tend to rouse its faculties, and to excite to important inquiries and interesting reflections. The science of mechanics presents us with many curious combinations of mechanical powers, which, from the simplest principles, produce the most powerful and astonishing effects. "What can be more strange (says a profound and energetic writer) than that an ounce weight should balance hundreds of pounds by the intervention of a few bars of thin iron?" And when we consider that all the mechanical powers may be reduced to the lever, the wheel and axle, the pulley, the inclined plane, the wedge and the screw, how astonishing are the forces exerted, and the effects produced, by their various combinations in wheelcarriages, mills, cranes, thrashing-machines, and pile-engines! Hydrostatics teaches us the wonderful fact, that a few pounds of water, without the aid of any machinery, will, by mere pressure, produce an almost irresistible force; or, in other words, that any quantity of fluid, however small, may be made to counterpoise any quantity, however large; and hence a very strong hogshead has been burst to pieces, and the water scattered about with incredible force, by means of water conveyed through a very small perpendicular tube of great length. On the same principle, and by the same means, the foundations of a large building might be shattered, and the whole structure overthrown. Magnetism discloses to us such singular facts as the following: -that a small piece of steel, when rubbed by the loadstone, and nicely poised, will place itself in a direction nearly north and south, so as to point nearly towards the poles of the world, that the north and south poles of two loadstones will attract, and two north or two south poles repel each other; and that the power of a magnet will pass through a thick board, and turn round a compass-needle, with great velocity, though placed at a considerable distance.

The science of optics likewise disclose a variety of astonishing truths, and is no less replete with wonders. How wonderful the fact, that light proceeds from the sun, and other luminous bodies, with a velocity of 195,000 miles in a moment of time; that myriads of myriads of rays are flying off from visible objects towards every point of the compass, crossing each other in all directions, and yet accurately depicting the same images of external objects in thousands of eyes at the same moment,-that the thousands of millions of rays of light which proceed from any particular object must be compressed into a space not more than one-eighth of an inch in diameter, before they can enter the pupil of the eye, and produce vision,-that the images of all the objects which compose an extensive landscape are depicted on the bottom of the eye, in all their colours and relative proportions, within

•Lord Brougham.

a space less than half an inch in diameter,—that the eye can perceive objects distinctly at the distance of six inches, and likewise at the distance of ten, fifty, or an hundred miles, serving the purpose both of a microscope and a telescope, and can be instantaneously adjusted to serve either as the one or as the other, and that the variegated colouring which appears in the scenery of nature is not in the objects themselves, but in the light which falls upon them, without which all the scenes of creation would wear an uniform aspect, and one object would be undistinguishable from another!

The instruments which the science of optics has been the means of constructing, are also admirable in their effects and productive of rational entertainment. How wonderful, that, by means of an optic lens, an image is depicted in a dark chamber, on a white table, in which we may perceive the objects of an extensive landscape delineated in all their colours, motions and proportions, and so accurately represented, that we even distinguish the countenances of individuals at the distance of a mile,-that we can see objects distinctly when a thick board, or a piece of metal, is interposed between them and our eye,-that the images of objects can be made to hang in the air either upright or inverted, and that representations either of the living or of the dead can be made to start up instantly before the view of a spectator in a darkened room,-that, by admitting into a chamber a few rays of white light from the sun through a prism, all the colours of light may be seen beautifully painted on a piece of paper,-that a single object may be multiplied to an indefinite number, and that a few coloured bits of glass may be made by reflection to exhibit an infinite diversity of beautiful and variegated forms! How admirable the effects of the telescope, by which we may see objects as distinctly at the distance of two or three miles as if they were placed within a few yards of us, by which we can penetrate into the celestial regions, and behold the distant wonders of the planetary system, and the millions of stars dispersed through infinite space, as distinctly as if we were actually transported by a supernatural power several hundreds of millions of miles into the regions of the firmament! And how curious the circumstance, that we can, by this instrument, contemplate such objects in all directions and positions,-that we can view them either as erect, or as turned upside down,-that we can perceive the spires, houses and windows of a distant city when our backs are turned directly opposite to it, and our faces in a contrary direction-the rings of Saturn and the moons of Jupiter, when we are looking downwards with our backs turned to these objects,-that we can make an object on our right hand or our left, appear as if directly before us, and can cause a terrestrial landscape to appear above us, as if it were sus

pended in the sky.* By the help of the microscope we can exhibit to a number of spectators at the same moment, a small animal scarcely distinguishable by the naked eye, magnified to the size of ten or fifteen inches in length, and distinguish not only its limbs, joints, mouth and eyes, but even the motions of its bowels, and other internal movements; and in every department of nature can contemplate an assemblage of beauties, delicate contextures, and exquisite contrivances, which excite the highest admiration, and which would otherwise have appeared incredible and incomprehensible to the human mind.

The sciences of electricity and galvanism likewise display facts both curious and astonishing. How wonderful the operations of the electric fluid, which can suddenly contract the muscles of animals, and give a violent shock to a hundred or a thousand persons at the same momentwhich moves with such amazing rapidity, that, in a few seconds of time, it might be made to fly to the remotest regions of the globe-which melts iron wire, sets fire to gunpowder and other inflammable substances, destroys the polarity of

This is effected by means of the "aerial reflecting telescope," lately invented by the author. The following is a general representation of this telescope in profile :

AB is a tube of mahogany about three inches long, which serves as a socket for holding the speculum; CD an arm attached to the tube, about the length of the focal distance of the mirror, consisting of two separate pieces C and D, the latter of which slides under the former, through the brass sockets EF. To the under part of the socket F is attached a brass nut with a female screw, in which the male screw ab acts by applying the hand to the nob c, which serves for adjusting the instrument to distinct vi

the magnetic needle, and promotes the vegeta tion of plants and the perspiration of animals→→ which can be drawn in vivid sparks from different parts of the human body, and made to descend from the clouds in streams of fire! And how powerful and astonishing the effects of the galvanic agency-which makes charcoal burn with a brilliant white flame, decomposes water into its elementary parts, and causes platina, the hardest and heaviest of the metals, to melt as readily as wax in the flame of a candle-which produces the most violent convulsions on the muscular system, causes a hare to move its feet, and a fowl to clap its wings, with force and energy, after life is extinct-throws the countenance, even of a dead man, into appalling grimaces and contortions, and excites the most rapid movements in his hands and limbs, to the horror and astonishment of all beholders!

The science of chymistry, throughout all its departments, is no less replete with wonders. How astonishing are many of the facts which it discloses, of which the following are merely specimens!-That all the productions of nature in

sion. G is the brass tube which receives the eyepieces. In looking through this telescope, the right eye is applied at the point H, the back is directly towards the object, and the observer's head is understood to be uncovered. When a diagonal eye-piece is applied, the object may be seen either to the right or to the left, or at right angles to its true position; or, it may be made to appear either upwards, as if hanging in the air, or downwards, as if below the surface of the earth. A particular description of this instrument may be seen in "The Edinburgh New Philosophical Journal" for July 1826, pp. 41 -52, and in the "London Encyclopædia." Art. Telescope.

K

E

C

H

perceive, how every step of the demonstration proceeds with unerring certainty, and leads the mind to perceive the truth of the conclusion to which it leads, with as high a degree of demonstrative evidence as that 3 added to 6 make 9, or that 5 multiplied by 4 make 20. In like manner, when it is clearly demonstrated by mathematical reasoning, that "the three angles of every triangle, whatever be its size or the inclination of its sides, are exactly equal to two right angles, or 180 degrees," and that "the sides of a plane triangle are to one another as the sines of the angles opposite to them," the utility and importance of these truths may not at first view be appreciated, however convincing the evidence from which the conclusions are deduced. But when the student comes to know that on these demonstrated properties of a triangle depends the mode of measuring the height of mountains, and the breadth of rivers,-of determining the circumference of the earth, the distance of the sun and moon, the magnitudes of the planets, and the dimensions of the solar system, it cannot but afford a positive gratification to perceive the important bearings of such truths, and that the astronomer, when he announces his sublime deductions respecting the sizes and distances of the heavenly bodies, does not rest on vague conceptions, but on observations conducted with the nicest accuracy, and on calculations founded on principles susceptible of the strictest demonstration.

"To follow a demonstration of a grand mathematical truth," says a powerful and enlightened writer," to perceive how clearly and how inevitably one step succeeds another, and how the whole steps lead to the conclusion,-to observe how certainly and unerringly the reasoning goes on from things perfectly self-evident, and by the smallest addition at each step, every one being as easily taken after the one before as the first step of all was, and yet the result being something, not only far from self-evident, but so general and strange, that you can hardly believe it to be true, and are only convinced of it by going over the whole reasoning,-this operation of the understanding, to those who so exercise themselves, always affords the highest delight." It is likewise a source of enjoyment to contemplate the experiments by which the doctrines of science are supported, and the reasonings and deductions founded on experimental investigations. When a person is told that the atmoshere presses on every part of the surface of the earth with a force equal to two thousand one Lundred and sixty pounds on every square foot, it must surely be gratifying to behold a column of water supported in a glass tube, open at the lower end,—and a square bottle connected with an air-pump, broken to pieces by the direct pres

the height of the mountains in the moon, when the ength to their shadows is known.

sure of the atmosphere,-and from a comparison of the weight of mercury suspended in a tube with the diameter of its bore, to be able to calculate the atmospherical pressure on the body of a man, or even on the whole earth. When he is told that one ingredient of atmospheric air is the principle of flame, is it not curious and highly interesting to behold a piece of iron burning in this gas, throwing out brilliant sparks of white flanie, and illuminating a large ball with a dazzling lustre ?-and when he is informed that fixed air is the heaviest of the gases, and destructive to flame and animal life,—is it not gratifying to perceive this invisible fluid poured from one vessel to another, and when poured on the flame of a candle that it instantly extinguishes it? Many of the deductions of natural science are so wonderful, and so unlike every thing we should have previously conceived, that to the untutored mind they appear almost incredible, and little short of unfounded and extravagant assertions. When such a one is told that “any quantity of liquid, however small, will counterpoise any quantity, however great,"—that the rubbing of a glass cylinder against a cushion will produce the effect of setting fire to spirits of wine, or of bursting a bladder of air at the distance of a hundred feet from the machinethat the galvanic agency will produce a violent and uncommon effect upon the nervous and muscular system-and that in certain vegetable infusions, myriads of animals of various forms, may be seen a thousand times less than the smallest visible point-such assertions are apt to stagger his belief as improbable and extravagant. But when he actually sees in the first case, a large hogshead that would hold above a hundred gallons, filled with water, and a long tube whose bore is not half an inch in diameter, firmly inserted into its top, and a small quantity of water scarcely exceeding a quart, poured into the tube-and then beholds the top rapidly swelling, and in a few moments, the whole cask burst to pieces, and the water scattered in every direction, or in the second case, when he sees alcohol suddenly taking fire, and a bladder filled with oxygen and hydrogen gas, exploding with a tremendous report, merely by the turning of the electrical machine at the other end of a long hall, and the interposition of a wire,-or, when in the third case, he sees a person drink a glass of porter which has a wire around it connected with a galvanic battery, and at a certain stage of the operation, receive a tremendous concus➡ sion, which makes him start and roar like a madman, or, in the last case, when he looks through a powerful microscope, and perceives hundreds of mites like so many young pigs, clambering among rocks of cheese, and thousands of fishes in a drop of water-such experimental illustrations of the truths of science, cannot fail to prove highly satisfactory, and to afford