An additional satisfaction in all the precision hobbies is the smug knowledge that these "snobby hobbies" exclude the imprecise and thus have a limited following. One such hobby is horology, the science of measuring time and the art of building and regulating timekeepers. There is little practical need today to build clocks, since accurate electric clocks are everywhere. Like the maker of sun dials, the amateur horologist or "clock maniac" builds from a love of mechanism and the other motives already named. There is a fraternity of horologists with their own periodicals, and a large technical literature on fine clocks.

The elder J. Pierpont Morgan used to observe that for most of our actions there are two reasons: the reason given and the real reason. The ostensible reason for including in the book Amateur Telescope Making—Advanced a chapter of instructions for building a Synchronome clock was to enable the amateur astronomer to use it in his observatory. Yet the amateur has little need for a clock precise to one second a week The real reason was the one already described: the amateur telescope maker is potentially an amateur precision clockmaker and horologist. No one knows how many Synchronome clocks have been built by amateurs, but this department knows of several and the total must be fairly respectable.

The Synchronome clock, invented by F. Hope-Jones of England, bears little resemblance to conventional mechanical clocks and none to the familiar electric clock. It has no gear wheels and pinions. It consists essentially of a seconds pendulum approximately 39 inches long, with bob attached, and about a score of simple, open parts. This unit is usually housed in a tall, narrow, glass-faced mahogany wall cabinet. Though electrically driven, it is entirely independent of electric power lines. It is run by two ordinary dry batteries which last for months or years because they work only 1/300 of the time.

The clock mechanism does not operate the hands on the dial by direct mechanical connection. Instead it closes an electrical circuit, energizing a magnet which moves the hands. This system permits the dial to be placed inside or outside the clock cabinet, in another room or even another building. In a series circuit one clock will operate a dozen or more dial movements; for example, one in each room of a residence, with, incidentally, a considerable cumulative saving in power cost. Since the Synchronome is accurate within a second a week, it will give even more precise time to all these dials in most localities than ordinary electric motor clocks which are regulated by the frequency of power-line alternating current.

This frequency is controlled by the power companies as accurately as practicable, yet it is often temporarily slow or fast. This is not the fault of the power companies or of the clocks. It is no one's fault. Each time a motor is started or a light is turned on, there is a momentary drop in frequency until the automatic speed governors on the turbines in the generating stations make the necessary adjustment for the change in system load. Thus, for example, in two interconnected Eastern states the nominal frequency of 60 cycles per second varies more or less constantly between 59.85 and 60.15, causing clocks to drift back and forth one or two seconds slow or fast. They are rarely more than three or four seconds wrong except during serious disturbances, and the error is usually corrected at the rate of one second in 20 minutes. The standard used is the National Bureau of Standards' time signals over Station WWV.

The Synchronome may be set by the same signals, which are sent out continuously night and day from Beltsville, Md., and Maui, T. H., on 5, 10, 15 megacycles and other radio frequencies, and almost hourly over U. S. Naval Radio Station NSS, Annapolis, Md., 4.39 megacycles; Station NPG, Mare Island, Calif., .115 megacycles, and others. These signals are determined by the world's most precise type of clock, the quartz crystal oscillator invented by W. A. Marrison of the Bell Telephone Laboratories, which is accurate to about one third of a second per year.

The action of the Synchronome is so simple that when the illustration above has been carefully traced through a single cycle its working principle is clearly understood. (The drawings in the upper corners are not related to this clock.) The little gathering jewel on the end of the short stem that protrudes to the left from the pallet on the pendulum reaches out every two seconds and almost silently pulls the unresisting "count wheel" toward it. This is not an escapement wheel, and the Synchronome has no escapement. Every 30 seconds the count wheel completes one revolution, carrying the tiny vane behind it around to trip the catch above it. Down comes the gravity arm, pushing the pallet and pendulum with a soft thud that blends instantly into a sharp click as it is thrown back upward onto its catch by the lively slap of the armature. The same electrical impulse moves the hands of the clock ahead half a minute.

There is a fascination in watching this action and listening for the widely spaced clicks, which in no way resemble the ticks of a conventional clock. Some persons in the families of amateur clock maniacs have loudly asserted their annoyance at these sharp clicks coming between long silences. No doubt they are relatives of those who tensely wait for the dropping of the other shoe. There are city people who when in the country actively listen for unfamiliar noises and thus are kept awake by katydids and crickets, though they easily fall asleep in the subway. Anyone who is distracted by the widely separated clicks of the Synchronome may be cheered to learn that a subsidiary seconds switch can be attached to the pendulum to make it click once a second like a conventional clock. This switch will also move the hands on the dial once a second, to please those who think a clock cannot be accurate if its hands move only once every 30 seconds. However, since this appliance is actuated by the pendulum, the clock will actually lose precision because of it. Physicists have long known what many clock inventors have ignored: that every interference with the freedom of the pendulum, whether from tangible or magnetic contacts or from escapements, steals energy from the pendulum and wars with good timekeeping.

As the astronomer Sir George Airy stated in a famous theorem, interference with the pendulum is least disruptive at the center of the swing, and most harmful at the ends—just where escapements do their interfering. In the Synchronome, where the mechanism monkeys with the pendulum only once in 30 swings, the addition of a seconds beat is a backward step except when required for some practical reason. The Synchronome has survived a host of forgotten clock inventions just because it does its monkeying scientifically, the interference is kept at arm's length from the sacred pendulum. The pendulum tells the gravity arm when to fall, and the gravity arm gives the needed impulse to the pendulum.

While it is fun to build a Synchronome, the best fun follows its completion. Unless the builder is not only a genius but a lucky one, the clock will not start out keeping within one second a week of the right time. Bringing the error down to that limit may involve weeks or months of sleuthing, adjusting and timing subsequent runs by the signals from WWV. Hope-Jones, the inventor of the Synchronome, has defined the ultimate target in terms of the barometer: "All other sources of error having been eliminated or sufficiently mitigated excepting only variations of air pressure, see that it gains with the fall and loses with the rise. One inch rise or fall of mercury will make a difference of about one third second per day." The density of the atmosphere keeps changing, offering greater or lesser resistance to the pendulum, and the clock cannot be made more precise than the limitation from this source.

The cost of building a Synchronome is comparable to that of a telescope. The castings and some of the parts are supplied by the Synchronome Company, Ltd., Alperton, Wembley, Middlesex, England. Import duty on small purchases is payable to the local letter carrier with no more red tape than a C.O.D. purchase.

Court G. Helmstetter, a tool designer of Detroit, Mich., made one of these clocks in his spare time between the months of January and August and 1ioused it in a mahogany and glass cabinet in his living room. "The best it performed," he states, "was one-second error in 11 days. It is almost unbelievable that a home-made clock can be so accurate, especially since it is not installed in a special vault or vacuum chamber but simply hangs on a wall."

A. P. Fletcher, a Detroit design engineer, built a Synchronome that once ran five weeks with an error of only half a second, though he attributes this partly to luck. "This clock hobby," he writes "has afforded me much pleasure and some very valuable information. A small adjustment of the parts accomplishes a large result, if it is of the right kind an in the right place. I have found about 10 of these places that affect the action of the clock.

Henry F. Millon of Brownsville, Tex. made a Synchronome of stainless steel that performed, he reports, "with phenomenal accuracy, two-seconds' error in 10 days. Ultimately the clock gained 15 seconds and for several days hung at that point, varying plus or minus only half a second. Frankly, I can't figure it out, since the clock is not supposed- to perform with such accuracy. I still get a kick every time the gong that I added to the dial movement rings on the hour." Later he wrote, "A run of less than one second variation has at last ended after 28 days, when the variation increased very sharply, no doubt because of spring fever."

William Buchele, a professional precision optician of Toledo, Ohio, is another who once made a Synchronome clock.

H. L. Rogers of Toronto, Ont., made his Synchronome's pendulum of wood instead of the specified Invar with a temperature-compensated bob. Nevertheless, he says, "it keeps better time than any other timepiece in my house. When I was regulating the clock I thought my watch was pretty accurate, but now that I have the clock regulated to within a few seconds of the time signals, my watch and all other clocks are set by the Synchronome. Certainly anyone with enough mental fertility to make a good telescope would not find this clock too difficult."

Some years ago L. C. Eichner of Bloomfield, N. J., built a Jaggar earthshock recorder or local seismograph (SCIENTIFIC AMERICAN, November, ]929), and made a Synchronome clock to mark time signals on its records in the basement of his home. "For a time," he writes, "it was fun to follow the passage of trains by means of the shock recorder, to be able to tell whether a Ford or a GM truck was passing my home, and to determine the exact moment when a bootleg-still in nearby Silver Lake blew up. But I found that the earth bottom beneath my community afforded too poor a base for a seismograph, and gave the Synchronome to the Custer Institute." The Custer Institute is a kind of amateur scientists' "Stellafane" at Southold, N. Y., near the eastern tip of Long Island, of which Eichner, a professional scientific instrument maker who remains an amateur scientist, is a member. Later Eichner built 10 seismographs for Columbia University and an extra one to give to the Custer Institute, where the Synchronome serves as a time standard

During World War II Harris Rush Of Westfield, N. J., built a Synchronome clock which has proved highly satisfactory, and which he proudly calls beautiful and distinguished. The conductor of this department has often watched this clock in action.

In 1940 Hope-Jones published the book Electrical Time Keeping, in which he described the history of the earliest mechanical clocks, the first electric clocks (1840) and their successors and his own invention of the Synchronome in 1895, with its principles and the subsequent improvements. The book was soon out of print, but is again available in a second edition from the N.A.G. Press, Ltd., 226 Latymer Court, Hammersmith, London W. 6, England. It contains facts that supplement the instructions in Amateur Telescope Making —Advanced for building the Synchronome, and provide a clearer understanding of its principles.

The earliest clocks, built at the end of the 14th century, worked on the principle of the verge and foliot balance, shown in the left-hand drawing in Figure 1. The unhurried medieval world put up with this crude mechanism, with its error of an hour a day, for three centuries until in 1588 Galileo Galilei discovered the isochronism of the pendulum—the independence of its period from the amplitude of its oscillation. In 1657 the Dutch physicist Christian Huygens, he of the famous wave theory of light, invented the pendulum clock. Huygens set forth its mathematics in 1670, in his Horologium Oscillatorium. Three years later the English physicist Robert Hooke, author of the classic Micrographia, invented the anchor escapement shown in the upper right-hand drawing. This was an immense improvement over the foliot balance, yet, as Hope-Jones states, "it involved almost continuous interference with the pendulum and prevented it from swinging undisturbed in its own natural period of vibration. The subtleties of the escapement," he adds, "provided a lifetime's job for the scientists of two centuries, and the science of horology may be said to have existed for the amelioration of escapement evils. When it failed the only thing to do was to dispense with the escapement altogether." It failed, Hope-Jones means, because it could not meet modern demands for clock precision.

Hope-Jones describes a vast amount of invented clock mechanism that fascinates the mechanically minded, the reason given for describing it being to show why most of it was bad. Clock-design inventors ignore physical laws and the failures that have preceded them, make the same mistakes over and over and never seem to learn. By a wide variety of electrical means they attempted to escape from the escapement, and Hope-Jones was the first to succeed.

He sought and found a way to relieve the pendulum of any share of the necessary contact. As shown in the drawing, all of the energy that lifts the gravity arm and thus indirectly keeps the pendulum swinging is transmitted through the electrical contact itself. Thus it simultaneously serves two ends: the first electrical, the second mechanical; the armature, moving forcibly against the gravity arm, provides an excellent contact during a full .06 second; then the contact is swiftly and cleanly broken by the momentum of the arm after the armature has reached its stop. A brute-force operation is thus accomplished without interfering with the pendulum, yet deftly timed by it.

Many other features of the clock are likely to be overlooked unless the builder reads the Hope-Jones book. It contains a chapter on synchronous motor clocks, e.g., the Warren Telechron, and one explaining the Marrison quartz crystal clock. The quartz crystal oscillator clock may not be beyond the skill of amateurs.

"He is a happy man," Hope-Jones concludes about the Synchronome and himself, "who can turn a hobby into a business. There are few more pleasant companions than a simple pendulum of one's own construction whose 'remontoire' compares itself with the wireless time signals, and remains 'within the six dots' for months at a time. And it is a pleasure which I have been able to share by giving facilities to many a keen amateur mechanic . . . with permission and assistance to make one for their own use, not for sale. Thousands have done so and, though the policy would never square with a businessman's ethics, it was never regretted. It brought enthusiastic friends and champions, and advanced horological education."

F. Hope-Jones is dead, but the Synchronome Company has continued his policy of supplying amateur builders with sets of the necessary rough castings for the Synchronome—a very small detail of their business of supplying factories, schools and municipal institutions with master Synchronome clocks that operate hundreds of dials. They require only that the amateur builder "give undertaking that such instrument when completed would not be used for any commercial purpose whatsoever." Since no one can make, even for his own use a patented article without the authorization of the patentee, this reservation is a legal right. The same free policy does not extend to the Shortt-Synchronome clock.

The Hope-Jones book is almost wholly about electric clocks; the beginner in horology may prefer a general treatise on horology to fill in his background. The most nearly up-to-date book in print is Time and Timekeepers, by the astronomer Willis I. Milham. To improve his knowledge of clocks and watches, Milham spent many hours with watch and clock repairmen. A less elementary treatment of clocks and timekeeping appears in a 30-page article by Ralph Allen Sampson in Volume 3 of Sir Richard Glazebrook's famous Dictionary of Applied Physics. Actually the dictionary is an encyclopedia. The article about clocks in the Encyclopaedia Britannica contains good data. Clocks, Watches and Bells by Edmund Beckett, published half a century ago, today out of print but available in some libraries, may also interest the amateur horologist. The quartz crystal clock is described in Evolution of the Quartz Crystal Clock, by W. A. Marrison.

Suppliers and Organizations

The Society for Amateur Scientists
5600 Post Road, #114-341
East Greenwich, RI 02818
Phone: 1-401-823-7800

Internet: http://www.sas.org/

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