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for a moment, then return to the hand, and back again to the conductor; and by a little management on the part of the operator, it may be made to do so at a distance much greater than that we have mentioned, and during many minutes in succession.

the opposite state. Before the electricity proceeding | or feather will fly towards the conductor, adhere to it from the machine can reach the ground, it must pass from one or both of the outside bells to that in the middle, which is accomplished by the brass clappers suspended between them, being alternately attracted and repelled in the same manner as the pith-balls already described; and thus, in conveying away the electricity, the clappers strike the bells and set them ringing.

Another experiment equally amusing as any of the preceding, and affording one of the finest illustrations that can well be imagined of the phenomena under consideration, is that of the dancing figures. It is performed in the following manner:-(see fig.) a a are two circular plates of brass about nine inches in diameter, or if these cannot conveniently be obtained, discs of wood the same size, and covered on both sides with tin-foil, will answer the purpose. One of these plates, or discs, must be suspended by a chain from the prime conductor, and the other at about four inches below it, supported by a suitable, but not an insulated, stand. Place on the lowermost plate, two or three pith figures of men or women, (which can be obtained at the philosophical instrument makers' very beautifully formed,) and on turning the machine the figures will start up and execute evolutions so rapid and fantastic, that they would be deemed hardly possible by persons who had not before witnessed them. In this case we see the force of gravity in the figures overcome by the attractive and repulsive influence of the electricity they are the means of conveying from the upper to the lower plate; a very feeble current of which is sufficient to preserve at least two of the figures in an erect posture, for any length of time that may be desired. To understand this experiment properly, the room in which it is performed should be partially darkened, when each extremity of the figures will be seen to be illuminated by the current of electricity which is passing through it. If the machine be turned quickly, more electricity will be excited than the figures can carry off; and then a portion will be observed making its escape from the edges of the uppermost plate into the atmosphere. Where pith figures, such as we refer to, cannot be had, their places may be supplied by paper ones; but the paper of which they are made must not be very thick.

It is impossible, within anything like reasonable limits, to give a full description of all the methods by which examples are furnished of electrical attraction, and repulsion, as accompanying every case in which the electrical relations of bodies are disturbed. But we shall mention a few more, and we hope to make them intelligible without the aid of figures.

Fix a short blunt wire into the prime conductor, and to the end of it attach a piece of sealing-wax. If the wax be for a moment inflamed, and just when it is blown out, the machine set in motion, a great number of long and very slender filaments will be separated from the mass; and if a sheet of writingpaper be held about a foot from the wax, the filaments will adhere to the paper in the form of very beautiful net work.

Hold in the hand, about six inches distant from the conductor, a piece of cotton wool or a very light downy feather. On exciting the machine, the cotton

Suspend by a chain from the conductor a small metallic bucket containing water, a tube being inserted in the bottom of the bucket, the bore of which is so small that water will pass through it only drop by drop. On setting the machine in motion the water will flow rapidly through the tube, separating into innumerable drops. If the charge of electricity communicated to the water be tolerably powerful, in a darkened room, it will have the appearance of a luminous shower

A pretty piece of apparatus we often use is made as follows:-Procure some fine spun glass, either Cut the white or a mixture of different colours. glass into lengths of about nine inches, and then place them together, fastening them at one end to a piece of wood or stout wire. If we attach this bundle of spun glass by its stem to the conductor, and slowly turn the machine, the fibres gradually separate until the whole bundle has expanded, resembling a full-blown flower.

It

To these, if we deemed it necessary, we could add many more illustrations of electrical attraction and repulsion. We must not, however, omit the following extremely simple, yet useful, piece of apparatus, which is called Henley's Quadrant Electrometer. consists of a stem of wood or metal, about eight inches long, terminating at one end in a ball, and the other tapered so that it may fit tightly into the conductor. To the upper part of this stem is attached a semicircular piece of some hard wood, or, what is much better, of ivory, on which is a scale of 180 equal parts, reckoning ninety from the upper and lower parts of the scale to the point most distant from the stem. In the centre of the semicircle is a pin, to which is suspended, so that it may move freely, a very slender rod of box-wood, or cane, say, five inches long, a pith-ball being attached to its lower extremity. The use of this instrument will be hereafter explained; but its action depends on the repulsion existing between the stem, when electrified by contact with the machine, and the moveable rod; and in proportion as the pith-ball recedes from the stem, do we judge relatively of the intensity of the charge of accumulated electricity.

THE character of the true philosopher is to hope all things not impossible, and to believe all things not unreasonable. He who has seen obscurities which appeared impenetrable in physical and mathematical science suddenly dispelled, and the most barren and unpromising fields of inquiry converted, as if by inspiration, into rich and inexhaustible springs of knowledge and power, on a simple change of one point of view, or by merely bringing to bear on them some principle which it never occurred before to try, will surely be the very last to acquiesce in any dispiriting prospects of either the present or future destinies of mankind;. while, on the other hand, the boundless views of intellectual and moral, as well as material relations, which open on him on all hands in the course of these pursuits, the knowledge of the trivial place he occupies in the scale of creation, and the sense continually pressed upon him of his own weakness and incapacity to suspend or modify the slightest movement of the vast machinery he sees in action around him, must effectually convince him, that humility of pretension, no less than confidence of hope, is what best be comes his character.-HERSCHEL.

THE VILLAGE OF LEADHILLS,
LANARKSHIRE.

THE village of Leadhills is situated in the parish of Crawford, and county of Lanark, Scotland, at the altitude of 1280 feet above the level of the sea. The prevailing rock in the neighbourhood is greywacké; but at no great distance clay-slate and green-stone are found, and coal within ten miles, at Sanquhar and Douglas. The altitude of the Lowthers, the highest hill in the neighbourhood, is about 2400 feet.

According to common report, the lead mines were discovered by a German of the name of Bulmer, when searching for gold in the banks of the adjoining rivulets. This account is extremely probable; for the numerous hillocks on the banks of the streams which discharge themselves into the Clyde and Nith, bear evident indications of having been thoroughly searched for that precious metal: even so much so that those miners who at present amuse themselves during their leisure hours, in searching for gold, cannot find a soot that has not previously been explored.

The method of searching for gold, is, I believe, the same in every country. However, the one adopted at Leadhills is as follows: the surface of the rock is laid bare; the earth, sand, &c., in its crevices, are collected, riddled, and washed. The water carries away the earthy particles, and leaves those materials which are of greater specific gravity than itself, as flint, quartz, and what gold there may be. The proceeds from one puddle, as it is called, are generally, at the most, not more than a few particles, not larger than the point of a pin; but a man in six hours, at an average, may collect about four pennyworth of gold. Some pieces, however, have been found as large as a pea, or small bean.

These gold-mines, however, were once productive; for history informs us that in the reign of James V. of Scotland, three-hundred men were employed in them; and when that monarch, in a hunting excursion in the adjacent moors, dined in Crawford castle, each of his retainers, for dessert after dinner, was presented, on a wooden platter, with a few bonnets crowns, as the produce of the soil. These pieces were coined from gold obtained in the mines of Glengonar, the rivulet upon which Leadhills is now built. Lead, however, for centuries, has formed the mineral riches of these mines. The vein has more than once expanded to the enormous width of fourteen feet; but I myself never saw it more than four and a half feet, and this was considered by the miners as a very good lead. At present the crip, or annual number of bars, (of one hundred and forty-four pounds each,) amounts to 10,000 in Leadhills, and to about 8000 in Wanlockhead; whereas at one period 35,000 were made at the former, and 15,000 at the latter.

fectly coincided with Newton's determination, that the revolving body was not an accurate elliptical spheroid, but approached infinitely near to that figure. When at Leadhills he instituted a library among the miners, and strongly advised them to subscribe; and with such success, that there is not a workman about the village who is not a member of the library. The number of volumes, embracing the standard works on every branch of science, in 1830, amounted to two thousand, whilst the miners at Wanlockhead, another mining village within two miles of Leadhills, but in the county of Dumfries, possess another library, almost equally extensive. The effects of such institutions have been felt, not only in civilizing the inhabitants generally, but the small village of Leadhills, containing twelve hundred inhabitants, has the honour of producing two men, whose names bid fair for immortality-Allan Ramsay, the poet, and William Symington, the engineer.

Whilst in other mining districts, crimes are of frequent occurrence, none, excepting petty offences, were ever committed here; and whilst the children of colliers and miners are generally entirely illiterate, there is neither a boy nor a girl in these villages, who cannot read, and most of them can write. To whatever cause it may be attributed, (and I think it is due to the taste for reading that has been produced amongst them)—the apparent comfort of the people, the neatness of dress of the children, and the intelligence of the men, cannot be denied. For not only to miners in other parts of the world are they superior, but to the working classes even in Scotland, which is admitted to possess the most intelligent peasantry on earth.

Seeing then that such beneficial effects have been produced by such apparently small causes, might not the overseers of other mining districts, instigated by the example of Leadhills, try to institute reading societies among their workmen? for it will always be found that correctness of moral conduct follows the cultivation and enlightenment of the mind. It is true that the Leadhills and Wanlockhead miners possess two special advantages; they only work six hours in the twenty-four, and have the perquisite of obtaining as much iand from their landlords, the Earl of Hopetoun at Leadhills, and the Duke of Buccleuch, at Wanlockhead, as they can cultivate with the spade. The last might be considered as of hardly any advantage in a pecuniary point of view, as the uncultivated land in the neighbourhood rents at two shillings per acre; but it is still unknown what spade labour can effect, even in the most unpromising circumstances, as will be proved from an account which I have received of the enormous crops that have been produced at Leadhills, and which I communicate as being important, not only in an economical, but also in a geological point of view

The account to which I refer appeared in the ScotsIt is not, however, to facts such as I have menman. It is as follows:-"Mr. John Hunter, Leadtioned, that I particularly wish to call attention, but hills, planted in 1835 sixteen Scotch falls (being the to the mental superiority of these miners over miners tenth part of a Scotch acre) with potatoes, which proin other parts of the world, and to show that even duced the extraordinary quantity of 335 imperial among a class of workmen who might be supposed stones, being at the rate of twenty-one tons to the incapable of profiting by good example, one man of Scotch acre (or seventeen and a half to the English). intelligence may produce beneficial effects, that for And from a square mile of surface, around the village, ages will be felt and duly appreciated. This indivi- it is calculated that 25,000 stones of hay (twenty-two dual was Mr. James Stirling, who in the middle of pounds to the stone), and 12,000 stones of potatoes, the last century, was overseer at Leadhills. Mr. Stir- are annually produced." The allotment system has ling is known to the mathematical world for two been strongly advocated by Mr. Howitt, as being well elegant propositions, which he communicated to the fitted to a considerable extent, and with great advanRoyal Society of London, in 1735, for determining tage, both economically and morally, as confirming the form of a homogeneous spheroid turning round the moral sentiments and social condition of the peoaxis; and which, when applied to the earth, per-ple, in the neighbourhood of Nottingham; but the

THE MEDICINAL LEECH, (Hirudo medicinalis,)

climate of Nottingham is, I believe, as fine as any in England; whereas at Leadhills it is quite the reverse : and still human labour has triumphed over the sterility of the soil and the backwardness of the climate. "When further attention," remarks the editor of the Scotsman, "is now so generally called to the practicability of improving our waste lands, this instance of productiveness at Leadhills, a mountain district higher than the summit of the Pentland range, near Edinburgh, ought certainly to be a strong proof of the possibility of employing our pauper population with advantage to themselves, to the benefit of proprietors, and the general improvement of our country."

The remark of the Scotsman applies to other countries besides Scotland. Several of the lower ranges of hills in England do not ascend to the altitude of Leadhills, and in a lower latitude the region of profitable cultivation will necessarily ascend higher, and probably in proportion, cæteris paribus, to the range of isothermal lines, or to the height of the curve of congelation in that latitude.

"The Duke of Athol has ascertained that whilst the Scotch fir thrives only at an elevation below 900 feet in the north of Scotland, the larch ascends to 1600 feet, and may ascend higher." The same fact I have often observed at Leadhills, for there Scotch firs will not grow, and all other trees are stunted, excepting larches, which grow luxuriantly when pro

tected. What a wide field for the cultivation of timber, both in England and Scotland, does not this discovery of the Duke of Athol's at once disclose? The unprofitable heaths of Scotland, when they are not cultivated, may be adorned with wood; and almost all the hills of England may have larches growing upon their summits. Instead of importing timber from other countries, we may then have more than we require; and thus obtain new resources, from being the exporting nation.

[Magazine of Popular Science.]

THE SEA SHELL.

HAST thou heard of a shell on the margin of ocean,
Whose pearly recesses the echoes still keep
Of the music it caught when, with tremulous motion,
It joined in the concert poured forth by the deep?
And fables have told us, when far inland carried,
To the waste sandy desert, or dark ivied cave,
In its musical chambers some murmurs have tarried
It learned long before of the wind and the wave.
Oh! thus should our spirits, which bear many a token
They are not of earth, but are exiles while here,
Preserve in their banishment, pure and unbroken,

Some sweet treasured notes of their own native sphere.
Though the dark clouds of sin may at times hover o'er us,
And the discords of earth may their melody mar,
Yet to spirits redeemed some faint notes of that chorus,
Which is borne by the blessed, will be brought from afar!
BARTON.

Ir is well known that time once passed never returns, and that the moment which is lost, is lost for ever. Time therefore ought, above all other kinds of property, to be free from invasion; and yet there is no man who does not claim the power of wasting that time which is the right of others. This usurpation is so general, that a very small part of the year is spent by choice; scarcely anything is done when it is intended, or obtained when it is desired. Life is continually ravaged by invaders; one steals away an hour, and another a day-one conceals the robbery by hurrying us into business, another by deluding us with amusement; the depredation is continued through a thousand vicissitudes of tumult and tranquillity, still having lost all, we can lose no more.-JOHNSON.

MAY be known by having six yellowish lines, or striæ, on its back, while the under part is of a greyish hue spotted with black; but, as we shall presently see, these markings are not uniformly found. The Medicinal Leech is common throughout the whole of Europe, but is much more abundant in the southern parts; it is generally about three inches in length. Formerly it was very abundant in Great Britain, but the improvements in agriculture, and the consequent drainage of the land, together with the great use made of it in medicine, have of late years rendered it of less frequent occurrence. On this account great quantities of leeches are imported; these chiefly come from Bordeaux and Lisbor

The prevailing colour of the Medicinal Leech appears to vary according to the nature of the soil on which it is found. In Winter the Leech retires to waters of considerable depth, and seeks shelter in the mud at the bottom; but in the Summer it appears to delight in shallow pools, basking, as it were, in the warmth of the sun: but if the water it frequents is in danger of being dried up by the Summer-heat, the Leech buries itself in the mud at a considerable depth. Just before a thunder-storm, Leeches appear much agitated, and rise frequently to the surface of the water; this, therefore, is considered by the leechgatherers as a favourable time for collecting them.

The property by which a Leech anticipates thunder, has induced some persons to employ it as a species of barometer; but its indications are very uncertain.

The Medicinal Leech appears during its whole life to exist on the blood or other juices of the creatures on whose body it fixes itself; this is not the case with the horse-leech, which lives entirely on the larvæ of aquatic insects, worms, &c. so that the common idea of the danger of the bite of the horse-leech is without foundation.

The horse-leech is exceedingly voracious, not only swallowing worms, tadpoles, &c., but even preying upon its own species. Sixty-five horse-leeches were placed in a glass vessel, and in five days the number. was reduced to fifty-two, and not a vestige of those that were missing was to be discovered.

A number of this species of Leech, inhabiting the water that supplied a trough in which a tench had been placed, fixed themselves to different parts of the body of the fish, and so effectually was the poor tench annoyed, that it was soon deprived of life.

From these habits it would appear, that the name of Hirudo sanguisuga, (the blood-sucking leech,) has been improperly applied to the horse-leech; on this account a recent author has suggested the name of Hirudo vorax, (the voracious leech,) as being more suitable to its nature.

The teeth, or rather piercers, with which the Leech is furnished, are three in number, of a hard gristly substance, and so placed, with regard to each other, as to meet in the centre at equal angles; these piercers are thrust into the skin when the animal attaches itself; not by one plunging effort, but by constantly scratching or sawing upon the surface (assisted at the same time by the sucking action of the lips); in this manner they gradually become buried in the skin, and there remain as long as the creature retains its hold; this movement of the piercers occasions the gnawing pain felt for the first two or three minutes after the Leech has commenced operation.

Leeches are at times so scarce and valuable, that great care has been taken in preserving them in a healthy state and fit for use. The principal art in managing them consists in placing them in vessels

sufficiently large, keeping the water clear, and in removing those which are unhealthy as soon as they are discovered.

THE MEDICINAL LEECH.

Leeches, when applied to the skin, frequently show little inclination to bite, and many plans have been resorted to, to induce them to commence operations, such as bathing the part with milk, &c.; but these methods may be considered useless, and the best plan appears to be, to wash the part clean, and this is the more necessary when any embrocation has been previously applied; but the surest way is to puncture the place slightly, so as to cause the blood to appear. If the little surgeon, before it is fully gorged, appears lazy and unwilling to proceed, it can be usually roused by being sprinkled with a little cold water.

After a leech has fallen off, it is usual to sprinkle salt on it to induce it to disgorge the blood it has swallowed; but as the salt frequently blisters its body, it has been recommended by Dr. Johnson of Edinburgh, from whose work on the Leech, we have obtained most of the preceding information, to apply a small portion of vinegar to the head of the Leech,

instead of salt.

It was long a matter of dispute as to whether Leeches were produced from eggs or born alive, but it is now ascertained that the ova are developed in a singular case, having some resemblance to the cocoon of a silk-worm. The following engraving represents this case, of its natural size: fig. 1. shows the perfect case or cocoon, and fig. 2. the aame opened, with the young Leeches contained within it; it is said that, at times, there are as many as thirteen or fourteen in one case. This cocoon is formed by the parent animal, and by it deposited in the mud or clay which composes the bed of the pool it inhabits. Fig. 1.

Fig. 2.

The fact of the young Leech being produced from these cocoons, although only latterly ascertained by naturalists, was long since well known to the dealers in Leeches on the French coast, who avail themselves of this knowledge of their habits, to multiply them for the purpose of sale.

It was by these means the leech-dealers of Bretagne, and particularly in Finisterre, replenished the ponds in which they preserved those leeches which were intended for the Paris market.

About the month of April or May, according to the nature of the season, they send out labourers, provided with spades and baskets, to the little muddy marshes, where they are known to exist in abundance. These workmen then set about removing those portions of mud that are known to contain cocoons, which are afterwards deposited in sheets of water previously prepared for their reception; here the young leeches quit the cocoons, and are allowed to remain six months, when they are removed to larger ponds. The subjoined graphic account of the mode of taking Leeches at another part of the French coast, is translated from the Journal des Hôpitaux :—

The country about La Brenne is, perhaps, the most un interesting in France; the people are miserable-looking, the cattle wretched, the fish just as bad, but the leeches are admirable. If ever you pass through La Brenne, you will see a man pale and straight-haired, with a woollen cap on his head, and his legs and arms naked; he creeps along the borders of a marsh, among the spots left dry by the surrounding waters, but particularly wherever the vegetation seems to preserve the subjacent soil undisturbed; this man is a leech-fisher. To see him from a distance, his woe-begone aspect, his hollow eyes, his livid lips, his singular gestures, you would take him for a patient who had left his sick bed in a fit of delirium. If you observe him every now and then raising his legs and examining them one after the other, you might suppose him a fool; but he is an intelligent leech-fisher. The Leeches attach themselves to his legs and feet as he moves among their haunts; he feels their presence from their bite, and gathers them as they cluster about the roots of the bull-rushes and sea-weeds, or beneath the stones covered with green and glutinous moss. Some repose on the mud, while others swim about; but so slowly that they are easily gathered with the hand. In a favourhours, to stow ten or twelve dozen of them in the little bag able season it is possible, in the course of three or four which the gatherer carries on his shoulder. Sometimes you will see the leech-fisher armed with a kind of spear or harpoon; with this he deposits pieces of decayed animal matter in places frequented by the leeches; they soon gather round the prey, and are presently themselves gathered into a little vessel half full of water; such is the leech fishery in Spring.

In Summer the Leech retires into deep water; and the fishers have then to strip themselves naked, and walk immersed up to the chin. Some of them have little rafts to go upon; these rafts are made of twigs and rushes, and it is no easy matter to propel them among the weeds and aquatic plants. At this season, too, the supply in the pools is scanty, the fisher can only take the few that swim within his reach, or those that get entangled in the structure of his raft.

It is a horrid trade in whatever way it is carried on. The leech-gatherer is constantly more or less in the water, breathing fog and mist, and fetid vapours from the marsh; Some indulge in strong liquors to keep off the noxious inhe is often attacked with agues, catarrhs, and rheumatism. fluence, but they pay for it in the end by disorders of other kinds. But with all its forbidding peculiarities, the leech fishing gives employment to many hands; if it be pernicious, it is also lucrative. Besides supplying all the neigh bouring medical men, great quantities are exported, and there are regular traders engaged for the purpose. Henri Chartier is one of those persons, and an important per sonage he is when he comes to Meobecq or its vicinity; his arrival makes quite a fête, all are eager to greet him.

Among the interesting particulars which I gathered in La Brenne relative to the Leech-trade, I may mention the following. One of the traders, what with his own fishing and that of his children, and what with his acquisitions from the carriers, was enabled to hoard up 17,500 leeches in the course of a few months; he kept them deposited in a place, where in one night they all became frozen into a solid mass. But the frost does not immediately kill them; indeed bear very hard usage. I am told by one of the they may generally be thawed into life again. They easily carriers that he can pack them, as closely as he pleases, in the moist sack which he ties behind his saddle, and some times he stows his cloak and boots on the top of his sack. The trader buys his Leeches without distinction, big and little, green and black, all the same; but he afterwards sorts them for the market. Those are generally accounted the best which are of a green ground, with yellow stripes along the body.

A GOOD Conscience is more to be desired than all the riches of the East. How sweet are the slumbers of him, who can lie down on his pillow and review the transactions of every day, without condemning himself! A good conscience is the finest opiate.-KNOX.

LONDON:

JOHN WILLIAM PARKER, WEST STRAND. PUBLISHED IN WEEKLY NUMBERS, PRICE ONE PENNY, AND IN MONTHLY PARTS PRICE SIXPENCE.

Sold by all Booksellers and Newsvenders in the Kingdom.

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THE town of Woolwich, at present so well known on account of its naval arsenal, was originally a small fishing village of little note. Its advantageous situaIts advantageous situation on the banks of the Thames, being only eight miles from London, and more particularly the great depth of the river at this spot, capable at all times of the tide of floating the largest vessels, have been the cause of its gradual increase in importance. These favourable circumstances were noticed as far back as the reign of Henry the Seventh, who had a large vessel built here, of a thousand tons burden. It was not, however, until the time of Henry the Eighth that any regular dock-yard was established at Woolwich. After his death the establishment was greatly increased by Queen Elizabeth, and since then it has been progressively improved and enlarged. In the reign of Charles the First, a large vessel was built, of 1637 tons burden, which was formidably armed, and superbly gilded: from its destructive powers, it was called by the Dutch, with whom we were then at war, the "Golden Devil."

Woolwich, up to the time of George the First, continued simply noted for its dock-yard; but in the reign of that monarch, the foundry for cannon was removed from Moorfields, where it had previously been carried on, to the Warren that adjoins the town. The cause of its removal was a dreadful accident, which occurred by the explosion of the moulds, which were in a damp VOL. XIII.

state, at the time of filling them with the melted metal. From this time Woolwich gradually assumed the character of a naval arsenal.

The appearance of the town itself, at least of the older buildings, is far from prepossessing; that part, however, which adjoins Charlton and the common, must be excluded from this censure.

It is to the public buildings that Woolwich owes its importance. The dock-yard extends along the bank of the river, for a mile in length: it contains, besides the dwellings for the officers, a smithery, in which there are two steam-engines, one of twenty and the other of fourteen horse power, the largest being employed in working two large lift- hammers, weighing nearly four tons each; these are raised by machinery, nine inches at each stroke, from thirty to fifty times in a minute: these hammers are employed in forging large anchors, and other iron work connected with ship building; the smaller engine is attached to the blowing apparatus, by which the fires of the forges are excited.

There are two dry docks, one double, and several slips, in which vessels of the largest size are built. A large basin, 400 feet long, and 290 feet in breadth, is also within the enclosure of the dock-yard, together with a mast-pond, a boat-pond, and numerous storehouses, and other buildings necessary for the work. men.

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