydrochloric acid, and the formation of chromate of soda. When the evolution of hydrochloric acid has ceased, the charge is drawn from the furnace, mixed with a proportion of charcoal or coal, and then reburnt. In this way the chromate of soda is converted into carbonate with the reproduction of sesquioxide of chromium. The soda is separated by lixiviation, and the sesquioxide is reserved for a future operation.

Two other technical processes deserve a short notice. One is for the extraction of indigo from rags dyed with that substance. The rags are first saturated with a weak solution of caustic soda, then placed in a boiler with a double bottom, and exposed for some hours to steam at 45lbs. pressure. The indigo in the rags is

* Bulletin de la Société Chimique de Paris,' Oct., 1867, p. 295.

reduced, and may be washed out. It may afterwards be precipitated from the soda solution, and recovered in a state equal to the best commercial sort.

Another inventor proposes to shorten the time of dyeing Turkey-red, by a previous oxidation of the oil used. This M. Bernard effects by heating the oil to 95° C. with a solution of chlorate of potash, and adding very gradually oxalic acid. The mixture is afterwards boiled for some hours. The oxidized oil, it is said, may be employed alone or in the form of an emulsion. .

In connection with technical chemistry, we may mention the publication of a valuable paper “On the Cumberland Hämatite Ores,” by Dr. E. J. Tosh.*

A very delicate test for hyposulphite of soda has been published by Mr. Carey Lea.f A very dilute, but rather strongly acid, solution of sesquichloride of Ruthenium is first rendered alkaline by ammonia, and then boiled with the suspected solution. If hyposulphite be present, the liquid assumes a red colour, which varies in intensity according to the amount of hyposulphite. A solution containing one four-thousandth gives a clear rose-red; one containing a twelve-thousandth, a well-marked pink colour. A strong solution gives a colour so intense as to appear almost black. Such a test will be highly appreciated by photographers; but, unfortunately, ruthenium is yet a very rare metal.

PROCEEDINGS OF THE CHEMICAL SOCIETY, The first meeting of the present season was held on November 7. After the adoption of an address of condolence to Mrs. Faraday, Mr. W. H. Perkin read a paper “On the Action of Acetic Anhydride upon the Hydrides of Salicyl, Ethly-Salicyl, &c.” A paper by Messrs. Chapman and Smith, “On Nitrous and Nitric Ethers,” was next read. It gave an account of the methods adopted by the authors for preparing the nitrates and nitrites of methyl, ethyl, and amyl, and described the reactions and decompositions which these bodies undergo when treated in a digestion apparatus with metals, acids, and other re-agents. The most interesting part of the communications was the description of an easy mode of preparing nitrate of amyl in large quantities. Three measures of a mixture of one part of nitric and two sulphuric acid are placed in a beaker set in a freezing mixture, and to these is added very slowly one measure of amylic alcohol. The addition is best made with the aid of a dropping funnel, the stem of which, reaching nearly to the bottom of the mixture of acids, serves as a stirrer. The nitrate of amyl is

of unications were re-agentsa ted in a digol decomposi

[ocr errors]

Chemical News,' Oct. 18–25, 1867.
Silliman's Journal,' Sept. 1867; and · Chemical News,' Oct. 25.

« PreviousContinue »