sunshine and darkness; their action differs only in intensity, which is greatest in the leaves. During the night they cause the oxygen of their atmosphere to disappear, and they replace it by carbonic acid gas, part of which they absorb; this absorption is generally less in the open air than under a receiver. In the dark they absorb more oxygen, when green, than when they are becoming ripe. During their exposure to the sun, they extricate, either wholly or partially, the oxygen of the carbonic acid they absorb during the night, and leave no trace of this acid in their atmosphere. Several fruits, detached from the plant, thus add oxygen gas to air which contained no carbonic acid. When their vegetation is very feeble or languid, they corrupt the air under all circumstances, but less in the sun than in darkness, Green fruits detached from the plant, and exposed to the successive action of night and the sun, alter the air but little either in purity or volume; the slight variations observable in this respect depend either upon their greater or less power of forming carbonic acid, or upon their composition, which is modified by the degree of their maturity; thus green grapes appear to assimilate a small quantity of the oxygen of the carbonic acid which they form in the air that they vegetate in night and day; while grapes which are nearly ripe, exhibit in their atmosphere entirely during the day, the oxygen of the acid which they produced in darkness. If there be no mistake in this result, which was not strongly marked, but constant in all my experiments, it denotes the passage from the acid to the sweet state, indicating that the acidity of green fruits tends to fix the oxygen gas of the atmosphere, and that this acidity disappears when the fruit imbibes only carbon from the air or carbonic acid. Green fruits decompose, either totally or in part, not only the carbonic acid which they have produced during the night, but also that which is artificially added to their atmosphere. When the latter experiment is made with watery fruits, and which, such as apples and grapes, evolve the acid gas slowly; they are observed to absorb in the sun, a much greater portion of gas than an equal quantity of water would do in a similar mixture. They afterwards disengage the oxygen of the absorbed acid, and thus appear to form it in their interior. Their power of decomposing carbonic acid becomes weaker as they ripen. During vegetation, they absorb the oxygen and hydrogen of water, depriving it of its fluid form. These results are frequently unobservable, excepting when the volume of air exceeds that of the fruit 30 or 40 times, and the heating action of the sun is much weakened: if these precautions be neglected, several fruits corrupt the air, even in the sun by forming carbonic acid with the surrounding oxygen; but still, in the latter case, the mere comparison of their effect in the dark, with that which they produce under the successive influence of night and of the sun, shows that they decompose carbonic acid. The differences of Mr. Berard's results and mine are principally derived from the circumstance of his having enclosed the fruits in a space not exceeding six or eight times their volume, which was too smal to prevent their suffering from the proximity or contact of the sides of the receiver heated by the sun. Some succulent plants resist this trial, and my results with the cactus, may have induced this chemist to treat fruits by the same process; but several of them require more careful management, not only than succulent plants, but even than the most delicate leaves. I think also that he ought to have nourished the fruits with a little water; the appearance of freshness which he observed in them after the experiments, might have some foundation if he had been experimenting with leaves which lose their appearance and consistence by the least drying, but it is of little value with respect to thick and fleshy fruits, which may deteriorate and lose weight, without giving any indications by mere inspection. If my remarks have shown a slight error in this single point in the memoir of M. Berard, it is too rich in new and well observed facts, to have its value diminished by it. [Annals de Chimie et de Physique. FROM THE PHILOSOPHICAL MAGAZINE, Analysis of the Rose. From 1000 grammes of the petals of the white Provençal rose lately analysed by M. F. Cartier, he obtained by incineration a residuum of 99 grs. containing subcarbonate of potash, phosphate, and traces of muriate of potash, carbonate of lime, phosphate of lime, traces of phosphate of magnesia, silica, and oxide of iron. The quantity of the last was ascertained to be 12.5. From 1000 of red roses he procured only 50 of residuum, containing no more than 4 oxide of iron. [Journal de Phar. Damp in Walls.-An easy and efficacious way of preventing the effects of damp walls upon paper in rooms, has lately been used (and as we understand) with complete success. It consists of lining the wall or the damp part of it with sheet lead, purposely rolled very thin: this is fastened up with small copper nails, which not being subject to rust, are very durable, and the whole may be immediately covered with paper. The lead is not thicker than that which is used in the chests in which tea is imported, and is made in sheets, of which the width is about that of common paper hangings. We have seen some which was rolled at the lead-mill of Messrs. Hutchinson and Co. at Pateley Bridge, in Yorkshire, and which was as light as eight ounces, and even four ounces to a square foot, and yet quite impermeable to water. The remedy for a very disagreeable occurrence is thus rendered not only easy but very cheap. Singular Phenomenon.-A number of hagberry trees, growing on the banks of the Girvan, about a mile beyond Kirkmichael, are at present entirely divested of their foliage, and covered with a sort of silky substance resembling in texture and appearance, the finest cambric paper, but much stronger, which is occasioned by myriads of small worms. These reptiles are first seen in an inactive state, hanging in large clusters under the branches. On bursting from embryo, they commence to crawl up and down the trunk and branches, each emitting a small slimy thread, somewhat finer than the spider's, which, from their incalculable numbers, unite together, and form this singular substance, which covers the trees, and imparts to them, when viewed from a distance, the appearance of blighted trunks covered a with snow. Some hundreds of these insects are at times observed suspended by as many threads, which are spun out till they join another branch, and form a passage across. Husbandry.—That variety of Phalaris arundinacea, which is frequently planted in our gardens, and is called ribbon grass, or striped grass, might be cultivated to very considerable advantage by the farmer. It is a very hardy plant; it affords excellent food for cattle; it may be cut three or four times in the summer: and what is not the least of its merits, it will produce an earlier crop than almost any other grass. It thrives very well on dry ground, though it rather prefers moist situations. It has been tried in the south of England with success. A quarter of an acre of land dedicated to experiments on this grass will not be wasted. It is very easily cultivated, as it grows rapidly from bits of the roots being planted in the ground, either by ploughing them in with a very shallow furrow, or by setting them in a hole made by a pointed stick. Curious mass of Iron and Zinc.-A curious concrete mass of iron and zinc, in weight more than a pound, has been presented to the Liverpool Royal Institution from a friend in London. It is part of the residuum which remained in an oven in which some millions of bank notes had been burnt, and is supposed to have been amalgamated from the materials which have entered into the composition of the ink. Improved Horse-shoes.-Col. Goldfinch, of Hythe, has obtained a patent for a new method in the formation of horse-shoes. The improvement consists in making the horse-shoe in two parts, or separating it in two pieces, by cutting it through near the toes. The object of the contrivance is, that the frogs of the horse's hoof may be enabled to expand and grow in a healthy state. The separation is to be made in an indented form, and the two parts fastened together by pins. It is further proposed to attach the shoe to a horse's hoof, by driving the nails obliquely, as in the French manner of shoeing. For this purpose, the situations of the nail-holes are to be from about one-third to half the width of the shoe distant from its outer edge, and tending in a slanting direction outwards. Mathematical Discovery-Mr. Herapath, of Cranford, who has lately become known by his physico-mathematical writings on the cause and laws of heat, attraction, and other phenomena, has just finished a discovery of the greatest importance in the mathematics. It is well known that Newton and succeeding mathematicians have extended their inquiries merely to fluxions and fluents or differentials and integrals of the form d'+', a +, &c. which indi +" * Picable to differentials, integrals, and functions of every possible ether the indices be whole, fractional, rational, irrational, or ) being confined to any particular species of calculation ; but is investigated on those general principles, that it extends itself with equal facility to every kind of calculus that is or appears likely to be discovered; and if the direct calculus be possible, it always makes the inverse or any real function of it equally possible. Manufacture of Glass.-M. Westrumb is said to have found, that the salts of potash and soda, deprived of their water of crystallization, answer as well as the pure alkali, for the manufacture of glass. In order to make an excellent glass, 24 parts of sulphate of soda are thoroughly dried, and mixed with 8 parts of powdered charcoal, and 16 of good white sand. The mixture must be calcined in the drying oven, until the sulphate is dissipated, and is then put into the pots for fusion. [Annales Ĝen. de Phys. de Bruxelles, May, 1820. Cleansing of Orchard Trees by Lime.-The use of lime has been highly recominended in the dressing of old moss-eaten orchard trees. Some fresh-made lime being slaked with water, and some old wornout apple-trees well dressed with it with a brush, the result was that the insects and moss were destroyed, the outer rind fell off, and a new, smooth, clear, healthy one formed: the trees, although twenty years old, assuming a most healthy appearance. Preservation of Eggs.-Eggs may be preserved, according to M. Cadet, a great length of time in lime-water containing excess of lime. An excellent mode of preserving them also, is to place them for about 20 seconds in barley-water; then remove, dry, and put them by. Eggs may be well salted throughout, if laid in brine for 8 or 10 days, and may then be preserved a great length of time. Magnetism affected by Earthquakes.-M. Arago has transmitted to the French Academy of Sciences, an account of an observation he had made, which proves that the recent earthquake, the shocks of which were felt at Lyons and its neighbourhood, also extended its action to Paris. M. Arago has an observatory at Paris, for the purpose of observing the variations of the magnetic needle. On the 19th February, the needle remained perfectly steady until half-past eight o'clock; at a quarter before nine, it became agitated in a very extraordinary manner, with an oscillatory motion in the direction of its length. On observing this truly singular phenomenon, M. Arago was of opinion that it was occasioned by an earthquake. At the same day and hour, M. Biot remarked an oscillating movement produced by the same earthquake, at his own residence in the College de France. Proper State of Prussic Acid for Medicinal Use.—A series of experiments have been undertaken by a company of associated physicians, surgeons, and naturalists at Florence, to determine the best state of the hydrocyanic or prussic acid for medicinal purposes. The experiments were made with great care, and varied several ways. Different preparations of the substance were used, rabbits being the animals on which they were tried. Their joint opinion is expressed as follows: |