Chapter II: Part 2

The wheels in the train should be as light as possible, for as the whole train is stopped every time a tooth drops on the pallets, it is plain that the driving weight must overcome the inertia as well as the friction of the train at every beat. To this end it has been customary to “arm out” the wheels, leaving a very light rim supported by light arms, the wheels being generally of cast brass, turned up, and cut, then lightened. We followed this plan for some time, but abandoned it, as we found great difficulty in making a perfectly round wheel. The arms serve as posts to support the rim in cutting or turning, but the space between is very apt to spring down. We prefer making the wheels of fine hard-rolled sheet brass; it is superior to cast brass, much finer, harder, and more durable, and is freer from flaws. After the wheels are cut, they are turned out on each side, leaving a thin web in the centre; they can be made lighter, finished easier, and are round.

As to the shape of the teeth in clock-wheels, the subject has been so ably treated by Reid, Dennison, and Prof. Willis (who has invented an instrument to assist in laying out the curves for the teeth of wheels), that we shall not attempt it in this paper; besides, there is so little of the entire theory that can be applied to a clock-wheel of two and a half inches in diameter, with 120 to 140 teeth, farther than to leave the wheel and pinion of the proper diameter, that we consider it unnecessary; for if makers of regulators and other fine clocks will use pinions of 16 or 20 teeth, the friction or driving is all after the line of centres, and the whole subject of cycloids, epicycloids, and hypocycloids is reduced to a very small point, and might be said to “vanish into thin air.”

Having given only a few practical hints, and not yet crossed the threshold of the subject, we propose to continue from month to month--if the readers of the JOURNAL do not weary--the discussion of the various parts that go to make the sum total of a fine clock, with notices of the various clocks made in this country.

* * * * *

It certainly comes within the province, and is the duty, of a journal devoted to Horology, to make a note of any and all the new improvements that pertain to the science. We give, then, some few, the merits of which have struck us as being a very important matter of consideration.

The best clock time-keeper is not absolutely perfect, so its rate must be kept; but the watchmaker ordinarily has no means of correcting the error of his regulator, until the accumulation renders it a serious inconvenience. Did he possess a Transit instrument, properly set and adjusted for meridian, together with the required books and knowledge of observing, he could from day to day correct his clock and keep accurate time; but these are all expensive, as well as involving time and labor. Suited to the wants of the artisan is a little instrument called the Dipleidescope; simple in its construction, and not liable to get out of position or order, it forms the best substitute for the transit we have seen. It is founded on the theory that the double reflection from the two surfaces of planes at an angle of 60° will coincide when the object reflected is in a true line with half the base of the whole triangle. Having a prism cut in an equilateral triangle, one angle is set directly down toward the centre of the earth, the base being brought parallel with the line of the horizon. Now, if the axis of the prism is in a line with the meridian, a reflection of the sun will appear, at the instant of crossing the meridian, on itself--that is, there would be but one image. If the instrument is well made, there can be no doubt of its accuracy and value to those who, wishing to verify their time, are not situated so as to use a transit.

Another improvement is a Bench-Key for watchmaker’s use. No one who has had any experience at the bench but will appreciate an article that facilitates the setting of time-pieces for his customers. In winding, it is equally valuable. It is not dependent for its strength of torsion on the spring-chuck principle, the power being applied close to the square by means of a pin that passes through the key.

Hall’s Patent Cutting Nippers are a positive desideratum; a large wire can be cut off without the least jar to the hand, the leverage is so great. The smallest sizes are suitable to the ordinary run of watch-work, and can be used in clock-work better than any cutting-plyers extant. Strong and durable, they possess one quality that all watchmakers will appreciate--if a cutting-jaw is broken it can be replaced by another.

Greenwich Observatory.

About two hundred years ago, England began to take a lead in the mercantile commerce of the world; her ships were daily passing across the Atlantic, and India also was beginning to attract her attention. It was therefore of the utmost importance that navigators should be enabled to find their longitude when at sea, independently of watches or clocks; and a reward was offered to any one who should discover a method by which this result might be obtained.

The plan proposed was, that the angular distance of the moon from certain stars should be calculated beforehand, and published, so that, for example, it might be stated that at ten minutes and five seconds past nine on such a day, the moon should be distant from Mars 40 degrees. If from a ship in the middle of the Atlantic, Mars and the moon were found to be 40 degrees apart, then it would be known that the time in England was ten minutes and five seconds past nine.

Here, then, was one item ascertained, and the method was a good one; but in consequence of the want of accuracy as regarded the moon’s motions, and the exact positions of the stars, it could not be practically carried out.

Under these circumstances, Charles II. decided that a national observatory should be built, and an astronomer appointed; and a site was at once selected for the building. Wren, the architect, selected Greenwich Park as the most suitable locality, because from thence vessels passing up and down the Thames might see the time-signals, and also because there was a commanding view north and south from the hill selected for the site. The observatory was completed in 1676, and Flamsteed, the chief astronomer, immediately commenced his observations, but with very imperfect instruments of his own. During thirty years, Flamsteed labored indefatigably, and formed a valuable catalogue of stars, and made a vast collection of lunar observations. He was succeeded by Halley, who carried on similar observations; and from that time to the present, Greenwich Observatory has been our head-quarters for astronomical observations.

The work carried on at Greenwich is entirely practical, and consists in forming a catalogue of stars and planets, and so watching them that every change in their movements is at once discovered. Now that this work has been performed for several years, the movements of the principal celestial bodies have been so accurately determined, that the _Nautical Almanac_--the official guide on these subjects--is published four years in advance, and thus we find that on a particular night in 1868, the moon will be at a certain angular distance from a star, and the second satellite of Jupiter will disappear at a particular instant. On the exterior wall of the observatory there is a large electric clock, which, being placed in “contact” with the various other clocks in the observatory, indicates exact Greenwich time. The face of this clock shows twenty-four hours, so that it requires that a novice should look at it twice before comparing his watch. On the left of this clock are metal bars let into the wall, each of which represents the length of a standard measure, such as a yard, foot, etc. And let us here say a few words about these standards. To the uninitiated a yard is simply three feet, and a foot is twelve inches--an inch being, we are told in our “Tables,” the length of three barleycorns. Now, as the length of a barleycorn varies considerably, it requires something more definite than this to determine our national measures. Thus, the question, what _is_ a foot? is more difficult to answer than at first sight appears. Many years ago the French perceived the difficulty appertaining to the national standard, and they, therefore, decided that a metre should be the ten-millionth part of one-fourth of the earth’s circumference--that is, ten-millionth of the distance from the Equator to the Pole. But here another difficulty was encountered, because different calculators found this arc of different lengths. By _law_, however, it was decided that one measurement only was correct, and so the metre was fixed at 3.0794 Paris feet; though since then, more accurate observations and improved instruments have shown these measured acres to have been very incorrectly ascertained, and thus the French method failed when practically tried.

The length of a seconds pendulum oscillating in a certain latitude has been our method of obtaining a standard; but this also has its weak points, so that to obtain a constant standard it is necessary to have some pattern which is unchangeable, and thus a metal has been chosen that expands or contracts but little either with heat or cold; and this, at a certain temperature, is _the_ standard measure, and such a standard may be seen on the exterior wall of Greenwich Observatory.

On entering the doorway--which is guarded by a Greenwich pensioner, who will possibly first peep at the visitor, in order to see who the individual may be who is desirous to tread within the sacred precincts--one finds a court-yard, on the left of which are the transit-room, the computing-room, and the chronometer-room. The transit room takes its name from the instrument therein, which is a large “transit.” This consists of a large telescope, the outside of which is not unlike a heavy cannon, as it is of solid iron. The instrument is supported by trunnions, which allow the telescope to be elevated or depressed to point south or north, and, in fact, to make a complete revolution, but never to diverge from the north or south line. The magnifying power of this instrument is not very great, so that it admits plenty of light, for it is intended, not as a searcher for or for gazing at celestial objects, but for the purpose of noting the exact time at which stars and planets pass south or north of Greenwich. Upon looking through this telescope, the observer’s eye is first attracted by a vertical row of what seem to be iron bars, placed at equal distances from each other. These, however, prove to be only spiders’ webs, and are used for the purpose of taking the time of passage of a star over each wire, and thus to ascertain the exact instant of its being in the centre of the telescope. During even the finest and calmest nights, there is occasionally found a tremulousness in the instrument, which, as it is rigidly fixed to the walls of the building, must be due to a slight vibration in the ground itself. Thus, many a feeble earthquake unfelt by the outsider may be perceived by the astronomer by the aid of his delicate instruments.

The various stars seem to be travelling at an immense rate when seen in the field of the transit telescope, and it is really nervous work noting the exact time when each wire is passed. The experienced observer, however, not only will give the minute and second, but also the decimal of a second when the star was on the wire. The result is obtained by counting the beats of a clock the face of which is opposite the observer. Thus, if at three the star seems as much short of the wire as at four it had passed it, then 3.5 might be the instant of “transit.”

At noon each day the sun’s passage is observed by nearly the whole staff of observers. One individual looks through the telescope, and gives the time for each wire, while others examine a variety of micrometers in order to ascertain the fractional parts of seconds, etc.,--these micrometers being placed at the side of the instrument.

In the morning, the principal work consists in making what are termed the “reductions” to the observations of the previous night. These reductions are the corrections requisite for the slight instrumental inaccuracy, for the refraction of the atmosphere, and for the known constant error of the observer. When, therefore, a bright winter’s night has occurred, the work on the following morning is usually very heavy. At noon the sun’s time of transit is taken, and at one o’clock the “ball” is dropped, by means of which the various vessels in the Docks and in the Thames set their chronometers, or ascertain their rate. In addition to this, the time is sent by electricity to Deal and one or two other seaports, in order that every vessel may be able to know the accurate time, if within sight of those places.

Not the least interesting portion of the observatory is the chronometer room. For a very small charge, manufacturers or owners may have their chronometers rated at Greenwich, which is accomplished in the following manner:

The chronometer is placed in the chronometer room, and compared with the large electric clock in the room, this clock being kept in order by the stars. Each day the chronometer is examined, and thus its rate is ascertained in its then temperature. It is afterwards placed in a sort of closet warmed by gas, a condition supposed to represent the tropics, and it is there kept for a certain period, being tested each day as before. This change of temperature is found to produce very little effect on the best instruments, which, when they have passed the ordeal, are returned to the owners with their character ticketed to them. Some hundred chronometers are often placed in this room; and to compare them is a science, the “expert” by a glance discovering the difference between the two instruments, whilst a novice would require to mentally add or subtract, and thus slowly to arrive at the same results.

As soon as it becomes dark enough to see stars by the aid of a telescope, one of the staff commences his observations. These are continued during the night; and a register is kept of each star, planet, comet or moon, which is “doctored” in the morning by the computers.

As all mortals are fallible, it is desirable to bring machinery into use where possible, and this has been managed in connection with astronomical observations. Instead of the computer registering by judgment the time of a star’s transit over the various wires, he strikes a small indicator, which, completing the electric circuit, causes a pricker to fall and make a hole in a piece of paper that is attached to a slowly revolving barrel. Each time the star passes a wire, the pricker descends and leaves its mark; and the interval between these marks being measured by scale, the mean time of transit may be obtained.

There is usually a feeling of the sublime that comes over us when we reflect upon the vast unexplored regions of space, or contemplate the stellar world that shines upon us. The magnitude and grandeur of some of the planets in the solar system strike us with a feeling of awe and wonder, while we are puzzled at the mysteries attending comets, double stars, nebulæ, etc. No such feelings or sentiments, however, are allowed to enter into the constitution or mind of an observer at Greenwich. Saturn, the glorious ringed planet, with its galaxy of moons, is simply “Saturn, Right Ascension 10 hours 8 min. 12 sec., North declination 16° 12´ 2´´.” Anything appertaining to the physical constitution, the probable cause of the ring, or the object of so grand an orb, does not come within the range of the observations at Greenwich, which are limited to bare matter-of-fact business work.

The southern portion of the observatory ground is devoted to the investigation of meteorological subjects, and is under the superintendence of Mr. Glaisher, who is now well known as an aerial voyager. It is here that an exact record is kept of the amount of rain that daily falls, of the direction and force of the wind, of the magnetic changes, of the temperature, amount of ozone, etc.--all matters which may, and probably will, lead us eventually to the discovery of some laws connected with the states of weather, and enable us to predict what may be expected from day to day. Whilst we are now able to calculate to a few seconds, and for years in advance, the instant when an eclipse may occur, and to explain the causes of the various planetary movements, yet we are in a sad state of ignorance as regards the causes of hurricanes, thunder-storms, continued rains and droughts; and thus we find that all the would-be prophets who from time to time spring up and oracularly announce a coming frost or fine weather, or the reverse, are perpetually meeting with most signal failures, which, however, does not deter future adventurers from attempting to gain a cheap temporary renown by trying their luck at a prophecy.

The perpetual accumulation of facts at Greenwich, whether these be of an astronomical nature, or appertaining to the air we breathe and its subtle changes, is a proceeding that must eventually lead us on to a correct knowledge of the laws which govern these matters, and also keep us acquainted with any variations that may be occurring in the elements that surround us.

The order and quietness necessary in such calculations as those carried on at Greenwich prevent it from being a “show” establishment, and hence visitors are not admitted except on special business. Then, however, every aid and assistance are offered to the student and inquirer; the use of books and instruments is freely given, and such information supplied as the little spare time of those belonging to the establishment enables them to afford. Thus a visit to or a period of study at Greenwich Observatory will amply repay those who wish to gain the latest and most accurate information on astronomical subjects, or to practise themselves at the adjustments and use of the instruments; and to those who have not such opportunity, we offer this slight sketch.

[_Chambers’ Journal._

Pinions.

Well made as to truth of centring, of division, of form of leaves, and polish, are, as the trade well knows, of vital importance to the value of the time-piece.

The making and finishing is one of the most troublesome, as well as most expensive of all the processes in watch work. The nature of the material renders it difficult as it approaches so nearly in hardness to the tools used in cutting. In the ordinary Yankee clock, the _lantern pinion_ has entirely superseded the solid leaf, which substitution was the greatest element of success in their cheap construction. The lantern pinion is really a nearer approximation to the required anti-frictional form than a majority of cut pinions in ordinary clocks. In the process of manufacture of the cut variety, the first consideration is the quality of the steel to be used. For this purpose it should be carefully selected by trial, thus ascertaining its fineness, uniformity, softness when annealed, together with its capacity for taking a good temper, with the least amount of springing during the hardening process. Very few pinions are cut from the solid piece--the drawn pinion wire being quite good enough, when milled and finished, for the ordinary run of watch work.

The steel wire having been selected, the first process is to cut it up in lengths a trifle larger than the required pinion. The separated pieces are then centred with care, and having been placed in a lathe, the staff and pivot are turned up to nearly the required gauge, leaving a portion of the whole piece the full size for the leaves. They are now taken to the milling tool to have the proper form given to the leaves. As this form is of the highest importance, it may be as well to give here the reasons. Supposing a wheel of 60 teeth, depthing into a pinion of 8 leaves, it can readily be seen that the arc of the motion of the wheel tooth is of greater radius than that of the leaf of the pinion, and it follows that if the teeth and the leaves are made in taper form with straight sections, there must occur a sliding motion on the surfaces of both--the power thus absorbed being totally wasted; but if we curve the surfaces we may approach a form so nearly perfect that the wheel teeth, being motors, really roll on the leaves, avoiding almost entirely the friction caused by sliding; the necessity for this curvature becoming greater the more the wheel exceeds the pinion in diameter. This curve, which has been demonstrated by very profound mathematical researches, is the “epicycloidal;” theoretically it should give no more sliding motion than the surfaces of two plain wheels revolving on each other. To obtain this perfect form, very great pains have been taken and expenses incurred, especially by the makers of the best time-keepers.

In the American factories the cutters are very elaborately made, the section being an object of great solicitude--it being an exact counterpart of the space between any two leaves, and also of one-half the top of the leaf from the curvature to the point, so that in milling, the space made by the cutter is its shape, leaving the leaf of the proper form. Generally the pinion passes under two cutters; the first to strike down the rough stock, the other to dress it to size and shape, with a light cut. The care and skill required to make these is certainly very great, and it is a proof of the wonderful ingenuity of man that they are made so perfect as to shape and cutting power.

A very ingenious device is used for dividing the leaves under the cutter, which revolves at a moderate speed over a slide, carrying a pair of centres, between which the turned up piece of pinion wire is placed. The slide is now pushed up to and under the cutter, and in its passage as much of a cut is taken as is desirable; in drawing back the slide the fresh cut space passes under a flat piece of thin steel, screwed on the frame, and set at a slight angle to the axis of the centres. On moving the slide towards the cutter for a fresh cut, the steel plate takes the last cut, and in passing by it the pinion is turned just as much as the angularity of the plate, which must be just one leaf. By this very clever device the division is effected without an index plate. This process, however, is not good enough for work intended to be very accurate--the pinion wire not being always, or indeed rarely correctly divided, the original error will be perpetuated in all the subsequent processes. These are all milled, with oil or soda water for a lubricator, and it follows that the speed of the cutter is regulated to get the greatest cut without dulling the tool. When dull, however, the mill is sharpened on the _face_ of the cutting tooth by means of small grinders of iron, using Arkansas oil-stone dust for the first grinding, and giving the necessary delicacy of the edge by means of crocus, or sharp, followed, when fine work is needed, by rouge.

It is necessary that this care should be taken, for if the edge is left coarse it will become speedily dulled, and leave a very unequal and rough surface on the cut of the pinion, which in the subsequent grinding gives rise to error in shape and size. The pinions, thus cut to gauge, are dried in sawdust, hardened, and tempered; the staff and pivots are now turned up to size, and then pass to the polishers. In the factory they are finished by means of what are called _Wig-Wags_, which it may be interesting to the reader to have a general description of.

Two Vs are arranged as centres, the pinion is placed between them, the circular parts resting in each V, but free to turn on its own axis. Immediately above the Vs is a frame on which a slide, carrying the polisher, may traverse--generally about two inches. This slide is movable vertically so as to accommodate itself to the pinion; attached to the slide is a connection which leads to a vertical lever, which is put in motion from a crank on the counter shaft. The grinding is effected by bringing the grinder, charged with oil-stone dust in oil, in one of the spaces of the pinion, which, of course, is so arranged as to bring it parallel and central with the grinder. The power being applied, the slide takes a very rapid reciprocatory motion, and the face of the grinder, so charged, rapidly reduces the uneven surface left by the cutter to what is called the _gray_.

The form of this grinder must be as perfect as the cutters, and the care taken to get the requisite parallelism is in equal proportion, and in all the best polishers is planed up while in its position. The grinder is composed of tin and lead, with sometimes a slight admixture of antimony, rolled to an even thickness, cut off in suitable lengths, and then mounted in the carrier of the Wig-Wag to be planed up to shape. There are too many minute adjustments in the machine to render a full description in this article admissible. It is large compared with the work it has to perform, but it is very admirably made, as indeed all the tools are, in the American factories.

The polishing of the leaves is the next step, and this is effected by means precisely the same as grinding. In each stage the pinions are thoroughly cleansed before entering on another. The polisher is made precisely like the grinder; but instead of oil-stone dust, crocus mixed with oil is substituted. Owing to the less cutting quality of the material used, the polisher loses its form sooner than the grinder, and has to be more frequently reshaped. In very fine work the crocus is succeeded by fine well-levigated rouge to bring up that jet black polish, which is considered a mark of quality by chronometer and watch makers.

With the exception of turning up the staff and pivots, all the work hitherto described has been expended on the leaves--a very tedious process, yet done, when the tools and materials are in proper order, with marvellous rapidity; but tedious as these have been, there are two others quite as much so before the leaves are finished.

The ends are to be faced--they must be flat (that is a true plane) and receive the same finish that the leaves took, and is effected by the wig-wag; only the pinion revolves between centres, at a high speed, the grinder being brought up to the turned face. Two motions operate--one rectilinear, the other circular--the result being a compound motion which prevents the grinder from touching the same spot twice in succession. To effect this more surely, the operator gives the grinder a slight vibratory vertical motion. The polishing of the two faces is effected in the same manner as the grinding; in all cases the cutting face of the grinders and polishers being kept in a plane perpendicular to the axis of the pinion, both vertical and horizontal.

The staff and pivots being in the same condition they came from the lathe, the next step is to grind and polish them. Before, however, we treat on this process, it may not be amiss to give the general watch repairer a process by which the facing may be done on a small scale.

As a rule, when the watch repairer has to replace a pinion he selects one from the material dealer, finished in the leaves, but not on the ends or faces. The following operations are simple, and any one may finish these faces with little trouble. Having turned up your pivots and squared down the face of the leaves with the turning tool, grind it in the lathe by means of a ring of metal, the inside diameter being somewhat larger than the diameter of the staff. This ring is held between two centres, thus allowing it a vibratory motion, so that when it comes up to the face it accommodates itself to its plane, and thus has no tendency to force it out of a true flat; the ring, being larger than the staff or pivot, admits a small lateral motion, enough to effect a continuous change of surface. The same little tool may be used for polishing by substituting another polisher and using crocus and rouge. For the repairer, perhaps on general work the rouge would be superfluous. Vienna lime, used with a little slip of boxwood, brings up a very fine and brilliant polish, and in replacing new work in an injured time-piece, the steel may always be polished with great rapidity by using the lime on the gray surface left from the oil-stone dust; being quickly done and affording a very handsome finish.

To resume the consideration of the pinion, the last stage is the polishing of the circular portions. Here again the wig-wag is the most useful tool, but it operates somewhat differently, for the grinder or polisher is pressed down by the finger of the operator, the pinion being held between the centres of a small lathe attached to the wig-wag; the staff is first ground and polished as the leaves have been before, and this is the last operation performed with the pinion between centres. From this stage it is chucked in a lathe very peculiarly fitted, the mandrel being hollow; and in it is fitted what is called a pump-centre, which is movable in direction of the axis of the mandrel, and capable of being securely fastened at any desired point. On the nose of the mandrel is secured a hollow steel chuck, the two sides of which have been filed out, thus leaving an open space between the end of the pump-centre and the end of the chuck. On this end a small steel plate, extremely thin, is fastened by means of shellac, and a hole drilled in the plate capable of taking in the chamfer on the shoulder of the pivot. The pump-centre being drawn back, the pinion is introduced into the chuck, the pivot placed in the hole in the steel plate, and the pump centre is drawn forward until it forces the chamfer to fill the hole; the pivot projecting from the chuck is now ready for all the grinding and polishing processes. Here the wig-wag steps in again, and from the delicacy of the pivots is modified to suit the case; this is done by having a polisher hung in the wig-wag on centres, so it may revolve; when in operation one side of the polisher rests on the pivot, the other on a ruby placed in a screw, and which screw enables the operative to insure the parallelism of the pivot. The ends of the pivots are next rounded off and finished in another set of tools. The pinion is now ready for use, assuming it to be of the proper gauge. In the American watches the scape and fourth wheels are generally staked on the staff pinch tight; the third and centre are staked on the pinion leaves, a rebate having been turned down on the ends, the wheel set on the shoulder, and the projecting ends of the leaves riveted down. This has not been designed as an exhaustive article on pinions; it is merely intended to open the subject as pursued in the factories. There is much more to be said; and the various processes on the small scale, as performed by the Swiss and English, together with their tools, will bear more than a general description, as they are applicable at any watch bench.

The subject will be continued, in the effort to give a full and useful article.

New Three-Pin Escapement.

A contributor to the _London Horological Journal_ gives the following description of his invention:

“The merit of this escapement is in a newly invented escape-wheel which is self-locking and requires no banking pins; the pallets are curved inside the impulse and outside the locking, to work with the curved points of the teeth of the wheel; being made of gold the wheel will go without oil. From its form it has the power of double impulse and double locking with the lever. The first takes place at the discharge of the escapement, the second does not act unless the watch receives a sudden motion, and then the pin or pallet in the roller strikes lightly on the lever, when the propellant power drives it back again. The balance passes through two turns before the second locking takes place, and is formed so as to be able to take up the lever, and the watch soon rights itself, and its time will not be affected. Another advantage is, that the lever is made of a flat piece of steel, as I have introduced a gold stud to receive the ruby impulse stone, which is made to adjust easily so as to bring the escapement to the closest geometrical accuracy. By its formation this ruby guides the impulse to the external edge of the roller notch. These advantages, and its simplicity, render it suitable to the best chronometer watches.”

A FEW years ago, in 1859 or ’60, Mr. Peabody, a very talented gentleman of this city, patented a three-pin escapement that performed extremely well. A full description of his patent and plan is not at hand, but we will endeavor to give it to our readers in our next issue.

English Opinion of American Watch Manufacture.

In the London circle of Horologists, more attention is paid to the scientific departments than the mercantile; but for all that, a Mr. Henry Ganney has held forth before the “British Horological Institute,” on “American Watch Manufacture.” Though an Englishman, with English prejudices, he certainly gives a very fair and impartial statement of the subject; yet he views it almost entirely in the money-making aspect. He gives all the credit deserved to American enterprise and ingenuity, and yet there is a certain sense of a drawback. He had before him samples of machine work; among others, to quote, “several movements made by the British Watch Company, which flourished and failed about twenty-five years ago; these were machine-made, and the perfection and completeness of the machinery they used for producing these frames has not been equalled, I believe, in America; several machines being used there to accomplish what was begun and completed by one here.”

Mr. Ganney is right in his statement, but the example given by the British Watch Company was the rock seen by the American navigators. One tool, for facing off, truing up, drilling, depthing, and doing all the work on the pillar plate, having cost, before completion, some three thousand pounds sterling, and from its very complexity being utterly inefficient--worse than useless. In the very inception of the American watch manufacture a similar mistake was almost made. Experience and sound reasoning proved, however, that a multiplicity of operations in any one machine rendered it entirely too complex, the adjustments too numerous, and the work totally worthless. We shall in another number refer again to Mr. Ganney’s lecture, and perhaps give some beamings of light on the early history of the American watch manufacture, derived from personal observation at the time.

Correspondence.

EDITORS HOROLOGICAL JOURNAL:

I received a Prospectus a few days ago advising me of your contemplated existence. I could hardly believe the fact; “the news was too good to be true.” However, I shall take it for granted, for I cannot see why somebody has not before had the enterprise to launch out in the periodical line on subjects connected with Horology, the field being so extensive and the want so severely felt. Enclosed I send you the subscription price; in this much I have accepted your invitation, but I also enclose some few lines on a subject not particularly practical or theoretical, but very near the truth, and may perhaps give you a view of our wants.

To tell the “plain unvarnished truth,” I am a watch repairer, located in a small country village, with a decent stock of tools and a moderate trade. In all this I am no exception; so I write this in the name of all who are similarly situated. Isolated as we are, we (the country village watch repairers) have few means to improve our knowledge of the trade, but work on the same old principles learned when we were boys and apprentices, and of better and more expeditious ways of doing our work we are entirely oblivious. True, our friends of the Hebraic persuasion, who, angel like, bring us face to face with the outer horological world by selling us material and tools, occasionally present to our benumbed vision something new, such as a Swiss lathe, or lathes used in the factories; but of what use are they to us? We purchase one; well, on the bench it may be an ornament, but for use, drilling large holes is the height of our ambition. We have not the time to learn by self-experience all the boasted usefulness and capacities of the tool; so we go back to our old verge or Jacot lathe when we have to put in a pivot or a new staff. We may know all about the escapement and be able to detect the cause of any trouble with it, but we have no knowledge of the latest modes of repairing the injury when it is discovered, and this knowledge is what I hope to find in your journal. I live in a section where the general class of work is of a very low grade, even the old verge being very common. Our stock of material has to be heavy in proportion to our trade, and then once in a while we are compelled to send our work to the city, some sixty miles distant, in consequence of not being able to do it, either from a lack of the material or want of a proper tool. To all intents and purposes we remain as stationary as the oyster. Not only do we have these vexations, but the ignorance of the public at large as to the treatment of their time-keepers is a fruitful source of annoyance; we are often charged with fraudulent practices, and a certain degree of caution is observed by more than the most ignorant. Thus, a few days ago, a stalwart son of the Green Isle made his appearance in front of the counter, and, projecting in front of our optics a huge English double-cased verge watch, spoke in almost dramatic tones:

“Plase, sir, av’ ye could make me ticker here go, sir?”

Answering in the affirmative we reached for the silent “ticker.” He drew back with alarm.

“Bedad, an’ ye’ll not stale a morsle frae this?”

“Well, but let me see the watch.”

“An’ will ye let me eyes be on yes all the time?”

“Yes.”

“An’ yes’ll not stale a jewil?”

“No.”

“Thin, there it is.”

On looking at the movement the verge was found broken, the injury explained, and the price given. He decided on the repairs being done, but said, “Give me the watch now and when ye gets the thing fixed its meself will come and git it and pay yes.”

“But we cannot repair the watch without having it.”

“Faith, thin, ye’ll not have it; ye’ll be taking something frae it.”

Now, this is an extreme case of ignorance, pardonable, perhaps, in this instance, but the public embraces multitudes just as ignorant where an allowance cannot be made. I do not expect the JOURNAL to reach such cases, or to influence the general mass, but my hope is that it will, by raising the general self-respect and tone of the repairers, indirectly elevate the respect felt for them by the public at large.

But I am writing too long and rambling a letter. I wish to express my hearty wishes for your prosperity. And, in conclusion, will you allow me to express a hope that you will give us the knowledge we need--that is, post us up on the minutiæ of repairing in the latest styles, the newest processes devised, and, above all, give us an article on the lathe and its uses?

Yours truly,
W. L. C.

We have the pleasure to give our correspondent the assurance that an expert will contribute to our next number an article interesting as well as valuable in instruction as to the use of the lathe.

Eclipse of the Sun.

The approaching total eclipse of the sun, on the 7th of August next, is exciting much interest. The obscuration first occurs in latitude 39° 53´ 3´´ north, longitude 138° 37´ 4´´ west--Washington being the meridian. The first totality is on the Pacific coast of Siberia, at sunrise, in lat. 52° 41´ 9´´ north, and long. 165° 26´ 4´´ west. The eclipse is total at noon in Alaska, lat. 61° 46´ 9´´ north, and long. 68° 4´ 6´´ west. The line of the total eclipse now runs south-easterly, grazing the coast near Sitka, thence north into British America; then entering the United States, near the head of Milk River, long. 30° W.; thence through the south-west corner of Minnesota, diagonally through Iowa, crosses the Mississippi at Burlington; thence through Illinois, a little north of Springfield, crosses the Ohio river at or near Louisville, Ky., passes through the south-west corner of West Virginia, through North Carolina, just south of Raleigh, ending on the Atlantic coast at sunset, just north of Beaufort, N. C., in lat. 31° 15´ 2´´ north, and long. 9° 36´ 6´´ east. The line thus described will be that of totality, only partial in any other part of the United States.

The United States Government is, or has been, establishing a meridian line at Springfield, partly to make observations on this coming eclipse, and with the further view of determining a standard of surveyed lines--all of the Government surveys in Illinois having been geodetic. Professor Austin, of the Smithsonian Institute, is in charge of the work, aided by an able corps of assistants.

Diamond-Cutting.

At the Great Exhibition in Paris, in a part of the park contiguous to the Netherland section, M. Coster, of Amsterdam, has erected a building wherein all the processes of diamond-cutting are carried on.

The first rough shaping of the more important facets of the brilliants is here seen performed by the workman, who operates on two diamonds at once, by bruising each against the other, angle against angle. The dust that falls from the stones is preserved for the subsequent processes of grinding and polishing those facets that distinguish the many-sided brilliant from the dull, original crystal of the diamond. It is used, mingled with oil, on a flat iron disk, set revolving with vast rapidity by steam-power, the stone itself being held upon this disk or wheel by a tool to which it is attached by a mass of fusible metallic alloy, into which the stone is skilfully inserted. Skill of eye and hand, only attainable by great practice, is needed for this work; but a skill not less exact is needed for another process, which may here be seen in daily operation--the process of cleavage. The diamond, when a blow is struck on an edged tool placed parallel to one of the octahedral faces of the crystal, readily splits in that direction. But to recognize the precise direction on the complex and generally rounded form of the diamond crystal; to cut a little notch by means of a knife edge of diamonds formed of one of the slices cleaved from a crystal, and to cut that notch exactly the right spot; then to plant the steel knife that is to split the diamond precisely in the right position; finally, with a smart blow, to effect the cleavage so as to separate neither too large nor small a portion of the stone--these various steps in the process need great skill and judgment, and present to the observer the interesting spectacle which a handicraft dependent on experience of hand and eye always affords. But Mr. Coster’s exhibition has other objects of interest. For the first time, we may see here, side by side, the diamond with the minerals that accompany it in the river beds of Brazil; and there are even examples in which crystals of diamonds are included within a mass of quartz crystals, which have all the appearance of having been formed simultaneously with deposits of the diamond.

The different districts of Rio and of Bahia are thus represented--the former producing a confusedly crystallized sort of diamond termed “bort,” and the latter an opaque black variety; both these kinds being found associated with the crystallized diamonds used for jewelry. Though useful in state of powder, the black carbon and “bort” are incapable of being cut as a jewel.--_“Maskelyne’s Report,” Great Exhibition._

The Alloys of Aluminum with Copper.

When Sir Humphrey Davy announced the fact that soda, lime, potash, magnesia, and the other alkalies were but oxides of a metallic base, it would have been deemed chimerical to have supposed that the discoveries he made by the expensive aid of the battery would at later date become of really commercial value. He did obtain both sodium and potassium in the metallic state. The substances in this form were new to the chemical world, still more strange to the popular. So new was it to the chemists, that, on a globule of the reduced sodium being presented to a very distinguished chemist, he, with some enthusiasm, examined it; and, admitting the fact of its being a metal, exclaimed, “how heavy it is!”--when the real fact was that its specific gravity was less than water; the expression was the result of the general preconceived opinion that a high specific gravity was a test of a metallic body. It was reserved for a French chemist, Henry St. Claire Deville, to utilize the metal sodium, and that, too, in such a manner that the demand aroused attention to its production;--demand will inevitably bring a supply.

The original reduction was made by Davy, by means of the voltaic battery. After it had been proved that these bases were really metals capable of reduction, chemistry brought all its resources to bear on the problem, and they were produced by other methods than the battery. All the processes adopted, however, were too expensive and laborious, involving an extraordinary amount of complicated manipulations with but inadequate results. The metal sodium, which is the immediate subject of our inquiry, long remained an object simply of curiosity or experiment in the laboratory.

The methods of reducing the metal have of late years been so simplified that, to quote Prof. Chas. A. Joy in the _Journal of Applied Chemistry_: “A few years ago a pound of this metal could not have been purchased for two hundred dollars, and even at that price there were few manufacturers hardy enough to take the order. At the present time it can be readily manufactured for seventy-five cents, if not for fifty cents a pound; and the probabilities are that we shall soon be able to obtain it for one-quarter of a dollar.”

Deville found that by the reaction of the metallic sodium on common chloride of aluminum a reduction was effected; the chlorine taking up the sodium, forming chloride of sodium (common salt), while the aluminum was left free in the metallic state. It is hardly necessary to go into the particulars of the process; but a metal well known to exist, had, for the first time, been brought to the world in such a condition of structure that its qualities could be tested, not only chemically, but mechanically. This was the direct result of Deville’s metallurgic process of obtaining the reducing agent--sodium.

Aluminum in itself would be of but little use, so that a brief description will be all that is necessary. It is about the color of silver, but susceptible of a higher polish, especially on a fresh-cut surface; it is much less susceptible of oxidization than silver; its specific gravity is but little more than pine wood, and its tenacity, ductility, and laminating qualities are nearly equal to silver. Its use in the mechanical arts is limited, notwithstanding all these qualities, from the fact of its low point of fusibility, and at the heat of the fusible point being easily oxidized, so much so as to prevent soldering, except by an autogenous process. But aluminum does possess a property peculiar to itself--that of forming a purely and strictly _chemical alloy_ with copper. It unites with it in any proportion; the compound formed by the addition of 10 per cent. of aluminum to 90 per cent. of copper has been found to possess all the properties of an entirely new metal, with qualities that render it a very valuable material in all fine work, such as astronomical instruments; and very fine machinery, such as watch-lathes, etc.

The French reports on the alloy are somewhat voluminous, but we give the following.

The color of this bronze so closely resembles that of 18 carat gold, such as is used for the best jewelry and watch-cases, that it is capable of receiving the highest polish, and is far superior in beauty to any gilding.

Samples taken from different parts of the largest castings, when analyzed, show the most complete uniformity of composition, provided only that the two metals have originally been properly mixed while in a state of fusion. These experiments have been made upon cylinders weighing many hundreds of pounds, and are entirely conclusive.

This valuable quality is not found in any of the more ordinary alloys of copper. The alloy of copper with tin, for example, known as _gun metal_, is notoriously subject to a phenomenon known as _liquation_; in consequence of which a great difference is found in the composition of the same casting, both in the top as compared with the bottom, and in the centre as compared with the circumference.

This phenomenon often causes great inconvenience, as the different parts of large objects will in consequence vary greatly in hardness as well as in strength. In casting artillery the difficulty becomes a serious one, and no means have yet been discovered by which it can be entirely removed.

This homogeneousness of aluminum bronze is a natural consequence of the great affinity existing between the two metals of which it is composed; and that there is such an affinity is clearly proved by the phenomenon attending the manufacture of the alloy. The copper is first melted in a crucible and the aluminum is then added to it _in ingots_. At first there is, of course, a reduction of temperature, because the aluminum in melting absorbs the heat from the melted copper; and this absorption is so great, in consequence of the great capacity for heat of aluminum, that a part of the copper may even become solid. But let the mixture be stirred a moment with an iron bar, and the two metals immediately unite; and in an instant, although the crucible may have been removed from the furnace, the temperature of the metals rises to incandescence, while the mass becomes as fluid as water.

This enormous disengagement of heat, not seen in the preparation of any other ordinary alloy, indicates, not a simple mixture, but a real chemical combination of the two metals. The 10 per cent. bronze may therefore be properly compared to a salt, the more so as it is found by calculation to contain, within a very minute fraction, four equivalents of copper to one equivalent of aluminum.

The 10 per cent. bronze may be forged cold, and becomes extremely dense under the action of the hammer. The blades of dessert-knives are thus treated in order to give them the requisite hardness and elasticity. But it has another valuable quality which is found in no other kind of brass or bronze: it may be forged hot, as well as, if not better than the very best iron. It thus becomes harder and more rigid, and its fracture shows a grain similar to that of cast steel. On account of the hardness of the aluminum bronze, rolling it into sheets would be a tedious and expensive process, were it not for this property of being malleable at a red heat. But it may in this manner be rolled into sheets of any thickness or drawn into wire of any size. It may also be drawn into tubes of any dimension.