cal scepticism; but was found to be true. Provided there were a sufficient number of such trees, there seems nothing improbable in the statement. Plants, being organized beings, require air to support them in life. They die if placed in a vacuum. They require that some oxygen (one of the two great constituents of the atmosphere) shold be present. It has been said that they can live in nitrogen (the other constituent of the atmosphere) alone; but that is not the case. Carbonic acid (of which the atmosphere contains one part in a thousand) is hurtful to them if too abundant. If you put a plant into a jar of air inverted over water, the latter will continue to rise during the whole night. This shews that the plant has absorbed some of the air; and the part absorbed is oxygen. Thus plants perform only one inspiration during the night. When exposed to the sun, they expire oxygen,-give it out again. If they were entirely excluded from the sun, they would probably continually vitiate the air, by absorbing oxygen, and giving off car bonic acid. It seems that some portion of carbonic acid is necessary for their existence'; for they will die, if enclosed in air deprived of carbonic acid; and if rather more than the usual proportion of that gas be present, they grow more vigorously. Plants which grow in water, are observed to have bubbles of air around them. This air consists of oxygen. The green conferva, on the inside of troughs, keeps the water from putrefaction, by continually giving out oxygen. Sir Humphrey Davy, in his Consolations in Travel, says that this little plant and others grow very abundantly round lakes in Italy, which exhale much carbonic acid. The agent in decomposing the carbonic acid, seems to be the chlorophel (as the green colouring matter of plants is called); for the white and the co. loured parts of plants,-such as the root, the flowers, and the fruit,-do not decompose carbonic acid. It seems that the violet rays of light have a peculiar power in producing green. Senebier made plants grow under glasses of different colours; and the plants in that glass which transmitted only violet rays, grew best. Generally, the upper surface of leaves is the greenest; for the light falls more directly on that surface. In the long leaves which grow upright in lilies and other plants, both sides are equally green. In rushes, the leaves are rolled up; so that their upper surface is concealed from the light, and is white; while their lower surface is outside, and is green. Leaves have a power of spontaneously turning to the light; and it is generally their upper surface that they present to it. In a field of trefoil, the leaves are seen to move round with the sun. The same thing is seen in vine-leaves. The sun-flower has acquired an undeserved reputation on this head. It is no doubt with a view to this exposure to light, that the leaves of plants have a peculiar arrangement on the stem. If you examine a plant, you find the leaves so arranged (by the different length of their leaf stalks, &c.) that no one leaf completely shuts out another from the sun's light. Plants which grow in the dark, are found to contain very little carbon (pure charcoal). Dutrochet found, that if he exhausted the irritability of the sensitive plant, if put into the shade, it never recovered; but it did if exposed to the light of the sun. It appears probable, from this, that light is the source of vitality, as well as of the power of gaining carbon. Light is also the source of the formation of aromatic oils, &c. Some have supposed that light itself is an ingredient in some of these substances; as in agreeable scents, and beautiful colours. But if it form part of otto of roses, it must also form part of assafoetida. Bishop Berkely treats of it, when writing on tar-water. - Plants regulate the distribution of water; for they raise it by means of their roots; give it out by their leaves; and condense it again, as dew. Wherever there are forests, springs and rivulets abound. This will remind many of our readers of the Indians' finding water in the woods, in "The Last of the Mohicans." Plants are very useful to animals as food; as in the case of the mulberry-tree and the silkworm. The mulberry bears to lose its leaves, better than any other plant. The cactus, again, is adapted for cochineal, which is an insect. Many trees afford habitations for insects. Sometimes the insects which infest plants, perform an office which is useful to man; as in the case of the insect which by piercing the bark of the oak, causes the excrescence to form which is called a gull-nut ; and which is so useful in the manufacture of ink. We once heard a lecturer inform his audience, that gall-nuts were the fruit of the oak; and when we ventured, after lecture, to state the impression under which we had lain, that the acorn was the fruit of the oak, he replied that such was the case with English oaks, but he had spoken of foreign ones! Our readers must have seen the little hole in the nut, by which the young insect makes his escape when the proper time arrives; but our learned friend informed us that this hole was made by the old insect trying to get in to eat the fruit! Some insects are very pernicious; as is the case with the catepillar, the turnip fly, &c. The leaves of plants are often very useful to man; as in the case of tea, vegetables, condiments, &c. Vine-leaves, as well as grapes, will make wine. Many leaves, such as those of the palm, are made use of for pa per in the East. Mosses keep up bogs, and afford fuel. Many of the inconveniences which we now suffer from the ravages of the caterpillar, would be obviated if we knew more of its habits. N. R. CAUBUL AND ITS DEPENDENCIES. (Continued from page 320.) AFFGHANISTAN. CAUBUL, according to the evidence of recent travellers, is a compact and picturesque city it abounds in all the necessaries, and no small part of the luxuries, of civilized life. Its houses are fair of appearance, its religion is carried on with propriety and becoming solemnity; and at those seasons when its state is pacific, and its government judicious, it is a. happy and desirable place. But, as regards the physical appearance of the territory without its boundaries, subject to its jurisdiction and sovereignty, scenes of another kind appear. No longer, when beyond what are strictly termed the limits of the city, is level pathway or trim street, intersected by water-streams, to be trodden by the foot; no longer does the brilliant bazaar, glittering with its rainbow-hued fabrics, delight or dazzle the eye, these give way to scenes of another nature. Instead of those mountains, rugged of surface, and sublime of height, at whose bases stretch out plains mantled with rich and fertile verdure, at one time overpower, and at another, please the eye of the beholder. And not untenanted are these varied sceneries. Thickly studded are they everywhere by the tents of various nomade tribes-here the Dooraunce abides -there the Affghan shepherd fixes for a while his moveable habitation. This lastmentioned nation, by far the most consider able of all which are tributary to the king of Caubul, is that which above all demands and deserves notice. From a faithful description, indeed, of this large nation, a correct notion may be formed as to the modes and habits of most of the other tribes spread over the kingdom. These, though they may indeed differ in trifling points, will, however, in their broad and general characteristics, be found to very closely assimilate. Of that immense country, known by the name of Affghanistan, we propose to speak-a country whose population is dense, and the tenants of whose soil, though they be entirely pastoral in the manner of their lives, yet, than whom, in the event of war, there exists not a more courageous or bellicose people. Upon the north of this great country, extend chains of mountains, covered with perpetual snow, from which issue many rivers. Round the eastern boundary, the great waters of the Indus roll as long as that river continues near the hills. The southern limits of the country are again bounded by hills, while plains and deserts make up the rest of its irregular boundary. Multitudinous are the countries which it comprehends, various in their level, climate, soil, and productions. These all bear certain names, for the Affghans have in truth no general name for their country but that of Affghanistan, which was, most likely, first employed in Persia, is frequently used in books, and is not, by this time, unknown to the inhabitants of the country to which it applies. Nothing can be more imposing than the appearance of the loftier mountains surrounding Affghanistan, and indescribable are they for the magnificence and variety of their towering summits. A peculiar beauty, too, belongs to the lower hills. From their summits, down to their bases, the different gradations of vegetation are remarkable. Snows lie for three or four months on their tops, which are almost treeless, and desolate, but their sides are embellished with forests of dark pines, oaks, and flourishing olives; lower down, enjoying a delicious clime, are many charming little valleys, irrigated by clear and beautiful waters. In this degree of latitude, the plants and flowers which adorn the gardens of Europe grow in profusion, and the ground is gaily variegated with the rich verdure of manycoloured mosses. For a country of such capacious extent, Affghanistan has few large rivers. With the exception of the river Indus, there is none which can be forded during the greater por-> tion of the year. The largest rush from their sources with the impetuosity of torrents. One chief cause of the diminution of their importance, is the practice in vogue among the people, of draining off their waters for the purpose of irrigating the fields which lie upon their borders. A river of magnitude is by this means consumed, before it can reach any other. It is according to the fall of the rains, that the husbandry of these parts flourishes or withers, indeed, it altogether depends upon the seasonableness and quantity of the rains. The rainy season, productive of the most calamitous effects, is that which is called the S. W. monsoon. Its effects are diffused over a wide space, and for a third part of the year, it absolutely floods all the countries over which it extends. Heavy masses of cloud, accompanied by a darkening of the air, are the general harbingers of its advent, and during the silence of the night is it that it sets in with the roll of thunder-storms, the rush of hurricanes, and the downfall of huge rainfloods. But out of this seeming evil marvellous good is educed; for no sooner has its intemperate fury ceased, than the whole length and breadth of the land, which was before arid and verdureless, sparkles with all the freshness and brilliancy of spring. During the first month, these rains descend only at intervals; for one month only they are at their height; during the third month they gradually lessen, and during September they almost entirely suspend their force, departing,› as they came, in thunders and tempests. During the depth and severity of the winter season, there falls also a second rain, and which, according to the temperature of the place, assumes the form of rain or snow: this second rain, by those who study agricultural pursuits, is held to be of much greater importance to husbandry than the south western monsoon. From the fluctuating nature of the climate, which is sometimes consumed by intense heats, at others, devoured by cold or devas tating rains, fevers and agues are very common in Affghanistan; colds are very troublesome, and are, in winter, not unfrequently fatal. Many are carried off by the ravages of the small-pox, though inoculation has been long in vogue, even in the most remote quarters of the kingdom. Weakness of the eyes, and opthalmic complaints, are also very frequent of occurrence. Of the characteristics of some animals which are indigenous to the country, there are some facts which are not uninteresting. During winter the wolves are particularly formidable; they gather together in numerous troops, and man himself is oftentimes attacked by them. It is remarkable, on the other hand, that the hyænas never assemble in bodies, but will oftentimes, with ferocious courage, attack a bullock singly. There is also a remarkable species of deer, noticeable for the size of its branching horns; the uneducated Affghan people entertain very curious notions relative to the means of its subsistence. They assert that it feeds wholly on snakes, and that within it is found a hard green substance, and this, by them, is reckoned an infallible remedy for the poisonous bite of the serpent. The furnishing of the armies of the king of Caubul with cavalry, depends much on Affghanistan. Numbers are bred in the Affghan dominions, and those brought up at Heraut are superb creatures. The fine grace ful shape, peculiar to the Arab charger, is frequently to be seen among them, united with superior strength. Though, indeed, the horses of the Affghan dominions are not, when taken collectively, to be considered as remarkably good, yet, in the province of Bulkh, they are very excellent and numerous. There is a kind of gad-fly, which makes continual inroads upon these animals, and, indeed, so violently harassed are they by them that they have been known, in many instances, to pine away and die. Mosquito, too, that everlasting plague of hot countries, swarms in these parts, and the natives are obliged to have mosquito curtains, as in Bengal. In the vegetable kingdom there exists an infinite number of trees, which are altogether unknown in Europe. Among others is the selgoozeh, whose branches are clustered with cones, larger than artichokes, and containing seeds resembling pistachio nuts. Here, also, flourish two species of oaks, the botanical name given to one of which is quercus beloot; and these, together with a sort of gigantic cypress, tower on the tops and sides of the mountains. There are other trees, which go by the names of secahcobb, purta, bulkhuke and zurung, which few travellors have met with. There are, however, many parts of the Affghan country which present a very destitute and forlorn appearance. There are continually to be met with, hills and waste, which are unmarked by any enclosures, unadorned by any trees or natural productions, unimproved by either navigable canal or public road, or distinguished by any single refinement of human industry. Neither again is the mere outward aspect of the people more prepossessing. Their features are high and harsh, their countenances dark and swarthy, from constant exposure to the sun, their beards are suffered to grow to a great length; and these, together with their loose clothing, and the shaggy skins which mantle their shoulders, strike the traveller with no little surprise. But, on entering their society, these sensations speedily give way to others of an agree able and pleasant nature. He beholds their martial and lofty spirit, and he at once yields the tribute of admiration: he partakes of their generous hospitality, and experiences deep-felt gratification; and while in those bold and simple manners which at first excited his displeasure, he begins to perceive many noble qualities, and the rudiments of many virtues. W. ARCHER. (To be concluded in our next.) Phenomena of Nature. WILL WITH A WISP. THE following letter from Mr. R. Overton, of Grimstone, appears in the Norwich Mercury, of Saturday, May 18, 1839:-" On returning home from Tatterford, on the 8th of May, at half-past 11 o'clock P.M., when within half-a-mile of Rudham, I observed two lights, apparently 200 yards distant, passing rapidly about two feet from the surface of the earth, through a dense fog, which covered a circumscribed spot of meadow-land to the extent of an acre: the adjoining land appeared perfectly free from that vapour. At first sight I supposed the lights to proceed from lanterns. I was, therefore, induced to stop and observe their movements, but was rather surprised to see them disappear; after travelling in a straight direction about 100 yards, another, much larger and more brilliant one, made its appearance, and in a short time disappeared. It was a beautiful starlight night, and the sky frequently illumined with flashes of vivid silent lightning, and the wind blowing briskly from the northeast. Several lights sprung up in different parts of the meadow, and moved about in various directions-and one, as if more bold than the rest, advanced in a straight direction to within about 90 yards of the place where I stood, remained perfectly still for a few seconds, described a half-circle, as if about to return, and instantly disappeared. Feeling fully satisfied that the phenomenon above described was an ignis fatuus, I remained a full hour to observe its gambols, which at times were truly ridiculous-and as I am not aware that it has been before noticed that these midnight luminaries are immediately connected with electricity, I beg leave to request you will do me the favour of giving a place in your valuable journal to the preceding phenomena. I particularly observed two or three of these lights instantly appeared with each flash of lightning, more or less brilliant, according to the degree of light caused by the lightning." LAW OF STORMS. A LECTURE on this interesting subject was delivered on Thursday evening, the 16th ult., at the Metropolitan Institution, Salvador House, Bishopsgate, by Mr. W. R. Birt, the librarian. After controverting the generally received opinion that the trade winds blow from the north and south, at the limits of the torrid zone, becoming due east at the equator, by showing that they first commence from the eastward, and gradually become north and south near the equator, the lecturer explained the theory so ably put forth by Colonel Reid, and, with the help of diagrams and maps, showed the phenomena that would arise from a cylinder of air rapidly rotating, possessing at the same time a progressive motion. He also showed the agreement of facts with theory, by a diagram, constructed from the published accounts of a storm that passed round the north off Scotland and along the eastern shores of England during the night, between the 11th and 12th of October In concluding, the lecturer endeavoured to show the vast importance of the inquiry, particularly to those individuals whose occupations are connected with the sea. last. Arts and Sciences. ACCIDENTAL DISCOVERY OF PRUSSIAN THIS colour takes its name from the country wherein it was discovered by accident, in 1704. It happened that a manufacturer, named Diesbach, was engaged in precipitating a solution of alum, to prepare the white body (as the basis of lake,) to be coloured with a decoction of cochineal, employed for that purpose some potass which had been given him by Dippel, and upon which the latter had several times rectified animal oil; but, to the astonishment of the operator, the precipitate, which should have been white, became blue. Dippel being made acquainted with the phenoinena, applied himself to examine all the circumstances connected with this strange appearance, and at last he succeeded in reproducing the new colour at his pleasure. The method of preparing the colour, which was kept secret by the inventors, was an object of research for many years among the chemists. In 1724, Woodward, who was a member of the Royal Society of London, published the following process, which has been for a long time the only one in use:-Some dried ox-blood and potass are mixed together and calcined; as soon as the vapours have ceased, and the substance has become of a dark red, it is thrown into water and boiled, to hasten the solution of the salts it contains. With this liquid, clarified by rest or filtration, is precipitated a solution of sulphate of iron and alum; the precipitate is then purified by hydrochloric acid and repeated washings. At the crystals drawn from it, and called prus the present time, instead of the Prussian lye, siat of potass, are used, The salt is a triple combination of Prussic acid, potass, and a little iron: the solution being much more Pure than the lye in which it crystallises, the blue should be, and is in fact, much more brilliant. If this colour possessed solidity, it would be one of the greatest utility: it has intensity, flows freely in the pencil, and is a good dryer; but it loses its brightness, becomes greenish and gray when exposed to a strong light: therefore, it never can be used to make green tints of a brilliant and durable nature. In the article on browns we shall show, that Prussian blue, exposed to a strong heat, becomes an excellent brown. When Prussian blue is prepared with proto sulphate of iron, the precipitate is first of a dirty green, and only becomes blue by contact with the air. It must, therefore, be well stirred; and when the blue is developed, it is washed by decanting or filtration. When the sulphate of potass is carried off by washing, the colour is soluble in water, and holds the same quality when dry; but this will not be the case if alum has been added to the sulphate of iron, or is contained in it.-Sarsfield Taylor's Translation of Mérimée's Art of Painting in Oil and in Fresco, &c. QUALITIES OF WOOD AS A MATERIAL SUCH is the form which, guided by experi ment and such other resources of science as we possess, we find ourselves led to give to the substance, iron, which, forming part of the solid materials of the earth, and ministering there to some wholly different use, we dig up and apply to our purposes of construction. Now let us turn to the architecture of trees, and examine Nature's material, and let us consider whether, guided by the light which our efforts to economise this artificial material of construction may have given us, we may not discover, in the material which has been elaborated wherewith to build up those stately structures, some feeble traces of that mighty and all-perfect wisdom of which ours, feeble as it is, is yet an emanation. And let the principle first of all be stated, as one observable throughout all nature, that creative power, infinite in its development, is infinitely economised it its operation. Were wood but as durable as iron and stone, it would supersede their use as a material of construction. If other evidence were wanting, the unparalleled boldness of the structures erected with wood would, for itself, speak to the fact. What have we to compare with the structures erected in wood? There is no arch of iron or stone, for example, that approaches to the span of the wooden arches which have been erected by Weibeking in Germany, or to that arch at Philadelphia, which, with one vast span of 350 feet, crosses the Schuylkill. The superiority of wood to iron or stone, as a material of construction, results from the extraordinary lightness which it unites with its strength. Thus deal has only one-fifteenth the weight of cast-iron, although it has considerably more than one half the tenacity, and sixteen bars of it would weigh only the same as one bar of the same dimensions of wrought-iron, although they would have together more than the strength of three. Now it is evident that a building erected with a material, however strong, which was in the same proportion heavy, might, and probably would, be a weak building. Such a structure, notwithstanding the great strength of its material, might load itself with its own mass to the utmost that it would bear, so that the slightest additional pressure would cause it to yield, as it is the last ounce which breaks the camel's back. Many, and memorable, are the instances of this weakness in artificial structures. The case of the Brunswick Theatre, whose iron roof fell in by the pressure of its own weight, and that of Mr. Maudeslay's manufactory in London, and of the Conservatory at Brighton, are in everybody's recollection. But wood falls short of other materials in durability. The food of living vegetation is extracted from decayed. vegetation; decay was thus, for the great purposes of nature, made its inseparable concomitant. This decay-which was a necessary property then of timber, as a material of nature's architecture-unfitted it for that of man; who, reserved for immortality, and struggling, even here, in an unceasing combat with the fleeting and transitory character of all that surrounds him, would construct for himself an abode whose durability may laugh to scorn the shortness of his tenure, and digs its material from among those mineral substances out of which the mass of the earth itself is builded up, and whose duration is coeval with it.-Moseley's Illustrations of Science. New Books. THE GIFT FOR ALL SEASONS. A LITTLE volume, most appropriately named, tion of that which, in all times and at all sea for its main object appears to be the promosons, should be the lantern of our paths, and which, in the hours of adversity or death, can alone afford us real support-Religion. There are amid its pages many pieces of great merit, particularly the Valley of Abourna, by Miss Pardoe, and a paper on the Jews, by Henry Innes, Esq. We subjoin the following beautiful poem as a general specimen of its contents. MY MOTHER. BY D. ROSS LIETCH, M.D. Nor storm nor fear can smother:" Thy sweet cheek simply shading; Bright thoughts lie brooding on that brow, Oh, Mother! thou art blent with all To thee that bliss is owing! Breathes from thy spirit o'er me: Thy love is like a light divine, A lustre rich and holy; Hate lives not in that heart of thine, 'Tis pitying melancholy! Thy gentle chiding, even more dear Than kindness from another; Reproof is Love, when from thy lips 'Tis breathed, my angel Mother] To bask beneath thy holy smileTo feel thy kiss upon me; To hear those gentle tones that oft From worldly thoughts hath won me; To live beside thee, and to touch,To talk of loved ones perish'd; Ye, Sacred Powers! can tell how much This lot by me is cherish'd! The hounding heart of Youth is gone, The flowers have left the wildwood; And dim, dim now the dreams have grown I cherish'd in my childhood. But, mother, oh! whilst thou art left, The true, the angel-hearted, Not all of boyhood's bliss is reft, Not all of youth departed! |