most beautiful and perfect instruments, magnifying objects in nature many thousand times their real size, and enabling the observer to view them not only void of all false tints, but to measure and ascertain at the same time the comparative sizes of their several parts. Of the latter, some have been constructed of six and eight powers, ranging from 130 to 74,000,000 times; as, for example, the one made by Carey for the Polytechnic Institution in London. Thus, the second power of this instrument magnifies the wings of a locust to twenty-seven feet in length; the fourth power magnifies the sting of a bee to twentyseven feet; and by the sixth power, the human hair is magnified to eighteen inches in diameter.

As we have gigantic microscopes, so also have we gigantic telescopes; that of Earl Rosse, completed about two years ago, being as yet by far the largest ever constructed either in this or in any other country. Its completion in 1844 was thus described by Dr Robinson the astronomer :- "The speculum, which weighs three tons, and has a diameter of six feet, with a reflecting surface of 4071 square inches, has been ground to figure, and can be polished in a day. The tube, partly a cubic chamber, where the mirror is fixed, and partly a cylinder of inch deal, strongly hooped, and eight feet in diameter at its centre, is complete. The massive centres on which the telescope is to turn are in their place, and the

iron apparatus which supports the speculum is also complete. The telescope is not to be turned to any part of the sky, but limited to a range of half an hour on each side of the meridian, through which

its motion will be given by powerful clockwork, independent of the observer. For this purpose it stands between two pieces of masonry of Gothic architecture, which harmonise well with the castle. One of these pillars will sustain the galleries for the observer, and the other the clockwork and other machinery. An extremely elegant arrangement of counterpoises is intended to balance the enormous mass, so that a comparatively slight force only will be required to elevate or depress it. The arrangement will not permit the examination of an object at any time, but only when near the meridian, when it is best seen. So large a telescope will always require the most favourable circumstances of air, &c. and there will always be enough of objects at any

given time to employ it fully. The aperture is 6 feet, the focal length 58, and the reflecting surface 4071 square inches." Herschel's celebrated telescope had only a focal length of 40 feet, and a reflecting surface of 1811 inches: dimensions, the bare mention of which will enable the reader to form some conception of this new and wonderful instrument. Herschel's telescope worked wonders in the starry field; what, therefore, may we not expect from that of Earl Rosse's, of more ample dimension, and of much more perfect finish? Indeed its wonderful revelations have already commenced, and nebula which baffled the instrument of our greatest astronomer are now resolved into clusters of stars.

TELEGRAPHS.

Telegraphs are machines constructed so as to enable two persons to converse with each other at a distance by means of signs, sentences, words, or letters, according to a convention previously agreed upon by the parties. This art of signalling is of great antiquity; but till within the last few years, it remained in a very simple and imperfect condition. Most of the signals employed, for example, were addressed to the eye, such as beaconfires, lanterns, skyrockets, flags, wooden frameworks with movable pieces, &c. and were therefore totally useless at great distances, or during close and foggy weather. In some instances, sounds were the signals agreed upon, and these were produced by the firing of cannons, sounding of bugles, beating of drums, and the like; means extremely simple, but very liable to be mistaken or rendered confused by similar sounds, or even by their own echoes. However primitive these methods, many of them are combined and arranged in highly ingenious manners, and are still in every-day use in the direction of our armies and navies, as well as in the rapid transmission of important intelligence. The time has arrived, however, when human ingenuity has triumphed over every difficulty connected with light or darkness; nay, we might almost say, over time and distance themselves. We allude to the electric telegraph, which, so far as the transmission of intelligence on land is concerned, may be regarded as the greatest marvel of the present day. Be the distance sixty miles or six hundred, be it by night or by day, be it foul or fair, it is of no moment; the most minute and particular information can be safely communicated, and that almost as quickly as it could be delivered viva voce; at all events as rapidly as it can be done by an ordinary penman.

The origin of the electric telegraph dates so recently as 1836 or 1837; and though several continental philosophers claim participation in the invention, it only be ame a useful practical application in the hands of our countrymen Professor Wheatstone and Messrs Cooke and Bain. By the latter, the whole arrangements have been considerably simplified; all that is now required being

a single connecting wire, with the necessary battery, index, and alarm. It is impossible, in our limited space, and without the aid of diagrams, to give a minute description of this surprising invention; all that we can do is to endeavour to convey a general idea of its mode of operation, for which purpose we shall avail ourselves of an account of a visit to the electric telegraph communicating between Gosport and the London terminus of the South-Western Railway—a distance of eighty miles.* Premising that the electricity is generated in the usual mode by a Smee's or Daniel's battery, and carried along the suspended wires from one terminus to the other, there is at each end a room, fitted up with proper apparatus, to indicate the motion which has been communicated by the individuals in attendance. "In this room," says the account alluded to, "the most striking object was a kind of cabinet, having all the appearance of a handsome table-clock. On a glass-covered metal plate in front are two disks, each furnished with a needle moving on an extremely sensitive pivot, so as to point upwards and downwards. At the base of this clock-like machine are two handles, by which the motion communicated to these needles by the electric current is directed. Exactly the same sort of machine stands at the Gosport terminus of the railway, and its needles move precisely in accordance with the motions of those we saw at work; so that the attendant at Gosport can read from the motion of the needles what the attendant at the London end intends to convey by the motion he gives to the Gosport needles by means of the London handles. The electricity, therefore, gives mere unmeaning motion to the needles at either end-the gentleman in charge of the instrument directs that motion, and by the different positions in which he puts the two needles, communicates such meaning to the motion as is perfectly intelligible to his companion at the other terminus. The code of signals thus established was partly explained to us :-The left hand needle when moved to the left gives E, to the right I; the other needle gives O and U; both pointing parallel, W or Y. The consonants most in use are given by two movements of the needle; and those very rarely required, such as J, Q, X, Z, by three movements. The word 'you,' for example, is expressed by both needles pointing parallel for Y; the right hand needle moving once to the left for O, and once to the right for U. A different set of oscillations are used for numerals. The gentlemen who direct this novel mode of communication do it so quickly, that all you see is the two needles shaking about and oscillating on their pivots with great rapidity. How the correspondent at the other end can follow such rapid signalling puzzles the uninitiated extremely; but Mr Cooke assured us that a young man, whom he pointed out, had been under instruction only three weeks, when, on going to the

* See No. 75 of Chambers's Edinburgh Journal, new series.

telegraph, he signalled so rapidly that the gentleman at the other end complained that his movements were far too electric, and that he could not follow him. Hoping to put the novice in a similar difficulty, he began signalling in return as fast as hean experienced signaller-was able; but the tyro read off every word as fluently as from a book-so simple is the code when properly understood.”

With such an extraordinary instrument as this at our command, it is impossible to conjecture what may yet be accomplished in the way of rapid communication between the most distant and remote places. "By means of a set of electric wires, extending between London and Pekin," says the authority before quoted, "the privy council of St James's and the Loo-poo board of the Celestial emperor might, without any imaginable difficulty, effect an hourly exchange of official sentiments, and settle the whole details of an important treaty in the course of a forenoon!" But, taking a more sober view of the matter, there can be no doubt that wires will now be laid along all principal lines of railway, and by these, not only the government, but private individuals, will be enabled, in cases of emergency, to communicate and receive almost instantaneous intelligence, let the station be ever so distant. Nay, for a small charge, parties will be enabled to transact urgent business, let it be, for example, between Edinburgh and London, and thus save not only time, but outlay of travelling expenses. There is, indeed, no necessary limit to the application of this novel power; and we rejoice to perceive that means are in adoption for carrying a line across the straits of Dover-the wire, under certain precautions, being equally fitted to convey the electric current through water as well as through the medium of the atmosphere. When this is completed, say the newspaper accounts, an electric telegraph will be established from the coast to Paris, and thence to Marseilles. Upon the successful issue of the submarine telegraph across the English channel, it is stated that a similar one, on a most gigantic scale, will be attempted to be formed, under the immediate sanction and patronage of the French administration. This is no less than that of connecting the shores of Africa with those of Europe by the same instrumentality, thus opening up a direct and lightning-like communication between Marseilles and Algeria.

MISCELLANEOUS ECONOMIC MACHINERY.

Under this head we mean to allude to some of the more wonderful inventions which occur among the vast assemblage of machinery that is now everywhere employed to lessen the amount of human labour. A century ago, such apparatus was of a simple and scanty description: agriculture could boast of nothing like machinery; spinning and weaving were done by hand; our ships were wafted by the breeze, or lay at rest when there was no breeze to waft them; printing, paper-making, and in fact almost

every art, was done with primitive hand-machines; the joiner, blacksmith, and mason, toiled on with patient ingenuity, little dreaming that the time was approaching when a machine, guided by a single hand, would accomplish with ease the work of fifty. Those things which we now regard as rude and primitive, were looked upon as marvels: a common damask loom, or a thrashing machine, was a curiosity worth a fifty miles' journey. Now all this is changed, and there is scarcely a single manual operation which is not less or more facilitated by mechanical aids.

In agriculture, the flail is superseded by machinery driven by steam; and this machine not only thrashes and winnows, but bags and weighs the grain for market. Sowing, drilling, and dibbling machines, of innumerable variety, are now on every well-regulated farm, doing their work with such nicety, that we might almost ascertain the number of grains necessary to the planting of a field. Ploughing has, in some instances, been executed by steam apparatus; and draining and drain-tile making have also come under the same omnipotent sway. Even reaping, one of the nicest and most careful of all agricultural operations, has been successfully accomplished by machinery, which does all but fasten the sheaf and arrange the corn in shocks. Thus one of the homeliest of all pursuits has its curiosities of art in the steam-thrashing mill, in the recently-attempted ploughing apparatus, and in the more delicate and complicated reaping machine. In operations little removed from agriculture as regards nicety of manipulation or delicacy of finish, the potent arm of invention has also been exercising its control. An excavating machine has been perfected in the United States, capable of performing the work of twenty-five ordinary labourers, and that in all sorts of soils unincumbered with rock. Machinery now presses peat into fuel, and fashions tiles and bricks by myriads; it breaks stones for macadamising roads, and dresses their surface for pavement; it sweeps our streets with a precision and rapidity which the scavenger cannot equal; it saws and polishes the marble of the sculptor, and converts the most refractory granite into the most beautiful ornaments. The joiner calls in its aid to saw and plane his timber; the cartwright to finish his wheels; the cooper to build his barrels; the carpenter to fashion and finish his blocks, as in Brunel's wonderful blockmaking machine; and the worker in metals makes the same power roll his material into sheets, square it into bars, fashion it into nails-makes it pierce holes, fasten rivets; directs it, in fine, to cut, file, polish, or stamp, with a rapidity and precision which is all but miraculous.

Again, if we turn to more delicate arts, we find its aptitude still more marvellous and universal. The sculptor and engraver perform their most delicate touches and finest tints by its aid-a few hours producing a delicacy, complexity, and regularity of lines, which the human hand can never possibly accomplish. The jeweller and goldsmith makes it perform his most delicate