Kitabı oku: «The Mirror of Literature, Amusement, and Instruction. Volume 12, No. 323, July 19, 1828», sayfa 4

SPIRIT OF DISCOVERY

FILTERING APPARATUS

(To the Editor of the Mirror.)

A A. The Pot. B B. The Triangular Board. C. The Cover. D. Vessel to receive the Filtered Water. E. Dotted Line, showing the Proportion of Charcoal and Sand.

Herewith I send you an outline drawing of an economical filtering apparatus, suitable for the use of any dwelling. Its construction is perfectly simple, and at the cost of a few shillings in its erection. The pot consists of an unglazed inverted vessel, manufactured at potteries for the use of sugar-bakers, and placed through a hole in a triangular board, resting upon two ledges, occupying a corner in a kitchen or any other apartment. In the inside of the pot a bushel of the whitest sand is to be introduced; which sand, after being washed in a clean tub with about three changes of water, to dissolve and clear away the clayey matter, is to be mixed with half a peck of finely-bruised charcoal. This will fill about one-third of the pot; but before the sand is placed in the vessel, the small hole at the bottom of the pot should have an oyster-shell placed over it, with the convex side uppermost, to prevent the sand washing through. This filters foul water perfectly pellucid and clear very quickly, as I have seen its effects for years with the most perfect success. When the sand becomes foul by time, it can be taken out and washed, or fresh materials can be repeated; great care should be observed not to put more water in the pot than your vessel underneath will receive.

JNO. FIELD.

Effects of Lightning

The analogy between the electric spark, and more especially of the explosive discharge of the Leyden jar, with atmospheric lightning and thunder, is too obvious to have escaped notice, even in the early periods of electrical research. It had been observed by Dr. Wall and by Gray, and still more pointedly remarked by the Abbé Nollet. Dr. Franklin was so impressed with the many points of resemblance between lightning and electricity, that he was convinced of their identity, and determined to ascertain by direct experiment the truth of his bold conjecture. A spire which was erecting at Philadelphia he conceived might assist him in this inquiry; but, while waiting for its completion, the sight of a boy’s kite, which had been raised for amusement, immediately suggested to him a more ready method of attaining his object. Having constructed a kite by stretching a large silk handkerchief over two sticks in the form of a cross, on the first appearance of an approaching storm, in June 1752, he went out into a field, accompanied by his son, to whom alone he had imparted his design. Having raised his kite, and attached a key to the lower end of the hempen string, he insulated it by fastening it to a post, by means of silk, and waited with intense anxiety for the result. A considerable time elapsed without the apparatus giving any sign of electricity, even although a dense cloud, apparently charged with lightning, had passed over the spot on which they stood. Franklin was just beginning to despair of success, when his attention was caught by the bristling up of some loose fibres on the hempen cord; he immediately presented his knuckle to the key, and received an electric spark. Overcome with the emotion inspired by this decisive evidence of the great discovery he had achieved, he heaved a deep sigh, and conscious of an immortal name, felt that he could have been content if that moment had been his last. The rain now fell in torrents, and wetting the string, rendered it conducting in its whole length; so that electric sparks were now collected from it in great abundance.

It should be noticed, however, that about a month before Franklin had made these successful trials, some philosophers, in particular Dalibard and De Lors, had obtained similar results in France, by following the plan recommended by Franklin. But the glory of the discovery is universally given to Franklin, as it was from his suggestions that the methods of attaining it were originally derived.

This important discovery was prosecuted with great ardour by philosophers in every part of Europe. The first experimenters incurred considerable risk in their attempts to draw down electricity from the clouds, as was soon proved by the fatal catastrophe, which, on the 6th of August, 1753, befel Professor Richman, of Petersburg. He had constructed an apparatus for observations on atmospherical electricity, and was attending a meeting of the Academy of Sciences, when the sound of distant thunder caught his ear. He immediately hastened home, taking with him his engraver, Sokolow, in order that he might delineate the appearances that should present themselves. While intent upon examining the electrometer, a large globe of fire flashed from the conducting rod, which was insulated, to the head of Richman, and passing through his body, instantly deprived him of life. A red spot was found on his forehead, where the electricity had entered, his shoe was burst open, and part of his clothes singed. His companion was struck down, and remained senseless for some time; the door-case of the room was split, and the door itself torn off its hinges.

The protection of buildings from the effects of lightning, is the most important practical application of the theory of electricity. Conductors for this should be formed of metallic rods, pointed at the upper extremity, and placed so as to project a few feet above the highest part of the building they are intended to secure; they should be continued without interruption till they descend into the ground, below the foundation of the house. Copper is preferable to iron as the material for their construction, being less liable to destruction by rust, or by fusion, and possessing also a greater conducting power. The size of the rods should be from half an inch to an inch in diameter, and the point should be gilt, or made of platina, that it may be more effectually preserved from corrosion. An important condition in the protecting conductor is, that no interruption should exist in its continuity from top to bottom; and advantage will result from connecting together by strips of metal all the leaden water pipes, or other considerable masses of metal in or about the building, so as to form one continuous system of conductors, for carrying the electricity by different channels to the ground. The lower end of the conductors should be carried down into the earth till it reaches either water, or at least a moist stratum.—Library of Useful Knowledge.

The Sketch-Book

THE MYSTERIOUS TAILOR

A Romance of High Holborn

It came to pass that, towards the close of 1826, I found occasion to change my tailor, and by chance, or the recommendation of friends—I cannot now remember which—applied to one who vegetated in that particular region of the metropolis where the rivers of Museum-street and Drury-lane (to adopt the language of metaphor) flow into and form the capacious estuary of High Holborn. Whoever has sailed along, or cast anchor in this confluence, must have seen the individual I allude to. He sits—I should perhaps say sat, inasmuch as he is since defunct—bolt upright, with a pen behind his ear, in the centre of a dingy, spectral-looking shop, quaintly hung round with clothes, of divers forms and patterns, in every stage of existence—from the first crude conception of the incipient surtout or pantaloons, down to the last glorious touch that immortalizes the artist. His figure is slim and undersized; his cheeks are sallow, with two furrows on each side his nose, filled not unfrequently with snuff; his eyes project like lobsters’, and cast their shifting glances about with a vague sort of mysterious intelligence; and his voice—his startling, solemn, unearthly voice—seems hoarse with sepulchral vapours, and puts forth its tones like the sighing of the wind among tombs. With regard to his dress, it is in admirable keeping with his countenance. He wears a black coat, fashioned in the mould of other times, with large cloth buttons and flowing skirts; drab inexpressibles, fastened at the knee with brass buckles; gaiters, which, reaching no higher than the calf of the leg, set up independent claims to eccentricity and exact consideration on their own account; creaking, square-toed shoes; and a hat, broad in front, pinched up at the sides, verging to an angle behind, and worn close over the forehead, with the lower part resting on the nose. His manner is equally peculiar; it cannot be called vulgar, nor yet genteel—for it is too passive for the one, and too pompous for the other; it forms, say, a sort of compromise between the two, with a slight infusion of pedantry that greatly adds to its effect.

On reaching this oddity’s abode, I at once proceeded to business; and was promised, in reply, the execution of my order on the customary terms of credit. Thus far is strictly natural. The clothes came home, and so, with admirable punctuality, did the bill; but the death of a valued friend having withdrawn me, soon afterwards, from London, six months elapsed; at the expiration of which time I was refreshed, as agreed on, by a pecuniary application from my tailor. Perhaps I should here mention, to the better understanding of my tale, that I am a medical practitioner, of somewhat nervous temperament, derived partly from inheritance, and partly from an inveterate indulgence of the imagination. My income, too—which seldom or never encumbers a surgeon who has not yet done walking the hospitals—is limited, and, at this present period, was so far contracted as to keep me in continual suspense. In this predicament my tailor’s memorandum was any thing but satisfactory. I wrote accordingly to entreat his forbearance for six months longer, and, as I received no reply, concluded that all was satisfactorily arranged. Unluckily, however, as I was strolling, about a month afterwards, along the Strand, I chanced to stumble up against him. The shock seemed equally unexpected on both sides; but my tailor (as being a dun) was the first to recover self-possession; and, with a long preliminary hem!—a mute, but expressive compound of remonstrance, apology, and resolution—opened his fire as follows:—

“I believe, sir, your name is D–?”

“I believe it is, sir.”

“Well, then, Mr. D–, touching that little account between us, I have to request, sir, that—”

“Very good; nothing can be more reasonable; wait the appointed time, and you shall have all.”

This answer served, in some degree, to appease him; no, not exactly to appease him, because that would imply previous excitement, and he was invariably imperturbable in manner; it satisfied him, however, for the present, and he forthwith walked away, casting on me that equivocal sort of look with which Ajax turned from Ulysses, or Dido from Æneas, in the Shades.

A lapse of a few weeks ensued, during which I heard nothing further from my persecutor; when, one dark November evening—one of those peculiarly English evenings, full of fog and gloom, when the half-frozen sleet, joined in its descent by gutters from the house-tops, comes driving full in your face, blinding you to all external objects—on one of these blessed evenings, on my road to Camden Town, I chanced to miss my way, and was compelled, notwithstanding a certain shyness towards strangers, to ask my direction of the first respectable person I should meet. Many passed me by, but none sufficiently prepossessing; when, on turning down some nameless street that leads to Tottenham Court-road, I chanced to come behind a staid-looking gentleman, accoutred in a dark brown coat, with an umbrella—the cotton of which had shrunk half-way up the whalebone—held obliquely over his head. Hastily stepping up to him, “Pray, sir,” said I, “could you be kind enough to direct me to – place, Camden Town?”

The unknown, thus addressed, made the slightest possible inclination towards me; and then, in an under tone, “I believe, sir, your name is D–?”

I paused; a vague sort of recollection came over me. Could it be?—no, surely not! And yet the voice—the manner—the—the—

My suspicions were soon converted into certainty, when the stranger, with his own peculiar expression, quietly broke forth a second time with, “Touching that little account—”

This was enough; it was more than enough—it was vexatiously superfluous. To be dunned for a debt, at the very time when the nerves could best dispense with the application; to be recalled back to the vulgarities of existence, at that precise moment when the imagination was most abstracted from all commercial common-places; to be stopped by a tailor, (and such a tailor!) when the mind was dreaming of a mistress—the bare idea was intolerable! So I thought; and, without further explanation, hurried precipitately from the spot, nor ever once paused till far removed from the husky tones of that sepulchral voice which had once before so highly excited my annoyance.

[The narrater then visits one of Mr. Champagne Wright’s masquerades, where he falls in love with a fresco nun. He receives a billet.]

I stood like one bewildered; but, soon recovering my self-possession, moved direct towards the chandelier, with a view to peruse an epistle expressive of woman’s fondest love. As with glistening eyes I proceeded to tear open the billet, a flood of transporting thoughts swept over me. I fancied that I was on the eve of acquaintance with –; but, judge my astonishment, when, instead of the expected document, the key to such transporting bliss, I read, engraved in large German text, on a dirty square card, embossed at the edge with flowers, the revolting, business-like address of