much of an-AMATEUR. ENGLISH MECHANIC AND WORLD OF SCIENCE: No. 1354. [78889.]-Circuit.-Will any reader inform me how current through a by-way, the known resistance of which moving the telescope, the patch did not move with it, but [78891.]-To Mr. Bottone.-Kindly tell me why I [73892.]-Steam Sirens.-How are these constructed? [73894.]-Electrical.-Can anyone give me an answer to the following? 1. Of what resistance must a wire be to require an E.M.F. of 1 volt in a battery-i.e., how many ohms resistance equal one volt E.M.F.? 2. How many volts must a battery be capable of giving to drive a 2H.P. electro-motor? Is it possible to judge, or must the resistance of wire, make of machine, &c., be taken into account?-GRISCOM. [73895.]-Tidal Action.-Will "F.R.A.S." kindly explain what T.J.J.See means by tidal action of binary stars in his article in the Feb. Observatory on page 93? -L. sketch of Manchester dynamo, capable of lighting three I would like to try a larger one to give, say, 50 amps. at MARCH 6, 1891. means this is effected. A few more particulars on this lately started grinding razors and scissors, and I find a dynamos, 100c.p., Manchester type, ring A., wound with if a motor or mechanism of any kind has ever been made MARSHALL. reader kindly tell me the size of driving wheels and tervals and perfectly clean? I am told that for some air engine. Air will be under pressure first. What is best oil for cylinder, and what is best form of piston? [73919.]-Hot-Air Engine.-I am making a hotWould the ordinary rings do!-CYRUS. give me the name of the wood that may be termed the [73920.]-Flexible Wood.-Will any of your readers and durable in thin cuts? Either home or foreign wood most flexible or elastic, impervious, least liable to fracture, will suit.-FRICTION. BRISTOL," OR "J. H."-Would you kindly help me in the following? two cylinders-reversing preferred-and to run at a steady [73921.1-Engine to Drive Dynamo.-To "T. C., 1-24H.P. or -man-power. steam-pressure, and revolutions. Engine of launch type, 1. I require an engine and boiler about dynamo at 3,000 revolutions, which has a fin, pulley, and Please give bore, stroke, speed. Also size of pulley required for same to drive a powerful enough for above? give the dimensions of boiler, vertical tubular, water boiler, vertical tubular, size 6 by 13, tested to 601b., round fire-box, to burn coal or coke. 2. Do you think the steam-engine and its construction, and which shows cylinders. Also could you inform me of a good book on Engine to have double the way to proportion and design the different parts in [73896.]-Battery-Spinal.-I am desirous of making a battery to give a current in one direction for application to the spine downwards in a case of paraplegia. My idea is to solder alternately strips of copper and zinc end to end, thus forming one long piece, the whole to be bent serpentine that half of each element shall dip in a cup of acid. Is this feasible, or must the elements be separated in the cells, and how few will suffice? Which terminal should be placed at the spine to insure the current running downwards to the lower limbs ?-BRUNO. condensers, -plate portrait combination, 9in. back focus portant of our day. And I think "F.R.A.S." will agree relation to its H.P., and to find its dimensions ?-F. S. W., [73897.]-Lantern. Given an optical lantern, 4in. lens, and 12ft. disc, wanted (1) relative distances of screen, lens, condensers, and light; (2) sketch of path of outside ray of light from source to screen.-TREDAGH. [73898.]-Electric Light.-Thanks to Mr. Bottone for reply to query 73598, and would he oblige me in the following? 1. What c.p. does the two 6-volt lamps give (incandescent), and are they equal to an ordinary gasburner? Also is it possible to get a lamp giving the c.p. of both lamps as above that your machine would drive, as I am experimenting? 2. What is a good mode to find out the candle-power of lamps required, or gas-jets, ordinary burners (Bray's)? Hoping I am not encroaching on too much of your valuable time.-F. S. W., Malta. [73899.1-Wiring Bells and Telephones.-Would either Mr. Bottone or Mr. Allsop be kind enough to give us a diagram of connections in the following case? Nos. TORING NO. 5 No4. BATTERY 州 7736 66 me sketch of a 6-hole indicator, showing connections for steam-engine. Would "J. H." kindly tell me best way much obliged for exact dimensions of Edison's latest wax [73909.]-Vacuum Tubes.-To MR. BOTTONE. 66 [73910.]-Bending Wood Hoops.-Would any of please give mode of bending strong wood hoops expeditiously ?-ASHEN. ours [73911.]-Lantern Slides.-How are the colours 1, 2, 3, and 4 are bells on one board, rung separately by but all recommend the colours water or oil as ordinarily used by the first-class slide-painters made or prepared? pushes, as shown. 1A, 2A, and 3A are one-way switches; sold. These, however, although producing good results, There have been many replies on lantern-slide painting, X is a three-way. The telephones are simple Bells', not do not come anywhere near the professional style. A prousing battery. Leclanchés, and is situated below the above-mentioned however skilful, to try and get these results, as the colours The latter consists of three No. 2 fessional told me that it was very little use for an amateur, board. The bells numbered 4 and 5 are telephone call-were specially made, and the secret kept as much as bells. Under ordinary circumstances, each bell is rung possible. If anyone doubts this, let them try to get a by its own push; but it is required at times that any push deeply dabbed and clear, say, pink or yellow.-E. W. will ring No. 5 bell only. It is sometimes necessary to cut off all connection with battery, and this we have formerly done by means of switch X-MARSHALL AND F. E.sults from so small an engine (2țin, by 5in. cylinder); but [73912.]-Gas-Engine.-I notice in "Jock's" answer (No. 73639, Feb. 20th) he gives quite astonishing re[73900.]-Clouds on Moon-Intra-Mercurial does in Dec. 7th, 1888, and a very important one to Planet.-Some years ago on turning the telescope on unfortunately he makes the same omission as "Yarg" the moon, I saw a misty patch on the Mare Crisium. reply and particulars he says compress the gas to 351b.; Thought it must be some dew on the object-glass, but on but neither of the above gentlemen say how and by what amateurs about to build a similar engine. In the latter's POWELL. White to play and compel Black to mate in two movem NOTICES TO CORRESPONDENTS. is already at K 4. you are right. All apologies for mistake. The English Mechanic There is, however, no pretence of wishing to make professional artisans by written information alone. More particularly it is AND WORLD OF SCIENCE AND ART. written for the amateurs of an art which has FRIDAY, MARCH 13, 1891. LATHEWORK FOR AMATEURS.-I. THE Introduction. been cultivated by thoughtful men and An inferior turner can make but one shape: he merely copies, and though his work may be very pleasing as a good copy, a defect in the material will prevent him getting his desired results. An expert will know how to make a defect disappear in some neck or hollow, made purposely, and harmonising with the beauty of the design, or at any rate not showing any sign of the cause from which it originated. Variations in form are HE want of an elementary treatise on recommended for practice: he who knows but the art of turning has been generally Several treatises on the art of turning now one or two methods of working gives but a felt for a long time. Plumier's book, which exist, each one having its merits, and in these poor scope to his ideas. The beautiful is is the first one issued on this subject, was will be found useful information happily ex-beautiful only inasmuch as it is useful, and followed by that of Bergeron. He was a pressed. This one is written not only for the prettiest vase could not please me if dealer in hardware, and had a large business those who are just commencing to learn, but solid, because its uselessness would be ever in lathes, tools, &c. Thus circumstanced, also for those who already have some know- apparent to my eyes, and I should never he felt able to produce a good work; he ledge of turning. These latter may skip over countenance it. My vases I wish to be at undertook it, and succeeded in filling a great those elementary instructions which explain least possible, and what is said concerning void which had been left by the first book how to hold and how to direct the tools. the beauty of a simple egg-cup should be on the art. This work obtained a well- They will be interested in the more advanced thoroughly understood. merited success; it was a good book, and in information, and will seek to find what new good hands, a new edition should have methods are introduced. Instead of extendsustained its reputation. The first edition ing this treatise to all those mechanical of Bergeron being exhausted, the second trades in which the lathe holds the principal edition, with its promised improvements, place, or is at least an indispensable acceswas waited for impatiently. This appeared sory, it is limited to the work of amateur in 1816; the hopes were vain-the author turners. was no more. Though all hard substances, without exThis second edition seemed written, not ception, may be worked on the lathe, in this for the turner's art, but for the tool-dealer's treatise most prominence is given to inforshop. Complaints came from all parts that mation on the manner of turning woods, this book, with its additional plates of little horn, shells, ivory, and bone, without use, was but a long list of the tools sold by neglecting the metals, and not omitting Hamlin, the son-in-law and successor to indications of the processes best suited for Bergeron. Beginners did not find in it the finishing the work-such as staining and explanations they expected, and adepts polishing, which should increase the elegance detected many omissions in this new edition. and perfect the work of the lathe. Each inIt left the art of turning at that point telligent amateur has his own particular to which it had been raised by Bergeron 25 method of working; some have a decided years previously. These complaints were liking for cement chucks, others will have not entirely without foundation; Hamlin's nothing to do with them. This treatise is book contained nothing about those things written for all classes, and if any reader which had been newly invented. Short- knows of any process which is easier to coming was also particularly noticeable in accomplish than those described, he is begged those parts which should teach the method to acquaint his fellow-readers with his of using tools. ment? views. Ivory turning is imagined by those who have not practised it, to be a difficult process which requires longer study and greater skill than for working in woods. This is a mistake which will be discovered after some short practice with the tools. Ivory, bone, horn, shell, and brass are easier to work than most of the woods. There is less fear of false cuts; a smooth surface is produced without trouble, and the hard, tenacious materials afford the means of giving delicate and graceful forms to the objects required. The finest screw-threads may be cut without tearing when wanted for eye-glasses, inkstands, handles for seals, and other things for which a beautiful material is required. Alabaster and white marble are turned equally well, and serve for works of great make it Knowledge of tools is the first to be acquired. Where is the genuine amateur These considerations, together with many It will be obvious in reading this treatise who does not work with greater care and others not detailed here, inclined me to that endeavours have been directed to show-greater enthusiasm in fashioning a good undertake the publication of a supplement ing, above all, that an amateur should him- tool than in turning a vase or some similar to Bergeron's book, which would show what self make nearly the whole of the appliances object? Tastes differ, and a badly-made vase time and fortunate discoveries had done for required for the work he undertakes. The may pass as equal to one better made; but turning. The intention was also to enlarge methods of holding and of manipulating the a defective tool will not work, and negligence upon demonstrations of the manner of tools are dwelt upon, but the treatise is not in the process of manufacture brings its operating upon wood, &c., and of mani- enlarged by giving geometrical demonstra- own punishment to the workman. Amateurs pulating the tools to the best advantage, tions. These are superfluous to mathema- are solicited to make their own tools-these these demonstrations being absent from ticians, and are skipped over by those who will be reliable. The kind of steel used in Bergeron's book. The criticism of a friend do not understand them. The same may be making them will be known, and the temperturned me from this project:-" At what said of the Orders of Architecture. The ing will be certain. Worn-out files, bars of price would you sell your supplement"? method of turning a star will be explained, cast steel, &c., will furnish tools of excellent said he. "Do you think 50s., the price of and also how this star is turned within one quality with very little labour. Bergeron's book, such a trifle that it should or more spheres. An amateur should use only such tools as be augmented by the cost of your supple- It will be seen that the principal object he can make himself. It is sorrowful busiYou think Hamlin's book contains has been to give precepts to the amateur ness to be unable to repair breakages, and to much that is useless? Why not make a turner; to direct him in all that he could do continually find one's hand on the latch of book at a moderate price which shall include with his own hands, both on the dead-centre the tool-vendor's door. I like to see only all that is useful to know? Act thus, and lathe and on the running-mandrel lathe, the raw materials bought it is with wood you will have written a book instead of a treating of appliances, parts, tools, and and with metal that workshop tools should supplement." work. Always endeavouring to give most be built up. There are some tools which it On reflection, I determined to undertake exact descriptions of these different things, is more economic to buy than to make, this treatise. A distinguished amateur had so that in cases when the reader cannot make assuredly. It is not suggested that an already commenced a work, and this it was them himself he can at least efficiently amateur should make his own steel; that he decided to continue and enlarge upon. It supervise their manufacture by ordinary should melt and cast his own brass; that he should be said that nearly one-third of this workmen under his own eyes. Amateurs should cut his own files, and make his own treatise is the work of this amateur, and will, it is hoped, welcome the extension given saw-blades. The individual tastes of my doubtless he would have written more had to that part which treats of making the readers, and their interests also, will teach not death prematurely ended his useful framework of lathes. This subject has been them even better than these instructions to labours. I have gathered together all that so neglected by my colleagues that their discriminate which are the things they should which practice and experience have most frames are as heavy and clumsy as those make, and which they should buy. The approved, and have faithfully explained used in the infancy of this art. The same amateur who has a forge and a lathe, and most advantageous methods of mounting observation should be made concerning the some small tools at his disposal, should work of all shapes on the lathe, making one boring collars, also of the screw boxes and rarely require outside aid. Making his own lathe serve for many varied purposes. The taps for wood. In general it is believed tools should be his great pleasure. endeavour in this treatise is to give the that there will be found in every chapter of lessons so clearly as to make it possible for this treatise additional matter and consider turning to be learned by merely reading able development. them. "Lathework for Amateurs" is mainly adapted from "L'Art du Tourneur," by Desormeaux; but deletions and additions are numerous and extensive. The illustrations The instructions in metal-turning will, it is hoped, be appreciated, and also the many new patterns which are given will merit esteem. A vase pleases by its form and by the material from which it is made. The object of this treatise would be greatly exceeded if extended details were given of all the machinery which constitutes selfacting complex lathes. The reason for restriction on these points is that only very rarely is an amateur turner sufficiently expert in the mechanical arts to undertake to manufacture the many complicated parts the longest sides. in steel, iron, and brass which form part of useful article, are things an amateur should | Eight pieces of the same material are cut to the the structure of a complex lathe. Whenever endeavour to produce. If he would proceed size and shape as a, Fig. 12, and two pieces like he desires to furnish his workshop with one further in the art, the metals open a vast b. The pieces a are fitted two together by a of these lathes, he will probably decide to buy field to his capacity. Let him make for mitre joint, and glued at the four corners of the it ready made, and conveniently fitted with himself his own oval chuck, turn his own baseboard to form the feet, the pieces being accessories, from some engineer whose busi- mandrels, make his dividing-plate, his die-fixed singly in the same manner at the centre of ness is to make and sell lathes. Natural stocks, and certainly his taps, and in making conclusions further determine these restric- these let him strive to attain perfection. This now required, which, of course, may be of any The castings of six brass pillars (Fig. 12, c) are tions: the art of turning on self-acting work will be more useful than the production pattern to suit the fancy. They are 3 in. between complex lathes consists much less in the of mere gimcracks which are shown with so the shoulders, a small stem, e, projecting from talent of the workman, who has acquired all much ostentation by those who know little the bottom, part of which is fin. square, the rehis skill in long practice on ordinary simple or nothing of turning. maining part having a fin. thread cut on it, on lathes, than in the accuracy of the parts With the exception of some processes con- which is fitted an hexagonal nut and washer. The constituting the mechanism of the complex nected with engine-turning on the lathe, I top of the pillars have a central hole tapped for lathe. The simple motion of the rotating have practised all that I teach. Passionately in. screws, by which the bed-plate is fastened flywheel gives an impetus and direct control fond of the art of turning, I have devoted to them. The tops are cut out with a round file quite peculiar, which are communicated to much leisure to it. I have visited work- to allow the tube on the bed-plate to fit in, so the work quite uninfluenced by the turner, shops, factories, and intelligent amateurs, the bed-plate, seen plainly in section at d, that the top of the pillars may firmly rest against who in certain cases even dispenses with whose ingenious ideas have lighted my path Fig. 12, four of them being cut on two sides manipulating the tool, which is almost ex- and directed my work. Tool-dealers will like g, and the two others on one side only. The clusively controlled by the combined actions reproach my treatise for ceaselessly preach-bed-plate is now drilled with six holes for the of the mechanism of the lathe and the slide-ing economy. I make no defence: I esteem screws of the pillars to pass through, and are rest. Also it may be truly said that the this virtue, and counsel it to others. drilled at such a distance from the edge that the merit in the work produced upon a complex Now to speak of the illustrations: there top edge of the pillars are vertically beneath the lathe belongs less to the worker than to the are several hundred figures in the whole edge of the bed-plate, plainly seen by referring machine employed. All these considerations treatise. I have endeavoured to draw these to d. confine us to giving briefly the simple analyses as exact as possible. Assuredly, a profesof these lathes, and the amateur is left to sional draughtsman could have worked more apply to those clever mechanics who make artistically; but I have thought that this them if he wishes to procure such lathes. could not replace the eye and hand of the The conic sections, tetrahedrons, hexa- master, and that it is better to have illustrahedrons, &c., are not treated upon. Trigo- tions less beautiful, but more correct. The nometrical calculations are intended for more things they represent are all my own, and serious applications than the designing of made by me; thus I execute the drawings arabesque figures and the incision of bad with ease. ornaments. Who amongst the readers This treatise, written hastily, doubtless esteems it important to know how to make a king of chessmen in ivory 18in. high turned circular, elliptical, eccentric, straight, obliquely, &c.? Who would waste his time and costly material in making something which would be useful only to keep under a glasscover and guard with lock and key? What tools and what care must be employed to make a masterpiece which would bring but a few pence from a dealer, and which has much less value than that of the raw material which was destroyed in the process of manufacturing it! A correctly-proportioned column, a beautiful vase, a graceful cup, any suitable and leaves much to be desired in point of style; (To be continued.) HOW TO CONSTRUCT A PHONOGRAPH.*-II. By W. GILLETT. 8.-Baseboard and Pillars. T 16in. by Gin., the top edges having a bold All rights reserved. 9.-Mounting Framework. The holes now being drilled in the bed-plate, it is laid on the baseboard and used as a template for marking off the holes on the wood, through which the stems of the pillars pass. The pillars, after having been turned up in the lathe, can now be fixed into the baseboard by means of the nuts and washers aforesaid. We can now proceed to fix the brasswork together. The gate-spindle is first screwed into place on the standard B, Fig. 2. The guiderods are then fastened, by means of their hexagonal nuts, into the holes SS, the rod without the square tube being in the hole nearest the gate-spindle. The opposite standard is placed on in the same manner, with the steelbearing centre in the hole x. The whole is then screwed down to the bed-plate, which has holes drilled corresponding to those in the bottoms of the standards, for the screws to pass through. The gate is now placed on its spindle, after having the spring centre screwed into it, and the milled nut screwed down over it on the spindle. previously ascertained that the hexagonal nut on The gate-catch is then screwed into place, having the guide-rod is firmly screwed up. The main shaft can now be mounted between the centres, the spring-centre pressing firmly against the end of the shaft, but not so hard as to produce excessive friction. The holes for the small central standard (Fig. 3) are now drilled in such a position that the standard just clears the end of the brass cone when screwed down to the bed-plate. If now the handle is pulled down 90°, the gate will fly open, and the shaft will rest on the central standard, allowing free access to the end of the cone. This completed part is now placed on the pillars and screwed down in place; of course, care being taken that the top surfaces of the pillars are all in the same horizontal plane, so that the bed-plate may not be sprung when screwed down in place. An elevation of the framework thus put together is shown in Fig. 8, some of the principal parts being lettered as before. Fig. 9 shows a plan of Fig. 8 without the baseboard. An elevation of the driving-wheel end of the instrument is seen in Fig. 10, while Fig. 11 shows the elevation of the gate end. By referring to these figures, the position of the various parts is easily seen; it also gives one a general conception of the complete instrument, and therefore the mind can more easily grasp the use, and conditions required, of the parts that have been and will be described. HOW BOOKS ARE BOUND.—XVIII, W given to the binder, who proceeds to execute his part of the work. If the book is to be bound 4-flush, he takes two sheets of paper same as the book, and folds them. He then lays them down upon a piece of waste-paper, and pastes or glues one page of each. He lifts them one at a time, and lays them, first one and then the other, upon the first and last page of the book. While doing this, care must be taken to place the fold of the paper evenly along the back of the book. These must be well rubbed down with the hand, to insure them sticking in every part. This accomplished, he takes a little piece of paste on the forefinger of the right hand, and, placing the thumb of his left hand against one of the slips, he pastes the inside of it and presses it down upon the book with his thumb. All the slips are pasted in like manner. The book is now taken and knocked up even at the back and head, and the back glued with good thin glue. A pair of boards are cut the size of the book from a sheet of straw- or mill-board. These are pasted and laid upon the book even with the head or top, and about in. from the back, as shown at Fig. 49. Be careful about this point, for if the board should be laid on close to the back, the book would have a bad opening. It is now placed in the standing press between two pressing boards. The press is screwed down tightly, and the book is allowed to dry while under pressure. As soon as it has become dry it is taken out, and a leather or cloth back is drawn on to it. There is little difficulty about this. The leather is glued, or pasted. The back of the book is also glued, and the leather drawn on so that as much of the looked, and that is when the book comes to be We will now suppose that the book has been the other side glued in the same way. The object of this is to glue the end-papers to the book. When both sides have been glued, the leather comes upon the one side as the other. book is laid between smooth pressing-boards, and Care should be taken that it is well rubbed down, placed in the press, where it is subjected to conespecially on the back; rub it well into the joint siderable pressure. Care must be taken to keep also. A sheet of marble paper is now taken, cut the slips outside when putting the book in the in two, pasted, and placed upon the boards, over-press. After allowing it to remain in the press lapping the leather about in. The book is now for some time, it is taken out, the slips are bound, and is laid aside to dry. When dry, it glued down, and the back is lined in the followis cut round at the guillotine, and the edges sprinkled or marbled. For binding with squares and tight-back -bound work, the modus operandi is much the same. The edges, however, will require to be cut before the boards are put on. After gluing the back, the fore-edge is cut and the back rounded with the hammer, as already described; after which the head and tail are cut, and after marbling or sprinkling the edges the boards are put on. The boards must be cut the exact size, allowing a square of about in. all round; they are now pasted on, and the book covered as already described. The instructions that I am now about to give for spring or open-back work will apply in every case, whether the book is intended to be halfbound or full-bound. The great point to be observed in account-book binding is strength, yet at the same time it is necessary to observe tters which will give the book a neat Tsurance. There is, moreover, another meant point which must not be over It would be superfluous to describe the process of marbling again. The treatment is the same as in letterpress, only that there are fewer colours used, and, with but few exceptions, one pattern, called "Dutch." and The next thing to do is to make the back. With a strip of paper measure the thickness of the back of the book; allow about in. or more, so that it will come over upon the side a little. This will, of course, be less or more, according to the size of the book. When you have taken the size, cut a piece of thin hard millboard the breadth of the paper size, and a little longer than the book. For large heavy books two or three pieces will be required. Take a sheet of brown paper, or the wrapper from a ream of paper, and cut a piece the length of the strip of board, and broad enough to lap round it several times; glue the paper and lay the board down upon lap it up; rub it well down, and leave it to become nearly dry. The back has now to be rolled to shape, and for this purpose rollers of all sizes are kept in stock. Each roller is provided with a sheet of stiff wrapper; the edge is glued to the roller; the back to be rolled is put in to this, rolled up tight, and the sheet of paper rolled over all. The whole thing is now rolled backwards and forwards on the bench until the back is forced into the desired shape. It is left upon the roller until it is fairly set. This operation is very important, and I trust I have made it sufficiently clear to be understood. Fig. 52 will perhaps enable you to form an idea of the shape of the back. There is a machine now in the trade for making these-and a great boon it is in a large shop where many backs have to be made in a day. A boy can make them easily, and stack them so that the binder can always get one or more when he requires them. The machine is supplied by Mr. W. C. Horne, 6, Dowgatehill, E.C. Before going further it will be well to say a few words about the boards. Boards for work of this kind have always to be made. They should be of the best material-"grey boards," as they are termed in the trade, is the right thing to use. They have sometimes to be made with two or three thicknesses; but they must always have a thin board, or "liner" to the inside. They are put together with paste, and the liner is only pasted about of its breadth, leaving open. The reason for this will be shown further on. Of course the boards must be made and allowed to dry sufficiently before they can be put to the book. When the back has been made and properly set, it is put to the book. There are different methods of doing this; but from long years of experience, I think the following may be safely relied upon. The back is forced on to the book -it should fit very tight--taking care to have it even. The first page of the end-paper, with the leather lining and slips sticking to it, is glued and folded back upon itself from the leather lining, and over the back to the other side; the book is turned over, and the other one glued and folded over in the same manner. A pair of pressing boards are now laid on, one on each side, and the book put into the press, which is screwed up tightly; this presses the paper close in, and, of course, draws the back close to the book. After taking it out of the press, the boards are Melt in an earthenware pot 6 parts of spermaceti, It |