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mefa-COPPKR HOILEK.-Toiiud the pressure the boiler will bear before bursting In the direction of its length, wo may assume the whole boiler lo bo a hollow tube of copper, and being capable of sustaining a certain weight hung to It, equivalent to ill* nressure on one of Its circular ends, tending to force or blow it to a distance from the other end-nrfe. "Circle of the Sciences" for further details. To And the area or a circular ring, add the inside and outside diameters together, this sum multiplied bv their difference, and by 8 705-1 gives the area in circular inches, or in our case :—

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1 clrcnL in. of sheet copper has a tenacity = 7K()lb. 0-31 eir. In. „ .. « -?

76 20 X 031 = 83021201b. As the area of the end is

141 x 3-141B

clr. in.

4 or 113 clr In. the boiler would bear a pressure of more than 201b. per clr. In. before parting lengthwise. 'When uniform tbln material is employed, acyllndri«sl vessel subjected to internal pressure (fluid) is almost exactly twice as strong lengthwise as It is clr<-uniferentially—A. ToLnAUSKN.

r237il And 2192.]-STENCILLING ON GLASSWRITING ON GLASS.—Stencil plates may be cut out of thin sheets of metal or cardboard, in the same manner a9 for wall decoration, Ac. If varnish colours are employed, lay them on aa evenly as possible, through theperforation* in tho plate, and harden afterwards in a stove or oven. The metallic preparations used in elm- staining and painting are also available, but rooulre firing in a muffle, or china painter's stove. The articles wanted for the first process can be bought of any artist's colourman ; for the second apply to Sle»srs. Battaro, China Painters, Johnson's-eourt, Fleet atreet, or inquire at tho South Kensington Museum. Should the process commonly called embossing te the one, meant paint the portions of u lass left uncovered by the spaces in the stencil plate with Brunswick black, dip in or oover with hydrofluoric acid, wash in clear water and remove the black ground. Every part that was covered will then present a a polished even surface, the remainder will have been eaten Icto by the acid. If the raised parts are to have a frosted appearance, rub them with a flat piece of marble moistened with fine emery and water. For putting patterns or lines on glass with a wheel, there are two methods, one followed by glass cutters, the other by the engravers on glass. The first-mentioned, rough in the pattern, with an iron mill supplied with a trickling stream of &aud and water, smooth out the rough marks on a wheel of York or Warrington, atone, polish on a wooden wheel of willow or alder moistened with pumice power, an*i finish on a cork wl • l with i» t y and rotten stone. The engraver cuts in and roughs the pattern with copper wheels, aided by emery of various degrees of fineness, and olive or sperm oil, and polishes the portions Intended with leaden discs and very flue pumice powder and water, The wheels or in ills for glaascutters are made to order, but can generally be purchased secondhand jn Clerkenwell or Birmingham. Lathes for glass engravers are never kept in stuck, they also can De found ready for use nmougst dealers. And, now, as a practical man, who has worked at every process described above, let me add one word of advice to those unacquainted with the glass trade. Have nothing to do with it, unless you wish to lose time, temperand money. Publicans' bottles are marked both by the lathe and acid. The former is the better and more expensive


l»74.]-BREWING.—"New Subscriber" omits to state whether he wants information on private or public brewing; if the former " Donovan's Domestic Economy," 2 vols., 8vo, Longman, I2s. : •• Levesque's Practical Brewer and Maltster," 'lit., Leath; " Black's Brewing," 10s. 6d., Longman. For public brewing, Tizzard is the authority price 2is., published by the author.—A Reader or Old Books.

[2375.]—LIFTING SACKS. — " Kustlcua" would aoon get over his difficulty, If he were to use Weston's differential pully blocks Weston's Patent Sack

have a piano or harmonium, tliey will find a perfect fountain of sweets, iu "Calcott's Half Hourr."somo of which the Doctor enjoys with harmonium or flute, content with the incomplete harmony resulting from deficient cello and violin. Cocks and Co.. of Iturlington-strcet, will furnish a l'st; some more are published by Cramer, Novello, Addison, tec. If thev cannot satisfy themselves In this repertory, I don t know what to say. Novello'* new publish " Caawll's Choral Music," which is chokefull of beauties; the concertina takes a flute or violin part well. If I can further assist them I well.—Henry Ussiier, B.A., M.I), Surgeon.

[2W8.] - BOOK-KEEPING. — Messrs. Efflngh am, Wilson.and Co.,are the publishers of the best works on book-keeping and mercantile affairs generally.—A Reader or Old Books.


Molesworth gives, when breaking wel<bt in cwt. at

centre of beam is represented by W

Ilreadtbof beam iu in. ,, II

Depth „ „ „ D

Span „ In feet „ 8

A certain co-efficient ,, K

which lias the value of 7 for teak, of (1 for a«h, of 5 for

English oak. of 4 for red plue, of 3 for elm, of 3 for

larch, of I) for beach.


W = K

S When the load Is placed out of the middle, the load may be Increased, because Its leverage to break the beam is diminished the farther it it from the middle point, and in this case the load hung from any point of a beam Is to tho load which may be suspended from any others as the product of the two lengths into which the second point divides the beam is to the product of tho two lengths into which the first point divides It.—A. Tolhausen.

[3402. 2105, 2KW, 241'-' ]—MANGANESE BATTERY. —So many engines beln* made as to Is to be feared there will be some little disappointments. The battery Is useful for some purposes, particularly bell ringing, but it is by no means the best, and has drawbacks, as may be supposed, from the circumstance, that it 1> an old form proposed years ago by De la Rive, and not found satisfactory. Now a variety of instrument makers have the impudence to call ft their battery, nud extensively; Indeed I think one has patented It. I have carefully tested it lately, and will give all particulars in an early paper. I should not have replied thus to questions put to others, had not E 0. Murray addressed the question to me. 1 will answer his questions as to details in due course. For manganese batteries, however, a very small line suffices ; one or two Jin. rods are abundant.—Sioma.

P404.]—MANGANESE BATTERIES—Asa rule, I think it will be found sufficiently accurate that the

3 zinc should be of tolerable thickness, say — In. of a

IS plate, and be at least as deeply immersed In the flnld aa the opposi'eclcment. That there is no precise rule, seems tolerable evident from the fact that Grove and Smee use about twice the area of zinc to the platinum aud sliver, Poggendorff about equal proportions, and J. Bunsen in the original German form of Ills battery—i.e. the zinc in a porous pot inserted in a carbon cell, not more than one half the area. From these E. C. Murray can take his ;hoice,— 1'. S. Conisuek. [2414.]-ALGEBRAIC QUESTION.—

(x + x + 2) [x (x + 21] = 1»

Multiplying out and dividing by 2,1 have

*« + S*'-r2a--»=0 I observe that 1 satisfies the equation, hence It is divisible by (i - 1) and

x3 + 3x> + 2x-6 = (x-l)(i' + 4x+a) = 0 This last equation give*

(x - 1 = 0, i = 1


x* + 4x + 6 = 0, x= - 9 + J~ 2

Bernardin. [2415 ]-SARSAPA RILL A.—Take Jib. rursaparllla,

Safety Lift ^preferable. I cannot suggest a safer or i 2oz. guincum, 2oz. sassafras., 2oz. liquorice root, cut up 'Ing labour.—F. Russell. I small, place in a large pipkin with 1 quart water;

better means for economising

[2877.]—GEOMETRY.—Please see my answer to query 2435.—Bernardin.

[2383.] — INSULATING POWER OF GUTTAPERCHA—Take air aa 10), gutta-percha = 24-8, Hooper's material 331, and pure India-rubber = about 40.—F. Russell.

[2390.]—INDUCTION COIL.—Tho power of the battery to be safely used with a coll of the dimensions given by T.J. O'Connor, will greatly depend on the perfection of the Insulation, but if it has been made with ordinary care in this respect, be might use 3 piut batteties of bunsen. In one of my coils made with special care for using high battery power with about the same length of secondary wire, I have used as many as fire cells, when 1 obtained a spark about {In. long. I need scarcely remind T. J. O'Connor that he runs considerable risk In using so much, unless he is aware how hiB eoil is constructed.—T. S. Conislee.

[2391.]—GAS STOVE.—When some years ago I made use of gaaonly to heat my workshops, I found a perforated coil surrounded by small aiecesof pumice stone the most effectual plan ; It answered well for working also, and I should think might be applied with advantage to beat the coll mentioned in this Qnery. Tbe only defect with me, was the apparent impossibility of preventing the men from wasting the gas, and thus Increasing toe company's bill, never at anytime too tight.-H. B. M.—f" H. B. M." will oblige by seeding tbe Editor his address]

[2391.]—NICOTINE. — "Maues" can thoroughly de-nlcotlnisetobacco bypassing the smoke through a solution of tannin in water, by which an Insoluble tannate of nicotine is formed.—R. G- Beckett.

(3396/]—CHAMBER MUSIC—"Ophelia and Alma" do nut want better music than Kozeluch, or Rcisaeger'a trios, some are very beautiful, and if they

gently boll until reduced oue-half. Tbe above mate I rials can be had at any herbalist's. Butler, CoventI garden, has supplied me frequently.— Patience And i Perseverance.

1 [2417.]—FERNS.—There Is a very good article on Fern or Wardian cases in "Chambers's Information for the People," with an illustration, and list of plants. Mr. Ward, the originator, wrote a very interesting work on the subject published by Van Voorst. There Is also a little book "Ferns, aud how to grow Them.'' I keep mine uuder glass in ornamental pots and like that plan best, as by it you can grow nearly every description of plant with a little trouble, the only drawback being that of the scented varieties you lose tbe perfume. A variety of ferus mav be obtained any morning at Covent-garden for a few shillings; the hestsoll is sandy peat, water well when first planted, and If the atmosphere of thecase appear to moist, admit a little air.—H. B. M.

[2419 ]—GALVANIC BATTERY.—It is better in all cases where galvanic, action of any strength or constancy is required, to amalgamate the surfaces of the zinc plates before using them. For the first time, rub them over with a piece of cloth dipped in hydrochloric acid until they are bright, and then pour on a little mercury, well rubbing it in until the plate is evenly coloured over, every portion to be exposed to the action of the fluid, bearing lu mind that local action takes place wherever uncoated, which lessens materially tho ultimate power g<ven off, and in some cases almost destroys it.—T. S. Conibbek.

[2421.]— MEDICAL WORKS.-Culpepper's London Dispensary. 1049. 4to.; Culpepper's hphemerlr, 1051. ►ivo. ; aud Galen's Art of Physic, translated by N. 0 , ir..v2, 8vo, are all iu the library of the British Museum, where they can lie consulted. Tho only way of obtaining copies Is by applying to a bookseller such as

Lilly, of Garrlck-itreet, Covent-garden, who deals in old books.—A Reader or Old Books.

[2423.]-AQUARIUM EXPERIENCE.-Theguttapercha tube will not affect Injuriously tbe water passing through it There is. or was lately, a dealer In plants. Insects, Ac. named Lloyd, of Portland-road, who supplies everything required for "Aquaria* The "P.O. Directory" contains the addresses of other dealers, or the materials can be bought at Covent-garden In any quantity. —II. B. M.

[2431]-WEDGWOOD PLAQUES.—The address of Messrs. Wedgwood Is Etrurla. Staffordshire Potteries ; the agenta in London are Messrs. Phillips, Oxford-street.nextthePantheon; and Mr.T.L. Brown, St. Marttn's-lane. between New-street and the church. No estimate of prices oan potisibly be given; some of the old plaques are worth t heir weight in gold, and some of tbe new ones would be dear if put into the scale sgainstcopper—I mean aa regards their artistic value—Engraver.

['.'434.1-MEA.SURING LABOURERS' WORK.— Any book on mensuration and practical geometry will give the information required, but as to field surveying, an hour or two passed iu actual work with a land surveyor will leach moro tbau several days' reading. When I waa young "Bonnycsstls" was the favourite authority, and is not, I believe, yet superseded. I wss reading lately " Geodesy," by the late Butler Williams, and found it an excellent work. -II. B. M.

[243J.]—PROJECTION.—I beg to propose the following solution of the problem :—A cube of lin. edge Is to be represented by its plan and elevation when the planes of two faces are inclined at 50? and 7')"' to HP. (i.) Construct a plane fQB, Inclined at 50" to Hor

Pl. 4.) From a point O O' of that plane, draw on it a per

pendlcular M N.

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c) Construct a plane passing through M N and Inclined at 70 to B. P. This plane will be I" S K, and the intersection of the 2 pi. J" Q R, and P"SR will be an edge ef the cube. d.) Take on that intersection a point A, and from that point draw perpendiculars on the traces of the 3 planes. <•.) Take the length lin. on the 3 lines, hence A B A C, A H, Ac. The cube can be drawn. (There are several solutions); the construction c might, perhaps, seem somewhat difficult, the exiquity of sketch no t allowing me todraw it in cxtctuo, I give It hereafter separately to construct a plane passing through a line M N, M -V, and inclined at a" to H P. Take a point O, Con the given line for vertex of a cone of a", and I construct a plane tangent to that cone and passing by M N, M' N', this plane (or, better 2 planes N T M and N'S M) wUl satisfy the required conditions, (v. Fig. 2.)

This solution may also serve with a slight modification as a reply to Query 2376.—Bernardin.


[2437.]-SIZE AND PRICE OF BOAT.-I want to know the size of a boat to carry three persons, and the proper length of oars and sculls. I should like to know the various prices of a boat between a pleasure and racer, and the prioes of oars aud sculls outriggers?—W. W.

[24S8J-DIAMOND CEMENT.-Can any of your kind readers inform me how to make a diamond cement that will stand hot water ?—Inquisitor.

[2439.]—SLOT CUTTING—A question was asked, may be, about two years ago, in tho English MeChanic, for which 1 looked out some time for an answer in vain. It waB required to designate a tool by means of which slots could be cut in wood with the help of the lathe. Probably some modification of the American twist drill migiit effect this, the Instrument being entered as a drill, and the slot being then completed by lateral pressure? Cannot our obliging "J.K. P." assist us?-F.R.0S.

[244H.1-TOBACCO PAPERS.—Does any brother reader know of a machine for wrapping up tobacco in Joz. and loz. papers as retailed by shop keepers; also of a machine for packing powders into paper pa«kages?-NEViLLE.

Mill ]—LACTAR1NE.—How can I make the lactariue (from milk) into a dry state, so that It will keep similar to dry albumen ?—T. E.

[2442 ]—MOUNTING LARGE CYLINDER.-Could any correspondent offer a hint as to how I cau mount a very large electrical cyliuder ; should caps be metal or wood; and be put over or fixed as plugs iu tbe axon? —Woodleioii.

[2443.]— FLY WHEEL—What weight and size ought a tly wheel to De for a ljin. bore cylinder.— Engine.

r2«4.]_BBARINQB FOR TUNING HARMONIUM.—Will Mr. H. Smith kindU- inform me the best method of laying- the bearings for tuning the hurraonium?— n. W. Fennell.

[2M5.]—GALVANIC BANDS—I would feel very thankful to '• Suffolk Amateur" for tho following information concerning his palranic bands, viz. :— Broadth of bands, what is meant by viippim joints with thread, the meauing of list, and the side to be worn next the skin ?—Galvanic Band.

[1446.] — MEAT PRESERVING. — Would any brother reader kiudly inform me the method of preserving meat, Ac.iu tins, for use during the voyage to Australia/—James Sm:th.

[24470-ARTIFICIAL PARCHMENT.—Cau anyone inform mo how to nake art i liei.i 1 parchment ?— D. Jones.

[244$ ]_PI,ANET NEPTDNE.—The new planet Neptune, was discovered simultaneously by Le Verrier (by calculation and observation!, and by Adams (by calculation only). Has the process employed by Adams ever been published, cither by himself, or in any philosophical transactions! I should like to go over his computations, and humbly to follow the footsteps of the discoverer. —Gimel.

[2W9.]—Oijd COIN—Will some brother reader kindly give me some information respecting tho coin,


a fnll size sketch of which I append? It is made of what appears to be brirts.—E. T. Moody.

[2450]-FASTENING PIN TO BROOCH.—Can any of your readers inform ine how I am to fasten the wire Into a jet brooch? I have tried bath-brick and resin, but It does not auswer. Any information will bo thankfully received.—Yorkshirebite.

[2451.]—DIAHKTERS.—I have a 31n. telescope, of which I have only lately employed the day powers of 40 and 00 for solar observation. I find they show the sun of enormous size, but 1 wish to know whether I am correct in saying that the actual size of the sun, with tnea bove powers is—

S0, * £ = i2& 1 Diameter.
3in. x 00 - 15ft. J

I am of opinion the diameter must greatly exceed these dimensions. The 00 power just fills the field— Amateur.

[2452.]-H AS VENUS A MOON 7-When looking at Veuus, In January last, with my 8£in. silvered glass reflecting telescope, usiug a power of 240, I saw what J at ouce thought to be amoon belonging to that planet, it having a sensible disc, and disappearing eutirely under a power of only 40. Its distance from its primary being, as near as I couldjudge, four to five times the diameter of Venus. 1 asked some one else to look at the planet, and they at once, without a word from nic, said, " Oh! it's got a moon, I never knew it had one' before." Will any of your readeis inform me whether my supposition is at all likely to be correct, as I see in Mr. Webb's little book, that others have aeen a somewhat'like appearance before ?—II. A. C.

[2453.] —FLASK AND BULLETS. — Will some brother reader kindly inform me how to bronze a small powder flask, and also what advantage is gained by greasing pistol bullets before loading ?—Kempster.

foiMZ-GLASS BURNING.—Will someone inform me what is tho best material for muffle for burning glass after beiug stained and painted; and best construction of flue for the earn*, as I am about to replace my old one (which is iron) with a larger one?— Muffle.

[2455]-FRET CUTTING ROLLED BRASS.—Is there any machine known for fret cutting rolled brass, lin, thick. I have tried many, and all fall to cut more than a smooth file after a very Bhort time, and arc only fit for amateurs or toys. Is this owing to the perpendicular motion of the saw, as when nBed by hand it describes an arc; or is it to the machine saw curving inwards, thus losing the projection of teeth 7 Any practical information will be thankfully received. —chip.

[2450.]—OLD COINS.—Can any of your readers in


form me what this coin is? I have two of them, and they are both alike with the exception of the inscription round the edge. If Mr. Batty, or any other skilled numismatist would like mc to submit the coin for his inspection, I shall be most happy to forward it. 1 have also a Coin with a head ou one side, and the inscription •• Voce Populi"; on the other side, Britannia seated on a harp. Can anyone inform me what it is? And I have a medal of Admiral Vernon's, 173'J ; Oh one side there is a fleet of ships, and on the other side Admiral Veruon with a drawn sword, it is a brass medal, and in very fair condition.


[24570—TEA CHESTS —Of what wood are the cheats made in which tea is imported from China ?—Grocer.

[2458.;—PREPARING RHEA FIBRE.—A prize of

G5000 is proposed for the best machine; would some one favour us with conditio us,.tc.— Inventor.

[A reply to the above will bo found in the present number—Ed. K. M.J

[245t>.]-BANKALWOOD—I wish som? some particulars about this woo I? It comes from the Philippine Islands —charles D. S.

[2400]-.METAL PENCIL FOR LATHE.—CM any of your correspondents inform me of some softer metal than lead, which would do to use instead of a black lead pencil In taking figures from tho nose of a chuck on paper,instea I of a tool on wood! It could be cast to shape, and be firm and true, which, however well-fitted, a black lead pencil never is. I ini-ht still act along with tho spring holder.—Waherof.

[2461.]—PREVENTING INHALATION OF IRON DUST.—Will one of our readers give me advice to prevent the inhaling of iron dust? J am a turner, aud am chiefly on cast iron. What do the needle grinders use to prevent the steel dust from entering the lungs? Is there any such thing as magnetised wire told in Loudon? Any advice that would be beneficial would bo thankfully received.—A Turner.

[2402,]— GAS GENERATING APPARATUS.—At the fat cattle show at the Agricultural Hal I, last Christmas, there was a staud with a number of gas jets burning in the window. The gas was generate! in a round iron vessel, about 3ft. across aud Din. or so high. I should be very glad to know whether any of your subscribers know anything of it; whether it is safe; and Whether the gas is liable to deteriorate after burning some time; what the substaLce is from which the gas is prepared ?—C. E. F.

[2403.]—TO MR. SAMUEL JAMES.—Having made a bicycle to drive by the back wheel, like Mr. Samuel James's, I find 1 cannot get it to go on the level road, it seems to me f must have got my swinging bar, or the bar that answers to his chains the wrong length, for he says he cau go with no noticeable pressure on the treadle, while with me ou. the level grouud it is such very hard work. My back wheel is 3ft. 2in., front wheel 2ft. 10iu., crank .Jin., the wheels are 1ft. apart. Is that the cause, or what can it be? Being ajoumeyman carpenter it is a consideration to me, and I want, if possible, to make it go, so as not to have my outlay for nothiug.—E. H. Preston.

[2464.J-TARNISHED SILVER-LKAF.-Will any correspondent tell me how to keep work covered with silver-leaf from tarnishing? About six weeks ago I made a picture frame, decorated with an incised ornament silvered, and hoping to preserve it from tarnish varnished the metal with mastic varnish, but it has already gone a very bad colour. 1 hod always supposed that the discoloration was owing to the action of the air on the surface of the metal, but could the air attack it through the varnish? Mr. Furze, of Hauway-street, produces silvered work which never tarulshes, aud has the appearance of being varnished, and I had hoped for a similar result. Perhaps I am wrong in using silver, and should use tinfoil, but shall bo glad of any advice, as I want to send the work home, and it cannot go in Its present condition— Working Woman.

[2405.].—COIL.—I have made an induction coil with 21b. No. 3D silk covered wire secondary, and 2 layer No. 10 primary, and can only get a spark (with 4 Groves's cells) of about 11a.; is that what I may expect? Would it spoil the coil to add 21b. No. 30, as I wish to get a larger spark; and what would be the best battery to use for strength aud freeuesa from noxious gas, which 1 fet-1 in Groves's very much? If "T. S. C," who replied to "Nemo," in No. 2, Vol. II. (or any other of tho many scientific readers who seem to take a delight In kindly Instructing ignorant young meu like myself), would kindly answer tho above, I should be greatly obliged.—Induction.

rMfl«J—ON SHEATHING IRON SHIPS WITH COPPER.—Many yearn ago I designed a method of sheathing Iron ships with wood, for the purpose of protecting them from corrosion and fouling by coppering the wood sheathing. This was communicated to the THmei. I think about 1802, but, straugo to say, not iuserted. Being too much engaged in working other patents at that time, I did uot patent this, which has since been adopted in the Royal Navy. Can you, Mr. Editor, or any of my fellow correspondents inform me tho date of the first publication of this plan for preserving iron ships ; and is it now practically superseded by sheating with zinc? Does zinc rapidly become foul /—the Harmonious Blacksmith.

[2407.]—DR. KITCHENER'S GRAND PIANO—I see an inquiry, No. 2273, for the late Dr. Kitchener's telescopes. May I also inquire what became of hiB grand piano? This instrument, I was informed, had the harpsichord action in addition to hammers, and several other musical instruments combined with it, which were performed on by the manuals and pedals. 1 should also be glad to be informed what has become of Earl Sunhope's huge uulchord grand piano; This instrument which was from 10 to lift, long, was thought an int resting production of acoustic science in Its day.—The Harmonious Blacksmith.

[2408.]—ANATOMY.—Can any one recommend me a good nook ou surgical anatomy, suitable for a wouldbe medical student? Please say price aud publisher. —busy Bee.

[2409.]-WALKIXG TOUR-I think of making a walking tour in the south of England, a lew hints would be acceptable.—Busy Bee.

[2470.]—HATCHING MACHINE—How can I make a compact hatching-machine? A rough Bkctch would be valued. —H.

[2471-] - SUMMER BEVERAGES. - Will some brother reader give a good recipe for making spruce and lemonade for summer drink 7—S. U. Ddston.

[3472.]—DYE FOR SILK PLUSH—Can auy reader inform me as to the be.-.t method of dyeing black silk plush?—J. LambeRt.

[2473.]—TURBINE.—Will one of your readers inform me if a turbine is suitable for driving a lathe and other amattur machinery, and, if so, what fall it would

require to produce, sav. A h p.. and where the best are to be obtained ?—T. W. Boord.


any brother reader be good enough to give the formula? for calculating the quantity of water thrown bv. and the h.p. required to drive, an Appold's centrifugal pump 7-R. H. M. ^

[2475 J-PRINTING WrTn COPPERPLATE— Can any correspondent tell mc the way to print with a copper plate?—Tom Tit.

[M78.] — CLEANING SOFT WASTE. — Will some kind reader inform me of a method for extracting the grease from the cotton that is swept off tho floors of cotton mills, so that the soft cotton sweepings may be worked over again ?—John Wild.

[2477.]-AIR STOVE.*-] with to know the amount of gas saved by using an air stove {i.e., a stove in which the gas Is mixed with air previous to combustion) instead of a common ring burner; or. in other words, when burning the same quantity of gas what is. approximately, the advantage in increased beating effect?

T247K] — PITCHING AND TRIMMING COG WHEELS.—Would Mr. BaskcrviUc or some ouc kindly give us some information on the practlea[ method of pitching aud trimming cog wheels just as it is done by any regular millwright 7-T. Grady.

[2479.J-MUSIC PUBLISHING—Which would be the cheaper process of publishing some music, by music type or lithography? Tbs music which I thua want reproduced is at present engraved; it would, therefore, be good copv to sel up from, or, I suppose ffor I know but little of lithography) to get " transfers * from.—Clerk.

[2180.1-STAMPING—I should be obliged if any of your numerous readers could toll me the chief compounds of a good stamping Ink, such as that used at the Poet-office, for it must be perfectly Ineradicable? —clerk.

[2181 ]-IS GUANO INJURIOUS TO HEALTH Could any brother subscriber inform fne if thev ever knew Peruvian guano (Cbincas) to nffect the health In any way, and if so In what manner?—Cape Horn.

[2482.] -FUEL FOR PORTABLE ENGINE.—I have a 6-h.p. portable engine. I wish to know whether tho using coke for fuel destroys the flre-box more than coal; if so, what per cent? Coals cost here 23s. per ton; coke, 10s. per ton.—Surscrirfr.

[2483.]—BUOYANCY—Supposing a tin tube exactly Oiu square and loft long, what weight would it take to sink it 4io. in the water; also, what is the weight required to sink a cubic foot of air just to the level of the top of the water 7—Oke In A Fix.

[2i84.]-C0MPRESSED COAL -I shall feel obliged If some of your correspondents will kindly give me the best and cheapest way of making small slock coal into blocks for using in engines, &c,T>y some process which is *' not a patent," and Inform me where I could get the machine, or see the way It is made?—A SubScriber.

[2485.]—GALVANIC ENGINE—Can any one oblige me by informing me where I can get any information of a galvanic engine, invented some years ago at St. Petersburg, for propelling vceels? I believe a model was shown at the Exhibition of 1851.—Old Salt.

[2480.J-RUBBIXGS AND SQUEEZES—Can any reader kindly tell me tho best way to take rubbings aud squeezes of inscriptions, and engravings of bells in a belfry? Where can long strips of suitable paper be bought, and what is the best way of fixing the same whilst taking the rubbing 7 What kind of clay is the proper to use, and how should I apply ft ?—T. A. T.

[2487.]-ASTRONOMICAL—The 7-inch Newtonian belouging to a friend persists in showing Jupiter, Sirius, &c, with a glare of light round them; can "F.R.A.S." or some other gentleman explain why? Jupiter fhows a clear neat disc, well defined; but after sunset a glare begins to form round it, aud sometimes extinguishes his satellites. Sirius also shows a very minute disc, well defined; but also has a similar glare, or cloud of light, round it. The speculum is only partially silvered, and the telescope only used with a single plane convex lens for au eyepiece. I may remark that increasing the power from 00 to -100 did not either increase or decrease this glare of light, and which presents Jupiter u If he was in the centre of a bright nebula. Au answer would greatly oblige my friend, and being unable to give one mvself, I appeal to "F.R.A.S.," Sir. Proctor, F.R.A S., Mr. Fothergill, F.R.A.S., Mr. Denning, and our other correspondents, for one—a Urs£ Minoris.

[24S8.J-ASPH ALTE FLOORING—*' Gulllaume" appears to have ignored my question to him under the above heading, Qy. 2001. If he cannot answer my question, can he substantiate his own stalemeut? If not, he ought to state his authority—Sergius.

[$m.]-VARNISH FOR PAPER—Will some one of your numerous correspondents kindly inform mc, through the medium of your columns, how to make a varnish suitable for paper, tha»: will fold without cracking, bear heat and pressure without sticking, and contain nothing injurious to bright steel goods; or I shall be glad to know where such varnish cau be obtained?—Geo.

[2400.] —VELOCIPEDE WHEELS.—I should be very greatly obliged If any of your readers could Inform me if there Is any chance of tightening the spokes of the wheel of a bicycle, loosened by the oil getting to them; and also as to the best manner of oiling such machines when the hind wheel runs loose on the axle T My plan of oiling has been with a hole drilled through the nave, and a brass tube inserted.—D. B.

[2491.]-THE EYE—Would Dr. U*sher tell me how I am to keep the patient's eye steady, while taking amole or fire off the eyeball ?—I. N. G.

[2492.J-BENNETTS CHUCK—Would "J. K. P." explain how the arUcle caught is set true in this chuck, as I •'■(• the screw travels in the sliding piece (piece or pieces?)—I. N. G.

f2t<K]-WAXING ENGRAVED BRASS PLATES. — Would "Engraver" tell me how to produce the beautiful gloss 1 Bee upon the wax of some newlyengraved plates? as it always comes dull off the stone and polishing-puff with me, aud If I try heat 1 Invariably »poil tue smooth surface of the wax — I314CIBEB.

|v>(94i_pASTE FOR STRAP FOB CARVERS' TOOLS.—Many thank* to "Gulllaume" for hia recipe for carvers' squeeze wax, which I find to be very Rood. Would he or »ome one also Inform me, If in hl« power, or any other reader, of the beat method of making a paste for strap for strapolng carvers" tools on, *o as to leave the tool bright ami keen; also, the best method of obtaining designs for carving natural foliage—it from books, where to obtain such ?—C. J.

r-'*9S 1-PAPER STAINING—lam ahuuc painter, and have at times found great difficulty in matching colours to paper hangings, for coraice-s of rooms. Ice. Would any brother reader, a paper statner, be good enough to inform mo, through your columns, what are the principal colours paper stainers use in the manufacture of paper hangings, viz., what whites, yellows, blues, Ac? It would be great assistance to country painters to know.—Haiimony.

(24961—TO "MU3."—Would "Mua"bekiQdeueugh to help me out ot a little difficulty? I started with every requisite for taking glass positives. Sly success was above my expectation. The following week I .rot half plain glasses; the third almost plain The titrate bath I made up every week with a plain 50 srrain solution, new developing and fixing solutions.— J. B.

r24or]_TO "A THINKER."—Would "A Thinker," who describes bis excellent velocipede on p. 155, No. 3, Vol. XI of the English Mechanic, kiudly give the dlmeneioue as follows, and oblige one much interested In the construction of velocipedes, and doubtless many others —Width of Irame at seat; width between the wheels; length of crauk; distauce of bar (on which the lront levers work) from the seat; also height of said bar from tho grouud; length of levers ?-coji


riM».}-TRLE8COPIC QUERIES.— Can any of Your subscribers inform me where I con obtain ItamsJen's eyepieces, and what is the probable eost? How can I deepen the colour of my sun-glass, which is red; or can it te coloured any different tint? In rclcrence to "Jupiter "' does he not find the two higher powers of his telescope unsuitable for tho planets, especially the higher power of 270? I should think the maximum power' which his telescope will bear in excellent weather. 90 as to ensure good defluitiou for the plnueta

e planting of gum trees InAlgoria a considerable trade iu North

will be 130; and Ibis power will have a limited field of view.—Willi Am Bagulby.

[24991-APPARENT ANOMALY. — Will any of your readers explain to me the anomaly there Is In the following case:—In all calculations respecting cotton spinning, tho avoirdupois lb. is the standard; and we are tolci that It coulaius 7W)grs. only, mid that Jlgrs. make ldwt., andaidwu. loz., and 16oz«. lib.: now, 2* x 20 x 16 = 7ftSo, which gives us GeVgrs. too much in lib. \ Will some one be so good as to explain this ?— Howard Habebghaai.

[25<>o.]—PAINT.—Will any of your numerous readers | kindly inform me what lire the ingredients uecessary to form a good lasting paiut; in wbut proportion should they bo mixed; and if any difference is necessary between the first or priming coat, and the last or finishing coats; if so, what is it? The above is for painting pitch pice. What varnish is the best to stand on pitch pine grained 0.1k! How can I detect any Inferior or adulterated paiuts, or if petroleum or other oils are used ?—Subveyos.

[?o01 '—INDUCTION COIL.—Will "Sigma" kindly assist mo out of a little difficulty? I havejuBt completed an Induction coll, but 1 cannot make contact between tho point of the screw ami the spring. The Instrument is of the vertical kind; the bobbin rests on a little table, supported by four brass pillars. The points of cantact are 1 nt platinised: the extremity of the screw is Iron, which rets against the spring, which is steel. The hammer is a piece of soft Iron soldered on the spring. 1 cannot see why it will not act, for if I place a piece of irou ngalust the screw, and allow its extremity to touch the spring, it will immediately commence lo work.—Thomab J. O'connok.

[2505J-C1RCULAR DISC.-I am much obliged to "J. B." and "S. B." lor answering my query according to their understanding of it. But it is nut oiniply a question of proportloual areas; and as 1 should feel thankful if "Bernardiu" or some other able mathematical correspondent will notice it, I repeat my query :- Required the size ot a circular disc, to be fixed with its centre in the boundary or circumference of a circular orifice, 1ft. diameter, so that half the area of the orifice is coveted by the part of the disc that projects over the orilicj. I liud "E. V. V," Louvain, submits a problem somewhat pertinent to my query (.No 2.1!ij), and which no one has yet noticed.—O. B. Hobker.

observed, deslltuie ..C odour, which plsysi»u'ulu^r"'" a part, often overlooked, in our Ideas of the flavour of particular objects In one series of experiments the Solutions were take., freely into th«m;mtb. rolled over all parts of the membrane lining II, and then discharged. In a second scries the solut oua were more carefully applied to the surface of tho tongue XZ l.y meais of. camel's hair brush twasfound in both eases that when a difference of :2 5 Per «»'• existed between the standard solution and the exptn mental one. the observers were able to formLa correct judgment on the point that there was a difference In 53 per cent, of the trials, but wl.en there was a differenco between tho two solutions amounting to 10 per cent, the answer, were rightly given iu 80 per cent of all the trials. A more correct Judgment was given when the stnndard solution was tasted before than after the experimental one with common salt and ouiulne and the acutcness lu the perception of a dl (Terence was greater when the trial soluti,.n was stronger than when weaker, but the opp -site held good for the other substances.

ASHWORTH'S PATENT LOOPED BINDER PORTFOLIO—We can very heartily recommend this binder (which has been sent us by Messrs. Ashworth, Brothers, of 1, Ashley-lane, Manchester) to our readers. It Is cheap, simple, eanuot easily get out 01 order, holds every leaf securely, aud yet can be opened at anypirt perfectly flat. Its principal advantage, however, is not only that a person can bind bis own serial literature, but that he can bind it as he purclmies if. thus effectually preventing the loss of copies and the consequent anuoyauco of procuring back numbers. Messrs. Ashworth prepare a binder especially lor the English Mechanic (both old size and new'haudsomely got up and lettered with tho title outside

GUM TREES—The bids fair to lead to i_

African timber. The Eucalyptus, or gum tree, was introduced by M. Reinel from Australia in lbM, and thrives wonderfully in Algeria. It s a general rule of vegetable growth that tho more rapid the iucreasc the less dense the wood, but the opposite Is the case with the Eucalyptus. It grows fast but Its wood Is at least as hard as oak. A gum tree of eight years growth will contain as many cublo lect of as solid limber as an oak of ulne times that age. At present M. 1 rattier is actively promoting its cultivation,

INDIGENOUS MEDICINAL PLANTS OF INDIA—The Secretary of State has authorised Mr. Hrougliton, the Govenirueat Qulnologist at Madras, 10 investVate the properties of me Indigenous medicinal plants of India. This is a most interesting and Important brauch of science—important to tho people ot India, whether regarded iu a sanitary point of view, or as a meanB for developing tho resources of the couutry,—and wo are very ».'lad to see the Madras Government has given it the attention it merits. Mr. Broughton appears to have carte blanche given him in all arrangements connected with the observations, aud the results arc to be embodied in an annual report to the India Office. WATERPROOF FACING FOR BRICK BU1LD

1XGS Tliin invention is intended to prevent the

brickwork of houses absorbing moisture, and Is to bo used instead of slates or compo. It consists lu moulding terra eotts, stoneware, or other plastic waterproof maturial, into slabs of convenient size and shape, aud working these slabs in with the biickwork somewhat after the manner of working facing bricks. One slab is made of such a shape that its edge, when placed on thnt of another, shall rest against a projectin" piece flush with the back of the slabs when superposed; by these means, any water that might accidentally enter at the joints of tho slabs, Is prevented from entering the brickwork. If desired the slabs may be glazed.

TREATING AMMONIACAL GAS LIQUOR.Thc liquor is raised by injected steam to 212" rah. Hydrated oxide of irou, sulphate of irou, or lime are added. The ammoniacal gas passes off, and Is arrested by the purifying substances used, if lime only Is employed iu the boiling, the liquor is purified by the addition of sulphate of irou, until no further precipitate is thrown down. The precipitate formed is available for a pigment; from 2 to 201b. of sulphate of iron may be required for 20 gallons of the liquor, according to its strength. The ammonia arising from the liquor is taken up by dilute sulphuric acid mixed wrth sawdust, spent tan, or shoddy. The iron is used for the purpose of removing the sulphuretted hydrogen.

MR. HAMPDEN'S GOOD FAITIt. —Both Mr. Hampden and Mr. Carpenter assented to the details of the experiment recorded by us last week, as con

rect oy .Ur. Carpenter and Mr. riainpdeu, stiosv tll'J ceutrnl signal more than 5ft. above tho Hue of the twj extremes, these gentlemen coolly claim the vlotory. and threaten to bring an action against the Editor of tho Fitld (who was appointed umpire by Mr. Hampden himself) for fraudently deciding against them 1


A Curious new tube-dwelling Stentor is described and figured in tho April number of the Monthly Microscopical Journal. In the same number Dr. Carpenter dDscribcs the structure of a very peculiar fish ovum.

M. Gacriel' Rivet has found that the spores of puccinia graminis, the fungus which causes one form of "rust" on our cereals, will not reproduce the fungus en the same plant; but that when sown on the berberry, they produce orange-coloured spots of <E:idium berberiilit, which in Its turn can be propagated only on cereals, when the original »»mni« is again produced. This fact (says th^ British Medical Journal.) points to rich stores of materials for experiment and discovery.

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THE SENSE OF TASTE.—The sense of tasto has rarely been submitted to scientific examination, or at all events has attracted far less attention than its aUter senses of sight and hearing, perhaps on account of the impossibility of treating it msthemnticiilly. That it differs to a remarkable extent In different individuals is, however, as every culinary artist would acknowledge, a matter of fact; aud it is also well known that it is capable of extraordinary cultivation in some men, as shown by wine and tea-tasters obtaining lucrative posts from the delicacy of their discrimination. Recently Dr. Kcpplcr has published a paper In Pfluger'a "Archives of Physiology," in which he gives the details of a number of experiments beperformed with a view of determining the limits of gustatory discrimination for sapid substances iu various degrees of concentration. In these experiments he first made a standard solution, and then successively employed weaker or stronger solutions, which were tasted with due precautions, sometimes before and sometimes after the standard solution, until no perception of flavour was distinguished. The substances ho selected were common salt, quinine, phosphoric acid, aud glycerine, all of them, be it

Crixikai, Litebatuxz.-j. H. T., W. F., Dr. U., Suburban Ho doulit the subject is a painiul and an important one (see lcltter, page 63, last week), but there are reasons why the controversy should not be continued, and the denunciations uttered in our columns. Verily the originator and Editor of the Illustrated Police Xties has Ins reward. Probahlv Parliamentary action will be taken on the matter.

B. C. (Southampton).—Coins—No. 2, denariuj of Gordtanus Pius The ether two are too indistinct, and a reply can only be hazarded; they are not worth illustrating. Try and decipher the legends.

WmioLM.—■ Coin struck for the Turkish Government for Egypt. The characters are Arabic.

Tau— Coin struck by the Russian Government for Finland.

OL» Coins.—"Flint" and "Taffy." Your queries will appear next week. .

F. J. Biggs.—Queries are frivolous. We do not reply by letter. ,

Music—Replies would occupy more space than so elementary a subject deserves. Consult any musical instruction book.

A Yot'NB SinsCElBEa —See back numbers.

Cbi Saoeb.— There is no "short and easy method. Pitman's is the best, but difficult, as everything is that is worth attempting.

G. S. Coplanu.—Try nitric acid.

Staeh.—Basv enough. Reduce to the lowest term; In this case farthings, and multiply the result by itself.

Hearty.—Send your address, that we may return your stamps. We do not insert puffs.

T. J. O'connor.—The first and lait four.

Electric Pike.—Sec back numbers.

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theory aloue, and that it had never, as far as he knew been tried. Now, tho lact really is, that in a little treatlBe published by "Parallax,' and which we (rVM)bave now iu our possession, with Mr. Carpeuter's uiuue on the title-page, in his own handwriting, nu experiment similar iu its nuluro is described as having been made on the very same piece of water as that on which we were thou occupied, with a result exactly the reverse of that which recently occurred Mr. Carpenter was, lu fact, engaged to deoldo a disputed question, of which he aud his principal professed to be practically ignorant, although it was iu print on the authority of the head of their sect, that it had already been tried In the same locality ; ami this must hurt licen Ihrn Horji to Mr. Carpenter, anj hit since been admitted him in our presence. The good faith and perfect fairness of Mr. Carpenter were not, therefore quite of the nature we then believed them to be, and we have no hesitation In affirming that he was a most improper person to be selected to aot as referee in such a matter. Tho deception was, to Bay the least of it "unscientific"; yet Mr. Carpenter and his master. •• Parallax," both profess to be ardent In the cause of science; and that it hns recoiled upon their heads can cause no regret to auyouo who values the truih. Although the diagrams of what was seen bv the telescopes used at both ends, and acknowledged to be cor

C t j.' —We do not care about advertising booksellers for nolhing. We always give their addresses. Write them.

V. R. Smith.— Send the drawings of the prie dieu to us.

J. P. (Post-office, Monkstowu).—No stamps enclosed.

J. R. Mason.—The advertisement columns are open to you.

Argkntk.—We cannot inform you.

„-. T.—Write to the Secretary of the Institution ot .\aval Architecture, 9. Adclphi-tcmice, S'rand, W.C

J. Crkhex.—Order through a bookseller or newsagent it you can, it is always best.

a Urs.k Minoris.—We are glad to know that our efforts are so much appreciated, and so useful.

J K SoFfE—About half a score have written to us about ')r Usher's advice. The Dr. did not send it as his own. See extract from his letter on next page. Quoiiug Irom memory, he made a mistake or two.

C Fallow, of Bathgate, Edinburgh, says, "lam only expressing the sentiments of the majority of my lirotner readers when 1 say that I feel excedingly sorry to see front ■ Adept's ' letter that he is still suffering from bad he ilth. I hone a short time will make liinl all right a-alu. and tHat he will be able to resume liis must interesting papers uu Organ Construction, which lor Bo long a irnc nuie g.arett the5 pages of our journal." We need baldly say that we heartily endorse Mr. tallow's expression of sorrow, and also ills hope.

Veritas.—Thanks for good wishes.

S., Post-office, Yeovil. —No sumps enclosed.

Dr. Ussber wishes to inform Henry Good, and, we may add, nutny others who have written on the subject, that his "ndvice is given in inverted cnnm s, and therefore not Ins own. He quoted it, ns he saw it printed on a slip SO years ago, when he was a little boy." Or. Ussber also raises his voice against many of the medical suggestions, as not only useless but in some instances mischievous.

W. Harris asks us to send him by post a receipt to apply a peculiar polish to tin. Wc do nut answer such queries by post, and tie ought not even atk^us to do so.

3 >'kwto».—We could not inform you.

Pizzled.—Our reporter says that according to the eleventh edition of the " Manual," page 60, paragraph 136, the positions of alt grammalogues are, aa a rule, determined by their vowels, whether long or short.

The Sixpenny Sale Column is the only place in which can appear queries forwarded by "A Druid," Neville (first and Ust query). Delineator, Geo. Maiden, *'C. C. C, ""Inquirer," J. Y. Titehmarch.

Gamma—Only as in everything else, by hard work, patience, utid a sharp eye for opportunities.

A Blacksmith.—We cannot answer your queries ourselves; they reouire the experience of half-a-dozen emigrants. Letters nave appeared in recent back uumliera, from settlers in the United States, from which you will probably gain information.

Builder.—We have described three flooring cramps within the last six months, the last one only a few weeks back. Why not take the trouble to look before writing?

G. H—Yes, 2s. 6d., or you can purchase a case through your bookseller.

Thomas—Your letter, which you say many are expecting to see, is inserted to-day.

C. H. \V. B.—Please send the description.

J. Estofk.—We don't remember receiving the query. It should be home in mind, that wc do not insert nil queries.

An Efficient Lathe.—W. J. Evans, of 104, Wunlourstreet, says, in a letter, that the lathe belonging to Titus Salt, and described last week, was almost exclusively made at his factory. The out lines oi" the designs of the lathe were made by Mr. John Smith, of Jersey, an able audi ngenious amateur.

D. T. Batty— Thanks for co-operation.

11. Adams.—Cyanide of potassium will remove nitrate of silver from the hands.

Subscriber From The First—We can offer no opinion as to the qualifications of different makers' bicycles.

II. 8., of the Irish Constabulary, Dulup, Drogheda, complains that he is obliged to give2}d. for each weekly numberof the English Mechanic. We can only say that a good percentage is offered to the trade R. S. must see that it will cost more to carry a copy to his quarters, than, for instance, to an ordinary English market town.

W. M. Mill denounces the system of trying to get subscribers to publications by offering to give away magnificent prises "for nothing." He knows of an instance where a subscriber was sufficiently fortunate to get a prize. He was very much elated. But it turned out that the prize after all was not worth the carriage. This is just what might have been expected. When every other dodge has failed such baits are offered to catch the anwary.

J. B. Halif.t.—Consult back numbers for varnishes.

Samukl Ward.—The alteration in the advertisement pages was made in obedience to continuous and repeated solicitations of subscribers. If the publication suffers, the subscribers will gain.


Subscriptions to be forwarded to the Editor, at 31, Tavistoci-strcet, Covect-garden, W.C

Amount previously acknowledged £164 1? 4

C. E. F. ... OS*

G. Gaterell 0 10

J. C. Shewan (2nd don.) _, 0 1 0

F. W. W. „ „ 0 10

164 18 10


BSS J. Sellers, Preston, shaping, euttlng, and boring wood

631 i-.. Punuell. 54, Bast-street, Brighton, signal alarum for rati way e

935 G. Parsons, Mnrtock, feeding apparatus for carding engines

930 M. Knowlea. and J. Conlong. nf Blackburn, and W. Frankland, of Grimlleton, looms for weaving.

957 J. Capper, Clifton-park. Blrkephead, chimney tops or cap*

03a CD. Austin. Newraatle-on-Tyne, lubricators

939 A. K. Heis. Lisbon, appar-.tiis applicable to barrels, casks, or vessels for the preservation of fermented Honors*

MO F. Tocher, 81, Jouthampton-slreet. Camuerwell. veuttla-, tion or hats

041 W. MeCraw. f, Wait Catherine-place, Edinburgh. 1mproyementa In photography

943 W. It Lake. Southampton-buildings. Loudon, mechanism for diminishing friction — A comnimiic-aUoA

043 J. H. Johnson, 47. Lincoln's-ttin-flelds, preparation of oluble phnsphatas of llmo

944 It, Scott. Addlewell. treatmentormlneral oils

945 J. M. Clark, Aberdeen, apparatus for soldering tin cases 9t0 J. N. Taylor, North Shields, clickouts or tools for drawing nails, spikes, and bolts out or timber or ot her materials

947 W. B. Quclon, Ktaplaton. chairs and fastenings-for mils 94* A. V. Newton.Gft, Chancery-lans. preparing Iceland and Irish moss for use as a food.—A communication 040 O. A. Hudriwrt. Hrvnklr. construction or railways 960 J. Batlo.v, Wandsworth-road, Surrey apparatus for registering figures or numbers

951 W. R. Mowbray, Dry pool, and J. Martin. Kinasfon-npnuMull. proiecUng goods, wares, or stock in vehicles, and


952 tt. Atkln. Burton-crescent, plait and fastenings orconnections for jewellery

058 J. Drabble, Chesterfield. 9. Raworth, Manchester, machines for doubling and spinning.

90t W. Maclean, Glasgow, improvements In printing, lithographing, aud zlncographing

955 F. A. Harrison, and O. Priestland. Birmingham, metallic adjusters applicable for adjusting braces, garter*. K,a

HMO. B. Parkinson, and J. Metcair, of Preston, improvements in working check straps In looms

057 C. Newhouse, Heywood, hoists

058 J. L. De Negroni. Parts stoppers for bottles. Jars, pots 950 H. J. Knddan, 21, Lupus-street, London, apparati for

assisting in the pedo-looomotion of the human brmv

9fWA. V. Newton. OO.Chancery-laiie, Improvement in sewing machines.—AJcoramuni cation

901 F. Field, Upper Marsh, Tamhe.tb, application ofanew material to the production of illuminating oils aud solid hvdrocarbons

902 A. Ody, Bristol weighing machines.

90S J.Chnmes. Clare-villas. Merton. arrangements for the safety and convenience of railway passengers

004 J. VVadsworth, Manchester, an improved portable oven

003 H. Law. 15, Essex-street, Strand, meters for measuring fluids

900 If. Jackson, Park-square. Leeds, drying grain, malt roots, speut malt or hops, megass or spent sugar cane, wool, and other substances

007 H. Jackson, Park-square, Leeds, improveme ts in mills f*r crushing and grinding

063 A. Barlow and J. Taylor, Bury, apparatus to be employed in preparing cotton

000T L. Livsey, Bury, apparatus employed for filling or starching woven fabrics

070 I. Summersfleld and J. G. Sanderson, Manchester, impressing machine for tailors.

971 W. smith. Manchester, railwav switches an* signals

072 W. Howrien, Whltstable, apparatus for reeling and stowing the sails of ships

973 W. E. Newton, 00,Chancery-tana, machinery for making horse-shoe and other nails—A communication.

974 J. R- Cadman, Christopher-street. HaMon-garden, constructing and fitting brackets for shoo windows

075 B. Thornton, Bradford, heating by the circulation or hot water.

070 J. Shackleton, Bradford, Iraprovenents in utilising exhaust steam

077". Wilson and John Peebles, Errol, improvements in equilibrium slide valves

07A H. J. T. Plerey, Birmingham, tube cutters aud screw stocks

979 A. M. Hobsou, Brixton, and B. C. Smith. Enfield, velocipedes.

OSoW. Johnson, Wyud's Point, Little Malvern, sheet-metal saddle-trees

081 G. Deadmaii, Hatfield Peveret, Improvements in horseshoes

082 \v*. N. MacCarinev. Glasgow, new process for dissolving crude or manufactured indiau rubber

083 J. v¥. Baker, Kradford. t;. Woranop, of Little Horton. and J. 'jrainge, of Bradford, improvements in Hie Ooustruotlou of kilns

084 P. R. A. Glover, Brading. anchors

085 A. Whltlaker and E. Stead. Bradford, machinery for spinning mottled yarn

980 A- T. An<iuetil, Paris, application of oleic and stearic acids for protecting m^inlUc surfaces from oxidation and preserving wood and other materials

0S7 vV. K. Lake, Southacoplon-buildings, London, an improved lluminated night Cook. — \ c unman leu ion

pss U. J. ryre, Westbourne-grove, securing envelopes and their contents


Iir obedience to the suggestions of a number of readers, we ha«re decided on appropriating a portion of our space to a condensed Hat of patents aa nearly as possible up to the date or our Issue.


910 R. G. Rain forth. Ktngston-upcn-HulI, consuming smoke Oil W. McXabb, 6, Cam bridge •terrace, Clapton, improvement a In bale*hoops

913 it. Saunders, Croydon, rendering water-tight dock gates, ships* ports, &o

918 P. J. Upton, 188, Long-lane. Bermondsey,hats

914 J. A. Lund. Corn hill, keys for watches.

015 A. W. R. Hoblneoo, and P. Wilcook, Roehdale, apparatus for preparing cotton

910 J. Holding and J. Keeles, Manchester, and W. 11. Cooper, Bowdrm, temple* for looms

917 U. Hughes, Homer ton, reducing metal rods

918 C. Cotton, Nottingham, knitted fabrics.

919 J. B. Paasedoit and L. A. Kitterbandt, 40, Eastbourneterrace, Hyde Park, manufacture of peal charcoal

930 J. Fennell. Salford. privies, closets, and commodes 93j T. A. Hicfcley. Temple, and W. Utting, Palsgrave-place, Strand, steering ships

923 G. Clark. 10. Craven -building, Drury-lane. heating, cooling, or evaporating liquids

933 H. B. Preston. Liverpool, evaporating sugar

934 J. Oofleld, 33. Kavenhnrst-street, Birmingham, fastenings for braees, belts, bonds, and straps.

930 J. Tietjen, Upper Charles-street, Goswell-road, improved endorsing stamp 930 J- Lister, 40. Puke-street. Moor, Shctlleld, knives 937 G. Flashman, Dover, mattresses

928 J. H.Johnson. 47, Lincoln's-lnn-flelds. artificial fuel.—A com m u ntoallun,

929 A. Stlefbold, and G. N. Cory, London-frail, concertinas and aooordlona.

930 O. Necker, Berlin, sewing machines,

931 W. Avery, Reddlteh, umbrellas and parasols

982/T.J. Smith, 160, Fleet-street, machines Tor reaping and mowing.—A communication.

3319 K.Ogrtendeodorizlng compound

3338 A- McNeill, a safe for ships carrying valuables

8300 W.Thomas. Improvements in obtaining power

8801 J. Fogg, machinery Tor dressing flags

530'i ■*. Cotton, machinery for preparing fibrous substances

3*01 W. O Mann, hats

3403 B. Goddard, improved machinery for pill mass mixing
3418 W. Pollitt, and W. J. Kuowlcs. Improvements in

maetiinery for washing

3-117 D. Barker, varnish and varnish paints

3418 J. Denis, producing pulp from wood

842-2 E. H Burke, metallic barrels

84'i4 W. Perkins, fusees, matches, &o

34S4 J. C^robe. machinery for hackling flax

8435 J. Pitt, J. Pitt. B. Pitt, and W. Pii*. of Cleckheaton apparatus Tor drill-cutting and shaping metals

8435 L. Pochet, dressing sumo

8441 S. Perry, J. J. Perry, and L. H. Perry, boxes Tor holding various art'oles

3100. J. and J. Wood, and W. H. Wood, ventilating hats

3440 R. Mil burn, andT. Browning, drying machines

3470 J- P. Crease, construction of tank filters

8472 W bpenco. manufacture or sodacrystals

3404 P. A. 8. Langlois, aud Tbomasnin, manufacture of sulphuric acid

3510 H. M. Nioholls, apparatus forj cutting continuous paper into sheets

8503 J. P. Alexander, undulating propellers for steam ships

3012 VV. McGeu and W. MoGee, machinery for doubling and winding fibrous materials

8057 G. vv Honey man, preparation for the removal and prevention of incrustation in steam boilers

8041 W' Potilds, apparatus for heating feed water.—A communication

3358'A. M. Clark, jacquard apparatus.—A communication

304) J. Smil<*s. breech-loading fire-arms

3705 .1. Bourne, apparatus for the irofluotlon of heat

3722 W. K. N'cwtt'ii. adjusting and packing the rails of railways,—A communication

8723 vv. K. \ewton, improvements in forming thejoiuts of t*e ermancnt way ul railways. — A communication.

4H W. Weild. machinery ror winding yarn or thread

0' P. H. Knevitt. improvements in shutters and blinds for wit dows

i:2 II- A. Bonneville, warming and ventilating close carrim es and bo«t sttloons

If 4. T, P. Hi la, moulding and comprossing substances for nil fieial fuel

10 J. M. Plefsner. ntpiratus for the treatment of liquid fuel

85 J ^. Dronsfleid, apparatus for /rimiing the card, covered tni aces of p >rtions oi the carding eugliica employed iu the jr'paration uf cotton

430 Alfred Fryer, preparation and preservation or aeimil

aim vegetable substanoes to be used as lood
4M w, Whieldon and J. Beck, cocks and valves
403 J. Hammond apparatus lor washing and cleAnsingclotuca
530 J.J. Aston, propelling vessels ou the Mater
5HA J. J. Holden, gas retorts
097 G. Fowler, smelting Iron ore
717 J. Wallace,apparatus for distilling
"3/ P. W, Spmiccr. ImprovemeiiTs In Hrm-klhis
708 J. Davis and W. N. Davis, two-furrow ploughs
*Ofl J. H. Johnson, improvements in onmping machines
MOT. Keely. manufacture of looped fabrics
S27 1L P. Fairle, wheels for rail or tramway locomotive

engines and carriages
8*7- W. K. Lake, improvements in wheelsfor railway engines

and carriages
817 J-H. Johnson, Improvements In locomotion and in the

means to be employed therein
850 C J. hyre. apparatusror producing motive power
8;n W. tt. Ijvke, improvemenis In turbine water-wheels.—A

STi W- K. Lake, preparation of ammontated sulphuric acfd

for tho manufacture of manure
88j W. R. Laan. improvements in valves.—A communication
800 It. Smith, machinery for doubling and winning cotton

Persons haviag an Interest in opposing any one of such applications are at liberty to leave purlieulars in writing of their object Ion a tog noli application at the said Oflictt of lui» Cuinmtsbiouera beforo April 20, IHjo,


1357 o. S. and H. Whiiechuroh, Herle-street, Linooln's-lnnflelds, Imorovfments in stoves and fire-places

2858 J.Butcher.Southport, l^ancaster,dentist,Improvements in fountain pens and pen-holders

2W5 E. ». Karcot. Boulevart Beau march ais, Paris, an improved mode of propelling and constructing ships and boat* and tht-ir accessories

2800 K. Broad bent, Islington, Birmingham, Improvements in gas governors

2S70 P. H. Hodge. Adam-street, Adelpht, C. Hengst. Fulhamroad, Chelsea, and N. Wilson. 144. High Holborn, certain Improvements in the manufacture and cementation or welding of steel and iron, iron aud iron, and steel and si eel together, aud] in adapting such improvements to various useful purposes

2375 b'lr C. T. Bright, Knight, Westminster Chambers, Victoria-street, improvements iu electric telegraphs

2870 O. Mather and W. Kosetter, improvements in warping or beaming machines

2373 P. P- Vlllepigue, Brewers-lane, Saint Martln's*in-theFlelds, an Improved method of and apparatus for piercing or boring holes in rock, mineral, or other material of a similar nature, applicable iu tunnel, mine, quarry, and other such work

tSSi W. Horsfall, New York, improvements In machinery for forging bolts, screws, and spikes

48H0 W. Morris. Triangle. Halifax, York, worsted spinner.and J. Teal. Sowerby. both in Yorkshire, improvements in machinery to he employed for coinbiug wool

2390 J. Kircher, Cnnnstadt. E. Fbner, Stuttgsrd. both of Wurtemherg. an improved black priming ink capable of being removed from paper

2892 K. Miiethurst. Stockport, Cheshire, Improvements in funnels or funnel measures forthc measuring and pouring of liquids into vessels

2305 W. Kicbardson, Oldham, Lancaster, improvements in machinery for hurring or cleaning wool, cotton, aud other fibrous materials

2971 J- Halford. BretteMane, Kingswinford. Stafford, coke burner, improvemisnts in puddling rurnaces used In the manufacture of iron aud in oilier reverbejautry furnaces

2093 W. KiMiii. Birmingham, a new or improved method of wsler-colour printing

8017 H. M. Marsden. Sheltleld. York, an Improved metbod or manufacturing sheep shears nnd other articles or cutlery

8051 D. Jackson and J. ttiley, both of Oldham, T An caster, and G. H. Kay, Dukindeld, Chester, improvements In machinery for cutting, shaping, and dressing stone

8072 A. M. Ulark, chancery-lane, Middlesex, improvements in hinges and hinge guards for railway CArrlag-e and other doors, part uf which improvements is applicable for warmii£ and ventilating railway carriages—A communication

2893 B. Wlgzeli. and J. Point, metallic pistons for earn

2913 A. Coleman, latches or locks applicable especially to railway earn ago doors

2015H. Sohiidherg, signalling apparatus Tor use in private or public buildings

2010 D- Parish, axle-bores.—A communication
2981 W.J. Jones, hot-water boilers

8031 J- More, oils for palming or other purposes
2040 M. Iteid, Portland and other cements

2011 W. N. Hartley, whitening or bleaching yarns

2943 B. II. C. iloiK-kton. improvements it: railways, in motive and locomotive power

2000 VV. Llncolne, securing the joints of belts.—A communication

2991 C. L. Page, packing cases or boxes for containing bottles

3040 W. B. Uobins, syringe*

3039 T. itevlngton and s. CourtAiild, and 3. A. Norberg, machinery lor breaking stone and ore

3121 H. B. Barlow, improvements in knitting machine*.—A communication

345.1 J. Speight, apparatus for spinning, twisting, and roving worsted

8003 H. B. Newton, Improvements in net machines

190 J. Pa ton, P. Harris, and it. Harris, apparatus for generating carbonio acid gas for extinction and prevention ordre

255 J. E. Standlleld. four-whenled carriages

204 W, tt. Lake, sewing machine needles and needle arms.— A communication

310 W. K. Lake, an improved friction clutch.—A communication

41S J, W. Dixon and J. Bates, machinery for filing

474 J. H. Johnson, apparatus for lighting, applicable also for signalling purposes

470 W. it. Lake, instrument for determining tho altitude an* zenith diatauoe of celestial bodies


031 W. B. Htlllard, Improvements in skates

043 E. S. Jones, an improved mode of and apparatus for rowing boats on wator

951 J.J. McComb, an improved mode of coupling telegraph. and other wires.—A ommuntcallrtn

941 U, Can ham. Improvements in means or apparatus employed In the cure oi smoky chimneys

974 H. A. Bonneville, a new and improved means of readily igniting fuel and ligtiiing (ires.—A communication

902 P. J. Manceaux, improvements in tire-arras and In apparatus for charging the same

970 A. V. Newton, improvements in sewing machinery,—A* communication

088 w. Clark, improvements in applying nnd fitting the tubesof multitubular hollers—A communication

997 I', fipence, separating zinc from certain ore* or minerals;, and In recovering other substances found tin row>ih

1044 W. it Lake, an improved mode of emb.timuig or preserving dead bodies and carcasses.—A communication

1181 A. Y. Xewion, blowing aud pumping engines-—A com mumcatlon

977 J- J- Meyer and A. Meyer, an improved system of tank locomotive engine

900 J. Pickering, Improvements In apppratus for raising weights

1000 J. Lsdley, apgaratus for spinning wool

1012 S. Perkins, manufacture of railway crossings


BEEN PAID. 507 P. it. Walker. Improvements iu valve* and in apparatus connected therewith

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F the undertaking of the following chapters, I hare endeavoured to lay before those interested in the subject an elementary treatise on the strength of materials sufficiently clear and compendious to exemplify the method of reasoning ia this part of applied mechanics, as well as to impart an accurate knowledge of its most useful proposition», wiih their application to practical parpases, avoiding at the same time as fa» as possible mere abstract mathematical investigations.

Uriginality is not assumed, for the materials are common property, and I have never hesitated ta consult the best modern authorities on the subject. I may mention Professor Rankine, Gregory, Rüb lmann, Zeuner, Banmgartner, &c. &c., when I thought I might obtain a more elementary demonstration and préciser results.

I hope that I have duly, yet at the same time honour&Mv, availed myself of the advantages which they supply, but still not so copiously as to diminish the utility of those volumes, or to make me an unfair borrower.

On a previous occasion, one kind of attraction— viz.. that of gravitation, has been discussed and popnlarly treated, and pursuing the examination of the invisible, active, and real forcee of nature, the attraction of cohesion will next engage our attention. .tu

The term cohesion is derived from the Latin

r«iri=togetheT^»ndft<rr<i=I stick, or cleave.and

may V>e definen as that force which tends to make

the atoms or particles of the same kind of matter

move towards each other, and to prevent them

being separated or moved asunder.

As examples of cohesion in daily life, we may cite .-—

2. The mannfactore of glass vessels, the materials of which have been soft and liquid in the furnace, and on the removal of the excees of heat, have become hard and solid, in consequence of the attractive force of cohesion binding the partide» together.

Î. The surfaces of an apple torn asnnder will not readily cohere, but if cut with a sharp knife cohesion easily occurs.

3. A. wound produced by a jagged surface is difficult, and takes more timo to heal than some of the most desperate sabre cuts, the cohesion of the surfaces of thus cut flesh being very rapid.

4. The art of plating copper with silver, which /s afterward» gilt, and then drawn ont into flattened wire for the manufacture of gold lace and epaulets, commonly called bullion, is another example of the wonderful cohesion of the practice« of gold, of which a single grain may be extended over the finest plate wire measuring 345ft. in length.

Of course these examples might be carried on to any extent; but as they are only inserted to convey more readily the meaning of the term cohesion to the mind of the reader, we shall restrict ourselves to the above.

The cohesive force existing more or less in all EMerials is not constant, but varies with tho atnre of the substance and the order of its »Vitn?, as is beet shown by the burning of argil, Urdening of eteel, &c, in which latter cases it breóme» greatly increased.

When the particles of a body become separated through the action of external forces, and the cohrwre force is not able to unite these again, the body breaks, causing those particles giving way either to move towards or from each other. The greatest or least force required to effect the arove is termed the tenacity, strength, or cohesion of that body ; the object of the present chapter is therefore the determination of this force in its various appearances, especially in thoie materials

with which the practical mechanic has to deal.
It íb one of the most important, and at the same
time difficult, subjects that we have to contend
with, owing ohiefly to the very different tenacities
of bodies of the same nature. For instance, the
strength of all kinds of timber not only depends
on the localities where they grow, age and
structure, temperature, and when felled, but ex-
perience shows that even timber obtained from
the same tree has not equal tenacity. Something
similar is found in iron, whose strength chiefly
depends on the quality of the ores whence ex-
tracted on its manufacture, and lastly on the pre-
cautions taken in heating, welding, hammering,
and stretching it. Hence all experiments are not
to be accurately relied upon, but only give us the
average strength of the respective material. _

All the possible straine to which materials
whatever be their forms and arrangements, can
be subjected, may be classed under five beads—
viz., 1. Tension. 2. Compression. 3. Trans-
verse strain. 4. Torsion or twisting. 5. Clip-
ping or shearing.

We shall now investigate these properties in their respective order.


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Tension is a strain acting in the direction of
the fibres of a body, and tending to pull it
asunder, as in the case of stretched ropes, bands,
tie-rods, and chains.

Every body subjected to tension may be con-
ceived as having its particles arranged in longi-
tudinal rows, each particle being held to the next
by some force which, as already mentioned, is
called the attraction of cohesion. Let us now
suppose that the applied strain is not capable of
breaking the body, but if increased by the least
imaginable quantity, a breakage takes placo;
this strain is then 'said to represent the absolute
tenacity of that body ; or, supposing an iron pillar
is capable of sustaining 16 tons and no more,
without breaking, we should call the absolute
tenacity of that pillar 16 tons.

The absolute strength of the different metals is determined by ascertaining the weight required to break square bars measuring an inch each way, or having a square inch of sectional area; the bars are laid horizontally, and fas-.ened firmly at one end, when at the other end a known strain acting in the direction of the bar is applied, which is increased, if necessary, till tho bar breaks. That the bar is not placed vertically has also a reason, for then additions to its length would increise the weight, stretching its upper portion, because each portion of added length becomes an added weight ; and again, that the length of the bar has no influence whatever on the breaking load is self evident ; for if any one part of its length is capable of sustaining tLe strain, and the bar be of uniform quality, every other part will be able to sustain the same; we have therefore the law that the tensive strength of a body, uniform in all its parts, is directly proportionate to their transverse area, whatever be thoir figure or length.

When a piece of material is being tested, two considerations must be taken intoaccount,namely, «hether the piece is to be afterwards used, or sacrificed for the sake of ascertaining the strength of the material. In the first case, it is self evident that the teeting load must be so limited that thereby the strength of the material is not in any way impaired, that is, it must not exceed the proof strength. Care should also be taken to avoid vibrations and shocks when the testing load approaches near to the proof strength. In the latter case, the load ought to be increased by degrees until tho piece breaks. To obtain a sufficiently correct result, the load, when the breaking point is being approached, has to be augmented by small weights. One method of approximately arriving at the proof strength of materials is to apply a moderate load, and remove it, then applying the same load again, and removing it two or three times in succession, noticing at each time of application of the load the strain or alteration of figure of the piece when loaded, by tension, compression, bending, distortion, or twisting, as the case may be. If that alteration does not sensibly increase by repeated application of the same load, the load is within the limit of proof strength. The effects of a greater and a greater load being successively tested in the same way, a load will at length be reached whose successive application produces increasing disfigurement of the piece; and this loed wll be gre .ter

than the proof strength, which will lie between the last load and the last load but one in the series of experiments*.

Materials used in machinery, and subjected to tensive strains, ought to resist the separation c.f their particles—fracture—as well as any material elongation ; therefore, in practice, where durability and adequate strength are required, it is necessary to give the materials we employ considerably greater dimensions than snch as would merely preserve them from breaking, or to load them with considerably less weight than those which would tear them aeunder. Again, materials subjected to considerable strains for long periods of time gradually lose their tenacity, which must be provided againet when permanence and stability are required.

To obviate these degradations of quality, it is found expedient not to load iron or wood ЬсуоЫ one-third, copper, brass, or lead beyond one-third, or even sometimes one-fourth, of their breaking strain (ultimate strength).

The following table contains the result of experiments on the cohesive strength of various materials. The numbers are given roundly, and may be safely used in calculation, as they have been reduced to one-third or one-fourth of their breaking strength.

Table I.

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By George E. Davis.


Symbols As Applied To Moléculas


MOST of the elements differ from each other in thoir degree of chemical force, and this force or power of tho element was for some time termed its atomioity, but now that term has been completely superseded by the term equioaUncy.

The equivalenoy of an element, then, is that power which it possesses of combining with other elements to b;oome saturated ; thus a tetrad will always exhibit some degree of chemical force if only partly satisfied, but if the f orce is completely neutralised by combination with other atoms, then a saturated and comparatively inactive body, taken as regards its chemical force, is fo- med. Hydrogen

'Professor Rankiuu s "Engineering."

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