MAGNETO-ELECTRIC APPARATUS.

Sir,-As it is my intention to construct a magneto-electric apparatus similar to the one represented and shortly described by Mr. Rutter, in No. 560 of the Mechanics' Magazine, I should feel particu larly obliged to that gentleman (or any other of your correspondents who possesses such an apparatus,) if he will describe more fully the various parts belonging to it. I should not thus intrude, but that it appears to me to be an apparatus requiring considerable nicety of adjustment; as I know a gentleman who has constructed one, in which the compound magnet is very powerful, but which is, nevertheless, quite inactive: I infer from this that the size of the armature, and the length and size of the copper wire forming the helices, are of considerable importance. He will confer an additional favour if he will inform me how the decomposition of water is effected by this apparatus.

I remain, Sir, yours, &c.
G. S.

Birmingham, May 22, 1836.

BRITISH MUSEUM.

The following petition was presented to the House of Commons on the 2nd inst. by the Chancellor of the Exchequer, and we trust it will be the means of securing to the world of literature and science that access to the treasures contained in the British Museum which a good classed catalogue alone can afford, for it would be futile to institute a comparison between this and a mere alphabet of names. To the Honourable the Commons of the United Kingdom of Great Britain and Ireland in Parliament assembled. The humble petition of John Millard, of Arlington-street, Camden Town, London, Showeth,

That by certain returns presented to your honourable House in the year 1833, it appears that there were in the year 1832, 218,957 printed books, 21,604 volumes of manuscripts, and 19,093 charters in the British Museum.

That several petitions have been presented to your honourable House during the present session, signed by many distinguished scholars and scientific persons, praying your honourable House that a

classed catalogue of these treasures might be printed and published in a convenient form and at a reasonable rate.

That, in the opinion of your petitioner, such a work would be a boon conferred on the world of literature, is indispensable to all who are engaged in literary or scientific pursuits, and is infinitely superior in point of utility to any alphabetical catalogue that could be formed of the books and manuscripts.

That Mr. John Murray, of Albemarlestreet, at the suggestion of your petitioner, has offered to print and publish, at his own risk, classed catalogues of the books and manuscripts in the Museum, if printed in octavo and sold in parts, and that by this means many thousands would be saved to the public.

That your petitioner has witnessed with the deepest regret, that in the report of the Committee appointed by your honourable House to inquire into the condition, management, and affairs of the British Museum, printed among the votes of your honourable House of the 14th inst., there is no recommendation to your honourable House on the subject of classed catalogues, nor any notice of Mr. Murray's offer.

That your petitioner has reason to believe that an alphabetical catalogue of the printed books is now in course of preparation, and that it is the intention of the Trustees of the Museum to print this catalogue at the national expense, probably amounting to some thousands of pounds, to the exclusion of a classed catalogue, which might be printed and published without any demand on the public purse.

Your petitioner, therefore, humbly entreats your honourable House, that your honourable House will be pleased to direct the Trustees of the British Museum, 1. Not to print the alphabetical catalogue of the printed books now in course of preparation, which in your petitioner's opinion would not pay a tithe of its expenses, which no bookseller would undertake the risk of publishing, and which would be comparatively useless to the public. 2. To resume and complete the classed catalogue of the printed books, the preparation of which it appears, from the annual accounts of the Museum, has already cost the nation more than 5000l., and to enter

esteam escapes by the plan before laid down.

The Power of the Wheel-The diameter of the wheel is four feet, and the diameter of the axle three inches. Semi-diameter of the wheel 24 inches, of the axle 1 inch 241 × 112 the weight of mercury in the ball, e, = 1792 lbs. minus 12 lbs. for friction, leaving a working power of 1780 lbs.

Quantity of Steam used.-As one foot will fill each ball, 4 feet will make one revolution, and nine revolutions will wind up seven feet of rope on the axle (3 × 1·1416 × 9-12=7). The number of revolutions made and the quantity of steam used to draw up 1780 feet 112 fathoms, or 672 feet, 112 × 6×7÷9 =864 revolutions; 864 x 4 = 3456 cubic feet of steam used, or 445 lbs. for every foot of steam.

Advantages. In the present engine, on Watt's principle, the steam has an absolutely dead weight to lift from a dead point, accompanied with all its massive machinery, and there is accurately speaking no power gained; for if we wish to raise five tons at one end of the bean, a corresponding pressure must be made on the other end or piston ; but in the present wheel we have only to raise 112 lbs. to increase its power nearly sixteen times.

The only mercurial steam-wheel I can get any account of was one erected by Messrs. Bolton and Watt, on Cardrew Downs, to drive a turning lathe; but the motion was not circular, but alternating, and was rendered circular by means of a crank and fly wheel.

I wish for some one who has got a spirit of mechanical inquiry and speculation to give the wheel a fair trial, and shall be happy to give him all the information that lies in my power. The wheel is pro bono publico.

The insertion of this in your valuable publication will oblige a subscriber and zealous promoter of your Magazine. WILLIAM JONES.

૪૧

Chacewater, near Truro.

MACKINTOSH'S ELECTRICAL THEORY OF THE UNIVERSE.

Sir,-Your correspondent Kinclaven has undertaken "to correct a mistake which," he says, " Ursa Major has fallen into." Kinclaven is very kind to Ursa

Major in thus tendering his services voluntarily and gratuitously to "pull the mote out of his brother's eye," &c. He tells us, that" Laplace has demonstrated (in the 1st and 4th books of the Mechanique Celeste), that when the sun and moon cause the ocean to swell to places under them, there is also a high tide at the same time in that part of the ocean that is diametrically opposite; and all this he has done in strict accordance with the principles of universal gravitation." That Euler, Maclaurin, Daniel Bernoulli, and " every writer of eminence in physical astronomy, has demonstrated the same thing; and all their demonstrations are founded upon the unerring principles of universal gravitation."

Ursa Major begs to assure Kinclaven that he is no stranger to the aforesaid demonstrations, and is of opinion that if he, Kinclaven, can any how manage to translate them into the language of common sense, he will do more for the doctrine of universal gravitation than has been done by the whole phalanx of demonstrations put together.

It may be unnecessary for me to remark, that I am far from giving an entire and full acquiescence to the electrical theory of the universe, at least in the form in which it presents itself to my mind at present. I am, however, still of opinion, notwithstanding what has been advanced by Zeta and Kinclaven, that some parts of this theory carry with them a very strong air of probability. In fact, the objections of these gentlemen amount to nothing. They have given authority for their opinions, it is true, but no argument; this will not do at the present day; one solid argument will go farther with the present thinking, searching generation of men than a thousand authorities.

It appears, Mr. Editor, that this new philosophy is making its way somewhat rapidly. In passing a public lectureroom in the neighbourhood of the Cityroad, a few days ago, I observed an announcement that a lecture would be delivered on the Electrical Theory of the Universe, which I had the curiosity to attend. The lecturer, a Mr. Thorne, I believe, a young gentleman who appears to possess talent and attainments of an eminent order, treated the subject in a manner which at once reflected great great credit on his own capacity and the

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theory he had undertaken to illustrate; and his expositions were received with evident marks of approbation, by what appeared to me a highly intelligent audience.

I remain, Sir, yours, &c.,
URSA MAJOR.

CASTING AND GRINDING SPECULA.

Sir,-In February, 1830, being wishful to obtain information in the art of casting and grinding specula for reflecting telescopes, I took the liberty of addressing you, in the expectation of receiving information on this subject from some of the practical correspondents to your excellent Magazine. However, in this I was disappointed, but in a subsequent volume it was promised, in answer to another correspondent (vide vol. xv. p. 271), to republish a curtailment of Edwards's treatise on that subject, as containing the best directions up to that time published, and which was generally followed by persons undertaking the construction of these instruments. I take for granted this intention was laid aside in consequence of Mr. W. Ettrick (vol. xv. p. 335,) promising to describe (by what method, is left in doubt,) a new discovered process of his own, completely superseding the old methods, and by which success was sure, and the whole processes of casting, &c. was completely freed from the uncertainty hitherto connected with them.*

Now, sir, as five years have since elapsed, and no tidings of Mr. Ettrick's discovery yet announced in your pages, I trust the want of patience will not be laid to my charge by thus calling upon him to fulfil his promise, if his subsequent trials and experiments have verified his theory.

It is scarcely necessary to state, that I have spent the whole of my leisure time, during a period of ten years, in prosecuting a series of experiments, and must confess, have theorised and practised in vain, finding that I am not much nearer perfection than at the commencement; in finding a certain method of casting free from surface defects and porosity of

Our correspondent conjectures rightly. If we do not ere long receive Mr. Ettrick's long-promised communication, we shall still publish an abridgment of Edwards's treatise.-ED. M.M.

metal, my experience teaches me to think little or nothing of the difficulties in figuring and polishing in comparison with those of the casting free from defects, before enumerated.

By drawing the attention of Mr. Ettrick and your numerous readers to this subject, I shall feel particularly obliged.

I am, Sir,
Your obedient servant,
C. G.

Gateshead, July 14, 1836.

P.S.-Perhaps Mr. Ettrick would favour your readers with a drawing and description of his instrument mounted for use, as there is a scarcity of such in mathematical works.

THE CHAFFINCH.

Sir,-To such of your numerous intellectual readers who take pleasure in the study of nature in the fields and woods, the following fact may prove interesting.

This day week, I think it was, it blew almost " a gale of wind." A chaffinch's nest, placed near the top of a high horsechestnut tree in the front of the house, was damaged, and one of the young nearly able to fly, came to the ground, and I caught it. It was old enough to eat of its own accord; and, until this morning, I kept it perched on a hencoop at the back of the house. This morning it had, somehow or other, contrived to get into the roof of a barn, and while I was attempting, by means of a clothes' pole, to get it down, and being surrounded at the time by four or five other persons (children) who were, of course, making a great outcry, for fear of the little orphan inmate being lost-the mother flew down straight from the other side of the house, and, without the least hesitation, seized her little one by the leg, and carried it off, over the house, to the top of the high tree from which it had fallen a week before! I look upon this as rather a curious circumstance of the kind; the power of wing in the old bird is not the least remarkable of its interesting features. I have the honour to be, Sir, yours, &c.

June 16, 1836.

F. MACERONI.

(From the New York Journal.)

A recent visit to Lowell, Mass., has affected me with much surprise, and afforded a high gratification. Extraordinary it may well be called, for here is a city at its maturity at the age of twelve years; here is a spot which seemed almost doomed to perpetual sterility, teeming with wealth; and in that short space the residence of a few straggling farmers, gathering, by severe toil, a scanty subsistence for themselves and their cattle, from an uncongenial and pernicious soil, is transformed into a busy and buzzing hive, with a population approximating twenty thousand, active with impetuous spirit of industry, stimulated by rapid returns of profit, taxing to its utmost speed all the powers of mechanical genius, and labour-saving art; and with a thirst for knowledge and improvement, which seems to gather quickness from sympathy with the movements of the machinery around them, erecting halls, laboratories, libraries, and cabinets, for the cultivation of science; and thus laying a broad foundation for intellectual improvement.

The moral spectacle here presented is in itself beautiful and sublime. The machinery of one of these great mills is not an unapt picture of society. Here are wheels within wheels; bands circling within bands; threads crossing threads; numerous and almost infinitely varied operations going on at the same time; much that is seen, and much that is unseen; mighty and concealed powers working in their subterraneous abodes with a tremendous agency, and sending out their influences to places far remote from their presence; human ingenuity strained to its utmost power, and human care equally concerned in the constant superintendence of this complicated apparatus; the powers of the physical world called into efficient action, moulded, guided, and brightened under the sharpened activity of intellect; the moral every where intermingling in order to preserve harmony and secure the fidelity of the intellectual and physical powers; and all, in all its parts and operations, all resting upon an unseen agency, whose activity is every where detected, but whose power is utterly unmeasured, and

the mode of whose operations the brightest philosophy has not even conceived ; all resolvable into one simple and great law, the law which pervades the whole material creation; hold fast the dust of the balance, the atom floating in the sunbeam, and the mightiest orb which brightens in the firmament; all, where each part retains its place, performs its duty and supplies its contribution, moving on in a beautiful harmony; producing results largely subservient to human comfort, improvement, and pleasure. On the other hand, all these results are defeated, when even the most minute and the humblest part of the machinery fail to perform their proper office; determine to go wrong, or refuse to go at all; when the wheels cease to revolve, or the filaments become broken; or the combination of physical, intellectual and moral energy, felt in a thousand hands, beaming from a thousand eyes, and operating in a thousand hearts, is broken up, withdrawn, relaxed or perverted. Now, this is a striking analogy of human society; this is a world in miniature. Laws bearing a strong resemblance to each other prevail in both. They are universal laws; they are uncontrollable and unalterable to human power or pleasure; they are ceaseless in their operation; and, like the great Being who established them, they are 'without variableness or even the shadow of change."

Lowell is principally devoted to the manufacture of cotton; but it embraces several other important factories; very extensive woollen factories, for flannel, broadcloth, kerseymere, worsted, and carpeting; extensive machine shops for the construction of various kinds of machinery, from that necessary to the furnishing of a cotton mill to railroad cars and steam-engines; together with a card and whip factory, planing machine, reed machine, grist and saw mills, glass works, iron furnace and powder mills, and extensive bleacheries and print works; in all, employing a popu lation of nearly eight thousand operatives, to say nothing of the persons subsidiary to their support and accommodation, and a capital of nearly nine millions of dollars.

The mills in general are of a large size; generally of brick, and seven or eight stories in height, well lighted, ven