Chapter 4

W, friction wheel attached to pendulum. L gives no impulse except when the electro-magnet is excited. K, lever and weight lifted by electro-magnet, E. A, open contact completed by pendulum each swing. B, battery. R, ratchet wheel and pawl. M, lever fixed at top. L, weight at end of bell crank lever, which drives pendulum once each minute, being raised by the electro-magnets.]

At the recent meeting of the Institution of Mechanical Engineers, Dublin, Mr. Davey, of Leeds, spoke of synchronizing mechanisms. He had occupied some of his spare time in attempting to synchronize clocks from a standard clock. The problem is similar to the present one, except that it is rough-and-ready, compared to the present one. He had a novel electrical pendulum, to drive a seconds pendulum by electricity. Electrical clocks are notoriously bad timekeepers; on account of variation in the strength of the electrical current, the battery falls off. He had constructed an electric clock having a seconds pendulum, and recording an impulse once a minute. On the pendulum he had a little ratchet wheel, R, having thirty teeth. The pawl was connected with a lever, M, fixed at the top. On the face of the wheel a little pin rotates with the wheel. On the side of the clock case was a contact maker, which closed the circuit by the pin on the ratchet wheel, R, once every minute. The weight was lifted by the electric current, and by its fall gave an impulse to the pendulum. The pendulum was a free swinging pendulum for 59 sec., and the increase of the arc could scarcely be detected.

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COAL TAR AS FUEL FOR STEAM BOILERS.

By JOHN McCRAE, of Dundee.

About three years ago, when the sudden and serious fall took place in the value of the secondary products produced in gas works, many gas managers--ever desirous of doing their very best for their employers--were forced to look around for some better market in which to dispose of the products which had so seriously fallen in value. This was no easy task; and even now it forms very uphill work indeed. A comparatively new market has been created for the disposal of boiled tar at several of the German ports. But the expense and difficulty of loading ships with tar in casks take very much from the saving derived from the new manner of disposal. It occurred to me, therefore, that we must look nearer home for a remedy.

In all gas works of any magnitude, a considerable quantity of fuel must be employed for the purpose of supplying the works with steam for the exhauster engines, chemical apparatus, thawing purposes, etc. Whether this fuel consists of coke or of coal, will not in the least affect or alter my figures. I have no doubt if any manager discovers that he is working more economically by selling the coke and using a cheap small or other coal, he will adopt the cheapest process. In Dundee, where we get a good price for coke, I found, for the purpose of steam fuel, it would be far cheaper to buy small coal costing from 5s. to 5s. 6d. per ton delivered in the works, and dispose of the coke. The question of fuel then lay between coal and tar; and I have experimented somewhat extensively to ascertain the true relative values of the two classes of fuel. For the purpose of this paper, and within the last few days, I made a further examination into the question; and the results arrived at will be those here quoted. The coal we employed was what is known as Stravenhouse small coal, which costs 5s. per ton delivered. The experiment in each case lasted 48 hours. The tar employed was what is known as boiled tar; the naphtha having been previously removed, but the pitch oil left in the tar. The value of this tar in Dundee is about 4s. per ton. The following are the figures:

Coal, 10 tons 16 cwt., at 5s. £2 14 0 Tar, 1,460 gallons (or 9 tons 3 cwt. 160 gallons = 1 ton), at 4s. 1 16 7 ------- Saving per day by using tar. £0 17 5

And this at the longest day, when we are using a mere fraction of steam, as compared with our winter requirements, and consequently the profit is proportionally less than it will be when we are in full work.

And now allow me to direct your attention for a short time to the appliance made use of in accomplishing this tar burning. On the wall is shown a diagram giving in detail the injector known as C. & W. Walker's patent tar sprayer burner; and it is supplied only by that firm. The tar, which has been brought forward to the boilers in a thoroughly liquid state, is discharged from the center of the injector into the furnace of the boiler. Surrounding the center nozzle of the injector is an annular space through which high pressure steam passes, also into the furnace. The meaning of this steam moving along with the tar is to force a draught, as well as to raise the temperature of the tar, and so partially convert the tar into vapor; thereby making the combustion more complete. The flow of the tar is regulated by the very delicate sluices attached to the injectors. These valves consist of elongated cones and plugs, and are constructed not only for the purpose of regulating the flow of tar, but also for removing any obstruction or incrustation which may accumulate in the nozzle. In order to keep the tar in a liquid state (which in the winter time is not an easy matter), a small steam pipe is passed through the center of the tar pipe; but, of course, no steam is discharged among the tar, as the presence of water in the injector prevents its correct working. The steam pipe is simply passed through the tar pipe, and a steam trap attached to its end. In changing from the coal or coke fuel to the tar, little or no difficulty is experienced, and very rarely is a shovelful of any kind of solid material required. The furnace bars have only to be kept covered to prevent the waste of tar and the too rapid ingress of air; and when the furnaces are in full work, and being well and carefully attended to, the tar will be found to have been nearly all consumed before reaching the solid material covering the bars. The action is very much the same as in the paraffin oil lamp. The wick is the medium by which the oil is brought to the point of combustion, where it is developed into light; but the wick remains little injured, although in close proximity to such intense heat. The oil burns, not the wick. In the tar furnace, the tar itself burns, and the tar only.

It will be easily understood that a little experience is necessary to enable the attendant to fully understand the quantity of tar by which complete combustion is to be obtained, and which in no case must be exceeded. The moment one atom of tar is sent into the furnace beyond that which can be thoroughly consumed, you have then the most hideous discharge of black smoke (carbon) which it is difficult to describe, but which can be easily understood, and, I believe, can be seen within a few miles of where we now sit. I should mention that the injectors are fitted on the furnace doors; but the connections are of such a nature that the doors can be opened without disturbing any of the permanent fittings.

And now I have told you that the results detailed in this short paper were those obtained in the Dundee gas works. This is so; but were I to leave the matter here, it might be inferred that I considered similar results might be obtained in any and every gas works. I would not mislead you; and therefore must detain you for a few moments longer in order to show you how my town is different from many others. Dundee is very peculiarly situated in this respect. It is a long distance from any tar distiller's works capable of dealing with the large quantity of tar we have for sale during the winter. A large portion of the value of our tar must, therefore, go to the railway company, to cover the cost of transit between the two points, and so the tar distiller can allow us but a small figure for it at the starting point. Then again, Dundee being far distant from the coal fields, the coal is exceptionally high in price. I quite believe that in many of the west country towns the coal for which we are paying 5s. per ton could be had for 3s.; and the tar for which we are receiving 4s. per ton, they would get not much under the double of this. Therefore, you see, in a place so circumstanced, the figures I have given would be most misleading. Still, I doubt not there are places as badly situated as Dundee; and it is to such places that my remarks are directed. I believe also that, in many towns distant from collieries, the tar might be sold to manufacturers for use in their steam boilers; and such an arrangement would, I think, prove advantageous both to the seller and the user of this liquid fuel.

I think that as much has been said in regard to my subject as is necessary; but permit me to add that I believe there is a future for liquid fuels. I do not say tar, but more concentrated fuels, such as crude naphthas, paraffins, and pitch oil. When you see one of our large steamers taking coal into her bunker, it must have appeared to you that there was great waste of power here. Every ton of coal laid in must require a certain amount of power to carry it; and every ton of coal so laid in reduces the cargo-carrying power to this extent. A few gallons of oil will give you the steam-producing power of a ton of coal; and this is a fact which the owners of non-paying steamships should note. Take our locomotives also. Everything I have said in regard to steamships applies to them; and the comfort to the stokers and the general reduction in labor would be very marked indeed. Of course, it may be argued that if there were such a large demand created for oils for furnaces, the old fashioned law of supply and demand might come into play, and so force up the price of the article for which the increased demand had taken place. But I think this state of matters is rather remote, when we bear in mind the great oil wells only now becoming developed, and the oils from which can be run in bulk direct from the wells into ships, and brought to this country at very low rates.--_Journal of Gas Lighting._

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WATCH CLEANING AND REPAIRING.

By "OLD FOGY."

Before proceeding with what I consider the best methods in this department of the watch and jewelry business, I will say that I do not, by any means, consider that my way is the best, for although I have been in the business quite a while, yet I find that I learn something new almost every day that I live, and expect to do so, so long as I continue in the business. Be very particular in selecting your tools; about three widths of screwdrivers, and keep them in the best of order, square across the point of blade, and never use a screwdriver too narrow nor too wide for the screw, and in using be careful not to let it slip, and thus mar the plates or bridges of a watch. I also recommend that the handles of these screwdrivers be of different shapes or styles, so as to save time in picking up the one you want (and just here I will say that every device or method that saves time will be of great value to the operator); then have about the same number of tweezers (3), one of good, solid, heavy points, say 1/16 inch wide at the points, for taking down a watch, and handling the heavier parts, and then one a little finer, and one very fine to work in about the train, hairspring, etc., and always keep these tweezers in perfect order at the points, so that whatever you handle, you will not mar or drop the things you are handling. Right in this connection I will say that I cannot find tweezers that suit me. So I make my own, and you can do the same if you will by selecting some nice steel. Then a good assortment of pliers, cutting, flat, and round. In selecting brushes, you will have to be very particular and secure the open and straight bristle brushes, which are also hard to find these latter years. Take all the coarser brushes and hold them on a coarse grindstone, running them whole length, both ways; this takes off the new rough end of the bristles before using first time. Then there are punches, broaches, drills, calipers, countersinks, files, etc., etc. Besides this, I have adopted the plan of making any tool I happen to need for any special purpose, so that by making these at the time I happen to want a tool that I cannot purchase, I have accumulated quite a variety of odd tools; among them are a varied lot of millers, for milling and raising jewels, and deepening the countersink holes for jewel settings and screw heads, also a tool for holding a roller, to set the jewel pin, and one for holding the hair spring collet, and a pair of tweezers for holding jewels while cleaning, etc., etc. As to lathes, I have found that there is a necessity of about two lathes; one a Swiss, light running lathe for cementing any pivot work, and I prefer these because they run much lighter and easier than those heavier American lathes; and yet if confined to but one lathe, I would use a small sized American lathe, with a good assortment of split chucks, particularly those with the smaller sized holes, for holding balance staffs, wheel arbors, etc., which come in use almost everyday, for taking off the burr from the point of a balance pivot, which has come from a collapse of the case; driving the end stones down on the end of pivots, even sometimes to the extent of heading them over inside of the hole jewel. These small size split chucks I have found extremely useful for the last named purpose, and I am not so "sentimental" but that I oftener use these split chucks, even for setting fine balance pivots, rather than take time to cement them; and while I do not advise the use of a split chuck for this purpose in every case, yet with a little experience one can tell when a staff is held so that the new pivot when set will "line" and be true, and of a clear beat or swing. To make a very nice pivot the cementing process is preferable, and yet, for nearly a year, my old No. 1 American lathe was not set up (for reasons I need not take space to explain), and during that time I employed a very skillful workman to do my pivoting, and this man would not think of ever doing a nice job unless he cemented it, and I can assure you that he put in more pivots out of line, and out of true, in the course of those few months, than I had done badly in my life. Speaking of "sentiment," I will say that too many young workmen use the lathe too much, and seem to depend on a fine looking lathe and handsome tools, and spend too much time in using the lathe and in decorating their bench with a fine display. But don't construe this as meaning that one can do nice work with a jack knife and handsaw, for I most certainly believe in a good and substantial set of tools, or I would not have taken so much space in speaking of them. Next, one must have a good bench, wide and of good length: and if no other drawers, a shallow depth drawer, exactly in center of the bench, with no knob in front, but rather a lip running its whole length, underneath. So that wherever you place your hand you can pull it out. This drawer I would have large and roomy (wide and long and extending back as far as the depth of the bench will allow, but shallow, not deep down in), and then partition it off by narrow slats, diagonally across it, running these slats from the extreme near right hand corner to the further and extreme left hand corner, so that as you reach your right hand in to take out a tool, you can grasp it naturally without twisting or cramping your hand. About eight inches below the top of the bench, I would place a skin drawer (the name comes from the practice at watch factories, formerly using sheepskins for the bottoms), which is made with a square frame (say like a picture frame), sliding on slats or a groove, so that it can be drawn out toward the operator, and when so drawn, the elbows will rest on this frame, with the wrists resting on the edge of the top of the bench, thus giving a firm support for both arms and hands, and this frame having stretched across its bottom a skin or canvas, will catch and retain anything that drops or rolls from the bench. This latter drawer I consider almost an indispensable article to doing good and successful work. At the right hand of these two drawers named, running down to floor if need be, there can be a series of drawers for tools and materials. Now with these equipments, and some others, not herein named, such as vise, file block, bench stake or anvil, and a large variety of such tools as will accumulate, I am ready to give you my ideas regarding the cleaning and repairing of watches. First and foremost, do not undertake any job that you have any or considerable doubt but what you can do successfully, and never leave a job worse than you found it; and never mar, cut, or slash any part of a watch. In other words, don't undertake a job that you have doubts as to whether you can do it correctly. One of my old masters told me never to undertake to improve on the maker's work, and this, while not true in every case (particularly cheap watches), yet is a safe rule to go by. Never allow your file, screwdriver, pliers, tweezers, or any tool to deface any part of a watch. I shall speak of this as I proceed. First, be careful and not let the movement swing so as to in any way injure the balance, in taking from case, and if a lever watch, take out the balance the first thing after getting out of case. Now see that the mainspring is let down and then remove the screws from the plates, taking care not to damage or bend any of the pivots as you do this. When all in pieces, before you proceed to clean, examine with a strong glass to see if the rim of any wheel is rubbing or clashing with anything, particularly the center wheel in any full plate American watch, for these wheels are often dragging on the plate or striking the ratch wheel because it is not true, and if examined before cleaning the places where it drags, are a tell-tale of the mischief. Also make any diagnosis of the watch that is needed to discover any errors from wear or accident, and correct them before going further, such as looking to each jewel, pivot, and other parts, and make all necessary repairs before cleaning. I have been in the habit for several years of putting my balance wheel separate from all connections, and trying its freedom in all positions, and if you will try this method, you will be surprised how many you will find that bind or are not perfectly free in all positions, when you give them the very slightest impulse by a twirl of the hand, holding the plate. Then, too, a careful examination of each jewel; you will be surprised how many are either loose in the setting or plate. In regard to cleaning, I use the old method (after trying all ways suggested)--that of chalk (but I use the old lump chalk, for those carpenters' chalk balls are made with some kind of paste that adheres to the plate)--and have this lump of chalk at my right hand, in a perforated bottom box, so that any coarse pieces fall through to the floor, and by rubbing the brush across it and then giving it a slight rap, before applying it to plate, any hard or heavy substance will fall out, and then with light pressure with the brush that is medium soft (and prepared on grindstone as before mentioned, if a new one) brush the plates, with an occasional breathing on the surface, clean the old oil or tarnish, and then peg out each hole many times, until you are sure every hole is clean, by pegging both sides, and then with a soft dust brush dust thoroughly by striking the brush into the holes on both sides. Of course, remove all end stones, and clean out with soft pith, holding the jewels in a pair of hook nose tweezers, mentioned. Should the plates and wheels be very much soiled and oily, a covered dish of alcohol is indispensable, and I have had a glass stopper bottle, with ether, in which to dip the jewels, pallets, and other small pieces, which takes the oil all off, but be sure and clean off with soft pith or pegwood such pieces as you have thus dipped. This ether will carry all loose lint or other things to its bottom, from hairsprings or roller table, and if held but a moment will do effective work, and not loosen shellac.

Regarding loose jewels, I am not so sentimental as to refuse using some shellac, if the burnished lip has been so thin as to be partially gone, thus loosening the jewel to hold in the jewel, by taking small and minute particles, and placing around the edge of the jewel, and then holding the plate or bridge over an alcohol flame, and allowing the shellac to flow around the jewel and fasten it firm, and by this process I have kept jewels firm in place for years, with no other attention than the first, and as a rule this can be done and not show. When you have thoroughly cleaned the different parts, holding everything with soft tissue paper, then with the paper put the watch together, never forcing any part into place, and when screwed or pinned together, try every wheel to see that there is the proper end and side shake to each pivot, then introduce the balance wheel, having been once tried alone as described, and see that the banking pins are so adjusted that the guard pin on the fork (lever) does not drag on either side, and that the jewel pin enters the slot, clearing the opposite corner, and that the guard pin is so in position that it will not allow the pin to pass by at any point and bring the jewel pin outside the lever, or so it will strike in hollow, or on the corners of the hollow of the roller. When you have oiled each pivot exactly on its connecting point of bearing with just the right amount of oil (of course, oil those jewels having end stones before putting watch together), your watch is ready for the dial, and in replacing the hands you cannot be too particular about their being free and clearing each other and the dial and glass. There is the care of the mainspring I have intentionally reserved till the last. There are lots of theories why a spring will break just after cleaning, but I only know that since I have adopted the method of never taking out the spring (except when, after taking off the cap of barrel, I find it is all gummed up with bad oil, and then of course clean it) I have found that a spring does not break any oftener than is common, even if the watch is not cleaned; but I invariably remove the barrel arbor and clean out the holes and the arbor itself.