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Artificers' Work.

No. I.

GLAZIERS' WORK.

GLAZIERS estimate the value of their labour by the square foot. They take dimensions in feet,

Notices to Correspondents.

** We shall be happy to oblige any Correspondent with any information he may desire to possess. Letters to be prepaid, and addressed to the "Editor of the DecoRATOR'S ASSISTANT," 17, Holywell-street, Strand.

inches, and parts, or feet, tenths and hun-x. Y. Z.-The following is an excellent solution to preserve dredths. Windows of every shape are measured as if they were squares, and the extreme lengths and breadths are always taken, in

wood:-Mix at the rate of five pounds of chloride of zinc to twenty-five gallons of water. This is the most effectual solution to steep wood in, to prevent the dry rot, even preferable to wood that has been Kyanised.

order to compensate for the waste attending A. B. (Glasgow).-See "Crescy's Encyclopædia of Engineerthe cutting and shaping of their glass.

EXAMPLES.

1. If the length of a window be 4 ft. 9 in. and breadth 2 ft. 3 in., how many square feet does it contain?

By Cross Multiplication.

ft. in.

4 9

2 3

6

1 2 3

10 8 3

By Practice.

ft. in.

3 (1) 4 9

2

9 6

1 2 3

10 8 3

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ing," published by Longman and Co.

J. ABEL (Dublin).-"Gwilt's Encyclopædia" will give you all the information you seek.

D. D.-The "Household Book of Useful Receipts," pub-
lished at 7, Brydges-street, Covent-garden, gives the fol-
lowing recipe for portable glue:-"Best glue, lb.; water
sufficient; boil it in a double glue-pot, and strain; add
lb. of brown sugar, and boil pretty thick; then pour into
moulds. When cold, cut into small pieces and dry
them."

G. A. R.-When a body is shaped irregularly, or when there
are two or more bodies connected, the centre of gravity is
the point about which they will balance each other.
Several answers stand over till next week.

THE LATE MR. HOLTZAPFFEL.-The mechanical world will have noticed, with universal and deep regret, the death of Mr. C. Holtzapffel, while yet in the prime of life, and while in the midst of those literary labours which, incomplete though they be, have gained for him an imperishable name. His last work, "Mechanical Manipulations," has been eulogised thus:-"No work on the mechanical arts produced in this country during the present century is to be compared with this for newness, exactness, and completeness of in6 formation." Workshops, and not libraries, were the great sources whence the author 6 filled his most instructive pages. We can hardly hope to see so great a loss as mechanical literature has sustained by his death soon repaired; but it is some consolation to learn that "considerable portions of the third and fourth volumes have passed through the press under the author's own superintendence, and that he had in great forwardness much of the MS. for the completion of these volumes, which will be submitted to the public at the earliest possible period."

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No. 2.-VOL. I.

and in which he seems to have attained much success.

The approaches to the house have all been re-arranged, separate entrances being provided to the royal boxes, to the boxes and stalls, to the pit, and to the gallery, with fire-proof staircases. The details in every part are also so arranged as to give the greatest comfort, and to enable a large audience conveniently to sit through a long performance, as well as to hear perfectly. This is really as great an advantage to the actor as to the hearer, as, without it, due attention cannot be paid to any representation, however skilful.

While we cannot withhold our testimony to the solidity of the construction, having inspected it in detail, we are bound also to notice the rapidity with which the alterations were completed, the old interior having been pulled down, and the new one erected from the foundations, within four months. This is a great feat, performed by Mr. Albano; and we must state that great credit is due to Mr. Holland, the builder, and Mr. Ponsonby, the decorator, for the rapid manner they have executed the work. The brilliancy of the gas also, it is to be observed, is due to the use of Mr. Low's patent for napthalising it.

Emproved Form of Omnibus.

A

MR. W. B. ADAMs has just patented an improved form of omnibus for passengers, which may be drawn by one or more horses; the front wheels are larger in diameter than usual, but are, nevertheless, enabled to turn or lock, in consequence of the pivot or perch-bolt being placed so far behind the central line of the front axle as to cause such an eccentric movement of the wheels in turning or locking as to avoid striking the body. The entrance door behind, and the central part of the roof, are higher than the two side-parts of the same roof, the height within the central part and in the doorway being sufficient to permit an ordinary-sized person to pass along the interior; the height of the two side-parts of the roof, over the seats for the passengers inside, being as usual. The central raised part of the roof, which thus affords convenient height for headroom, along the centre inside, also forms convenient seats for passengers on the outside, with their feet upon the low sides of the roof. Ventilation can be effected by openings in the front end, or in the sides of the raised central part, or in the upper part of the door. greater number of passengers can be seated ORIGIN OF THE BIRMINGHAM GUN TRADE.- outside with convenience, and such an omniWilliam III. was once lamenting "that guns bus will occasion less labour to the horses than were not manufactured in his dominions, but usual in proportion to weight, by reason of its that he was obliged to procure them from larger front wheels. For the purpose of reHolland at a great expense and with great tarding such omnibus, while descending a hill, difficulty." Sir Richard Newdigate, one of or to assist the horses while stopping suddenly, the members for the county (Biriningham), a brake or clog is applied to one or both the being present, told the king "that genius hind wheels, which the conductor (without resided in Warwickshire, and that he thought descending from his place behind) can bring his constituents would answer his Majesty's into action to press against the exterior cirwishes." The king was pleased with the cumference of the wheel or wheels. The front remark, and the member posted to Birming-end of the pole is furnished with a broad ham. Upon application to a person in Digbeth, buffer, or stuffed cushion, elastic or nonthe pattern was executed with precision, and, elastic, fixed firmly or swivelled to the pole, when presented to the royal board, gave in order to diminish the force of any collision entire satisfaction. Orders were immediately that may take place therewith. This brake issued for large numbers, which have been so may also be brought into action by the driver frequently repeated, that they never lost their of the omnibus, by means of a pedal within road; and the ingenious artists were so amply reach of his foot, and connected by a rod or rewarded, that they have rolled in their car-chain and pulley, with the lever of the brake, riages to this day. In 1813, Government or otherwise connected therewith. authorised the gunmakers of Birmingham to erect a proof-house of their own, with wardens and a proof-master, and allowed them to decorate their guns with the ensigns of royalty. Sir,-In answer to your correspondent for a All fire-arms manufactured in Birmingham receipt to take out glass, I have used the foland its vicinity are subjected to the proof lowing:-American potash three parts, and required by the Board of Ordnance; the expense is not to exceed one shilling each piece; and the neglect of proving is attended with a penalty not exceeding twenty pounds.-Wm. Hutton's History of Birmingham.

TO REMOVE GLASS FROM OLD SASHES.

one part unslaked lime; lay it on both sides with a stick, and let it remain twenty-four hours; the putty will then be soft enough to cut out easily. It will also take off tar and paint, as I had an occasion to prove in this NIAGARA WIRE BRIDGE.-The Rochester neighbourhood, a gentleman having tarred the Democrat intimates that the Niagara Suspension-bridge Company will shortly proceed to the erection of a wire bridge across the Niagara River, the Queen's assent having been obtained. The whole of the stock, 200,000 dollars, has been taken-one-half in Canada, and the remainder in New York and Rochester.

inside of his cottage, in spite, about three years since. The person who has recently bought it employed me to make alterations. The painter refused to undertake cleaning the tar off; the above receipt I used, and took the whole paint and tar off as clean as if the doors had not been painted at all.-Yours, J. G., Croydon.

mercury in metallic connection with the other

Electric Telegraphs in Present Use. element or metal plate; and a galvanic circuit

being thus alternately completed and broken, by the rapid depression and liberation of the key, the index or pointer at the receiving Or all the adaptations of scientific discovery, station is advanced step by step to any rein modern times, to the exigencies of every-quired division on the dial. In our engraving, day life, by far the most important, next to D and E are two electro-magnets fixed on the steam-locomotion, is undoubtedly that of vol- upright backboard F. A ratchet-wheel (G),| taic electricity to the purposes of telegraphic carrying an arbor (c), is placed in the same communication. To trace the successive steps plane as the magnets; two levers (HH) are by which the practical employment of the supported on pivots in the brackets 1 I, and, in electro-telegraphic arrangements now in use order to render the action of these levers have been arrived at, would far exceed the simultaneous, they are connected at a point space we are enabled to devote to the subject; immediately over the arbor c, by a link (a); suffice it, however, in justice to the early from the ends of these levers are suspended by labours of previous discoverers, to notice, that joints, two pallets (b c), which are pressed into there seems to be but little indeed in any of the teeth of the ratchet-wheel & by delicate the more modern systems, however dignified springs; the extent of the action of the pallets, by high-sounding names, or fortified by legis- as they are raised by the attraction of the lative protection, in the shape of "royal letters magnets, is limited by the stops d e, causing a patent," to distinguish them, as regards any dead-beat movement of the apparatus. When novelty of principle, from the first contrivances the key к is depressed by the operator, the adopted by various inventors, including Ro- levers HH are attracted by the magnets D E, nalds, Alexander, Morse, and Davy, who causing the pallets be to be raised; the pallet b already, in 1839, specified his Patent Electro-catching a tooth on the ratchet-wheel, moves Magnetic Telegraph, in which he used clock- the index B through the space of one division. work, acted upon by electro-magnets, pro- The signal, which it is necessary to give to the ducing a step-by-step motion, similar to the correspondent at the distant station, as an intiseconds' hand of a watch or clock, the signals mation that a message is about to be transbeing registered by dots upon a prepared mitted, is conveyed in the usual way, by fabric placed in the machine; whilst that of causing a bell or alarum to sound; and this is Alexander, of Edinburgh, in 1837, was put effected by a slight modification of the coninto operation by means of a key to be pressed trivance hitherto adopted in most of the predown by the finger of the operator, connected ceding electric telegraphs, for a similar purwith the end of the conducting wire, which pose, namely, by the action of a lever, which, dips into a cup of mercury when the key being raised by the attractive force of an addiis depressed, and completes the electric cir- tional electro-magnet, comes in contact with cuit. It is with no unfriendly feeling that we the short arm of another lever, which strikes have thus prefaced the description we are now on a bell; and, by a repetition of the action, about to lay before our readers of the latest of produces any required number of sounds, the electric dial-telegraphs, namely, that of the conventional meaning of which may Mr. Nott, which, we understand, is now being have been previously arranged and agreed erected at the House of Commons for the in- upon. stantaneous conveyance of messages from the various committee-rooms to the messengers' lobby.

In all this modification of previously existing apparatus, we recognise considerable ingenuity of detail; but nothing of an approach towards obviating the disturbing effects of atmospheric electric currents, or of the other now well-known disadvantages attending the transmission of the galvanic current through very long lengths of wire. In this arrangement we have still the trouble and uncertainty attendant on all the systems as yet introduced, wherein the message has to be deciphered letter by letter-a necessarily slow, and, at the very best, unsatisfactory process. In our next number, we purpose giving a description of the latest improvements of a far-preferable system of electro-telegraphic communicationnamely, of self-registering electric telegraphs, for some time past in use in America, and now on the eve of introduction into this country.

Our engraving represents a front view of the dial with its alphabetical circles and pointer; and on the other side is a view of the interior of the instrument with the dial-plate removed, in order to show the arrangement of the electro-magnets, connecting wires, toothed wheel, and pallet movement, alarum detent, and index. The rim of the dial is marked with four concentric circles, containing four several series of the letters of the alphabet, and two inner circles of numbers. With each successive tick of the ratchet-wheel, the hand or index moves through one division of the circles, there being ninety-six equal divisions; and as each of these divisions is marked with a letter, the hand is made to stop in its circuit at any one of the divisions at pleasure, and thus The system of "deflected needles" hitherto to point to any particular letter of the word employed, and which the above arrangements intended to be conveyed by the distant corres- are intended to supersede, we shall now endeapondent. For this purpose, a key resembling vour to explain to the general reader by means that of a piano-forte is employed. The pointed of the accompanying diagrams, illustrative of end of one of the wires in communication with the general principle on which the "needle one element of a voltaic battery, is, by de- telegraphs" are constructed. If a permanently pressing the key, made to dip into a cup of magnetised needle be nicely poised on a pivot,

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