The nature of the scent of flowers is not well understood, though it must arise from very minute particles diffused from the flower through the air, and thence conveyed to the organ of smell. Chemists have attempted, but hitherto without success, to make some investigation of the constituents of aroma. The extreme fineness of the particles is proved by the fact, that a piece of musk which has been for years diffusing its aroma, does not sensibly lose any thing considerable of its weight. One of the most universally cultivated garden flowers in bloom this month is the Greek valerian, Polemonium coeruleum, very often called Jacob's ladder, probably from the regular ladder-like steps of the winged leaves. It is a native of this country, but is rarely to be met with in a wild state, no doubt because when it is found, the roots are so frequently transplanted into gardens. We once found it growing below the rock called the Lover's Leap, near Buxton, in Derbyshire, the flower being of a colour which we have never seen in gardens; namely, a rich purplish blue, somewhat like that of the sweet violet, but not quite so dark; whereas the garden varieties are more purely blue, without any shade of purple, though they vary much in the depth of the colour; and some are pure white. In the same way the columbine, Aquilegia vulgaris, of which we once found a large patch growing wild in Ireland, near Cork, was of a colour between yellow and white, which we have never observed in the garden varieties, though they are very much disposed to vary in colour. The greater uniformity in the colours of wild flowers, as well as of wild animals, is a very remarkable circumstance; but the illustration thereof would lead us beyond the space which we can at present afford. OSTRICH EGGS. J. R. IT has been thought that the ostrich, after depositing its eggs in the sand, this. remarkable bird generally leaves them to be hatched by the genial rays of the sun; but the following facts will show the erroneousness of such an opinion, although maintained by some who have confidently assumed the character of historians. 66 "On approaching the nest," says the Rev. J. Broadbent, we saw the female ostrich sitting upon it; and though she had been disturbed before by the Hottentot, she remained till we were very near, and then ran off at the report of two guns which were fired. The ground was sandy for several miles round, and covered with thinly scattered bushes. There lay a great number of loose ostrich feathers about the nest, which appeared to have come off the female while sitting, and she had the naked appearance which domestic fowls have at such times. "The eggs were forty-two in number, including two which had been taken away, and were arranged with great apparent exactness. Sixteen were close together in the middle of the nest; and on these the ostrich was sitting when we arrived; they were as many as she could cover. The remaining twentysix were placed very uniformly in a circle, about three or four feet from those in the middle. The eggs which were in the circle we found to be quite fresh, at which I expressed my surprise. The Hottentot informed me that these had been provided by the ostrich against the hatching of those in the middle, when she would break them, one after another, and give them to her young ones for food; and that by the time they were all disposed of in this manner, the young ostriches would be able to go abroad with their mother, and provide for themselves such things as the desert afforded. This fact affords as fine an instance of animal instinct, and as striking an illustration of a superintending Providence, as perhaps the whole circle of natural history is capable of furnishing. 66 During the time that we continued beside the nest, which must have been near an hour, for the Hottentots kindled a fire, and broiled some of the eggs, the ostrich remained at a short distance, looking towards us; and there we left her. The eggs weighed three pounds each, and measured seventeen inches in circumference. We took the greater part of the fresh ones. Seven were as many as I could conveniently carry. One of the Hottentots ingeniously contrived to carry a great number, by pulling off his trowsers, tying up one end, and filling them with eggs."-Kay's Caffraria. THE INTERNAL COMMUNICATIONS OF Ar the time of the introduction of canals into Great Britain, rail-roads were in a state of relative insignificance, compared with the character which they at present assume. They have, however, been progressively improving; and, since the application of steam power to drag the carriages upon them, they have attained such value, as to entitle them to the most serious attention of the public. The idea of forming smooth surfaces for carriage wheels to roll upon, is not of modern origin; but no horse could draw with advantage on a smooth pavement; hence, in Florence, where the wheel-tracks are paved with hard marble, wrought smooth and level, the horse-paths are of ordinary paving. At an early period, a similar advantage was obtained in our Own country, at the collieries of Newcastle, by putting down rails of hard wood for the wheels of wagons to run upon; and more recently rails of cast-iron have been employed, and with more advantage, being much harder and more durable than even the marble wheel-tracks of the Italians. By using iron, we obtain a smooth, hard, and even surface, at an expense comparatively small, and the moving power has very little more than the friction of the axis to contend against. A carriage moving under such circumstances, bears the nearest analogy to a body impelled on the smooth surface of ice, where it is well known that the velocity which may be given by a small power is immense; what the rails want in smoothness, being compensated for by the use of wheels. These important advantages of rail-roads were foreseen some years ago, by Dr. Thomas Young; for he concludes his notice of them in these remarkable words :"It is possible that roads paved with iron may hereafter be employed for the purpose of expeditious travelling, since there is scarcely any resistance to be overcome, except that of the air, and such roads allow the velocity to be increased almost without limit." Speed and certainty of conveyance are of such primary importance in commerce, that a small increase of expense to obtain them is not a material object. Also the certainty of supply must tend much to diminish the fluctuation of prices, and remove those alternations of glut and scarcity which are perpetually occurring in the markets, from contrary winds, frosts, floods, etc. Every thing which tends to render the conveyance of goods certain, must lessen their expense to the consumer, by diminishing the amount of dormant capital, and the necessity of keeping large stores in expensive warehouses. Also with a good system of conveyance, when a sudden call does take place, the whole stock of the country becomes available. A cheap and regular mode of conveyance, besides rendering the produce of fertile lands accessible at a less price to any portion of the community, also affords new markets for other articles. It creates new sources of exchange and supply, and causes the advantage of labour and industry to spread; and it expels the idleness and indifference which engraft themselves among those people who, without such means, barely obtain the common necessaries of life. The ordinary mode of land-carriage makes every heavy commodity so expensive, that the inhabitants of inland districts are denied the use of many things. In many places they are nearly destitute of fuel, and while moderate exertion gives them the scanty supply of comforts within their reach, their utmost efforts scarcely do more, and, therefore, they sink into that languid state of indifference, which we find so generally prevalent in such countries. the Tyne, to the various coal works. The rails employed are now all of the kind called edge rails; and it appears from experiments, that on the level rails, when they are in good condition, a force of one pound will draw a weight of one hundred and seventy pounds, or one horse will draw twenty-five thousand five hundred pounds' weight, including the weight of the wagon, at the rate of two miles and a half per hour. The immense advantages of railways at Newcastle, soon caused them to be spread to the mining districts of Yorkshire, Derbyshire, Wales, and Scotland; and are now rapidly extending them over the United Kingdom, for the general purposes of trade. The Surrey rail, or tram road, which commences on the north bank of the Thames, near Wandsworth, in Surrey, proceeds in a south-easterly direction to Croydon, and from thence to Merstham, making a total of about eighteen miles, was constructed in the beginning of the present century, about the year 1805. There are two kinds of railways in common use. The most extensively adopted plan being what are termed edge railroads, which are adapted for the use of carriages with guiding flanges The first rail-ways appear to have (or shoulders) on their wheels, as shown been used in the neighbourhood of in the annexed cut; where ▲ ▲ repreNewcastle-upon-Tyne, about 1680; the sent an end view of the rails resting rails were of wood, resting upon wooden in their supports; c c called chairs, transverse beams, called sleepers. The which are fastened to stone blocks, wooden rails are, however, now aban-D D, imbedded in the ground; and doned for iron ones, of which there B B represent the wheels of the carriage are an immense number branching in as seen end-ways. various directions, from both sides of It is necessary that a line of railway | ful power, which, in the hands of James should be as nearly level for its whole length as the circumstances of the country will admit of, and therefore it frequently happens that railways are made very circuitous, to wind round hills, and avoid deep valleys. When, however, these natural difficulties cannot be avoided, they are boldly encountered; and there are railway works now in progress, where to produce a level, or nearly so, an immense slice has been cut out of a hill for its whole breadth, sixty, eighty, and even a hundred feet deep; the earth thus removed has then been carried to fill up some distant valley to the required height; so that travellers passing along these great lines of railway, will be, for a few seconds, at the bottom of an immense excavation, and, before they can cast their eyes upon the strata of earth cut through, they will find themselves on the top of a high embankment, moving in the air with astonishing velocity, the whole country stretched before them like a map: houses, plantations, woods, farms, villages, and all the varied scenes of agricultural life, passing, as it were, before them in rapid succession; new objects constantly appearing in the distance; almost in an instant they are beneath their gaze, and as rapidly disappear behind them. We must now endeavour to explain how this wonderful velocity is obtained, the railroad itself only forming a smooth and nearly level surface for the wheels of the carriages to roll upon. The motive power is steam, that wonder Watt, and his successors in mechanical engineering, has given such power to an engine, which, in its present improved state, "appears," says an elegant writer, "a thing almost endowed with intelligence; it regulates with perfect accuracy and uniformity the number of its strokes in a given time, counting or recording them moreover, to tell how much work it has done, as a clock records the beats of its pendulum; it regulates the quantity of steam admitted to work; the briskness of the fire; the supply of water to the boiler; the supply of coals to the fire; it opens and shuts its valves with absolute precision as to time and manner; it oils its joints; it takes out any air which may accidentally enter into parts which should be vacuous; and when any thing goes wrong which it cannot of itself rectify, it warns its attendants by ringing a bell: yet, with all these talents and qualities, and even when exerting the force of hundreds of horses, it is obedient to the hand of a child. Its aliment is coal, wood, charcoal, or other combustible; it consumes none while idle; it never tires, and wants no sleep; it is not subject to malady when originally well made; and only refuses to work when worn out with age; it is equally active in all climates, and will do work of any kind; it is a water-pumper, a miner, a sailor, a cotton-spinner, a weaver, a blacksmith, a miller, etc., and a small engine in the character of a steam pony, may be seen dragging after it, on a railroad, a hundred tons of merchandize, or a regiment of soldiers, with thrice the speed of our | fleetest horse coaches. It is, in fact, the king of machines." The engraving at the head of this article represents a locomotive engine, constructed on the most approved principle. Its mechanism is so simple, that a short description will be sufficient to explain its mode of acting. The principal parts of the engine are, the fireplace and boiler, which constitutes the means of raising the steam; the slides and cylinders which are the means of bringing into action the elastic force residing in that steam; and the cranks and wheels, by means of which the motion is transferred from the piston to the engine itself. The following engraving represents the internal structure of this important machine, by the help of which, and our first engraving, we hope to make its principle of action clearly intelligible; the same letters of reference being applied to both engravings. The above engraving shows the body of the machine, as composed of three distinct compartments. The one on the left, or fronting the machine, and which is surmounted by the chimney c, is separated from the two others by the partition t t. The two others form the boiler; both are filled with water to near the level of the tube marked 'v and "v, but part of their internal space is occupied by the fire, as will be next explained. In the hindmost compartment is placed a square box e, which contains the fuel, or forms the fire-place of the machine. Between the sides of that box, and those of the compartment in which it is contained, a space q q is left, which communicates freely with the remainder of the boiler, and which is consequently filled with water. The fire-box e, being thus placed in the middle of one of the compartments of the boiler, would be surrounded on all sides with water, were it not for the aperture 7, which forms the door of the fire-place, and of the bottom n, which forms the grate, the ashes falling through into the space beneath. Near the door I, and in the machine, is placed a strong platform, represented by B, for the engine-man to stand upon. Directly behind the engine is attached the tender-carriage, with coke and water, so that it is easy for the fireman to throw coke into the fire by the door 7, and to let water pass into the boiler whenever it may be necessary. This supply of water takes place by means of a forcing pump, put in motion by the engine itself. The lower part n of the fire-place is occupied, as we have said, by a grate, and remains constantly open, ad |