Time Taking, Time Keeping (1913)

TAKING KEEPING ‘ \\‘\ \ z‐rfi ’fl xxxl\‘> * 4/4 ”744"< ‘n ”k1 The Elgin Observatory where time is accurately determined from the stars TIME KEEPING AN ILLUSTRATED BOOK‐ LET PUBLISHED IN THE INTEREST OF CORRECT‐ ING THE ERRONEOUS IDEAS PREVALENT IN RE~ GARD TO THE CORRECT MAINTENANCE OF STANDARD TIME THE ELGINNATIONALWATCH @ ELGIN ILLINOIS 1913 I515’ II ‘tqfléblfim fi 4 < >‐<-,-> \\:'t"1/ ,-,; >>gfifl am GRAN US I M E ! One of the tightest, trimmest words in all the English tongue‐and yet, can you name another that has more power to provoke thought, to stir imagi‐ nation, to start the pulses of action? What was time to the shipwrecked Crusoe on his desert island? A vague, indifferent quantity, as valueless as the Spanish coins t h a t he uncovered in a seaman’s chest! Darkness and dawn and the flux and flow of tides were the hands that spaced the dial for the solitary castaway. He needed nothing ’ more exact. The contact of man with man is what touches Time into life, compels the j familiar modern question, “Correct time, i please?” and makes seconds more vital and precious t h a n hours or days of Crusoe’s ‘ companionless exile. “Correct time!” Did you ever think what this term might mean under circumstances so normal that they are repeated almost daily? The skill of , a dramatist is n o t required to conceive a situ‐ Lation in which each tick of the watch is ‘ translated into a human pulse-beat. Life itself arranges these situations in variety so astonishing that they become accepted com‐ monplaces. ~ “&5§§W“%»§7 fl“ ‐ Here is a passenger train driving east‐ ward with its load of human freight over single track line in the undeveloped West. Running against this train, on the same track, is a freight. At the last stop the freight engineer has received orders to p u t into the siding at X and give the passenger train the right of way. When he received this order he had an easy margin of five min- utesoverthetimerequiredtoruntoX,but a slight accident, a brief stoppage, has reduced that margin to less than sixty sec‐ onds. The engineer of the passenger train is tight up to schedule; according to his watch he will pass X on the appointed second. The watch in the hand of the freight engineer tells him that he can round the curve and slip into the siding with thirty seconds to spare‐just thirty seconds at best. What if the passenger engineer’s watch were forty seconds too fast or the freight engineer’s watch forty seconds slow? Here is where ,’ “correct time” spells human life! In a hun- ‘ dred ways this drama of Correct Time might " «g be varied‐but in each case be true to the ‘ “f‘f‘ letter of modern life. No man can consider for a moment the meaning and importance of “correct time” without raising the questions: “ W h a t is cor- rect time? Where do we get i t ? ” Probably notonemanin ahundredthousandisableto answer either of these questions “offhand.” ’ r M . y;‘ W@§h§®% " , ‘ 7‐ 1 i ' . { as Most Americans would reply: “ W h y , the $7 correct time is the right time, of course, and ‐ they get it from Washington.” In the minds of those who give this answer “correct time” is an arbitrary thing officially fixed and certi‐ ; fied by some obscure servant of the govern‐ ment at the National Capital. Others, even less thoughtful, answer: “They get it from the Western Union,” or, perhaps,“From the time-ball on the Ex‐ change Building.” These ingenuous answers suggest the reply of the city child in the tene‐ m e n t district, when asked by her teacher , wheremilkcamefrom. W W/V///M g , s\% 1 , “ I know,” was her eager response, “from the milk wagon.” B u t the opinion held by the person of average education is unquestionably that the right time is determined from the sun. A popular expression of the opinion held by the f ; whole American people would probably vote I the honor of Time Maker to the sun. But ? great majorities are often wrong‐and sel‐ i dom more so than in this case. On a hill overlooking the works of the Elgin National Watch Company is a trim Glittle building that is a “standing mystery” \ ' to the uninitiated stranger. At first glance , you might take it to be a modern residence, 0 I of square, stocky type. But one end of it is crowned with a squat dome, as round as half an orange. In broad daylight you might , I I {lil- fiv///‘:f if \\ b mlll~“*«ltl% fl Q, , N I“) .\ ' possibly pass this odd structure with hardly ‘_ a second thought‐in spite of its strange dome. But, after dark, that building will stop you in your tracks. You can’t get'past j\\ it, and you will not leave Elgin until you ”’ ‘ have found out why its lights blink on and 3 off, with nervous irregularity, all day and “‘ all night, day after day and year after year. ' There is something weird, uncanny, in the impression that this half-human structure makes upon the unprepared mind of the stranger who chances to come upon it. Probably there is n o t another building in f the United States that better deserves to be surmounted with a statue of Father T i m e ‐ ‘ with flowing beard and swinging scythe‐ than this modest little structure. Certainly ‘ thereisnonewhosedoorstoneismoreworthy to bear the crisp legend “Correct T i m e ” ‐ for it is dedicated to the purpose of reducing “ t i m e variations” of clocks and watches to , the minutest fraction of a second. As y o u enter this mysterious structure . y o u might easily persuade yourself that y o u are in an ordinary business office~for there ' are desks and tables littered with record , ‘ H ' , books and figuring tablets covered with com‐ putations. B u t just as y o u begin to recon‐ ‘ cile yourself to the commonplaceness of y o u r surroundings, a pilot light over the larger desk flashes on~‐and as suddenly blinks out. Then y o u begin to catch the weird under- ' T H E RIEFLER PRECISION CLOCKS THESEclocksareenclosed1' nhermeticallysealedglassJarswhich guard against atmospheric fluctuation. A delicate thermo‐ stat keeps the room at constant temperature the year round. The clocks are mounted on solid concrete piers separate from 11 the rest of the building, to insure absence of vibration. One “1" erlock indicates Sidereal Time and the other Central Standard ‘ 1me. 1 311§fiaga1gs tone of the place‐a symphony of mysterious § pulsations, punctuated with thesharp click t of shifting levers in secret places. The very walls seem alive and charged with super- automatic activities. In the clear and cheer- ful light of high noon it is no place for a nervous man! But in the dead of night it is ominous, fantastic. Beyond a doubt, there are thousands of persons who would be com‐ pletely unhinged if compelled to spend a night alone in this abode of marvelous mech- anism were n o t the meaning of each muffled sound, each sudden flash of light, each per‐ sistent» monotone of pulsation first fully explained to them. B u t the most patient explanation of the mechanical nature of the startling freaks of light and sound is a poor preparation against their unexpectedness. A “queer feeling” is bound to haunt the stranger until he becomes attuned to the rhythm of the vaulted clocks, the blinking lights and the muffled click of concealed ‘ levers. One element, however, is possessed by “ this place of mystery that cannot fail to tem‐ per the weird impression that the super-auto- , ‘ matics of the building invariably make u p o n the mind of the visiting stranger. This is the serene and genial personality of the white‐ haired m a n who sits at the business-like desks and fills sheets of figuring pads and pages of record books with computations so intricate lg1s *\\\NM?/ . z. // ‘X *\ " \ ‘ f fiWé imAW\g” \ R; W‘ 7_ AQ) 7 ¥ V’. .x ax I andextensiveasto makeanordinarayc%count‐ / ant gasp. Prof. Payne, the presiding genius ’ ofthisTempleofCorrectTime1,ssowarmly§ human that his smile antidotes the mystery ‘ ’ and the uncanny automatics of his environ‐ ' ment. Once start him talking of the science of time-taking and he’ll lead y o u , charmed " and unresisting, along the glowing pathway ‘ ‘ of the stars. His keen eyes were half-closed and there seemed to be a mist of dreams before them as he warmed to the theme ‘ which has absorbed the best p a r t of his rich life: 7k “Time!”heexclaimed. “Why,theaver‐ agemanknowssolittleofthattermthatI’d ‐ hardly know how to choose the words with which to make clear to him What the astron‐ omer means by ‘correct time.’ There’s my neighbor, out there‐just going home to his luncheon. He’s a college m a n and a lawyer. One day I sounded him on this subject and ‘ he confessed that he held the notion that ‘the experts get the time from the sun, set a big clock by it and then pass it along down the 1ine’‐no doubt he had the Western Union Line in mind‐so that all men who , were careful about their watches m a y square them by it. That was his whole idea of cor‐ rect time.” “ B u t what is the source of absolutely 1 correct time?” interrupted his caller. “The revolution of the earth on its axis,” .\\\ _‐;i\\\§f\W \ ~\ _ \ = ~ ‐ ‐ // answered the astronomer. “That’s the only clock known to man that doesn’t vary a hair’s breadth. It’s the most regular move‐ m e n t in all the universe, so far as science has been able to determine, and the astrono‐ mers have been busy at this problem ever since Galileo invented the telescope‐cen‐ turies ago. It’s so regular‐this revolution of the earth on its axis‐-that it does not vary a hundredth of a second in a thousand years, and astronomy and the science of time‐ measuring are so exact that if it did vary a hundredth of a second in a thousand years they’dcatchtheOldEarthatit! Thisstate‐ ment sounds incredible to the average lay‐ man‐but not to the astronomer. To him a thousand years is a short period. “But to go back to the common notion that our time is taken from the sun: there are m a n y things which forbid this. The fact is that we get o u r time from the stars. There are many fixed stars on which we can get a line at the instant that they coincide with a given meridian. On the other hand, the sun . passes our meridian but once each day. So, . you see, we can get almost as many ‘shots’ at the stars, a n y clear night, as we choose to take‐as against only one shot at the sun. , Again, the sun is hot and likely to disturb ' r 5 our instruments, sothat we may not get the same results in the latter portion of an obser- . r &\ ‘ vation that we secureat its beginning. 1@§i’3§%@a\%fia ” “But there is little use trying to make a i , layman understand how we get Correct Time . i e of the kind that he uses until he is given some little understanding of the different ‘ ' kinds of time from which the commercial " product is extracted. Then he can form 1‘ some notion of the p a r t played by the vari‐ Yous instruments in the observatory. Sup- _ pose I turn you over to Mr. Urie, my assist‐ a n t , who makes the observations. If it 1 wouldn’t be too startling for a m a n of science 3 to make use of a bit of modern slang, I ’ d say that Mr. Urie cans the time and I make a =‘ chemical analysis of it later. He’ll show the clever machinery used in the canning p r o ‐ cess. Mr.Uriehasaveryclearwayof stat‐ \, ing scientific facts and I think he’ll be able to define the different kinds of time so that almost anybody m a y identify the various brands on sight.” Left with the lithe, active, clean-shaven young assistant to the senior astronomer, I instantly exclaimed: “Now tell me: What makes the light over the desk blink s o ‐ a n d the other lights, too? A n d what are all those queer, uncanny . , noises? This is just about the weirdest place ‘ I was ever in.” “Oh!” he laughed, “I’ll get to that later and show you the skeleton in every closet, but it will all be Greek to you unless I first give y o u some idea of the different kinds of mfi§%@ 7m “Uh“‐ ~4 X Q _‐‐‐_‐_‐7‘A‐ 2 5fl2 2 4w § awe/m4 THE TRANSIT INSTRUMENT ' THIStelescope is mounted on a solid concrete pier entirely separate from the rest of the building, so that no vibra‐ tionnorjar canreach it.’«With this telescope thefixed stars are observed asthey pass the meridian. These observations enable the astronomer to determine the correct time within o n e one-hundreth (0401) of a second. 13“; 7 4 m ”/,1 ‐ ; ‘ astronomical process. To the astronomer ‘ there are four kinds of time: Sidereal, True Solar, Mean Solar and Standard. “Sidereal time is literally star time and time with which we have to deal andhowwe ‘ arrive at them. Then y o u will have the \ basis o f the whole w o r k ‐ t h e realvital mean‐ ing of the various pieces of mechanism that . are so mysterious to the average layman. ' “Youseeit wasnotuntiltheseventeenth century, after the invention of the telescope by Galileo and the application of the pendu‐ lum to the clock by Huygens, that time‐ keeping w a s placed on a scientific basis. During the last three hundred years constant progress has been made in astronomical instruments and methods, which has resulted ‘ in the marvelous accuracy of the present ‘ Y day Time Observatory. As we take the time \ from the stars, time-taking is purely an r; is derived from the revolution of the earth on its axis, which, asProf. Payne has said, is the most uniform and constant motion known to science. The time that it takes the earth to make one complete revolution on its axis i s c a l l e d t h e S i d e r e a l D a y , w h i c h i s t h e funda‐ mental time-unit in astronomy. “True solar time is derived from the sun, the interval between t w o successive passings of the sun across the same meridian being H defined as the True Solar Day. Now, the ; earth in its yearly course around the sun, f/ sg Vat/213”- *‐ , . fist/rail, A g a t a ; ’ , travels with greater velocity in winter than 7 in summer; consequently the t r u e solar day varies in length at different times of the year and is n o t therefore suitable for general usage. “MEAN SOLAR TIME is an inVention of man, made to adapt True Solar Time to human consumption. In order to overcome this difficulty of days of unequal length at different times of the year, a fictitious sun is imagined to move with uniform velocity so that the length of the day will be the same, / twenty-four hours, at all times of the year. This is the basis of mean solar time. “Standard Time is a still further refine‐ ment in the line of reducing time to the needs ' of men who live in a world of fast travel. It might well be called Business Time, or per‐ haps a better name would be Trans-conti‐ nental Time. Anyhow, the adoption of Standard Time was the step that put time on the commercial m a p and made it a definite and easily interchangeable quantity all over 1/ the world. Before time was standardized it , was something like the wildcat currency‐a } local thing that wasn’t always easily ex‐ changeable at face value when taken out of its home territory. Now the other kinds of time that I’ve defined are local, that is, they vary with one’s longitude or distance east or " west of Greenwich. When railroads came into general use it became necessary to have s § § ,.rmeganfi , afiww / a uniform time system over a large section of the country. This resulted in the adop‐ tion of STANDARD TIME, which is now used over a greater p a r t of the civilized world. Twenty-four meridians, each fifteen ~‘ degrees apart, with the meridian of Green‐ wich as the starting point, are taken as refer‐ encelines. Thelocalmeantimeofanyof li” these meridians will differ from Greenwich mean time by exactly one or more whole hours. The standard time at any given place is then defined as the mean time of the stand‐ ard meridian that is nearest to it. In other words, a n y place within 7% degrees of a standard meridian should use the time of that meridian. This rule is n o t always fol‐ lowed, and the actual boundaries between the different time zOnes are very irregular, depending u p o n the points where the rail- . roads change their time. “Standard time is a matter of longitude. ' You must know your exact longitude in order to translate sidereal time into standard time. Take it with this observatory, for example: the way we obtained our longitude was by hooking up‐on the telegraph wires‐with wthe Washburn Observatory, University of ' Wisconsin, at Madison, Wisconsin, whose longitude had already been determined. The ,' same twenty stars were observed by Prof. Comstock at Madison and by Prof. Payne at Elgin. The exact time of each star was / s r §\\‘v/‐¢ ** v\% flK , / ii ‘ \\4/4A ?\fl ? X Q W \ M w , . W I x MI / V / M W W V ’ m a ' R tgeeg flashed between these t w o stations. F r o m . the data furnished by these simultaneous ‐ observations it was easy to determine o u r exact longitude. Of course, Madison secured her longitude by hooking up with the United States Naval Observatory at Washington and going through the same process. Wash- ington, in turn, got her longitude from Green- ' “ wich, England, which is the fountain-head and starting point of all longitude. After we had fixed the longitude of our observatory to ~ a hair’s breadth it became a mere matter of ‘ mathematics to reduce o u r standard. sidereal t i m e to . , rotating on its ‘ “ N o w , the earth, while axis once in a sidereal day, revolves about t the s u n once a year; hence the sidereal day is slightly shorter than the mean solar day, which is the day in ordinary use. The differ‐ ence between sidereal time and mean time can be best understood when it is stated that there are 366.24 sidereal days and 365.24 -__ mean time days in a year. A clock to keep ' sidereal time m u s t therefore be regulated to gain twenty-four hours a year, or three min- ‘ utes and 56.555 seconds a day. “To sum it all up, it is impossible to ‘ determine Mean Solar Time from any heav‐ enly body because it is founded on a ‘ficti‐ tious sun,’ or rather upon the fiction that all days are of equal length, and Standard Time is merely an adaptation or a geograph‐ ,mmwéalgwg\i..‐§\\\ 1 , ‘ , * ion. Aside from these nervous and oddly ' arranged electric fixtures, the only objects in the room are two stately clocks incased in " huge glass jars or tubes. “These lights,” explained M r . Urie, “are merely for the purpose of keeping the clock vault at a fixed temperature. Why? Be‐ cause even a slight variation of temperature ‘ causes a corresponding variation in the pendulums of the clocks and consequently affects the accuracy of their time-keeping powers. Probably there are no better clocks in the world than these‐but to eliminate a n y temperature compensation errors that might possibly exist in their pendulums we had to devise some scheme that would auto‐ matically check any change of temperature marked enough to affect the pendulums. This is done by a very delicate thermostat, which, through an electric relay, automatic‐ ally turns off the electric heaters when the temperature rises above 81 degrees and turns ' them on when the temperature falls below ; that point. The average daily maximum ' variation of temperature is only 0.1 degree ‘ Fahrenheit. H o w do we know that? Because = we have an automatic record of the tempera‐ ture for every moment of every day. “ T h e thermograph, or recording ther- mometer, gives a continuous record of the temperature of the clock vault, the accu‐ racy of the temperature control being indi- \ ‘ ~ l \ , , , 1 / \ “ g u y 1 ‐ - ‐ ' ~ " ‐ ‐ >, ' 7 ' , , ‐ =m:es%@@awa@ , Maw/flex neg-fig l / Cated by the straightness of the line on the Z; thermograph sheet. In a word: the tem- .\ 5.~‘ perature takes a continuous moving picture of itself. It can’t play a n y trick on us and 7 get away with it.” ' No m a n who is thoroughly human can ‘ stand before these vaulted and pampered clocks and listen to their soft, rhythmic pul- ' ‘ sations without feeling a touch of solemnity. They compel silence. They forbid human chatter. Finally, however, I summoned courage to say to my guide: ‘ “Theclocks‐tellmeaboutthem,please.” \ “I never escape from feeling a little awe , of them‐they’re so unhumanly exact!” he ‘ responded. “When the Elgin National Watch Company decided to have as fine a time observatory as could be found in' Amer‐ ica‐really they determined to have the most lN‘ perfect on the continent‐the site on which to locate it was a problem. Finally the hill on which this building stands was selected for the reason that it is a gravel hill and the gravel greatly reduces the vibrations of the earth. Each clock is set u p o n a concrete pillar, separate from the building itself, that , runs down deep into this bed of gravel. This . reduces vibration to a minimum. “ A s a rule the less frequently a time-piece requires to be wound the more desirable it is in the eyes of the public. These Riefler clocks, however, are wound automatically, asg rfiwz/cz-fi.;.~ " ‐___‐=:__ ’ / , ‘ W$7Mm0“.01\“ AMA %\ \ by electricity, every thirty-six seconds and are inclosed in hermetically sealed glass jars. . The air in the jars is partially exhausted and is kept at a uniform pressure, thus eliminat- ‘ é 7 \ ' ing barometric corrections. The regulation . 4 of these clocks is effected by changing the air g pressure. Inside the clock is a barometer ‘ ‘ graduated in millimeters from O to 760; a change in pressure of one millimeter on this scale willchange the rateof the clock eighteen‐ thousandthsofasecond(0.018)aday. This is the most refined method of regulation yet devised. It’s the next thing to regulation by imagination. Now come back in the even‐ ing and see the process of time-taking. The , actual observation of one set of stars will make the real nature of this work clearer to an outsider than any amount of talk. ‘Canned time’ is no slang phrase here‐it’s almost literally descriptive of the physical records ‘ , from which our deductions are made. But you’ll see, to-night!” ‘ And see I did! The upstairs of this won‐ derful Time Observatory has three apart‐ ments: the telescope room,the clockroomand a neat little chamber in which the observer , finds a comfortable bed when his vigils keep him to a late hour. The Sidereal clock, the Mean Time clock and the telescope each stands onanindividualconcrete pier,separate from the building. These clocks are prac‐ tically identical withthose in the lowervaults. . , “la Close beside the clocks is a small b u t elaborate mechanism operating a drum. As M r . Urie covered this drum with a sheet of stiff white paper and clamped it tightly into place he explained: “ T h i s is the time-canning machine. We call it a Chronograph. It is literally ‘hitched up’ with the Sidereal clock. The cylindrical ‘ drum carries the record sheet and makes exactly one revolution a minute. The record‐ ingpen that I’mnow filling and putting into position bears its trailing point upon the cylinder of paper. It would cover that paper / with straight parallel lines precisely a min‐ uteinlengthwereit notforthefactthat,at e v e r y second, it is moved sidewise by an electro-magnet that is in circuit with the Sidereal clock. The fifty-ninth second is always omitted to show where the minute begins. The record, tracing, autograph or ; snap‐shot of a second of time is about half ' an inch in length and that of a minute is about t h i r t y inches long. The mechanism ‘ was constructed to give a second this amount of ‘spread’ on the sheet so that the fractions ' of a second could be easily determined. ' “When I ’ m at the telescope, out in the other room, making an observation, I hold , in my hand an electric push-key that, when » i pressed, deflects the recording p e n and makes T \f a peculiar waver in the line that it is tracing. “ N o w for the telescope. This is set 21m“ fi é/ u / \; fi 5 exactly N o r t h and South, as all time obser‐ vations m u s t be made in the meridian. In . other words, we have a table of several hun‐ dred stars showing the hour, minute, second and fraction of a second when a particular star is due to cross the meridian on which our telescope is set. Take a look into the eye-piece of the telescope and you will see what appears to be a group of wires. In reality each wire is a single strand of spider’s web, so delicate that y o u could hardly see it with the naked eye. The star appears as a bright point of light moving between the horizontal wires; whenever it passes one of the vertical wires the observer presses the electric key that he holds in his hand. The result of that sudden pressure is an odd little jig in the line that the pen is tracing on the paper-covered reCording drum. As there are eleven of these vertical wires and the key is pressed as the star passes each strand, it follows that there are eleven little deflections in the record line that the pen is tracing‐ eleven little points in the picture of that minute. “ T h e time, by the Sidereal clock, that the . . star crossed the meridian is obtained by plac‐ ing a graduated scale on the chronograph sheet. In this manner each mark is read, and the average of the eleven marks is the Observed Time by the clock when that star crossed the meridian. The American Ephem‐ %@@%@% AUXILIARY CLOCKS A N D SWITCHBOARD THESE Riefler Clocks are used in connection with the routine work of the Observatory. One clock indicates SiderealTime, and the other Central Standard Time. The Observatory switchboard,from which all electrical apparatus is controlled, can be seen at the right of the illustration. ‘ m“ff§f§///@éw% A‘v // mm /',”L \\ “b” ~ 28 /\\ QTSENW ,, “54 eris and Nautical Almanac, published yearly by the United States Nautical Almanac . Office, contains the times of meridian pas‐ sage of 800 stars; from this list we obtain \\ the Correct Time of passage. Now the dif‐ ' ference between this Correct Time and our Observed Time is the amount that the clock \ i is out, or the ‘Clock Correction.’ Twelve or more stars are observed on clear nights and the average of the whole set is taken as the clock correction, which is accurate to one‐ hundredth of a second. You see nothing is left to guesswork under this system of deadly , averages. Our telescope is so hung that it maybesettoaperfectleveleachnightbefore ‘ an observation is made. Again, as an extra precaution, we always observe some stars to the north and some to the south on the same night.” A glance o u t the window provoked the visitor to ask: “And what’s that queer little house out . there?” , “That’s what we call our Meridian -’ House,” was the answer. “ I n it we keep the meridian mark‐a sort of a target, so to . speak, by which we can make whatever i“ small adjustments of the telescope that m a y be found necessary from time to time. What is a meridian mark? It’s a solid con‐ crete pier surmounted by a lens with a disc behind the lens. This disc is pierced with a hole (0.002) two-thousandths of an inch in diameter. Back of this hole is an electric light. This tiny dot of light is the mark or target‐not a big target, but when you look at it through the transit telescope y o u could hardly tell it from a genuine star. Because this artificial star is stationary it can be used as a fixed basis from which to make ' adjustments of the telescope.” “But what,” I asked, “is this odd little device over here for?” “Just another super-extra check on the accuracy of o u r work,” was the answer. “ It’s what we call the personal equation machine. Each observer is temperamentally different; one will press the recording key a fraction of a second before the star is on the wire, another a trifle after it has passed the line. One is over-anxious, previous in tempera‐ ment, the other hesitating and conservative. 1 This is a miniature telescope trained on an artificial star and so geared that it records when the ‘star’ is actually on each line as well as when the observer‐by his pressure on the key‐says that the wire and the star coincided. From that record is determined the average hesitancy or the average p r e ‐ viousness of the observer and this is used as a ‘personal equation correction’ in the com‐ ,,’ putations determining actual time observa‐ \ tionsmadewiththetelescope. Oh,wetryto ‘ cover and allow for every possible kind of W< W§@”§W@eW/% 30 ‘ error that might affect our results by/the hundredth of a second.” Then the amazed guest of honor cut in with a question: “ B u t how about the cloudy nights when there isn’t a star to be seen? Sometimes we havemanyofthoseinsuccession. Idon’t‘\ see how you can maintain your check on Correct Time then‐particularly when you’re so strenuous in trying to crowd out a varia‐ tion so fine as a hundredth of a second.” “Oh,that’s easy,” came the quick answer. “ W e carry the time between infrequent observations by allowing the Sidereal clock to ‘run on rate,’ as we call it. That is, the Siderealclock isneversetnorregulated. Each observation gives us the clock correction; hence by subtracting the correction on one date from the correction on another date , and dividing by the number of intervening days, we obtain the Daily Rate of the clock for the intervening period. The requisite of a good clock is the steadiness with which it ' repeats its daily rate. With Riefler Clocks the daily rate is most constant, seldom vary‐ ing more than two-hundredths (0.02) of a .second from one observation to the next. Knowing the correction and rate of the clock it is possible to compute the correct time at a n y given instant. “The mean time clock, which furnishes standard time to the Elgin National Watch g i g - WWW/w THE U.S.WEATHER STATION AT ELGIN OBSERVATORY H I S little shelter contains the standard weather instru‐ ments. Dailyrecordsof temperature,relativehumidity, rainfall,wind~direction, etc., are made, and monthly reports are sent to the U. S.Weather Bureau. m a®%e§ authority to which they are attuned is the Z pulse-beat of the Master Clock, whose author- z; 5 i t y is derived, through its Sidereal Sister and ‘ $ KP W the telescope, from the stars4those fixed, 5\ \\ e/ flaming markers o f the heave ns from whic h Al “ ' the astronomers have learned that the revo- g» g lution of the earth does not vary one one- “ hundredth of a second in a thousand years! i‘ Apart from the big factory building is a small structure in which M r . Urie pursues patient investigations into the problems of watch variations. It is a laboratory for the f \ scientific study of watch eccentricities. W h y \ m does a watch identical with its orderly sister “movements” that keep excellent time, go off on tangents, play pranks of variation, , take spurts of acceleration or drop into languors of time loss? This is what the lab‐ oratory is trying, with fine scientific earnest‐ ness, to determine, and how impossible its progressive work would be without the almost perfect standard of time measurement ’ . wrought out in the little observatory on the , hill! The soft pulsations of that Master Clock really reach to remotest parts of the ‘ world‐wherever a watch from the famous , factory travels! Mariners on the high seas » have more than once made their reckonings from these watches; exploring scientists in the most outlandish corners of the earth have based their calculations u p o n the time given by these watches, and thousands of engineers / ‘\\\‘ if F‘W‘zs/ffi, ‘ \ xx,\ 38 //@V \x\Wjé» ~ l/ shine, the amount of rainfall, and the velocity / of the wind. On the roof are two standard $ ~ rain-gauges, the sunshine recorder and the \ \’ weather vane, containing the wind-direction apparatus and the anemometer or wind‐ velocity gauge. The Elgin Observatory ‘ WeatherStationisascompleteasanyofthe ‘ government stations in the larger cities. In addition to the daily weather reports sent to Springfield, for government use, local daily reports are furnished to the local news‐ papers. Twice each day a weather report is sent to the Elgin National Watch Company’s factory, where humidity conditions have a vital bearing u p o n certain delicate processes ‐ of watch manufacture. Elgin Watches The illustrations shown on the following pages offer but a slight suggestion of the great range of variety in which Elgin Time‐ pieces are made. There are nearly one hun‐ , dredstyles,gradesandsizes; awatchforevery ‘ requirementwheredependabilityandaccuracy areessential. Thereareladieswatchesin pend‐ antandbraceletstyle. Thebusinessorpro‐ fessional m a n will find the small thin models especially suited to his need, while the strong, substantial movements are particularly well adapted to withstand the shocks and jars to which the railroad man’s watch is subjected. W~W/ //¢A@/wA\ @g@m@§wW 5 Any jeweler can supply you. mtg/air??‐ 77 ~I / \ THE E l g i n “ V e r i t a s M o d e l " k e e p s c l o s e t i m e i n t r y i n g c o n ‐ ditions. It is a sturdy, compact model,andreceivesthe most careful scientific adjustment under the direction of the ElginObservatory. It is the watch for scientists, field engi‐ neers,railroadmenandother out»of‐door workers who need accurate time. “Veritas Model” watches are sold by all jewelers from $29.00 in a nickel case to $52.00 in a gold filled case. fi ’ i g fi lWM‐ l. ‘! v ' / / 4§1\\4‘u»; "fines , " ; We?“ m e%w;%<§ THE 16 size Lord Elgin in its finish, mechanical design, material and timekeeping qualities, is the peer of all fine timepieces for men. Sold by jewelers for $125.00 to $150.00 in solid gold 18k and 14k cases. THE I 12 size L o r d Elgin, because of its compactness and _. general attractiveness of size, appeals to the fastidious. Sold by jewelers for $120.00 to $140.00 in solid gold 18k and 14k cases. \,/1~ émfifiififiéflféfiw \ THE14 size Lord Elgin is an exclusive model that meets the presentdayrequirementfor an ultra light,thin,accu‐ ratewatch. Soldbyjewelersfor$35.00to$75.00insolidgold 141:case, $25.00 to $40.00 in gold filled cases. ELGINWatches for women are made in three sizes and eleven grades, costing $15.00 to $100.00 at a l l jewelers. ll 1@§/@%, afifiggg Na1, ELGINBraceletwatches for women m a y behadin plainor decorated gold cases or in platinum cases paved with diamonds, at prices ranging from $50.00 to $1000.00.