THE ART OF TURNING.

it has not undergone any change, and shows no signs of corruption.

The animal charcoal which has been thrown into the pond may, when taken out, be used as a manure; and this manure, which, by slow degrees, imparts to vegetables the substances which it has absorbed, is one of those which merit a most attentive examination.

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THE ART OF TURNING:

structed a rude lathe, that would perform all the different processes of elliptic and eccentric turning, at an expense not exceeding that of a common lathe, such as is sold at any of the tool-makers in town; and hence I am induced to believe, that the ingenious mechanic, were he aware of the methods used in the higher branches of the art, would find no difficulty in adding to any common lathe the necessary apparatus.

The work before me, of Mr. Ibbetson, furnishes precisely the information that is required; and the perusal of it, I am sure, will amply repay, not only the amateur, but the workman, and furnish hints for the formation of almost any eccentric figure wished to be produced. There is much to be admired in the beauty and accuracy of the illustrative plates, but much more in the very clear method pointed out to the workman to produce their counterparts. As the work itself contains so many practical problems, it may not, perhaps, be uninteresting to many of your correspondents if some notice is taken of them, and the various purposes to which this part of the art may be applied,

SIR,-Amongst the various works that treat on practical mechanics, I have often felt surprised that so few have been given to the public on Turning, which is not only an extremely useful, but highly ornamental art. For though, of late years, many gentlemen have turned their thoughts to this subject, they have not condescended to publish to the mechanical world the fruits of their labours, and to treat the subject in that scientific manner which it demands: indeed, the only work that seems at all calculated for the practical mechanic in the higher department of the art, is one that is but very little known, but which deserves more consideration than it has hither- Our author gives six specimens of to met with-I allude to a publica- eccentric circular turning, in the like tion, which came by mere chance number of beautiful plates, which are into my hands very lately, entitled, all varied in such a manner, that Specimens of Eccentric Circular every one of itself contains some new Turning, with practical Instructions application of the tool and chuck for producing correspoding Pieces in used, and the whole together forms that Art," by Mr. Ibbetson. It is a a series of examples, whereby the work extremely well calculated to artist may form an infinity of various direct the workman how to execute beautiful ornaments. An account of those embellishments so often pointed two or three of the specimens will out to his imitation in remarkable give an idea of the whole. Plate 2. specimens of turnery, but which, exhibits a specimen ornamented with unfortunately for the mere work- an Etruscan border, produced by a man, are but little known, partly multitude of small circles, arranged owing to the very expensive appara- in the form known, particularly tus thought requisite, and partly to the want of a familiar explanation of the manner by which the various combinations of eccentric and concentric circles may be produced. I will venture to affirm, and, indeed, know by practical experience, that those expensive and highly finished engines are not absolutely necessary to the practical workman, whose object, in the tools he uses, is not elegance, but utility. Some time since, I con

amongst cabinet-makers, by the title of the à-la-Grecque border, and appears at a little distance from the eye like a broad line. In the centre of plate 4. is a star with circular radii, formed by portions only of circles eccentric to each other. Plate 5. is, aspecimen of that ornament which is so frequently seen in watch-cases, and has somewhat the appearance of a wheel with circular spokes, or radii, diverging from the centre. Indeed,

AMEICAN INVENTIONS--BROWN'S GAS ENGINE.

the whole of the specimens form a series of beautiful ornamental engraving, that may be applied with advantage to a variety of useful purposes, such as the embellishment of watches, snuff-boxes, trinkets, &c. It will also be highly useful to the engraver, to form borders, &c. to cards and cheque plates. The examples, moreover, are so selected, that they can be adopted either in part or as a whole.

If this notice of a work deserving of perusal should be the means of raising an emulation amongst our working turners to improve their art, and raise it above what it has too long been, rather as a secondary branch of mechanics, I shall feel happy to have rescued from mediocrity a class of workmen, that, I am sure, want only encouragement to raise their art to a level with others, to which it has hitherto but lent its aid.

If you think some drawings of the

various chucks and tools used in the

art of turning, would contribute to

the advancement of an art of which I am a great admirer, I may, at some future period, send some, with practical illustrations of their several uses.* I am, Sir, yours, &c. G. A. S.

AMERICAN INVENTIONS AND

IMPROVEMENTS.

A Mr. Alfred Churchill, of Batavia, United States, has invented a new Screw, which is thus spoken of in the American papers: "The screw is concave, and meshes, with admirable regularity, with the cogs placed in a circular wheel, which is moved with ease and rapidity, with the application of small power. To show its immense strength, it is only necessary to mention that the thread of the screw, in its evolution, presses at all times upon four of the cogs of a wheel containing eleven cogs, and may be so constructed, if necessary as to encircle five-elevenths of a circle."

The same Mr. Churchill is said to have invented a new and ingenious hydraulic model; its power for raising water bids fair to excel

66

We shall be happy to receive and give them a place.

any preceding principle, where the height required should not exceed the half of the diameter of the wheel used in lifting and discharging the water."

hall, of New York, pretends that he Another machinist called Salstonhas discovered a new Wheel, adapted to all mechanical purposes, but more particularly to time-pieces, the powers of which exceed all belief. It is said to be "founded on the motions of the solar system," and to be

66

66

capable of taking any power, and to any extent;" its cause is selfitself in motion," but " existing," and it can not only "set mate nature to revolve of itself;" cause inaniand, finally, it "will keep a continued circular perpetual motion !!" Who can doubt that this is all a chimera?

The inventor refers to the principle of the invention as "recorded in States;" but we do not find that the Patent Office of the United

any

America have yet thought it worth of the scientific Journals of the trouble of mentioning.

"We have examined," says the Massachusetts' Spy, "a sample of leather tanned in a new mode, by Capt. Charles Munroe, of Northborough, in this county, which is pronounced by competent judges to be of the first quaility. The sample is calf skin, and was tanned in ten days. By this process the expense is somewhat reduced, and the capital employed may be turned much oftener than in the old way. Sole leather may be tanned three times, upper leather six times, and calfskins nine times in a year, in regular business, with no danger of failure or injury to the leather. The liquor for tanning is used cold."

BROWN'S GAS ENGINE.

A Company, upon a large scale, has been formed in the City, for the purpose of applying Mr. Brown's carriages. The capital is two hundred Gas Engine to the propelling of wheel thousand pounds, in shares of ten pounds each, of which ten per cent, is to be deposited in advance, and no more will be required until the pro

IMPROVEMENTS OF LONDON-SCHWEINFURT GREEN DYE.

jectors shall have driven a carriage object, in the progress of the next from London to York, and back again, five-and-twenty years, in carrying inat the rate of ten miles an hour. All to effect some well-adapted and elethe shares are already subscribed gant plan for improving the metropofor, and they expect to be enabled to lis generally; it would surely be well start their first carriage in about two laid out, and an expenditure which months after this date. the most rigid economist of the pubWe still look upon Mr. Brown's lic money would not grudge, if so invention as one of the first discoveries applied. The Athenians, I believe, of the age in which we live, and we dedicated a tenth of the spoils of have not the slightest doubt of the war to the embellishment of their success of the experiment. The city; by which they made it the power applied is so portable, that a wonder of the world, and the resort man of ordinary strength may carry of the wealthy and curious of all an engine of two-horse power upon nations, whose expenditure would his back; and the quantity of power, doubtless make an ample return to therefore, to give velocity, need only the inhabitants of that superb city be limited by the necessity of study- for the cost of its embellishment. ing the safety of the passengers and Our Government hitherto unfortuthe public at large. If it is found nately have managed things differthat a carriage can travel, without ently; but let us hope that it is not danger, at the rate of twenty miles an hour, the necessary power can be applied quite as easily as if it were only required to propel it at the rate of ten.

IMPROVEMENTS, OF LONDON.

too late to expect of them some attention to this truly national object; and that they will by their example, give an impulse to the national taste, which shall extend itself all over the country. Then may we expect, in another century, if the prosperity of SIR,-In one of your late Numbers, the country continue, that our chila Correspondent, who signed himself dren's children will see London another Athens, in elegance of arrangeJulius," has given an outline of a plan for rebuilding London after the ment and splendour of decoration, great fire, by Sir Christopher Wren. with a tenfold increase of magnitude. Should any of your correspondents The idea appears to have been a magnificient one, and worthy of the possess the book alluded to, and will genius that proposed it; and it is favour the public with an outline of much to be regretted that the op- Gwynne's plan, it cannot fail of being portunity was lost, perhaps for ever, acceptable. It will show how far it of carrying it into complete effect. I has been acted upon in our day, and remember to have once met with a will prove, that however lang sugbook published by a Mr. Gwynne, gestions of this nature may lie dorand dedicated to his Majesty, some- mant, in the end it is not labour spent where about the commencement of in vain to point out the means of juhis reign; being a "Plan for the Im- dicious national improvements; and provement of London and Westmin- that though the projector may have ster;" and which, from the recollection I have of it, must have furnished hints for many of the improvements

the mortification to see his plans neglected and apparently forgotten,time and circumstances may at least combine to bring them into notice, and ensure their being carried into effect. J. N.

CHEAP PROCESS FOR MAKING THE

since made, and some of which are • now in progress. The improvement of such a metropolis as London, which may now, without the impu tation of notional vanity, be considered the emporium of the worldthe centre of commerce, arts, and elegancies-is surely an object highly The Schweinfurt Green Dye, which deserving the attention of Govern- has recently acquired great reputament. And if only the sum of three tion' on the Continent, has been anaor four millions were devoted to that lysed by two chemists, M Braconnot.

SCHWEINFURT GREEN DYE.

and Dr. Liebig who have not only discovered its constituent elements, but pointed out how it may be compounded The process of Dr. Liebig, which seems the simplest, we extract from the "Annales de Chimie."

"Dissolve, in a copper kettle, by heat, one part of verdigris, in a sufficient quantity of pure vinegar, and add to it an aqueous solution of one part of white arsenic. A precipitate of dirty green generally forms, which must be renewed by adding more vinegar, or till the precipitate is perfectly dissolved. After boiling this mixture, a granular precipitate will, in a short time, form, of the most beautiful green colour, which, being separated from the liquid, and well washed and dried, is the required colour. If the li

quor, after this, contains copper, more arse. nic may be added; and if it contains an excess of arsenic, more copper may be added, and the process repeated. When the liquid contains an excess of acetic acid, it may be employed in dissolving more verdigris.

"The green prepared in this way has a bluish shade; but the arts often require a deeper shade, somewhat yellowish, but of the same beauty and elegance. To produce this, dissolve a pound of common potash a sufficient quantity of water, and having added to it ten pounds of the colour prepared as above, warm the whole over a moderate fire. The mass will soon acquire the required shade. If it is boiled too long, the colour will approach to Scheele's green; but it always surpasses it in beauty and sple dour."

GEOMETRICAL EXERCISE.

a

A

Let OY be any fixed line drawn is required to prove that the point E within the right angle A O X from is nearest O, when OC bisects the the vertex Ö, and B be any fixed angle A OY; that is supposing O C point in A O produced. From O let in the figure to bisect AO Y accuany line OC be drawn within the rately, and O e to be determined siangle A O Y, and to it a parallel BD milarly with O E, but from a line Oc through B, meeting O Y in D. Com- which divides the angle AO Y into plete the parallelogram B C. and unequal parts, it is required to prove from C draw CE perpendicular to that OE is less than Ó e. OC and meeting OX in E. Then it

SIR,-I take the liberty of submit- place of the wards, shooting the bolt ting, for your inspection, a Lock (for as it goes round. The slits answer which I have obtained a patent,) the purpose of keeping out any false which, in itself, I may say (with the pipe, or skeleton-key, which might greatest mechanics who have seen it,) be introduced. The cap of the lock is the most secure and simple now in is made with a large bush, similar to Mr. Bramah's patent, so as to leave no possibility of a picker entering.

use.

Description of the Lock.

A is the brass plate of the lock. B the pin which goes into the pipe of the key, having at the lower part a circular piece of brass, which revolves round it; this has four slits to receive the corresponding parts of the key.

C the tumbler.

The price of Mr. Bramah's lock is 8s. 6d.; but the utmost which can, with propriety, be charged for mine, is only 1s. 6d. ; while it is equally, if not more, secure. Any of my make I will warrant beyond all possibility of being picked.-I remain yours, very respectfully, ŠAM. ELLINGTON. Wolverhampton, July 24, 1824.

INUTILITY OF THUNDER-RODS.

The utility of Thunder-Rods has, for many years, been an universally admitted fact among philosophers; so much so, that one of the most celebrated scientific controversies in England turned on the important question, whether, in order to make the most of them, they should be terminated by points or by knobs ?

The advantages of this lock will be obvious from the description. In stead of a great heavy key, with a large bit of iron (called a bit,) being required, as in locks of the kind now in vogue, you have a key so small, that it may be attached to the watch- The powder magazine at Purfleet, chain; nor is there any possibility of the bit breaking in the lock, as is sometimes the case, and valuable articles of furniture being thus destroyed or damaged.

In the next place, there are no wards to break or bend; the brass circular revolving talent answers the

though guarded by pointed conducters, happening, in 1778, to be struck by lightning, the Privy Council made an application to the Royal Society to investigate the cause of this accident. A committee was accordingly named of its ablest members, who, still adhering to the hypothesis of