angles to the atmospheric line. Then, with the scale, which is attached to every instrument, he must read off the number of pounds indicated by each line. When this is done, the ten results must be added together, and the sum thus obtained divided by ten. It is not absolutely necessary that the diagram should be divided into ten parts; it may be divided into eleves, twelve, thirteen, or any other number of parts we wish. But the division into ten is that which is usually adopted, and for two reasons-first, because it is sufficiently accurate for all practical purposes, and secondly, on account of the division by ten being so easily and quickly accomplished, simply by removing the decimal point one place to the left.-THOMAS J. O'CONNOR. [4824.]-FAN BLAST.-I enclose a sketch of blast fan, which I hope may meet with the requirements of A G. Cook. Fig. 1 is a side elevation; Fig. 2, sectional elevation through A B; Fig. 3, ground plan. a a represents bearings for fan shaft; b, small pulley; c, aperture for admission of the atmosphere to fan; d, delivery pipe, which I propose making of gas pipe, said pipe to be reduced to about 1" diameter at the nozzle, by diminishing socket or any suitable contrivance, and to be fastened into mouth of fan box by wedges of soft wood, well smeared with white lead or some similar substance; e is a pair of glands to ensure the wedges remaining in their place. In the sketch I have given the sizes I think necessary, and the driving pulley of course can be fixed in any convenient position; the sides of fan box to be of plate, periphery 1-16" plate, slightly flanged for making joint; joint to be screwed up with " bolts and nuts, and to have a little white lead between to make it air tight.-ASSISTANCE. [4970.]-PROBLEM.-Suppose a pole to be 100ft. in height and standing perpendicularly, what part of the pole will have to be cut off for it to touch the end of a base line 30ft. from the bottom of the pole, which is perpendicular to the base? Solution: (vide figure) we have the following g equations: (Euc. I. 47.) 302 + x2 = (100-x)2 -200 x + x2; = 1002 hence 200 x = 1002- 302 x 45.5.BERNARDIN. 100-3 30 [4371.] CHANGE WHEELS.-I have never seen a rule in any book for the wheels "Good Words" mentions that will act correctly; but the way I calculate them is in the following manner, which Ifind comes a great deal nearer the mark than any book rule that I have seen (and they are many books I mean): You find the wheel by proportion first, and then again by square root or evolution, then add the two answers together, and divide the product by two, and the answer will be the wheel to put on. Suppose the frame is making a 8 hank, with 30 wheel, and you wish to change to a 5 hank, square the 30, multiply by 3, divide by 5, and extract the root of the product, then proceed by proportion. 3 30 :: 5 8 5)90 1o answer by proportion 23 evolution FIC.2 A them was not given by me. The job will be troublesome, the tool is under in. in flat or circumference, make and a muddle when done.-SIGMA. . will [4376.]-COD-LIVER OIL.-If "A Mechanic" should cloves that of senna.-KANSAS. [See "C. J. H. W.'s" letter in answer to this query.] [4376.]-COD-LIVER OIL.-Squale oil seems more palatable and as efficient as cod-liver oil.-Address, Dr. Delattre & Co., Dieppe, France.-BERNARDIN. [4376.]-COD-LIVER OIL.-There is no good substitute for cod-liver oil. If it is good it ought to be very nearly tasteless. But if "A Mechanic" tries this "dodge" I think he may take it without tasting the flavour; it is so P.S.-The above will do for lift and twist; multiply by with me. Having put some water in a wineglass pour 5 and divide by 3 for ratchet. in the oil; then to swallow it place your tongue right out and the oil will glide down your throat without your on the outside of the glass, then throw your head back tasting it in the least. If " Mechanic" fails at first let him try again.-C. J. H. C. [4371.]-CHANGE WHEELS.-In answer to "Good Words," I beg to submit the following simple rules :Multiply length by breadth by the weight of a cubic inch of the material required; then divide the required weight by this product, which will equal the thickness of pattern in inches. Weights of a cubic inch of different material: steel, 282; wrought iron, 28; cast iron, 26; brass, 3; copper 32. Example.-It is required to know the thickness of pattern for brass from the dimensions given by "Good Words"-9in. by 144in., and to weigh 60lb. 9x14 x 3 = 89.15. Now, 60 divided by this = 1.5in. thickness of pattern required.-C. N. [4871.]-CHANGE WHEELS.-In answer to "Good Words," I beg to offer the following rule. Rule.Multiply breadth by length and by the decimals 263 for a divisor. BURGE. Divide the weight required by this divisor, which will equal thickness of pattern for cast iron. Ex. 9" x 14" x 263 = 34-32 34.32 18" thickness of pattern. Then for wrought instead of cast iron x 28 brass x 3 copper × 32 ASSISTANCE. [4378.]-ELECTRIC ATTRACTION.-If "Electron " refers to vol. X., page 319, sec. 19, he will find an experiment very like his own as he was practically presenting his electric or proof-plane to the stem; his ball suspended by linen thread, which is a conductor, answers to the wired ball. The experiment appears to me to indicate clearly the fallacy of the "fluid and charge" notions of electricity, because the ball is continuously attracted by the electric if presented to it, but repelled when the electric is presented to the stem, because, according to my views, this interferes with the polarized circuit at first set up, and brings into operation the outer circuit formed by the electric through the operator to surrounding objects, as explained in my earlier papers. The glass carboys could be got of any wholesale druggist at about 58., I think. "Electron " will please remember, however, that the advice to use [4376.]-COD-LIVER OIL.-Take of cardamom seeds 1oz., gentian root 1 oz., soak these for a fortnight in a pint bottle of good rum. Dose-A tablespoonful to be taken three times a day in a wineglass of water. This, I should think, would answer the purpose of cod-liver oil, as it is both a tonic and a stomachic combined.-W. F. TRINDER. [4976.]-COD-LIVER OIL.-Those who have a difficulty in taking cod-liver oil will find an excellent substitute in cod-liver pills. They are a French preparation, and a medicine far more palatable than the ordinary oil. I believe these pills are not generally known.-T. A. [4376.]-COD-LIVER OIL.-"Mechanic "should take an ounce of mutton suet chopped small, boiled in a gill of new milk as a daily diet. It is a thousand times superior to cod liver oil. (From Dr. Skelton's "Family Adviser," page 218.)-J. LIGHT. [4377.]-TEMPERING BRACE BITS.-Your correspondent, "G. W. A.,"in answering query 4377, causes me to send this short reply, if you think it worthy of insertion. In the first place, cast steel and shear steel are both very different to temper. If the articles to be tempered are made of cast steel or old files, let them be first heated to about the colour of a biggareau cherry, and then plunge ihto cold water. Afterwards rub them with a bit of Turkey or grit stone-Turkey in preference; then hold on a bit of red hot iron about 2in. or 3in. from the cutting point or edge, and then various tints will show on the brightened surface. The proper temper for wood-cutting tools is a little less than gold colour; and for iron or steel, blue, to within of the cutting part. The straw so much recommended, is too hard for cast steel, especially when it has been forged two or three times. For shear steel make very near white hot, and plunge in oil (vegetable oil), brighten, and let down to a pale straw colour, as that is not too hard for a shear steel tool. If cherry hot and plunge in a piece of soap.-W. REED. [4380.]-COLZA OIL is the same as rape-seed oil vide my note on "Vegetable Oils and Fats" in ec ENGLISH MECHANIC of 24th of June, p. 331. For my particulars vide Technologist, vol. 4, p. 425, a note tracted from the Mechanics' Magazine.-BERNARDI [4380.]-COLZA OIL.-Colza oil is an expresad made from the seeds of Brassica campestris; n rape oil is sometimes substituted for it.-T. W. At [4381.]-COURT PLASTER.-Court plasiral by applying several coats of a solution of th a little tincture of benzoin added, whilst w brush to a piece of silk stretched on a frame, being allowed to dry before the next is put a 1 pose it is so called from having been used in best times by Court ladies for their patches.-T. W. Boa [4385.]-BRAZING OR SOLDERING.-The edgol the brass to be united should be filled or scraped gi clean, covered with a mixture of hard solder powdered borax, made into a paste with water, then allowed to dry, being kept in position by in binding wire, or otherwise; when dry they should b for very light work perhaps soft solder, used in the oce exposed to a clear heat, sufficient to melt the soldst nary way, would suit "Edinburgh."-T. W. BOORD. thrown on [4386.]-OPTICAL ARRANGEMENT.-The instr ment this correspondent wants is called an opaqu lantern, and to do the work at all well he is not t wrong in hinting at an unknown number of gaines A very powerful light is required to illuminate an opaqu object in such a manner that its enlarged image may a screen; nothing less than the oxyb drogen light will answer, and after getting such a ligh it would obviously be foolish to use any but a good (ai consequently, rather expensive) optical arrangement The optical part is essentially the same as that of magic lantern; the light is concentrated on the objec at an angle of about 45° by a condenser, and a magnifyin lens of short focus (as in the magic lantern, a phot graphic portrait lens will answer) throws an enlarged image on the screen. The accompanying diagram wil Б explain the arrangement. The effects are very striking. The colours of natural objects, such as flowers, insects. and feathers, coloured drawings, cartes, and watchwork in motion, are shown. If only the light can be obtained. the ordinary fittings of a magic lantern may, with a little ingenuity, be adapted to the purpose.-A, the light: B, condensing lens; C, object; D, object glass or photo. graphic lens.-NORBITON. ENGLISH MECHANIC AND MIRROR OF SCIENCE. [4387.)-SULPHATE OF COPPER BATTERY."W. G." can divide his trough into three equal parts with glass or slate partitions, and use flat porous cells to contain the zinc between two copper plates connected together. The sides of the trough should project beyond the ends, which may be tongued in and screwed together with two bolts at each end, and the bottom may be secured in similarly. Joints should be made with shellac varnish, the wood well soaked with melted parafin, and the inside coated after making with a cement of resin, gutta percha, and a little linseed oil A look at p. 196, No. 269, may help melted together. "W. G." Either dilute sulphuric acid or a saturated solution of common salt will answer for the zinc cells; with the latter the zinc need not be amalgamated.SIGMA. [4883.]-WEAK EYES.-If "Peregrine Pickle" will, on rising every morning, put his face into clean cold water, keeping his eyes open, and remain in as long as he can keep his breath, he will derive great benefit therefrom. Tried and approved.-A CHIP. [4888.)-WEAK EYES.-I would recommend "Peregrine Pickle" to lave his eyes copiously with cold water. It relieved me under like circumstances.-C. J. H. C. [4388.]-COLLYRIA, OR EYE-WASH.-Alum: Dissolve half a drachm of alum in eight ounces of water. Use as an astringent. When the alum is doubled, and only half the quantity of water used, it acts as a discutient. 2. Sulphate of zinc: Dissolve ten grains of white vitriol in a pint of water or rose-water. Use for weak eyes. KANSAS. [4888.]-WEAK EYES.-Take a teaspoonful of the best vinegar and put it into a pint of clean water; bathe the eyes while warm two or three times a day.-E. W. BARNETT. [4389.]-LATHE QUERY.-To make a set of draughtmen, turn a cylinder accurately to the diameter required, cut it into slices of the desired thickness with a thin parting-tool in the slide rest, turn out a boxwood spring chuck to the size of the discs, and face up the whole with a round-nosed tool in the slide-rest on one side first; then advance the tool slightly and face them on the other side. If desired they can then be ornamented with the excentric cutter or other tool in the same chuck. Grooves on the edge should be made with a point tool in the slide-rest before the cylinder is cut up.-T. W. BOORD. [4391.]-SCREW TAPS AND DIES.-"W. Reed" should bake his nipples and sockets in a retort well charged with powdered yellow prussiate of potash, and while red hot plunge them into urine; if they do not harden the fault is with the iron. He can make his taps and dies of good wrought iron and bake them in the same manner. If he is an old subscriber, and can refer to Vol. 1V., p. 993, he will there find my modus operandi fully described. With good iron the process is a success; but with bad iron I think nothing can be done in the way of steeling or case hardening.-AB INITIO. [4392.]-CALLIPERS.-You can see these in any tool maker's shop window. Sketch the shape and cut them out of sheet steel. Five shillings would buy them better made than you could make them at hoine probably.-T. W. BOORD. Manufactures," and "Watts's Dictionary of Chemistry." seeing that it is specially designed for the condensation of vapours.-AN ASSOCIATE OF THE ROYAL SCHOOL OF I should think it was totally unfitted for raising steam, MINES. or more. [4425.]-MALLEABLE CAST IRON.-Dr. Percy's "Iron and Steel" is out of print, and can only be purchased at an advance of two or three pounds Most public libraries upon the published price. Mudie's have two possess a copy of it. pig iron should make good Cumberland hematite malleable castings without previous refining, but other impurer brands would require refining. Why not purchase old cast iron of good quality? It would be cheaper than to make it on a small scale. A good flux for a pretty good hematite, such as the Ulverstone, is as iron; 8 lime. follows:-2 glass, free from lead or Another:-2 parts lime; 2 parts Kaolin or china clay; half part sand. Shale or fireclay may be substituted for the china clay, and thus have the advantage of being much cheaper. I have proved them many times in assaying. Fluor spar and lime would form a good flux with the addition of silica. I do not know the quantities, but they could be easily ascertained by trial. The slag produced should be nearly colourless, of a green If there be an excess of lime it tint, and well fused. will be porcelainous. You can purchase the abstracts of specifications.-AN ASSOCIATE OF THE ROYAL SCHOOL OF MINES. [4425.]-MALLEABLE CAST IRON.-Percy's work is, I believe, out of print, and can only be obtained second hand at considerably more than the published I know they had a copy lately. The patent specifications could be obtained by sending the price, or through price; Spons, of Charing Cross, would be a likely place. bookseller, but the numbers would have to be ascerAny good pig-iron will produce the tained and given. Limestone is used as a so-called malleable castings. flux in cupolas principally to combine with the sand adhering to the pigs, and to act on the ashes where coke or cinder more freely fusible; but if lime or other is used. Fluor spar is of very doubtful utility. Its principal action in furnaces is apparently to render the slag base were deficient it would no doubt act on the description of the lathe and rest he requires in No. 2, silica itself, and in any case be apt to injure the lining. [4404.]-BLAST GAS FURNACE.-Drawings and particulars of Griffin's blast gas furnace may be obtained from J. J. Griffin, 22, Garrick-street, Covent Garden. The blast burner I use is a modification of Griffin's, aud consists of a large Bunsen's burner, with a brass pipe projecting through the bottom, and branching into three or four brass tubes of 4th bore, which extend to the top of the burner, and through which a blast of air from strong bellows is set. The pressure of air must be at least six times the pressure of gas; length of burner, 9in.; inside bore, lin. The difference between this and 14419-WATER GLASS.-Dry carbonate of soda, 54 Griffin's is that mine will burn as an ordinary Bunsen's parts; fuse together. Soluble in boiling water.-T. W. burner without blast (Griffin's will not), and is therefore parts; dry carbonate of potash, 70 parts; silica, 192 BOORD. useful for gradually heating up crucibles, which are liable to be cracked with the sudden heat of Griffin's burner. By building up a small fireclay furnace with this burner I can melt 5oz. or 6oz. of 18-carat gold in seven or eight minutes, and 101b. zinc in fifteen or sixteen minutes. It has the advantage over Griffin's that I can do without blowing, except during the last few minutes, and I can leave it at any time. When the blast is put on, the flame drops instantly to about one-fifth [4427.]-CASE HARDENING.-Charred sheep shanks is the very best material for case hardening; if these are broken up and placed in a sheet-iron box, luted with [4437.]-FLUORIC ACID.-It is highly probable that fluoric acid is made in America, since fluor s par occurs at several places in America. According to Dana, the following are amongst the localities which provide it, none, I believe, very abundantly: at Muskelonge Lake, St. Lawrence Co., N.Y.; at Westinoreland, N.H.; Putney, St. Lockport, N.Y.; and Shawneetown, on the Ohio.-AN ASSOCIATE OF THE ROYAL SCHOOL OF MINES. clay, he will have no scaling of his work.-R. N. [4444.]-JELLY-FISH IN STONE.-The greenish-yellow veins and markings in the granite slabs are probably of Epidote-a mineral which often occurs in this way. It is a compound silicate of rather complex and varied composition. I need hardly say that no fossils at all have been found in granite, and it is utterly impossible that such an organism as a Meudsa could be. Granite is the most highly metamorphosed rock with which we are acquainted.-AN ASSOCIATE OF THE ROYAL SCHOOL oF MINES. FOR GARDEN PATHS.[4445.] -ASPHALTE "Sabbas" will find the following a very simple, cheap, stone broken rather fine; spread it out, basin fashion, and durable method:-Procure a sufficient quantity of and into the basin pour some heated tar; mix well. quick lime over the top, and roll.-J. NASH. THE Then lay over your paths smoothly, sprinkle powdered FRESHNESS TO [4449.] RESTORING FILTERED WATER.-Perhaps the flatness may be removed by aerating the water; this may be done by allowing it to fall from a height, say six or more feet, in a thin stream, or in a drop.-AN ASSOCIATE OF THE ROYAL SCHOOL OF MINES. [4450.]-BATTERIES.-"A New Subscriber's" questhe points he asks for have been recently fully examined tions are scarcely fair to old readers or myself, as all The arrangeby me. If he has not got them he had best send to your office for Nos. 267, 270, and 275, which will, I hope, give ment of the plates is a mere matter of economy; in the him all he wants in an answer like this. Smee one silver plate is used, because it is clear; but the zinc is really best in the middle as in the bichromate. The Smee is the best for electrotyping; the bichromate for working a coil; so that each has advantages over the other. In the bichromate and in all batteries the zinc ought to be amalgamated.-SIGIA. [4451.]-MOULDS OF COINS.-I have found a mixwith a small quantity of rotten stone, to give good ture of equal parts of spermaceti, stearine, and wax, results. Fusible metal, gelatine, and sulphur may also be used.-T. W. BOORD. [4452.]-LIGHTNING CONDUCTOR.-"Iron" must get a pointed steel rod for the attractor, about 3ft. in length, and then must procure enough gin. iron wire to come from the attractor to the ground. This must not be allowed to touch the wall of the house, but be passed through broken bottle necks, which are fastened to the wall by staples. The attractor must be fastened to the iron wire, and supported without metallic connection with the wall. The other end of the iron wire is fastened to a piece of iron plate, and buried about 1ft. deep in the earth. The conductor will now be complete. The lightning will pass down into the earth without touching the house, if care is taken not to allow any part of the conductor to touch the house, except through the bottle necks.-F. WALKER. [4452.]-LIGHTNING CONDUCTOR.-Of all materials copper is the best, and provided the conductor contains sufficient surface, it matters not how it is It may be carried through the fastened to the house. house or built into the walls, and will do its duty, so long as it is taken deep enough into the ground to insure its always being in a moist place. I use a copper and can be had ready for fixing at Newall's, in the band nearly 4in. wide; but the wire rope is very good, Strand, at, I think, 1s. per foot, head and cramps in- 103, Vol. 1). My friend said he did not believe it. The [4456.]-PLUMBAGO BOTTLE BATTERY.-I rather wonder the querist was not subjected to the 6d. tax; however, his question being inserted, I suppose he will get my reply. Elliot Brothers, the instrument makers, Strand, near Charing Cross, are, I believe, the agents for Faures's battery; and the price 4s. or 4s. 6d.; but I do not know if this includes the zincs, &c.-SIGMA. QUERIES. [4464.]-THE MANGANESE BATTERY. If Dr. Stone is still a reader of our journal will he kindly state whether the manganese battery he described in these pages about two years ago is still at work, and whether he has found it satisfactory; likewise his experience in the matter?-M. D. [4465.]-TRACING PAPER.-How can I make some tracing paper, and the carbonic papers that are used by "manifold" writers ?-H. U. [4466.]-CLEANING PRINTS.-Can anyone tell me how to clean prints that are soiled, such as steel engravings, &c. ?-REBAF. man" [4467.]-IMPRESSIONS FROM PRINTS.-How can I take an "impression" from a print ?-SABBAS. [4468.]-MAGNETIC BATTERY.-"Ignorant Irish(p. 453), in reply to my query, mentions the mag neto-electric battery. I would ask him to oblige by giving a further description, with sketch of the same, as most probably that will best suit my purpose; more so that the magnetic battery which he goes on to say will not produce a current, the especial object at which I am aiming.-BERIRO. [4469.]-NEW DYE WOOD.-I read in a German review that Messrs. Walker & Co., Mansell-street, Aldgate, London, have introduced a new dye, extracted from a kind of wood very common in Africa and in the West Indies. This colour is said to be extremely fast, and equal in lustre, &c., to aniline colours. I wish a few more particulars, name of wood, &c.-BERNARDIN. [4482.]—OVAL.-Will any of your correspondents [4483.]-DEEP SEA SOUNDINGS.-Will some corre- An [4484.]-BUNSEN'S BATTERY.-Will some friend subscribers give me any information as to whether there [4486.]-SHORTHAND.-Will one of your shorthand turn red?-YOUNGSTER. reader oblige me with instructions for black bordering [4489.]-TURNING COPPER.-Can any of your corre [4470.)-REMAK BATTERY.-Could any kind brother reader favour me with description of this battery ?--T. 0. B. EDMEL. [4471.]-INSULATING VARNISH.-I tried to cover copper wire, after having sulphurated it, with a coating of shellac, then with gutta percha dissolved in benzine, but my coating was never solid enough. Would any correspondent afford me assistance in improving my pro cess?-INSULATOR. [4472.]-BRITANNIA METAL TEAPOT.-Can any reader tell me how to solder a spout on a Britannia metal teapot without soldering-iron or blow-pipe? been told that where Britannia metal teapots are made I have no soldering-iron or blow-pipe is used.-J. B—H. [4473.]-INTENSITY COIL.-I am making an intensity coil according to Dyer's instructions, 1" priinary (16), "secondary (39); but I find the winding on of the S. wire very tedious; is there a quicker mode of winding? Is there a possibility of overdoing the insulation? I give each layer a coat of shellac varnish, three layers of G. P. tissue, and one of tissue paper. Although I have only two layers on, it gives a shock not to be borne at all comfortable.-R. F. D. [4474.]-HORSE POWER.-Will some brother mechanic kindly give me a simple formula for ascertaining the horse power of an engine by the diameter of a cylinder? or if he could recommend a good work on the subject I should feel obliged.-E. WELLARD. 14475.]-THE JERSEY TIGER.-Will some kind brother reader please to inform me whether the Jersey tiger, a species of moth, can be truly considered a British species ?-J. J. M'CARTEY. [4476.] -TEMPERAMENT OF ENGLISH CONCERTINA. I shall be obliged if a brother subscriber can tell me how to set the bearing (for tuning) the English concertina, it not being tuned to equal temperament, there being A flats and G sharps, and D sharps, and E flats.-CONCERTINIST. [4477.]-BOOKS.-Will some brother reader kindly inform me of a good and reliable book on the breeding of dogs, their diseases and cures; also a book on extension motions, as used in the army, stating publishers' name, and price of each? I shall feel very grateful.-A CHIP. [4478.]-BLUE WRITING INK OR FLUID.-Will any of your numerous practical readers kindly furnish me with a tried receipt for making good unchangeable blue writing ink, or fluid, which will dry quickly, and may be used either with quill or steel pens?-LEX. [4479.1-COLLODION.-When I pour my collodion on the plate and return it into the bottle again it forins into ridges, and seems cracked. How can I remedy this? -W. CRAWLEY. [4480.]-COW-MILKING MACHINE.-Can any reader give me information respecting the above? It was exhibited in the 1862 Exhibition by Messrs. Sanborn & Co., of 99, Cheapside, who appear to have removed from that address since then. Does the machine answer its purpose, and where can it be obtained, either in England or the United States, and what is the price?-KANSAS EMIGRANT. [Experience proved the machine referred to by "Kansas Emigrant" to be a failure.-ED. E. M.] [4481.]-A DIFFICULTY.-Will some reader clear up a difliculty of mine respecting the use of the screw at the bottom of the barometer? I read the following passage to a friend, a maker of barometers:-"In other forms of the barometer, the mercury in the cistern is always maintained at the same level, for which purpose the cistern is formed partly of leather, so that, by means of a screw at the bottom, the surface or the mercury may always be adjusted to the neutral point before taking an observation"-" Cyclopædia of Useful Arts and Manufactures," edited by C. Tomlinson, Art. Barometer, page [4500.]-SILVER THIMBLESsilver thimbles that have been som have lost their whiteness?-A. T. X. MACHINES.J. G." for his kind reply). [4501.)-SEWING required, and therefore unable t posed to understand it was called i It w alterations and trials, arrived at th that the hole in the cutton reel wat fore occasionally altered the tension. anything stiff with plenty of dress is was wound around the spill. of coarse silecia it is completely usele bad as before (see No. 278, July 22nd correctly, supposing I took it to plans professor stitch it, and I consider Eis factory. What part would be most ħże hook detached from the rest ?-H. W. [4502.]-ZOOPHYTES.-How can I pa for mounting, as some preparative apl them?- L. B. [4508.]-MENSURATION OF SUPER the three sides of a three-sided triage. In [4504]-ELLIPSES.-I should be h and how it could be made. —NEMO. of the correspondents of your excellent tell me of any simple instrument for de l None suit me--quill, steel, bone, glass de [4505.)-PENS.-I write a great drah process? Can nobody improve on it? pencils. After all, are not pens and mis the substitutes in pencil style; t gold pencil case, the inside being all t Mr. Needham, gunmaker, who int or so, but the ink caked at the point: yet not the thing." The black of th &c., is too indistinct. Could there be → act chemically on the paper, without marking-ink does not injure liner solid not fluid affair. Still better piano keys, letters and capitals, figa away and print your copy. trivance among the fossil projects. [4491.]-THE TELESCOPE.-Can any reader, inmethod for clamping the draw-tube of a 3in. achromatic, terested in the subject of the telescope, favour me with a so as to retain any particular focus?-LANCASTRIAN. ful if some practical man would give me information in [4492.]-RAISING WATER. I should be very thank-write very rapidly, I am always betheny the following matter:-A friend in the country has a cylindrical iron buckets hung on an endless chain, after well about 285ft, deep, from which he obtains water by is a vertical tread-mill driven by a donkey. Owing to the manner of a dredging machine. The motive power the tremendous wear and tear of the chain (which has caused it to elongate about 20ft. in five years) constant hitches and breakages occur; in such frequency, indeed, that my friend intends to abandon the present system and to adopt the old way of raising water by two alternately rising buckets. This will necessitate two cisterns, one each side, and other minor alterations; he is, however, most anxious to preserve the present motive power. Now, as the action requires to be reversed each time a bucket reaches the top, and as this constant reversal cannot be obtained by stopping the donkey and ment for obtaining the desired action of the horizontal turning him round, what will be the simplest arrangespindle of the tread-mill? I should also be glad to hear whether a very stout vulcanized india rubber band (of course purposely made and with layers of linen) would prove strong enough to be substituted for the iron chain, which is a tremendous weight to fish up from the bottom in case of any fracture.-A. C. G. GIMEL. Is condescend to say whether it would [4493.]—COIL.—TO SIGMA."-My best thanks to describe how to construct the commutator for sending "Sigma" for noticing my query, and will he kindly the secondary current in one direction only? The in--W. REED. formation. I sought for was to enable me to graduate the tube that slides over the core, so that each division [4508.]-TO" INDUCTORIUM."— My best should be an equal increase in power, as I find that the for the description of what I have always che ont, and I do not know what that ratio is. Pigotts, of coil Mr. Apps, of the Strand, is as his pat power increases in a greater ratio than the tube is drawn the best form of intensity coi; but, then, b Piccadilly, has the tube of his atmospheric battery and the model of the one he male for the Polyte the penalty of the Patent Law, as it is precisk which it is done. divided to do it, but I should like to know the rule by And all amateurs may not know that they cannot s venience, tell me how to construct a tangent galvano-Inductorium" add to our oblations by stating Will "Signa," at his earliest con- make a patented article even for themselves. meter; also what a British unit is? I know the Varley size of his secondary wire and the best way of sors unit.-R. N. in. between the primary and secondary, .., .*? if some of the inductive power is not lost by ha it; also size of soft iron wire for one or bundle: tube, fin. for ring ?-R. N. me how I can dissolve resin without the use of spirits [4495.]-IRIS DIAPHRAGM.-I should feel greatly kindly inform me what the following copper coin is: [4497.1-ENGRAVING BALANCE METAL PLATES. AMATEUR. 5 I can catch large quantities of river fish-roach, da weight of a cast-iron ball or wrought say, 7in. diameter, impossible to count the number of revolutions of a blast diameters of the two pulleys, but I have forgotten it. and should be obliged to any friend who can inform me through your columns.-RALPH. a given boiler being (as indicated by an open mercuris! [4513.]-HORSE-POWER.-1. The steam pressure in gauge) 60lb. per square inch (i.e., supporting a straight before, the pressure, as indicated by open merze. 3. How is the theoretic Rof a compound double high or low pressure) condensing steam engine Given boiler pressure, as before, = 60lb. 12 or square inch (as indicated by an open mercurial respectively 15in. and 26in. diameter, stroke each) 3ft., renolutions 55, i.e., speed of pistons, minute; steam used to full stroke in high cylinder, and, for simplicity sake, no account to of condenser back pressure. A clear and full the foregoing would much oblige one of your pectful of readers, who signs himself what he -A WORKING ENGINEER. Simple syrup, 1 gallon. order, is rarely consumed by the modest middle-class families of England. Its very high price is the simple cause of this fact. We have thought, therefore, that it might prove useful, if we were to indicate how a very good substitute could be made at a moderate cost. It is Rub the acid with a portion of syrup, add ext. vanilla, impossible to dispense altogether with the fowis' liver; and mix. Take of Ground roasted coffee, 4 ounces. but two livers from either goose or turkey will suffice The TO PRESERVE PEACHES.-A correspondent, Mr. Smith, of Exton Park, has handed us (Gardeners'Chronicle) the following reply to an inquiry as to the best method of preserving peaches: --"The following is the recipe given to me by the chef de cuisine here: Split the peaches in halves; scald them in thiu syrup to remove the skins; arrange the halves in clean pint tins filled Infuse the coffee in the water until cold, strain, add up with rather thick syrup, made of 21b. sugar and a the sugar, and make a syrup. STRAWBERRY SYRUP. Take of Fresh, ripe strawberries, 10 quarts. Spread a portion of the sugar over the fruit in layers, let it stand four or five hours, express the juice, strain, washing out the mare with water; add remainder of sugar and water, raise to the boiling point, and strain. SYRUP OF RASPBERRY. Proceed as for Strawberry syrup. PINE-APPLE SYRUP. Take of Ripe pinc-apples, No. 2 or 3. Cut the fruit in thin slices, spread sugar over them, let stand twelve hours. Pour off juice and sugar, and set aside. Express the fruit, adding a little water. Then take water, q.s., to make, with the above liquid (juice and sugar), 1 gallon. Form a syrup with the sugar and water, and boil the pieces of the fruit already expressed. When the syrup is nearly completed add the fluid and boil a few minutes to clarify. Remove scum and strain. These three fruit syrups should be bottled when warm, corked tightly, and when wanted for use add equal parts of the fruit syrup and simple syrup. They will keep a year without a change. Mix. NECTAR SYRUP. Take of Vanilla syrup, 5 pints. CREAM SYRUP. Take of Fresh cream, pint. Fresh milk, pint. Powdered sugar, 1 pound. Mix by shaking. Keep in a cool place. The addition Manufacturing Gas from Vegetable Substances, of one-half drachm bicarb. soda to this syrup will prevent rapid change. 855. Reed Organ, 358. Refrigerator, 358. Strengthening Steel Wire, $58. 1 Slits in Steel Gauges, 358. 0 Smoke Burning, 355. 2 Boring Bar, 355. 4 Geology, 358 19 Crayon Drawings, 358. 14 Lathe Work, 359. SYRUPS FOR SODA WATER.* AKE of White sugar, 14 pounds (com.) From the Food Journal. GINGERBREAD PUDDING.-Take equal quantities of flour, bread crumbs, and suct, one or two eggs, four tablespoonfuls of treacle, and a tablespoonful of ground ginger; boil, in the shape of a plum pudding, and serve with custard around it, carefully beaten up in a glass of sherry. COCOA-NUT TOFFY.-Chop a cocoa-nut into small pieces; mix one pint of milk and four tablespoonfuls of treacle; boil over a hot fire, adding foz. of butter and the chopped cocoa-nut. When sufficiently boiled, pour into a soup-plate, and leave until perfectly hard. BŒUFA LA MODE, FOR SUMMER TIME.-Brown a piece of beef (3lb.) and a calf's foot, with loz. of butter, in a covered saucepan, for an hour; then pour the grease off (the real gravy will adhere to the saucepan), and add six spring onions, some new carrots, a tablespoonful of vinegar, a pinch of flour, a dozen peppercorns, salt, a bay-leaf, a piece of thyme, and parsley. Siminer the whole on the side of the fire for three hours. The thyme, parsley, and bay-leaf ought to be tied together, so as to be taken out, as well as the calf's-foot, before serving. GREEN PEAS.-An excellent method of preparing green peas, whea small, is to cook them, without water, in butter alone. For this, 3oz. of butter are necessary for and a half on a slow fire, in a copper, or, still better, an earthenware saucepan, well covered in either case. An onion, a piece of parsley, and a lettuce-leaf or two, cut small, must be stewed with the peas, and the saucepan must be carefully shaken every few minates to prevent the peas from burning. It is better that the peas should not be washed beforehand. When peas are boiled in the water, the French cook also adds an onion and lettuce-leaves; then, ten minutes before serving, strains the water off; and, adding a piece of butter (the size of two large walnuts), and a lump of sugar, tosses them over the fire for the remainder of the time. pint cold water; boil for four minutes; have the tins covered; put them into a vessel; pour sufficient cold water on them to reach within half an inch of the top; submit them to twenty minutes' gentle boiling; keep in a cool place for use." MACEDOINE DE FRUITS.-This is certainly the best way of eating uncooked fruit, and particularly when it is not of the finest. The method is simple enough. White and red currants, cherries, ripe gooseberries, and raspberries, are mixed together in a deep dish, after being picked; sufficient white sugar, according as the fruit is more or less acid, is placed in water enough to dissolve it, and poured, when melted, over the fruit, which must then stand for two hours before being put on table. Thus prepared, it acquires the rich taste of cooked fruit, and yet retains all its freshness. If the means of icing be available, the macedoine ought to be put into a mould and iced, when it makes a most recherche dish for dessert. Waterproof packing paper is thus made by some manufacturers: The paper is covered with a resinous liquid, then painted over with a solution of glue and soot, as without this the paper will later show blotches. After this is dried, the actual waterproof coat is applied. This is prepared with two and a half ounces of powdered shellac, dissolved into two pints of water, which is gradually brought to boil, and stirred until the substance is perfectly dissolved and softened, when gradually one third ounce of powdered borax is added, until au intimate union of the substances takes place. The liquid is then left to cool, and while still hot any mineral colour may be added, such as lamp-black, yellow ochre, red ochre, iron blue, or burnt umber, whereupon it is left to get entirely cold. It is then ready for use. It is said the operation can be so quickly performed with a brush that two women can prepare 3,000 feet in ten hours. OLIVE OIL.-The oil made in the district of Oneglia is better than that of Southern Italy, and large quantities are refined before being exported. The process of refining the oil is very simple. Large shallow tin boxes are made with small holes pierced in the bottom; this is then covered with a thin sheet of wadding. Four, five, or more of these boxes are placed on frames one over the other, and the oil being poured into the top box, is allowed to soak through the wadding and drop into the next box, and so on until it gets into the last, when it runs off into the tanks. The wadding absorbs all the thick particles contained in the oil when it comes from the mills, and leaves it perfectly clear and tasteless. The oil thus refined is almost exclusively exported to Nice, where it it is put in bottles, and sent all over the world as "Huile de Nice." Olive oil is all sold by weight. The total quantity exported from Oneglia in 1863 was 6,182.490 kilos. (121,822cwt.); of these, 257,610 kilos wore shipped direct to England; 5,885,592 kilos. to France; 89,288 kilos to Genoa, to be there transhipped for America. Dissolve with the aid of a gentle heat, strain, and half a peck of peas, and they must remain for an hour some material such as clay or earin, which can oxdise when cold add the white of two eggs, previously rubbed with a portion of the syrup, and mixed thoroughly by agitation. SPITTING OF IRON AND STEEL.-The carbonic oxide which causes the spitting of steel and cast iron is considered by Caron not to be absorbed from without, but to be formed in the metal itself by the oxidation of its carbon. Iron only spits in an atmosphere of hydrogen or carbonic oxide when it has been smelted with the carbon of the iron, or provided the hydrogen contained watery vapour, by means of which a portion of the metal can be oxidized by the water giving up its oxygen to the carbon of iron; cement iron, from which cast steel, with 1 per cent. of carbon has to be prepared, must therefore contain from 2 per cent. to 24 per cent. of carbon. Carbonic oxide is evolved to a scarcely appreciable extent all the while iron is melted, and Spitting is first noticed when the metal cools. Good quality iron oxidizes when melted just as steel does, but does not spit, because the oxide formed comes in contact with but little, if any, carbon. The scintillation is in no way connected with the spitting. Iron, like steel, burns with an evolution of sparks at a red heat in pure oxygen. POLISHING WOOD CARVING.-Take a piece of wadding, soft and pliable, and drop a few drops of white or transparent polish or French polish, according to the colour of the wood. Now wrap the wetted wadding up in a piece of old linen, forming it into a pad; hold the pad by the surplus linen; tough the pad with one or two drops of linseed oil. Now pass the pad gently over the parts to be polished, working it round in small circles, occasionally re-wetting the wadding in polish, and the pad with a drop or so of oil. The object of the oil is merely to cause the pad to run over the wood easily without sticking, therefore as little as possible should be used, as it tends to deaden the polish to a certain extent. Where a carving is to be polished after having been varnished, the same process is necessary, but it can only be applied to the plainer portions of the work. Plane surfaces must be made perfectly smooth with glass paper before polishing, as every scratch or mark will show twice as badly after the operation. When the polish is first rubbed on the wood, it is called the "bodying in;" it will sink into the wood and not give much glaze. It must, when dry, have another body rubbed on, and a third generally finishes it; but if not, the operation must be repeated. Just before the task is completed, greasy smears will show themselves; these will disappear by continuing the gentle rubbing without oiling the pad. You should now be able to see your face in the wood, at least, so says the Cabinet Maker, from which we take the above directions. NEW COATING FOR FIRE-ARMS.-For some time past the officers of the American Government have been successfully experimenting with a new metallic covering for fire-arms. The object (according to the Mechanic's Magazine) is to protect the steel of the weapon from oxidation, and from the discolouration produced by the burnt powder after discharge. Other governments have also been experimenting in the same direction, the covering generally attempted to be used being, we believe, nickel deposited in its pure state by a process known as that of Isaac Adams. This process, it appears, is being worked by the United States Nickel Company in America. It is a matter of fact that owners of favourite fire-arms often have them coated with a deposit of silver, which, however, tarnishes with the sulphurous gases produced on firing. It is also very expensive, which, of course, renders its application impracticable for the army. It was always known that the use of nickel would obviate both these disadvantages, being exceedingly hard and capable of taking a very high polish. The difficulty, however, has been that it could not be deposited by any known process, although partial success has been achieved by Becquerel, Kurtz, and others. But the Adams' process of the American Nickel Company has overcome this difficulty, as has been clearly demonstrated by searching experiments. In one experiment two revolvers were taken, one of them being coated with nickel by the above-named process, and the other being carefully covered with oil. They were buried together for some time in wet sand, the result being that the nickelled weapon came out bright and and as free in movement as when buried, whilst the other was clogged and coated with rust. The introduction of this improvement will prove of great value both to the troops and to the country-saving the former much labour, and the latter much expense in preserving military arms. AUDIBLE RAILWAY SIGNALS.-The necessity for some better means of communication with railway trains, especially within the metropolitan district, during foggy weather, when the signals at present in use are almost valueless, has induced Mr. Baines, of Smethwick, to invent an audible signal, which can be so arranged that communication from a station to an incoming train may be readily effected, thus permitting the traffic to go on as safely and regularly during the prevalence of fog as at other times. The inventor provides a treadle bar at the side of the line of rail, in such a position that a train in passing along the line will depress it or tread it down, and in doing so act on a bellows-like apparatus, and cause air to be forced through a whistle or other wind instrument. The apparatus can be thrown out of use when not required by means of a wire passing to the signalman at a distance. NEW BUILDING MATERIAL.-The objection of want of novelty is sometimes raised against concrete as a building material, even by those who appreciate its advantages; but the same objection is not likely to be heard with regard to the new material proposed by Mr. Hillstream, of Lawrence, Kansas, who has discovered a means of preparing coal-tar in such a manner that it may be used not only for building, but for many other purposes, for which metal, clay, or other similar materials are at present regarded as essential. DESTROYING BLIGHT ON PLANTS.-A useful composition for this purpose may be manufactured of: -Sulphur, 350 parts or grammes; soda salt, 250 parts or grammes; gas waste, 100 parts or grammes; ashes of vine cuttings and of oak twigs thoroughly baked, 180 parts or grammes; lime, 50 parts or grammes; animal charcoal, 20 parts or grammes; ochre, 50 parts or grammes. All these substances are placed together in oven suitably heated, and are then ground and an sifted. MODELS FOR INVENTORS.-We have from time to time received requests from our subscribers, for the addresses of good and reliable model makers. One correspondent some time since proposed that some one should commence such a business, and notify the fact in our advertisement pages. This suggestion seems to have been adopted by Messrs. A. Davies and Co, of 14, Strand. They announce the adoption of a novel substance-leather-as the material for such models, which, on account of its cheapness, durability, and capability of manipulation, they consider well-fitted for the purpose. The great cost of models has hitherto prevented many inventors from ordering their construction-a mistake in one way, inasmuch as failure has thereby often resulted. Those of our readers who care to perfect their inventions before patenting, would do well to avail themselves of the facilities now offered. VACCININE.-Vaccinine is a crystalline principle extracted from the leaves of the cowberry (vaccinium vitisidea, L.) The amount of vaccinine in the shrub is about 1 per cent.; it forms long acicular crystals of somewhat bitter taste and devoid of smell. This substance is scarcely soluble in ether, better so in cold water and alcohol, but best of all in boiling water; a saturated solution of this substance in the latter yields, on cooling, a solid mass. When the crystalline substance is heated it melts to a clear liquid. It is not precipitated by either sub-acetate of lead or tannin, is neutral to test-paper, and contains no nitrogen. THE USES OF PAPER.-Interesting articles might be written upon the raw material now used in the manufacture of paper. In Australia, the husks of corn are not only made into paper but into clothing, and a good article of food is also produced from them. Paper clothing is also made in China and Japan, where a good coat can be made for ten cents, and a suit of clothing for a quarter of a dollar. In Germany, paper napkins are now introduced, the cost of them is a trifle, and they can, after having been once used, be thrown into the common stock to be worked over again. ANSWERS TO CORRESPONDENTS. All communications should be addressed to the EDITOR of the ENGLISH MECHANIC, 31, Tavistock street, Covent Garden, W.C. ANOTHER TESTIMONY. I have found your excellent publication unexcelled as an advertising medium.-J. ANDERSON, Blairgowrie N. B. The following are the initials, &c., of letters to hand up to Tuesday morning, August 2, and unacknowledged, elsewhere: Sergt. W. C., J. B. Spicer, W. Hall, J. Elwell, J. F., W. T. W., Capt. J. H., Jas. Mills, An so forth, J. W., Rob. Billing, An Amateur, Jas. Gosling, J. R. W., J. H., J. S., A Learner, All Serene, J. H. W., W. W., Revd. R. F. G., J. M., A. D. & Co., E. Wood, Fred. Foster, S. Barrow, Rev. R. C., E. Potter, R. C. B., J. H., J. W. B., T. O'B., Colourman, S. Ibbotson, Semper Paratus, H. Harrold, Hermann Smith, W. H. Child, A. A., R. L., Rev. E. Kernan, D. G., É. L. G., S. A. R., E. H. T., R. A. Proctor, F.R.A.S., A. Tolhausen, J. K. P., T. S. H., J. S. Partridge, Veritas, J. P. Jackson, A Constant Subscriber, J. R. D., H. H., J. N. Thos. Pollard, Operator, Photo, J. Cooper, W. Hall, Virtumnus, Wreath, W. Bury, Anthony Grey, Soda Water, J. Bell, Nobody Knows Who, Hy. Mace, Wood Spoon, R. N., Raymond, J. Hastings, Velocipede, Hy. W. Henfrey, Rev. E. Kernan, Steel Pen, R. A. P., C. Draper, J. H. T., Omega, Col. S. number. R. S. S.-We don't know the address. AN AMATEUR.-Your first query is an advertisement. DEWSBURY MUTUAL IMPROVEMENT SOCIETY.-John Tarnhill writes to say that there is no necessity for a new English Mechanic Society in this town, as there is a Mutual Improvement Society there already, but he admits it is mainly for those who have received little or no education. Possibly "F. S. H." (p. 448) wants something better or different. J. J. M'CARTEY.-The accounts of "Tourists' Trips" were pressed out by other contributions more in keeping with the general scope of the ENGLISH MECHANIC. Besides, the accounts were not sufficiently compact CHARLES E. MAY.-We have no room for illustrated and practical. Thanks for congratulations. notions for ocean railways. Yours is purely chimerical. OLD HUMBUG.-The deserving and successful are generally abused, hated, or envied by the weak, the vicious, and consequently the unsuccessful. RALPH WILLIAMS.-All are in print. Q. YORKE.-Mr. Charsley's velocipede was illustrated in No. 232, on page 526. THE SIXPENNY SALE COLUMN is the only place in which can appear queries sent by W. F. Trinder, T. Grist, A Subscriber, G. W. Tipton. H. LEDGER. No stamps in your letter. D. SIBSON. We do not remember your former letter The initials you refer to were not yours, exchanges T. J. O'CONNOR.-The value of your replies would be not being acknowledged there. enhanced, and we should be saved much labour, if you OMNIGENIOUS.-See reply 3877 on p. 404. would in each case prefix No. and title of the query. W. BASSETT.-We cannot guarantee the truth of any statements made by advertisers, but we know the advertiser you inquire about to be a respectable tradesman, and do not think you would have reason to complain of him. With regard to the other advertisement we know nothing of the advertiser or the result. R. N.-Should be glad to receive proffered drawing of Mordan's chuck. R. M'LOUGHLIN. We know of no such journal You should apply to the Commanding Officer of the Lond Corps of Commissionaires, 4194, Strand, London, P. M., J. N., AND OTHERS.-See notice at the head "Answers to Queries," referring to the unmbering titles of queries. Attention to tliose matters diminish the editor's labour. There were G. W. WHITAKER (Helmshore). stamps in your letter. R. B. The letters will be continued. You are mistar if you think we "care little for the thanks" of subscribers. A FOREIGN ENGINEER.-Consult advertisement page. A. L. B.-Read the articles on mathematics, I "C. H. W. B." which have appeared during to last few months in our pages. Your other query inserted. A. B. (Portsen.)-Such queries are not inserted e in the Sixpenny Sale Column. W. B. CUSTANCE (Ely).-Stamps sent are only s cient for one insertion. KANSAS EMIGRANT.-You can have the ENGLEZ CHANIC sent to you in Kansas, by subscribing, tim the post. We have already a considerable circum in the States. Messrs. Trübner's address noster-row. H. A. C.-We imagine the last of the diviners to the rout by honest old Jonathan Oldbuck, i 2 Antiquary." We certainly cannot give any infor about any living members of that honoura rather untrustworthy, profession. ERRATUM.-In "Beta's" letter on "The CompaS the Human Body," in our number of July 2 should have been that "chloride of sodium es the blood and other secretions," instead of "er i secretions;" and the quantity of potassium should is been 290 grains, and not 2oz. 290 grains. POSTULATA. "Benefit of Clergy" was a privil granted to the clergy, and generally to all atte read, in the middle ages; by claiming which, when c victed of some greater crime, they either escape punishment altogether or in part. The framers! fater laws against certain crimes-such, for instan as uttering of base coin-saw the evils attending s a course of procedure, and it became common decree that the punishments mentioned therein shot be incurred by all persons alike "without beneft af clergy." HOBBY.-Replies on "Warming Baths by Gas, have appeared in our last volume. BERIRO. We were obliged to leave over many letters on "Shorthand" from want of space. ONE IN A FIX.-Find the number of cubic feet and reduce to gallons. A cubic foot contains 6-232106 imperial gallons. A A. B.-He would be liable to a penalty. T. O'BRIEN of North Wall, Dublin, writes:-"I h H. COULSON.-Write him that you have commu W. JOHNSON.-We cannot undertake to examine report on inventions for obtaining perpetual motion OXONIAN.-One query inserted. The others have bec answered in back numbers. A. NOTTLE.-Our space is too valuable for the discu sion of crude theories like yours. G. E. D.-M.S. came to hand. THE MICROSCOPE.-A. Allen says:-"It would affor J. H. BUFFHAM.-Both letters received. We fear thst |