TURRET CLOCKS. form an aliquot part of 12, we must make an allow- P.S. Your highly-instructive correspondent "F.R.A.S.," whose papers it is a pleasure to peruse, recommends "Heather on Mathematical Instruments and Dialling Scales," but I venture to say that although its contents are most valuable, and its directions on dialling quite sufficient for those to whom the art is like A BC, yet it is not full enough for others, nor does it give any directions whatever for the construction of declining and reclining dials. The hour arcs may also be found by that useful rule, the sector, but with much more trouble and far less accuracy than by the method prescribed, which is nothing more than addition and subtraction. In last letter, page 15, in the diagram, for "60" read "68°;" and for the "angle A C B 309 + 90◄ " read "angle A C B 27° + 90°." EXPLANATORY. SIR-I cannot see anything in my letters entitling "FRA.S." to suppose I had him in my thoughts when I referred to what the German poet has said about "strong men." All the same, I would submit to him my doubts whether it befits a real lover of science, as he undoubtedly is, to "eschew discussion ab initio on every moot point whatever; " nor can I think that the abandonment of "a winning cause" (in itself hardly a commendable thing) would justify the course of dropping an argument when one finds one has made a mistake. ber of strokes is determined by the distance of the notches in the locking plate, which, in this case, is also the pin plate, and works two levers. The lifting piece B must fall quite dead, or it may fail to stop the train, and therefore the detent F must not touch the bottom of the notch. The hour-discharging mechanism is the same, only then the locking plate I have brought no charge of either sort, however, does not work the hammer lever, and the lifting piece against F.R.A.S.," for whose scientific attainments end is not pressed down, but raised by the pin in the and surprising general accuracy (when one considers the wide range of objects he treats of) I have the high-going part, I said nothing about the dial work, or the est possible respect. If I were disposed to do so, I way the pointers are driven, because it is not done in should be far more inclined to dwell on his spectrum the usual way. analysis illustration than on his theory respecting object glasses. The latter is a matter of opinion, the former a question of fact; and any one who is desirous, as I confess I am, of seeing the truth laid as clearly as possible before people, might fairly object to a statement which is opposed, I submit, to the very principles on which spectroscopic analysis depends. But in praising (as was just) our contributor T. A." I was not "making a cap; "so that I need dwell no farther on a discussion which I also have desired to drop.* RICHARD A. PROCTOR. There was an old thirty hour clock, which had been going for nearly two hundred years, and was about showing the hours. About three years ago I put worn out, already in the tower; it had only one hand, machinery to it for striking the quarters. Change published in the ENGLISH MECHANIC. I also put wheels were used, and I sent a description, which was another hand to the clock, showing the minutes. The hand was next the dial, fastened on a tube. I should method was simple, but objectionable, as the minute prefer to use dial wheels in the usual way; they would be much more costly than change wheels, When I removed the old clock, I found the wheels none the worse for their nearly three years' work. The quarters had been striking at their regular intervals, and I had been well repaid for my labours by hearing their musical sound. on four bells, as at Westminster. It can be done very well with six bells, if they are in the key of E flat. I should be happy to describe the machinery, together with a novel method of fixing the hammers to the bells, if it would be of interest to your readers. THE ILLUMINATED PORTION OF THE SIR,-I think Mr. Beardsley is right in not accepting the explanations alrendly given as exhaustive; for if, when the moon is only two days old, an imaginary line be drawn from its centre, and made to pass through its surface in the centre of the edge of the illuminated are and prolonged, fa would not cut through the sum at all, but would be almost at right angles with that luminary; but a line drawn from the centre of the moon through that part of the surface which is in the centre of the illuminated half (for we all know that one-half of the moon is always to the sun was prolonged, it would cut through the centre of the sun. Now, Sir, when the moon is about the end of the first or third quarter, one-half of the illuminated portion is turned towards the earth, the other half of the illuminated portion is turned away; therefore, in this case, the centre of the whole illuminated moon, and the centre of the illuminated edge as seen from the earth, coincide; so that in this part of its orbit the illuminated portion of the moon's disc is fairly directed to the sun, allowance being made for optical effects. W. F. SWALLOW. BREAD-MAKING, SIR, I cannot pass over "T. Estee's" letter with- THE AUTHOR OF THE ARTICLE ON UNFERMENTED 'SIR,-"T. Estee" makes a vital mistake in confounding fermented with unfermented bread. The with a little water, while no amount of kneadlatter may be kneaded into a kind of raw paste ing will effect this change in the former, which, for persons, including the writer, cannot eat unfermented this reason, sits more lightly on the stomach. Many bread. Yeast acts chemically on flour, "powders "act any bookseller for theory, aud when you have spoiled mechanically. Buy a shilling treatise on baking of a few bakings and brewings you will find out how good sweet bread is made. If you value this commodity your trouble will not be lost. Don't try to make good bread out of bad flour. Don't let rice come in contact with yeast. NEW SUBSCRIBER. CARBURETTING GAS. "Ado CRIMINAL LITERATURE. SIR, A clergyman, on the 31st ultimo, wrote under the above heading thus to the Times:"Sir,-A short time ago you recorded the conviction of A correspondent asks why I use cast iron wheels several vendors of immoral prints, not on the prosecution in preference to brass ones. Simply because iron SIR,-" Adolescens "asks, at p. 645, Vol. X., if he can of the Government, but of a society whose successful wheels cost only about a quarter of the price of brass fit gas burners to his 4in. condenser lanterns? and as I operations have made them insolvent. To-day you ones. No doubt the train is a coarse one, but with have done this for some years past, I am happy to record the words of Mobbe, the murderer:-I had weight enough on the barrel it will do its work well. tell him how I fitted them, as " V. W." page 659, proseen a picture of the man Baker murdering the girl in For the going part, 150lb. is hung on a 6in. diam. poses a method which I think would prove a very the hop-gardens.' Week after week the illustrated barrel; that is a great deal, but with a gravity escape- dangerous one, and 1 should like to know if he has records of crime are circulated over the length and ment it does not interfere with the time-keeping pro- actually used the arrangement he describes. breadth of the land. In my country parish the Illus-perty of the clock. I believe, from what I have seen lescens" will have to select very fine hole argand trated Police News has a large circulation. Its pictures of the performance of the clock-and I kept it going burners (32 will be required for such powerful lanterns represent crime in varied phases; its letter-press is in my workshop during the time the hour and quarter as he has), and they must be fitted with a conical ring explanatory; but its most damaging part is to be pasts were being done-that it will not vary more than round the outside of the burner, to cause a current of found in its advertisements. And yet as the law a minute in a month from mean time, when the pen-air to impinge upon the outside of the flame, and thus stands I much question if it can touch this publica-dulum, of varnished steel, is regulated. It takes about compress the flame to a smaller diameter. I have tion. Has no M.P, time to consider first and give half a minute to wind the going part up, and by lift- found with such burners that a common straight notice next of a motion upon this subject? Surely ing up a ratchet lever, geared to the third spindle, chimney gives the best light, but he must fit fine wire crime in England should have its share of considera- from below, a maintaining power is kept up. The gauze under the centre of the burners to obtain a pertion with crime in Ireland, and it strikes me that it is weight on the barrel of the hour part is 350lb., and fectly steady flame. Ordinary coal-gas will not give somewhat important to protect innocence as we lifts a hammer high enough to bring out the sound a sufficiently powerful or white light for lanterns, and spread education; but it unhappily appears that well from the tenor bell, weighing, I should say, 16 or must be carburetted, as described by "V. W.; " but I while we are squabbling as to whether religion may 17 cwt. The quarter bells in proportion. I obtained advise Adolescens" not to attempt to make a vessel be taught in our schools, we are permitting vice to be the change wheels of J. Buck, Newgate-street, but inside the lanterns, as, unless he is an experienced taught everywhere." Mr. Lloyd, 135, Steelhouse-lane, Birmingham, has hand, he will be very likely to have a dangerous explosent me his supplementary wheel list, and it appears sisu, as the heat of the lanterns in use would soon he can supply many other numbers of teeth besides cause the naphtha in the tin vessel to volatilise too those I mentioned, amongst others, the 130 tooth wheel rapidly and burst the vessel, or make a smoky flame I wanted, from excess of hydrogen vapour. A simpler and cheaper plan is to use a common glass round pickle bottle, which can stand on the floor or table, on one side of the lanterns, out of the way, and the whole affair will not cost 64., and yet answers the purpose admirably. Two pieces of compo. pipe, each 6in. long, must be fitted through a good bung in the mouth of the bottle, the inner end of one being flush with the bottom of the bung, and then curved to an elbow. The other must be thrust through the bung about half SIR,-I send you a few of the tests that have been way down the inside of the bottle, and the outer end put upon a telescope in my possession. It is 3in. also curved to an elbow. This will be for the inlet for aperture, 4ft. focus, 3 eye-pieces of 35, 60, and 96 Allow me, Sir, in conclusion, to say I like the new the gas. Now tie a sponge or large-sized argand cotton diameters. With the lowest power I can discern shape the ENGLISH MECHANIC has taken, and that I wick to the inner end of the pipe, on which a plug of Jupiter's satellites before sunset, and with the high-hope it will continue to be successful! I have sub-wood or a cork with a hole through it is fitted tightly, est power I have observed the transit of the satellites. scribed from the first, and have always endeavoured It shows distinctly 4 stars in the trapezium of Orion, to make it known to my mechanical friends. it splits Castor easily, shows the companion of Sirius, also Rigel; Cor Caroli it shows beautifully with the lowest power; Mizar also. I have seen the trapezium through a 3in. and 4in., and see 5 stars in one, and 6 in the other. The 3in. shows the belts of Jupiter more distinctly than a 7in. silvered glass reflector. If "F.R.A.S." can give me further test objects, I shall be greatly obliged. If such men as Mr. Edward Henri Todé (who started, and for some time edited that journal), and who afterwards started and edited the Fenian), and others like him, cannot be induced on moral grounds to forbear from publishing their filthy broadsheets, it is time for the law to interfere. I trust therefore you will allow these few lines to appear, that now, when there seems a chance of the matter being agitated, we, who are represented by you, may not incur the reproach of having remained silent. KAPPA. TEST OBJECTS. There is no reason why every village church, if it has a bell, should not have a good public clock. A clever blacksmith, with a lathe and slide rest, could put such a clock as I have described, up in almost any town, for £25, if it only struck the hour, and make very good wages. The bearings for the spindles, I forgot to mention, were flat bars of iron, screwed to the wooden frames. The pivots work in brasses, rivetted in the bars. The pallets are made of sheet brass, and the 'scape wheel of steel. The pendulum bob is a cylinder of lead, weighing 15lb. SYDNEY MADDISON, Hastings. I was engaged previously in putting up, in the tower so as to keep the wick distended, which will then hang down to the bottom of the bottle. Pour in about halfa pint of benzole, not rectified, but what is sold as ordinary benzole by chemists, at about 18. 6d. a pint. Then close the bottle, and connect the inlet pipe to a gas branch (after taking off the burner), and connect the end of the outlet pipe with the pipe leading to both lanterns. This latter connection must not be of india-rubber tubing, but either compo. or flexible tubing (to be got at all gasfitters), as the india-rubl been once broken and the sod rotted. It is not adapted | material may be mixed in proportion, as we may wish NEW CARRIAGE BRAKE. SIR,-In your excellent journal of the 28th of January last there appears a notice of a new carriage brake. On reading the description of it, I was much surprised to find that a carriage or cart brake exactly The teeth or tines of the fork are cast steel, self-similar in every way to that now patented by Messrs. sharpeners, of the simplest possible form, 8in. in Parry and McHardy was exhibited at the show of the length, and are secured to the bar by a clamp, or Highland and Agricultural Society of Scotland held at stirrup, and wedge, and can be taken off or put on in Dumfries in the summer of 1860, and that to it was the field by any person, as each tine and stirrup will awarded a premium of £10. It attracted great attenfit the fork-bar of any sized spader. Great care has tion, and was universally approved of. It was made been exercised in determining the strength necessary and shown by Mr. Thos. M'Cririck, agricultural in these parts; but if broken, and no extras are at implement maker, Old Cumnock, Ayrshire, who has hand, may be replaced by any good blacksmith. A team in ploughing a furrow one foot in width long been well and widely known in the south and west of Scotland for his many useful improvements travels 8 miles to each acre (besides turning corners), and ingenious and original inventions in connection or 16 miles in ploughing two acres, which is a good with agricultural machinery, but whose diffidence of day's work for both team and man, and is not always disposition (which is so frequently found allied to true well done with a furrow of that width; if a narrower and original genius) has hitherto kept him from one is turned, the travel is increased. The five tine patenting any of his many inventions; and as he has spader works three feet in width; therefore six acres Dow considerably passed the allotted span of threeare spaded to 16 miles travelled, or as much as three score years and ten his career as an inventor may be pair of horses, three ploughs, and three men will do: said to be over. Still it is right that he should not be and but 275 miles of the team is required to spade 100 robbed of any honour which justly belongs to him; acres; making a garden bed of the grain-field at less and undoubtedly he is the original inventor of "the than half the cost of ploughing; and this may be done new carriage brake" described in your journal of the by any one able to sit on an easy seat and drive the above date. Messrs. Parry and McHardy may not team-no walking or other labour required. have seen Mr. M'Cririck's brake, and they may have been original inventors also; but even if such has been the case, they have been forestalled in it by Mr. M'Cririck by nearly ten years. A photograph of the brake, and of the cart to which it was attached was taken at the time. Could we have obtained a spare one, we would have enclosed it; and we may do so yet, when more of them are taken. A. B. TODD, Old Cumnock, Ayrshire. SIR, The ENGLISH MECHANIC of the 1st April, 1870, has just come to hand, in which I have noticed a letter that bears the initials of "S. B.," who says he was in hopes that some of your "qualified" correspondents would have answered "Veritas." because a fraction is a part only of a whole. It "The I-005998 is a fraction." This is not the case, "S. B." had stated that 1005998 was the proportion, ratio, or quotient of two distances or values, he would have been nearer the truth. Mr. S. B." has one fundamental error in his calculation of the mean diameter of the sun-namely, he whereas, he ought to have used the mean semi-diameemploys the equatorial semi-diameter of the earth, ter in order to arrive at a mean value of the sun's diameter. I beg to submit the following facts as given by It will thus appear that the values of "F.R.A.S." and "S. B." are wide apart. Perhaps the best that could be done under the circumstances of the case is to appoint a scientific pope for the purpose of a final settlement of our scientific differences. VERITAS. BOOKBINDER'S CUTTING PRESS. SIR,-I send a sketch of a bookbinder's cutting press, although I firmly believe it will be "Love's labour lost," for those whose trade it is to provide book binders with cutting presses do not always turn out a good press; but as Maschil" and others have inquired about the apparatus, I thought it would perhaps be best for the interests of "our" MECHANIC to comply with their wishes. Persons out of the trade seem to form the most erroneous ideas of bookbinding. gilding leather, &c. I should much like to see some tightly fixed, which causes the cheek A to recede from or approach to the cheek B. GG are the heads of the two screws, through which are two holes, about of an inch in diam., in which the press-pin, or lever, which is about 20in. long, is inserted. HH are two strips of hard wood, placed about 1in. apart, for the plough to traverse .in. The cutting press here shown, is 2ft. between the screws. II are two guide rods, firmly fastened in the cheek B, which keep the cheek A in its proper position. AB INITIO. THE "ENGLISH" VELOCIPEDE ON A NEW PRINCIPLE, AND OUR ENGLISH ROADS. SIR,-For many years my attention has been directed to the subject of velocipedes, both theoretically and practically; and when your third volume was coming out I saw it was treated of therein, since which time I have been a subscriber. The wheels, as will be seen in the drawing, are The frame of this velocipede consists of angle Iron This latter remark leads me to refer to the worker A THINKER. The German On the 15th THE ENGLISH MEC HANIO. "An Old Subscriber" writes: "Allow me to congratulate you on the decided improvements recently made in the ENGLISH MECHANIC. Issuing the index with one of the numbers, separating the advertisement sheets from the body of the work, giving the contents on the outside page, increasing the size and at the same time improving the form of the publication, giving a list of the new patents -these, with what we have had before, combined with a greater variety of contents, and, I think, a certain sifting of the Notes and Queries department, make the ENGLISH MECHANIC AND MIRROR OF SCIENCE the principal scientific journal published. You need not stoop to the miserable and deceptive manœuvre of offering to give away prizes for nothing,' in order to bolster up an artificial circulation; you can stand on your merits. BENNETT'S DIE CHUCK -Edwin Baker writes:Will you allow me to correct an error in last week's number, with respect to Bennett's die chuck? Mr. Bennett invented and made that chuck while he was in the employ of the Messrs. Holtzapffel, and not Mr. Evans's, as it was given us to understand. I question if Mr. Bennett ever was in the employ of Mr. Evans at all," A GOOD RECIPE FOR HOME-MADE YEAST OR BARM.-Place a quart of malt in some wooden vessel, boil one ounce of hops in three quarts of water one hour; when clear from the vapour arising therefrom your over the malt so as just to scald it. Cover over with thick flannel or baize till morning, when it should have a frothy thead on; strain. Put half-apint of this liquid to 71b. flour, set your sponge over night, in the morning mix and bake in the ordinary way. This is an excellent recipe, and was given me by the late Sir Charles Napier's cook. Nothing can equal the sweetness of bread made from this.-W. I. MEDICAL OPINION-Dr. Burdwenii in a letter says: "I love your MECHANIC, but I dislike to see medical questions, and often very absurd ones, asked through it. It is almost impossible to give an opinion without seeing the patient, and in most cases it would be dangerous to act on good avice given under such circumstances." NAME OF STAR.-"Conjecto" writes:-"Allow me to thank Omicron (page 656) for the (probable) name of the star which I saw in conjunction with Venus on the evening of the 3rd Jan. I am somewhat surprised that no other mention has been made of this (to me) most interesting sight. I have watched many sented by Venus and this star, which I watched from occultations of stars by the moon, but have never been so pleased as with the beautiful appearance prethe early evening until they disappeared together behind the distant tree-tops. The star was at least as bright as Jupiter's 3rd satellite, and shone with a steadiness quite remarkable for a fixed star." TO MAKE GOOD BARM.-"T. S. T." says:-" Boil loz. of good hops in 2 quarts of water an hour. When strained and milkwarm, add lb. of brown sugar and lb. of good mealy potatoes previously boiled and squeezed stone jar, and place by the fireside for one day and two nights. When it has done working put in a handful of salt, and cork the jar tight and place it in a cool corked after pouring any out. It is well to add a fresh place. This you may use immediately. Keep it closely for use when made six months. At about four o'clock quantity before the whole is used. It will keep as well set your barm-that is, get two or three potatoes (or one good large one), mash them up very fine, put them in a sieve and strain about three pints of lukewarm water over them into a crock (throw away the remainder), then throw the barm down on the top of this, then shake a couple of handfuls of flour on the top of this, and cover with a cloth and let stand before the fire till about 9 o'clock-by this time it will have risen, and fallen a little again. A regular quiet heat must be kept to it. At that hour throw a little salt through It should read 4810 square yards, being the flour, mix the barm well through the flour, and if too dry add a little warm water. Work it up until 69yds. 1ft. 10in. each way." Next morning, when "J. K. P." also writes:-"Under the above head-quite fit to put into the oven. well risen, divide into loaves (two quarts of flour to a ing, on page 23, you state a German mile at 1806 yards. loaf). After making the loaves, lay them on the board 'stunde or Now a German mile is what they call a hour, ie, an hour's walk, and Adcock's Pocket and cover with a cloth for about twenty minutes. Do Book gives 10126 yards, which agrees with Cham- not shake any flour on them at night after mixing the bers' Encyclopædia." Adcock states the Turkish mile barm in the evening. About fourteen quarts of flour at 1826, while you give 1626, and I have no means of to this much barm (three pints of made barm) -Buns telling which is right. A German short mile' is for breakfast: 1lb. of flour, whites of two eggs, 2oz. 6859 yards according to the Imperial Dictionary, and butter, two spoonsful of barm; mix together with milk to a light dough, put at the fire for one hour to is quite enough for an hour's walk for me." rise-five minutes will bake them. Mix as for a cake.' I will be as brief and as plain as I can in what I am about to say, for my aim is the diffusion of clear views of the correct principles of velocipede construction, and to assist in its inauguration as a really useful machine. I have had several inachines made on different principles and designs. One, a three-wheeler, had two driving wheels, between which the rider sat. It could be worked up hill pretty well. Afterwards-thinking back, it would be easier to get up hill, I had one that if one were made for two to work, sitting back to very reverse anticipated! Two could not possibly made for two; and what was the result? Why, the work it up anything like a hill, and, strange to say, one could! This was about two years ago, since which time I have endeavoured to trace the reason of this; and about twelve months since I succeeded in what I thought might be some explanation of it. Suppose a man had to take two sack-loads of potatoes (weighing, say 5cwt.) a mile, and he had before him the choice of a wheelbarrow and a truck (a two-wheel handcart) to take them with; and granting that the truck weighs EXTRACTS FROM CORRESPONDENCE. as light as the wheelbarrow, which should we suppose he would choose? Common sense would say the INTERESTING FACTS." Pneuma" writes as truck, because he could balance the load on it, and all he would have to do would be to roll or wheel it follows:-" In your number for March 25, page 23, along. In the case of a wheelbarrow, he would have is a small paragraph headed Interesting Facts, to lift half the load before he could wheel the other among which are two or three statements which half. Now, as wheeling a load is easier than carrying perhaps you will allow me to correct. a load, it is evident that the wheelbarrow is a foolish mile is much more than 1800 yards. The German vehicle where a truck can be used. Let us look again short mile is 6859 English yards, and the German long at the above velocipede. We see that the spokes of mile 10126 English yards, and the Hanoverian mile the driving wheels act similarly to a man's legs in a 11559 yards (see Kelly's 'Cambist'). The greatest wheelbarrow, with this difference, that whereas in a depth of the sea is more than 4 miles. wheelbarrow a man's legs have only to overcome the November, 1849, Lieutenant (now Captain) Maury, in friction of half the load, in this machine the wheels the 'Fancy,' let out 5700 fathoms of line (about 6 miles) have to be made to overcome the friction of nearly the without finding a bottom. This was in lat. 31° 59' N. whole of the load before it can be moved. Again, let and long. 58° 43′ W. This depth exceeds the height of Mount Everest, in the Himalaya, by a mile. us now look at the truck. Its two wheels act as guid-statement respecting the English acre is evidently ing wheels, at the same time bearing the load, and the man's legs act as the spokes of a driving wheel. Now, if a velocipede were made on this principle, the question would be, Would it be easier to propel than the other? I was soon convinced that it would; and having proved it to my own satisfaction, I have laid down this maxim or principle as being the correct one in the construction of all velocipedes-viz., that no more weight should be placed on the driving wheel than is actually necessary for driving purposes. To illustrate this still further, take the case of a luggage train. Suppose that instead of the locomotive drawing its load of 200 tons behind it, the whole of the 200 tons were to be placed right over and upon DR. USSHER'S ADVICE.-Hy. Good sends us the the driving wheels of the engine, what would be the following." Will you allow me to point out one or consequence? Why, the power of any ordinary locoFirst of all, it two errors in 'Dr. Ussher's Advice?' motive would most probably fail in endeavouring to overcome the enormous friction caused by the load is not Dr. Ussher's, for I have now before me Cowabove. Observing the above principle, I designed per's Poems, in which I pasted a label more than the following velocipede, which at a glance will be thirty years since, a copy of which I enclose. perceived to be self-adjusting as regards the load on quite sure that it is an oversight of the doctor to the driving wheel. It also meets every other require'For oft-imparted knowledge doth ment that is looked for in the velocipede-viz.: Diminish learning's store." 1st. It is light and simple in construction and working 2nd. It is perfectly safe, easy to work, and You will also observe that the words 'I often lent comfortable to ride. 3rd. It is easy to guide,' and with all the wheels being free of each other. it turns sharp corners. 4th. It has a minimum of friction consistent with a maximum of power, as both hands and feet would be used; but I never found it to require more than the use of one hand with the feet up the steepest hill, the driving wheels not slipping. wrong. The I am FREE SCHOOLS OF INDUSTRIAL ART.-A say-plan is now before the Massachussets State Legislature, U.S., by which every town of a certain size will be compelled to maintain, in connection with its town school system, an evening school for education in "the industrial arts." These evening schools will be open two hours on five evenings in the week, with a competent master or mistress for every 25 pupils. Travelling loan collections of models andcasts of works of art and design are to be formed, the expense of which will be borne by the commonwealth. A monthly system of examinations is also proposed, with the exhibition of meritorious works. should be it often lent.' If some of your subscribers " "St. George' REPLIES TO QUERIES. [1908.-ETCHING RAZORS. - For H,SO, read H2SO4.-F. B. KNOX. has not suffered from the malady from that day | The content may also be found by obtaining the solidity [1967.]-PESTLE AND MORTAR.-Sulphuric acid 3 16 this go over the work a second time. Oil of vitriol diluted with water and applied with a brush makes a good black stain.GUILLAUME. [2098]-DISCONNECTING STEAM PIPES.-Putting brown paper between the flanges and the indiarubber washer will keep it from adhering to the iron. I have found this to answer well.-ABERDEEN MECHANIC. [2098.]-DISCONNECTING STEAM PIPES.-Canvas steeped in red lead is frequently used instead of india rubber; or if the flanges have been faced, a little plain red lead will do. Another way-Steep plaited gasket in whitelead, and by working it in the hand it may be used several times; or, instead of whitelead mix blacklead with boiling oil into a paste and work well into the gasket; if the flanges are rough or uneven, equal parts of redlead and whitelead with fine metal borings. In using gasket, canvas, &c., care should be taken that the ends do not overlap, but meet nicely. ZINC PLANT. In reply to "Saul Rymea's" In reply to "Professional," p. 637, I beg to say that I [2044.]-REPOLISHING STEEL WATCH CHAIN. -"H. B.M." should rub his chain between his hands, dusting them with fine flour of emery from time to time; he will soon get it tolerably bright, then fasten it to his bunch of keys which he carries in his pocket, and the chain will soon become burnished, Proved. -F. H. [2055]-COIN OR COUNTER.-My statement on p. 20 is incorrect; as stated by Mr. Batty, the pieces referred to are certainly weights.-HENRY W. HENFREY, M.N S., &c., &c. [2059.]-CEMENT FOR AQUARIUM.-1 India- [2062.]-SODA WATER BOTTLING MACHINE. [2110] TO REMOVE RUST.-Plunge the hooks into a bath of diluted hydrochlorie (muriatic) acid, say 1 pint of acid to 1 quart of water. Leave them there for twenty-four hours, then take them out and rub them well with a scrubbing brush. The oxide will come off like dirt under the action of soap. Shoult any rust still remain, as it is likely in the corroded parts, return the hooks to the bath a few hours more, and repeat scrubbing. Afterwards well wash in plain water several times and thoroughly dry before a fire. Lastly, a little rubbing with oil and fine emery powder will restore the polish. Should grease have mingled with the rust, it is necessary to remove it with a hot solution of soda, before submitting the metal to the acid.-GUILLAUME. [2116.]-WATER POWER.-I find that my answer to this question last week had reference to 200 cubic feet of water per minute falling from a height of 30ft.. whereas the question was: What would be the power of 200 gallons per minute falling from that height? The answer should have been 14 h. p., reduced to a useful effect of 1-h.p.-C. S. 1 6 [2117]-CEMENT FOR IRON ROOM.-" T. S. H." will find the following to answer his purpose: 1 bushel of sand, 4lb. of red lead, llb. of whiting; mix up with boiled linseed oil and a little boiling water.-SWEEP Ho. [2119.]-CLEANING PIANO KEYS AND TEETH. -If the discolouration does not extend much below like its original condition is obtained, then smoothed the surface, the ivory may be scraped till something with very fine glass paper, aud finally polished with a leather buff and whiting. As to teeth, if "Ilex" means natural ones, which have simply obeyed the laws of nature, I with him should be glad to know of any to their present or future usefulness, but such a remedy means to restore their pristine whiteness without injury I fear, will be as easily obtained as a mill for grinding old age into youth.-F. F. C. [1820]-HOW GLASS FOR CHURCH WINDOWS IS FIRED.-When the windows are painted with the requisite colours, they are placed in an oven much resembling the ordinary bakehouse oven. Around this oven are iron shelves, upon which are placed large iron plates very level; on these plates the glass from the windows is placed; the oven is then very gradually heated. The beat is adapted to the nature of the colour required; if the flux is hard the heat is much greater than when soft. This requires great nicety, and perfection can only result from much practice. It sometimes happens that one or two moments of too Again, cubical content of globe, taking d = diameter chisel-and apply to J. Blakeborough for a patent tap, prolonged an heat, will spoil an entire batch of window =3·1416. = ... V V cubical content π 6 (3d 2h) h2 BLUE RUIN. [2094.]-SUBMARINE LAMP, &c.-I send the fol- d Diameter 39 8 = Solidity s = d x 2618 (3d), From three times the total length of vessel subtract If = 10ft., and d = 4ft., we have = 16 x 2048 × 26 = 108 9088 cubic feet. [2121.]-BOILER TAP. Had "Gilder" followed the suggestion of some of our correspondents, adding oil. It will not stop the leaking, but make the tap use"proved," he could not have recommended emery and less. Let" R. A." pound a piece of freestone, and sift it through a piece of coarse packsheet. Mix this with water and grind it, adding no sand, but keeping the plug wet for five minutes before drying the plug and bill. This, if properly done, will make the tap perfectly tight. Proved-CONICAL PLUG. [2121]-BOILER TAP-I should advise "R. A." to take his tap out-he may do so with a hammer and which he may fix himself. It will not leak for years; and then it can be made good without taking it off. Address J. Blakeborough, Commercial Brassworks, Brighouse. Yorkshire.-SWEEP HO. [2126.]-JOINING WIRE.-" E. H. B." will make the best connection by first cleaning or scraping with an old knife three or four inches of the wire ends; cross them at right angles, hold firm with a pair of pliers, and twist the ends tight around each other; then solder with rosin.-SWEEP Ho. [2131.]-PUMPS.-In reply to Plumber," although this does not seem to me to be plumber's work, a turbine may be made to receive a supply of from 40 to 50 gallons per minute (say 45) with a fall of 8ft, and to deliver water at a height of 70ft. above it at the rate of 3 gallons per minute. This is a small quantity, but it is as much as can be done with the power and under the circumstances named, A water ram would be a more suitable appliance, and would cost less. would deliver about the same quantity.-C. S. It [2139.]-BOILER.-If John Jones will state, through the MECHANIC, the length and diameter of the boiler he intends to put down, and what is the greatest height he can put his water-tank from his steam boiler, and the pressure of steam at its highest point, I will send him a rough sketch of a self-acting feed that I have at work at present on two boilers working at 15lb. per square inch -ANTI-EGYPTIAN. [2143.]-SOFTENING CAST IRON.“ G. B. K. cannot soften cast iron. But by chipping off the surface or skin with a chisel he will find it easier to cut -BLUE RUIN. [2152.]-PAINT ON BICYCLES.-Grind the dry colour; thicken with good pale copal varnish, then thin with turpentine; lay on evenly with common paint brush. This should have very dull appearance, and dry very hard. When thoroughly dry, varnish with good pale copal (or carriage) varnish; put in a warm place, and away from dust (after varnishing), until thoroughly dry.-W. H. [2160)-PRESSURE ON COLUMNS.-If"W. R. E." will give the length of columns, and state whether they are composed of cast or wrought iron, I shall be happy to answer him.-BLUE RUIN. (2100)-PRESSURE ON COLUMNS.-This question cannot be completely answered in its present following figures, from the Engineer's Pocket Book," form, as the weight of the columns is not given. The may, perhaps, suffice:-Solid cast-iron columns, 34in. diameter, will each bearHeight in feet | 6 1 8 10 1 12 14 16 Load in cwts. | 282 214 | 191 | 172 | 156 -J. B. 136 [2160]-PRESSURE ON COLUMNS.-According to Molesworth, the breaking-load distributed equally on 34 376 [2183.]-TAXIDERMY.-There are a few chapters on the above, as well as on skinning and preserving birds, reptiles, fishes, &c., at the end of "Beeton's Book of Birds," which may be ordered through any bookseller.-VIVIS SPERANDUM. [218] SULPHATE OF LEAD BATTERY.Some time ago I decided to fit up my house with some half a dozen electric bells. I got all the apparatus I but took some time to consider this matter, as I wanted required from a firm at Halifax, except the battery. one which would fulfil two conditions-cheapness and constancy. I at last decided upon a sulphate of lead, one which I must say has answered perfectly both. I made it up myself as follows:-I obtained 6 glass pickle jars and 6 porous cells, I then made 6 cylinders of thick sheet zinc to go easily into the glass cells. I got some No. 8 copper wire and wound into spirals to fit loosely into the porous pots. After placing them all in their proper places I mixed up some sulphate of lead with water and nearly filled each porous pot. I all four columns = 596- whereby L is the length then filled each glass cell within an inch and a half of the top with clean water, adding some crystals of Tidman's sea salt, and after connecting the copper spirals of the one cell to the zinc cylinders of the next all through the series, leaving a zinc unconnected at one end and a copper unconnected at the other end, it was all ready for use. I placed it upon a shelf at the top of my cellar and connected the wires communicating with my six rooms and bells. It is now nine months since it was set going and appears as good now as at first. It cost me for material about 153,, the cells are quart size, I am very proud of my handiwork, and believe it quite as good and far cheaper than the trade would have supplied me.-A GOOD BOY. L 17 of a column, assuming L to be greater than 15 times statement I confirm.-W. H. I. P. [2162-SEAMS OF MACINTOSH.-Nothing is better than india rubber dissolved in naphtha.-J. B. [2169]-PROBLEM.-Through A draw A F parallel B H But since BH have sometimes to wait a considerable time, I generally manage to get what I am in search of.-H. B. MILLER. 12215.]-BRONZING BRASS.-Some time since, I asked through these columns how to bronze the ferrules of fishing rods, without eliciting any reply, I fortunately found a tradesman who kindly told me, and I succeeded perfectly in giving the brass an appearchloric acid. Clean the brass well to get rid of lacquer ance of real bronze. The recipe is, ld. of oxide of iron (rust), 1d. of arsenic, mixed in a pint of hydroor grease, and apply with a brush until the desired colour is obtained. Stop the process by oiling well, when it may be varnished or clear lacquered.-VIVIS SPERANDUM. [2218.]-GEOMETRY.-Theor.: three circles being given, the lines respectively tangent to 2 of them bave their intersections on the same straight line. "X. X." asks a geometrical proof: perhaps the following Draw a plane through the 2 might satisfy him. centres; on each side of this plane we can construct one tangent to the 3 spheres constructed on the circles; these 2 symmetrical planes will cut the plane of the centres on the same line. Now, supposing 3 cones respectively tangent to 2 spheres, those 3 cones will be langent to the 2 planes, and have their vertices on their line of intersection, and those vertices are the intersections of the tangents to the circles. Other demonstration, Analytic, v. Salmon, "Conic Sections," No. 117.BERNARDIN. (2220)-SOLDERING.-File the end of the iron pipe bright, then see that the soldering iron (which should to BC, and equal to the difference between A C and [2188.-VELOCIPEDES, &c.- In every case a I can.-JOHN W. BEDFORD. more convenient to get at for cleaning and repairs—a [2224]-BOILER.-In reply to inquiries from "One in a Fix" respecting the use of Carrigeen moss to prevent the incrustation of boilers, I was recommended reason why it should not be put in feed cistern and to use it by an inspector of boilers. I do not see any drawn directly to boiler, provided there is no overflow from cistern that would carry off the moss as waste. The quantity I would recommend for 50-horse boiler would be a stone weight per week (the present cost of the moss is about £10 per ton here in Ireland). I cannot speak of its merits as a purgative of a very foul boiler, as I never allow a scale to get on mine; but I do think from using it that it prevents the formation, and I am certain that it is a very harmless article. [2225.]-VACUUM IN CYLINDER.-The exhaust steam leaving a high pressure cylinder causes no vacuum, but, on the contrary, should the passage be too small it often causes back prefsure and compression on the return stroke by not fully and easily exhausting.-H. SUMNER. [2227.]-LIFE PRESERVERS.-The life preservers found on all sea-going vessels are composed of slices of cork, neatly arranged and compressed together so as to form a zone 30" in diameter, 6" in width, and 4′′ in thickness; it contains about 12lb. of cork, is generally covered with painted canvas, and will support 6 persons. Inflated belts are liable to get punctured, and so tendered useless.-VIVIS SPERANDUM. [2227.]-LIFE-BELT.-" Avalonensis" would find Aquatic "the buoyant waistcoat" made by the Safety Company "better for boating than any of the ordinary life belts. My friends say they are the best and most portable things of the kind yet out.W. H. I. P. [2228.] ADDRESSES WANTED. If "Foreign Correspondent" will get the Mineral Statistics of Great Britain and Ireland," by Robert Hunt, F.R.S., published by Longmans, Green, Reader, and Dyer, and by Stanford, Charing-cross, price 2s., he will find the name of every colliery in the United Kingdom and where situated, and owner's name, besides & quantity of other useful information.-S. W. T. [2233.]-STAINED GLASS.-A small treatise on "Glass" is contained in Vol. 115 of Lardner's "Cabinet (2182)-CONSTRUCTING COILS." Nemo" will Cyclopædia:" after this, study the works of the late Charles Winston, to whom every glass painter is deeply for a coil the size he purposes making it would require about 40 yards of No. 16 primary wire; will [2204.]-PROBLEM.-If " W. B. S." considers his indebted for the untiring attention bestowed on this art, be better to use No. 12. The number of sheets or wil problem, he will see that it resolves itself into finding from 1830 until his lamented death in 1864. They printo the pound of course depends upon its thickness; the height of a cylinder of water weighing 25 lb., and cipally consist of "An Introduction to the Study of the best foil, however, runs about 60 sheets Ift. square standing on a circular base 12in, diameter. I think he Painted Glass, with Remarks on Modern Glass Paintto the pound. If the coil is well constructed the maxican work this. With regard to his second questioning." 1849, Parker; "Memoirs Illustrative of the Art of Glass Painting," 1865, Murray; "An Inquiry into mum spark will be about 6in. long. The number of the atmospheric pressure per inch which susbottle batteries requsite will depend on the surface of (2203); in. of mercury in the barometer is the weight the Difference of Style Observable in Ancient Glass carbon exposed: he will probably require five are of tai 35 30ubic inches of mercury, a table of specific Paintings, especially in England, with Hints on Glass The secondary wire should be first covered gravities will inform him that a cubic foot of mercury Painting," 2ud edition, 2 parts, 1867, Parker and Co. with silk and have some insulating material, in a fluid weighs about 136000z. From this he can calculate the "Proba est materia, si probum adhibeas artificem."Erasmus. I trust this reply may not prevent Mr. state, brushed over each layer as it is wound on the pressure required.-PNEUMA. coil. Thin paper saturated with paraffin wax may be substituted for gutta-percha tissue. The silk used for [2203.]-CERAMIC MANUFACTURE.-The treatise Leicester from rendering his highly-valued assistance. -H. B. MILLER. on porcelain in Lardner's "Cyclopædia," which may covering wire differs from ordinary silk in not being generally be bought at bookstalls for about 2s. 6d.. [2234.]-FROM "JUPITER."-My 3in. glass was twisted.-J. D. M. contains an account of the colours used in painting got from S. and B. Solomon's, 39, Albemarle-street, (2183.1 TAXIDERMY. Taxidermist's and printing. There are several editions of Brong- London; price, on pillar and claw-stand, £5. It has one Manual," &c., by Capt. Thomas Brown, F...mist' niart, but no cheap one. The way I pick up my books day eyepiece about 40 power, and one night-power lished by A. Fullarton and Co., London. Price 38. 6d. at a low price is by reading the catalogues of dealers 100, but I have added several others since-20, 60, 75, ?).-WILLING. in secondhand books, or sale catalogues; although I (100 day eye piece), 150 and 275. The latter works very The |