the bells have since lain on the ground. One of them is nearly twelve feet in height, and its diameter seven and a half: in figure it is almost cylindrical, except for a swelling about the middle; and the thickness of the metal about the edges is seven inches. From the dimensions of this bell, its weight is computed at 50,000 pounds. Each of these bells has its respective name, as the hanger, the eater, the sleeper, &c. Father Le Compte adds, that at Pekin there are seven other bells, weighing 120,000 pounds a-piece; but the sounds even of the largest are very dull, as they are struck with a wooden instead of an iron clapper.

The Russians, however, have surpassed all other nations in the size of their bells. With them bells form no inconsiderable part of public worship, as the length or shortness of their peals denotes the greater or less sanctity of the day. They are hung in belfries detached from the churches, and do not swing like ours, but are fixed immovably to the beams, and are rung by a rope tied to the clapper. Some of these bells are of truly stupendous dimensions: one in the tower of St John's church, Moscow, weighs not less than 127,836 pounds, being 40 feet 9 inches in circumference, and 16 inches thick. It is used on important occasions only; and when it is struck, a deep and hollow murmur vibrates all over the city, like the fullest and lowest tones of a vast organ, or the rolling of distant thunder. In Russia, it has always been esteemed a meritorious act of religion to present a church with bells, the piety of the donor being measured by the magnitude of his gift. According to this standard, Boris Godunoff, who gave a bell of 280,000 pounds to the cathedral of Moscow, was the most pious sovereign of Russia, until he was surpassed by Alexis, at whose expense a bell was cast, weighing upwards of 443,000 pounds, and which exceeds in size everything of the kind in the known world. It has long been a theme of wonder, and is mentioned by almost all travellers. "The Great Bell," says Dr Clarke, known to be the largest ever founded, is in a deep pit in the midst of the Kremlin. The history of its fall is a fable; and as writers are accustomed to copy each other, the story continues to be propagated. The fact is, the bell remains in the same place where it was originally cast. It never was suspended; the Russians might as well attempt to suspend a first-rate line of battle-ship, with all her guns and stores. A fire took place in the Kremlin; the flames caught the building erected over the pit where the bell yet remained; in consequence of this, the metal became hot, and water thrown to extinguish the fire, fell upon the bell, causing the fracture that has taken place. entrance to the pit or excavation is by a trap-door, placed even with the surface of the earth. We found the steps very dangerous; some were wanting, and others broken. In consequence of this, I had a severe fall down the whole extent of the first flight, and a narrow escape for my life, in not having my skull fractured

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The

upon the bell. The bell is truly a mountain of metal. It is said to contain a very large proportion of gold and silver. While it was in fusion, the nobles and people cast in, as votive offerings, their plate and money. I endeavoured in vain to assay a small portion of it. The natives regard it with superstitious veneration, and they would not allow even a grain to be filed off. At the same time, it may be said the compound has a white, shining appearance, unlike bell-metal in general; and perhaps its silvery aspect has strengthened, if not excited, a conjecture respecting the costliness of its constituents. On festival days, peasants visit the bell as they would resort to a church, considering it an act of devotion, and crossing themselves as they descend the steps. The bottom of the pit is covered with water, mud, and large pieces of timber; these, added to the darkness, render it always an unpleasant and unwholesome place, in addition to the danger arising from the ricketty ladders leading to the bottom. I went frequently there, to ascertain the dimensions of the bell with exactness.

No one,

I believe, has yet ascertained the size of the base: this would afford still greater dimensions than those we obtained; but it is entirely buried. From the piece of the bell broken off, it was ascertained, however, that we had measured within two feet of its lower extremity. The circumference obtained was 67 feet 4 inches; the perpendicular height 21 feet 4 inches; and its thickness, at the part in which it would have received the blows of the hammer, 23 inches. The weight of this enormous mass of metal has been computed to be 443,772 pounds; which, if valued at three shillings a-pound, amounts to £66,565, 16s.-lying unemployed, and of use to no one."

Besides the above-mentioned bells, there are others which have been long regarded as curiosities, chiefly on account of their gigantic proportions. Thus the great bell of Rouen cathedral weighs 36,000 pounds; the brass bell of Strasburg, 22,400 pounds; "Old Tom" of Christ-church, Oxford, 17,000 pounds; "Peter" of Exeter cathedral, 12,500 pounds; the great bell of St Paul's, London, 11,470 pounds; and the celebrated "Tom" of Lincoln, which is more than 22 feet in circumference, 9894 pounds. To these has been recently added another, now the largest in Britain; namely, "Peter" of York Minster, founded in 1845. This bell is five tons heavier than "Old Tom" of Oxford, and seven tons heavier than "Tom" of Lincoln. The cost of it was above £2000: its height is 7 feet 4 inches, and its greatest diameter 8 feet 4 inches. It is placed (at a height of nearly two hundred feet) diagonally in the tower, for the greater security to the building; and above three hundred cubic feet of timber have been used for its support. It may be rung with two wheels, and will revolve entirely, if necessary. The weight of the bell and its appendages, together with the frame, is calculated to be twenty-nine tons; but the strength of the tower is equal to triple that weight.

GIGANTIC AND CURIOUS CANNONS.

As an appropriate sequel to bells, we notice a few of the remarkable field-pieces which have been cast and constructed in various countries since the invention of gunpowder. Such instruments are often regarded with interest, either on account of their stupendous size, or the ingenuity displayed in their construction and mode of appliance. The largest known guns are, we believe, to be found in India, where they were cast during the meridian of the Mohammedan power. One of these brass pieces, known as "The Lord of the Field," now lies on the bastions of the walls of Bejapoor, and is not less than 14 feet 9 inches long, with a bore of 2 feet 5 inches in diameter-thus requiring a ball of 2646 pounds! This stupendous gun was cast at Ahmednuggur, one hundred and fifty miles distant from its present situation, and must have cost no ordinary amount of labour to transport it, seeing that the thickness of its metal is fully 14 inches.

On the ramparts of Brunswick there is a curious brass mortar, said to have been cast so early as 1411. It measures 10 feet in length, and 9 in extreme diameter; requires for an ordinary charge fifty-two pounds of gunpowder, and is capable of throwing bombs of 1000 pounds weight! Another continental curiosity of this kind was the "Monster Mortar" of Antwerp, constructed some fourteen or fifteen years ago, but since destroyed by an overcharge of powder during an experimental exhibition. This huge instrument of destruction was cast at the royal foundry at Liege, under the superintendence of Baron Evain, the Belgian minister of war. It was 5 feet long, and 3 feet 4 inches in diameter, having a bore of 24 inches, and weighing 14,700 pounds. The weight of the empty shell fitted for it was 916 pounds; of the powder contained in the shell, 95 pounds; and of the shell, when fully charged, 1015 pounds. The powder chamber was made to hold thirty pounds; but a considerable less quantity than this sufficed to discharge the shell when the range did not exceed 800 or 900 yards. The weight of the wooden bed which contained the mortar was 16,000 pounds. "The name of 'Monster Mortar,'" says the United Service Journal, I was well selected, for it is scarcely possible to conceive a more ugly or unwieldy implement. With the exception of the mortar at Moscow, the bore of which is 36 inches in diameter, and which, if ever used, must have been employed for projecting masses of granite, the Antwerp mortar exceeded in magnitude any other engine of the kind hitherto known. The immense pieces called Karthauns, which were common on the continent in the early part of the eighteenth century, rarely exceeded between seventy and eighty hundredweight, and projected a ball of not more than 60 pounds weight."

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The largest gun ever made in Britain was one cast a few years ago for the pacha of Egypt. It weighs nearly 18 tons, is made on the howitzer principle, and is about 12 feet long, with an immense quantity of metal at the breech. The diameter of the bore is about 16 inches, and the weight of the ball with which it will be shotted 455 pounds. Immense field-pieces have sometimes been constructed of malleable iron, by fashioning the body of bars, as a cooper forms a pail, and then hooping them closely round by other bars of great strength. The old piece known as "Mons Meg," and exhibited as a curiosity on the upper parapet of Edinburgh Castle, is made on this principle. It is now a wreck, and was for long the only piece of the kind; but some years ago the United States government gave orders for several of the same kind, of much larger dimensions. The largest of these was placed on board the "Princeton" steamer, measuring 16 feet in length, and capable of carrying a ball weighing 230 pounds. During one of the experimental trips with the new vessel, this monster gun was shotted, and fired, when unluckily the breech exploded, causing the death of several of the States' functionaries on board, besides killing and wounding a number of the crew.

Among the curiosities under this head, we may justly notice the steam-gun of Mr Perkins, invented some thirteen or fourteen years ago, and which many of our readers may have seen exhibited both in London and Edinburgh. It consists of an ordinary metal tube, of any calibre, connected with a compact steam apparatus of proportionate power, and movable at pleasure, in any direction, by means of a universal joint. With onefourth additional force to that of gunpowder, it will propel a stream of bullets, whether musket or cannon balls, at the rate of eighteen or twenty a second, for any length of time during which the steam-power may be kept up. One gun is in itself a battery in perpetual and incessant motion, moving horizontally or vertically, sweeping in a semicircular range, and pouring all the while a continued volley of balls with unerring precision when directed point-blank. Two of these guns in a ship would sink any vessel instantly; and what force could pass by such a battery on land? In the models generally exhibited, the noise made in firing is little more than that caused by the rush of a column of steam from a narrow aperture. It is curious to see a small tube of polished steel spitting (for that term is most expressive of its action) forth a shower of bullets and steam without the least apparent effort.

OPTICAL INSTRUMENTS.

To the uninitiated, a common convex or concave lens is a curiosity. Why a bit of transparent glass so fashioned should magnify or diminish the objects seen through it, is a marvel until the optical principle is explained. The same remark may,

with greater justice, be applied to convex and concave mirrors; to the telescope and microscope-instruments with which every schoolboy is now less or more familiar. Common as optical instruments of every description may have become, there are still a few, the ingenuity, beauty, or magnitude of which must strike every reflecting mind with curious interest.

Among these, we may mention the curious metallic mirrors of the Chinese, in which the figures stamped on the back are clearly reflected from the polished surface, as if the metal had been a transparent, and not a dense and opaque substance! These mirrors are generally from five to ten inches in diameter, have a knob in the centre of the back by which they can be held, and on the rest of the back are stamped certain figures and lines in relief. It is these figures which are reflected by the polished face -a fact, the explanation of which at one time greatly amused and perplexed the savans of Europe. One individual ingeniously conjectures that the phenomena may have their origin in a difference of density in different parts of the metal, occasioned by the stamping of the figures on the back, the light being reflected more or less strongly from parts that have been more or less compressed. Sir David Brewster, however, is of opinion that the spectrum in the luminous area is not an image of the figures on the back; but that the figures are a copy of the picture which the artist has drawn on the face of the mirror, and so concealed by polishing, that it is invisible in ordinary lights, and can be brought only in the sun's rays. "Let it be required, for example," says he," to produce the dragon which is often exhibited by these curious mirrors. When the surface of the mirror is ready for polishing, the figure of the dragon may be delineated upon it in extremely shallow lines, or it may be eaten out by an acid much diluted, so as to remove the smallest possible portion of the metal. The surface must then be highly polished, not upon pitch, like glass and specula, because this would polish away the figure, but upon cloth, in the way that lenses are sometimes polished. In this way the sunk part of the shallow lines will be as highly polished as the rest, and the figure will only be visible in very strong lights, by reflecting the sun's rays from the metallic surface. When the space occupied by the figure is covered by lines or by etching, the figure will appear in shade on the wall; but if this space is left untouched, and the parts round it be covered by lines or etching, the figure will appear most luminous." Which of these surmises is the true explanation of the phenomenon, we cannot determine; but either way, the construction of these curious mirrors is confined alone to the Chinese, no other people having as yet hit upon the secret of producing the deception.

Of late years, wonderful improvements have been effected on the microscope, both in the common compound achromatic and in the oxy-hydrogen. Of the former, we have now the