%.■;' * V > e ♦ ^. ' ^ <. x ^ ~* A V * ,^ ^^^. ■ \ ., s* «> ^' V -> <" xO'=C<. .V- 4" 'V -\'< -• ■ -4.. ' ^•^. ' :> <, ^ '^ «!,*^ , <" ;- "^A V* -6" it- '/ ^^ °^yiv^.- ^% aV „ <*. ^0 o. ,^^ -^^^ Oo. - A^ '- ■< - ", ''^^ - ' ^■5 •^^ \\ .^^ *e CONTENTS CHAPTER I HISTORIC OUTLINE Time as an abstraction. — Ancient divisions of day and night. — Night watches of the Old Testament. — Quarter days and hours of the New Testament. — Shadow, or sun time. — Noon mark dials. — Ancient dials of Herculaneum and Pompeii. — Modern dials. — Equation of time. — Three historic methods of measuring time. — "Time-boy" of India. — Chinese clepsydra. — Ancient weather and time stations. — Tower of the winds, Athens, Greece Page 13 CHAPTER II JAPANESE CLOCKS Chinese and Japanese divisions of the day. — Hours of varying length. — Setting clocks to length of daylight.- — Curved line dials. — Numbering hours backwards and strange reasons for same. — Daily names for sixty day period. — Japanese clock movements practically Dutch. — Japanese astronomical clock. — Decimal numbers very old Chinese. — Original vertical dials founded on "bamboo stick" of Chinese clepsydra. — Mathematics and superstition. — Mysterious disappearance of hours 1, 2, 3. — Eastern mental attitude towards time. — Japanese methods of striking hours and half hours Page 25 CHAPTER III MODERN CLOCKS De Vick's clock of 1364. — Original "verge" escapement. — "Anchor" and "dead beat" escapements. — "Remontoir" clock. — The pendulum. — Jeweling pallets. — Antique clock with earliest application of pendulum. — Turkish watches. — Correct designs for public clock faces. — Art work on old watches. — 24-hour watch. — Syrian and Hebrew hour numerals. — Correct method of striking hours and quarters. — De- sign for 24-hour dial and hands. — Curious clocks. — Inventions of the old clock- makers Page 37 CHAPTER IV ASTRONOMICAL FOUNDATION OF TIME A^stronomical motions on which our time is founded. — Reasons for selecting the sidereal day as a basis for our 24-hour day. — Year of the seasons shorter than the zodiacal year.- — Precession of the equinoxes. — Earth's rotation most uniform mo- tion known to us. — Time stars and transits. — Local time. — The date line. — Stand- ard time. — Beginning and ending of a day. — Proposed universal time. — Clock dial for universal time and its application to business. — Next great improvement in clocks and watches indicated. — Automatic recording of the earth's rotation. — Year of the seasons as a unit for astronomers. — General conclusions Page 53 ILLUSTRATIONS Page ortrait of James Arthur 8 iterpretation of Chinese and Japanese Methods of Time Keeping 15 ortable Bronze Sundial from the Ruins of Herculaneum 16 oon-Mark Sundials 17 'odern Horizontal Sundial for Latitude 40°-43' 18 he Earth, Showing Relation of Dial Styles to Axis 18 odern Sundial Set Up in Garden 18 rime-Boy" of India 19 ion-woo-et-low," or "Copper Jars Dropping Water" — Canton, China 19 Modern Sand Glass or "Hour Glass".... 20 ower of the Winds, Athens, Greece. . . .20 ey to Japanese Figures 25 ipanese Dials Set for Long and Short Days ,25 ipanese Striking Clock with Weight and Short Pendulum 26 ipanese Striking Clock with Spring, Fusee and Balance 26 ipanese Clock with Vertical Dial, Weight and Balance 27 ipanese Clock with Vertical Dial Having Curved Lines, Weight and Balance. .. .27 ipanese Vertical Dials 28 ipanese Striking Clock with Two Bal- ances and Two Escapements 29 Pwelve Horary Branches" and "10 Ce- lestial Stems" as Used in Clocks 30 Page Key to "12 Horary Branches" and "10 Ce- lestial Stems" 30 Dial of Japanese Astronomical Clock.... 31 Use of "Yeng Number" and Animal Names of Hours 32 Public Dial by James Arthur 37 Dial of Philadelphia City Hall Clock 37 Verge Escapement 37 De Vick's Clock of 1364 38 Anchor Escapement 38 American Anchor Escapement 39 Dead Beat Escapement 39 Remontoir Clock by James Arthur 40 Remontoir Clock Movement 40 Antique Clock, Entirely Hand-Made. .41, 42 Double-Case Watch of Repousse Work. 42 Triple-Case Turkish Watches 43 Watch Showing Dutch Art Work 43 Triple-Case Turkish Watch 44 Watches Showing Art Work 45 Antique Watch Cock 46 "Chinese" Watch 45 Musical Watch, Repeating Hours and Quarters 47 Syrian Dial 47 Hebrew Numerals 48 Twenty-four Hour Watch 48 Domestic Dial by James Arthur 49 Local Time— Standard Time— Beginning and Ending of the Day 57 Universal Time Dial Set for Four Places. 61 James Arthur Mr. Arthur is an enthusiastic sciciilist, a successful inventor and extensive traveler, who has for years liecii iiiakiiifr a study of clocks, watches, and time-meas- uring devices. He is not only a fjreat aiitliority on this subiect, but his collection of over 1500 timepieces gatliered from all parts of tlie frlobc lias been pronounced the tin- est collection m the world. Mr. Artliur is ,i ))Kasin- exception to the average busi- ness man, lor he has found time to doa laif,-e ainonnt of study and research alon" various sciciititic lines in addition to conductint;: an important manufacturing busi- ness in Ne%v York City, of which he is president. Mr. Arthur is 67 years of age.- H. H. Windsor. " CHAPTER I HISTORIC OUTLINE Time as an abstraction. — Ancient divisions of day and night. — Night watches of the Old Testament. — Quarter days and hours of the New Testament. — Shadow or sun time. — Noon mark dials. — Ancient dials of Herculaneum and Pompeii. — Modern Dials. — Equation of time. — ^Three historic methods of measuring time. — **Time-boy" of India. — Chinese clepsydra. — Ancient weather and time stations. — Tower of the winds, Athens, Greece. TIME AND ITS MEASUREMENT CHAPTER I Time, as a separate entity, has not yet been defined in language. Defini- tions will be found to be merely ex- planations of the sense in which we use the word in matters of practical life. No human being can tell how long a minute is ; only that it is longer than a second and shorter than an hour. In some sense we can think of a longer or shorter period of time, but this is merely comparative. The dift'erence between 50 and 75 steps a minute in marching is clear to us, but note that we introduce motion and space before we can get a conception of time as a succession of events, but time, in itself, remains elusive. In time measures w^e strive for a uni- form motion of something and this implies equal spaces in equal times ; so we here assume just what we can- not explain, for space is as difficult to define as time. Time cannot be "squared" or used as a multiplier or divisor. Only numbers can be so used ; so when we speak of "the square of the time" we mean some number which we have arbitrarily assumed to represent it. This becomes plain when we state that in calculations relating to pendu- lums, for example, we may use seconds and inches — minutes and feet — or sec- onds and meters and the answer will come out right in the units which we have assumed. Still more, numbers themselves have no meaning till they are applied to something, and here we are applying them to time, space and motion ; so we are trying to explain three abstractions by a fourth ! But, happily, the results of these assump- tions and calculations are borne out in practical human life, and we are not compelled to settle the deep question as to whether fundamental knowledge is possible to the human mind. Those desiring a few headaches on these questions can easil)^ get them from Kant and Spencer — but that is all they will get on these four necessary as- sumptions. Evidently, man began by consider- ing the day as a unit and did not in- clude the night in his time keeping for a long period. "And the evening and the morning were the first day" Gen. 1, 5; "Evening and morning and at noonday," Ps. LV, 17, divides the day ("sun up") in two parts. "Fourth part of a day," Neh. IX, 3, shows another advance. Then comes, "are there not twelve hours in a day," John XI, 9. The "eleventh hour," Matt. XX, 1 to 12, shows clearly that sunset was 13 14 TIME AND ITS MEASUREMENT o'clock. A most remarkable feature of this 12-hour day, in the New Testa- ment, is that the writers generally speak of the third, sixth and ninth hours, Acts II, 15; III, 1; X, 9. This is extremely interesting, as it shows that the writers still thought in quarter days (Neh. IX, 3) and had not yet ac- quired the 12-hour conception given to them by the Romans. They thought in quarter days even when using the 12-hour numerals! Note further that references are to "hours ;" so it is evi- dent that in New Testament times they did not need smaller subdivisions. "About the third hour," shows the mental attitude. That they had no conception of our minutes, seconds and fifth seconds becomes quite plain when we notice that they jumped down from the hour to nowhere, in such expres- sions as "in an instant — in the twink- ling of an eye." Before this, the night had been di- vided into three watches, Judges VII, 19. Poetry to this day uses the "hours" and the "watches" as symbols. This 12 hours of daylight gave very variable hours in latitudes some dis- tance from the equator, being long in summer and short in winter. The amount of human ingenuity expended on time measures so as to divide the time from sunrise to sunset into 12 equal parts is almost beyond belief. In Constantinople, to-day, this is used, but in a rather imperfect manner, for the clocks are modern and run 24 hours uniformly ; so the best they can do is to set them to mark twelve at sunset. This necessitates setting to the varying length of the days, so that the clocks appear to be sometimes more and sometimes less than six hours ahead of ours. A clock on the tower at the Sultan's private mosque gives the impression of being out of order and about six hours ahead, but it is running correctly to their system. Hotels often show two clocks, one of them to our twelve o'clock noon sys- tem. Evidently the Jewish method of ending a day at sunset is the same and explains the command, "let not the sun go down upon thy wrath," which we might read, do not carry your angei over to another day. I venture to sa} that we still need that advice. This simple line of steps in dividing the day and night is taken principal!] from the Bible because everyone cai easily look up the passages quoted anc many more, while quotations fror books not in general use would not b so clear. Further, the neglect of th Bible is such a common complaint i: this country that if I induce a few t look into it a little some good may re suit, quite apart from the matter religious belief. Some Chinese and Japanese method of dividing the day and night are ind: cated in Fig. 1. The old Japanes method divides the day into six hour and the night also into six, each hou averaging twice as long as ours. I some cases they did this by changin the rate of the clock, and in others b letting the clock run uniformly an changing the hour marks on the dia but this will come later when we reac Japanese clocks. It is remarkable that at the preser time in England the "saving daylighl agitation is virtually an attempt to back to this discarded system. "Joh Bull," for a long period the time-keep of the world with headquarters i Greenwich, and during that time tl most pretentious clock-maker, now pr( poses to move his clocks backward ar forward several times a year so as "fool" his workmen out of their be^ in the mornings ! Why not commen work a few minutes earlier each for night while days are lengthening a tiie reverse when they are shortenins This reminds me of a habit whic was common in Scotland, — "keepin the clock half an hour forward." ] those days work commenced at s o'clock, so the husband left his houf at six and after a good walk arrived the factory at six ! Don't you see thi if his clock had been set right he woul have found it necessary to leave at ha past five? But, you say he was simpl deceiving himself and acting in an ui reasonable manner. Ceitainly, but th average man is not a reasonable beinj TIME AND ITS MEASUREMENT 15 Vid "John Bull" knows this and is try- '}\g to fool the average Englishman. Now, as to the methods of measur- iig time, we must use circumstantial 'vidence for the pre-historic period. tive methods like setting up a stick and marking its shadow so that a party trailing behind can estimate the dis- tance the leaders are ahead by the changed -position of the shadow. Men ^•,/# Fig. 1 — Interpretation of Chinese and Japanese Methods of Time Keeping The rising and the going down of the sun — the lengthening shadows, etc., must come first, and we are on safe ground here, for savages stilHis e pri mi- notice their shortening and lengthening shadows to this day. When the shadow of a man shortens more and more slowly till it appears to be fixed, the 16 TIME AND ITS MEASUREMENT observer knows it is noon, and when it shows the least observable lengthen- ing then it is just past noon. Now, it is a remarkable fact that this crude method of determining noon is just the same as "taking the sun" to determine noon at sea. Noon is the time at which the sun reaches his highest point on any given day. At sea this is deter- mined generally by a sextant, which simply measures the angle between the horizon and the sun. The instrument is applied a little before noon and the observer sees the sun creeping upward slower and slower till a little tremor or hesitation appears indicating that the sun has reached his height, — noon. Oh ! you wish to know if the observer is likely to make a mistake? Yes, and when accurate local time is important. Figf. 2 — Portable Bronze Sundial from the Ruins ol Herculaneum several officers on a large ship will take the meridian passage at the same time and average their readings, so as to reduce the "personal error." All of which is merely a greater degree of accuracy than that of the man who ob- serves his shadow. ^/The gradual development of the primitive shadow methods culminated in the modern sundial. The "dial of Ahas," Isa. XXXVIII, 8, on which the sun went back 10 "degrees" is often re- ferred to, but in one of the revised editions of the unchangeable word the sun went back 10 "steps." This be- comes extremely interesting when we find that in India there still remains an immense dial built with steps instead of hour lines. Figure 2 shows a pocket, or portable sundial taken from the ruins of Herculaneum and now in the Muset National, Naples. It is bronze, was I silver plated and is in the form of a hamj suspended from the hock joint. From the tail, evidently bent from its original position, which forms the gnomon, lines radiate and across these wavy lines are traced. It is about 5 in. long and 3 in. wide. Being in the corner of a glass case I was unable to get small details, but museum authorities state that names of months are engraved on it, so it would be a good guess that these wavy lines had something to do with the long and short days. In a restored flower garden, within one of the large houses in the ruins of Pompeii, may be seen a sundial of the Armillary type, presumably in its orig- inal position. I could not get close to it, as the restored garden is railed in, but it looks as if the plane of the equator and the position of the earth's axis must have been known to the maker. Both these dials were in use about the beginning of our era and were covered by the great eruption of Vesu- vius in 79 A.D., which destroyed Pom- peii and Herculaneum. Modern sundials differ only in being more accurately made and a few "curiosity" dials added. The necessity for time during the night, as man's life became a little more complicated, ne- cessitated the invention of time ma- chines. The "clepsydra," or water clock, was probably the first. A French writer has dug up some old records putting it back to Hoang-ti 2679 B.C., but it appears to have been certainly in use in China in 1100 B.C., so we will be satisfied with that date. In present- ing a subject to the young student it is sometimes advisable to use round numbers to give a simple comprehen- sion and then leave him to find the overlapping of dates and methods as he advances. Keeping this in mind, the following table may be used to give an elementary hint of the three great steps in time measuring: Shadow time, 2000 to 1000 B. C. Dials and Water Clocks, 1000 B. C to 1000 A. D. TIME AND ITS MEASUREMENT 17 Clocks and watches, 1000 to 2000 . D. 1 have pushed the gear wheel clocks id watches forward to 3000 A.D., as ley may last to that time, but I have 3 doubt we will supersede them. At le present time science is just about ady to say that a time measurer con- sting- of wheels and pinions— a driv- g power and a regulator in the form ■ a pendulum or balance, is a clumsy )ntrivance and that we ought to do itter very soon ; but more on this :)ped-for, fourth method when we ach the consideration of the motion 1 which we base all our time keeping. It is remarkable how few are aware lat the simplest form of sundial is the jst, and that, as a regulator of our •esent clocks, it is good within one or vo minutes. No one need be without "noon-mark" sundial ; that is, every le may have the best of all dials. Take post or any straight object standing )lumb," or best of all the corner of building as in Fig. 3. In the case of le post, or tree trunk, a stone (shown solid black) may be set in the ■ound ; but for the building a line may ten be cut across a flagstone of the lOtpath. Many methods may be em- oyed to get this noon mark, which is mply a north and south line. View- g the pole star, using a compass (if le local variation is known) or the old ethod of finding the time at which le shadow of a pole is shortest. But le best practical way in this day is to 56 a watch set to local time and make le mark at 12 o'clock. On four days of the year the sun is ght and your mark may be set at 12 1 these days, but you may use an al- anac and look in the column marked nean time at noon" or "sun on meri- an." For example, suppose on the "ight day when you are ready to place Dur noon mark you read in this )lumn 11 :50, then when your watch lows 11 :50 make your noon mark to le shadow and it will be right for all me to come. Owing to the fact that lere are not an even number of days a year, it follows that on any given ?arly date at noon the earth is not at Fig. 3 — Noon-Mark Sundials SUN ON NOON MARK, 1909 Date Clock Time Date Clock Time Date Clock Time Jan. 2. ..12:04 May 1. ..ll::-.7 Sept. 30. ..11:50 " 4. ..12:05 15. ..11:50 Oct. 3. ..11:49 " 7. ..12:00 " 28. ..11:57 " 6. ..11:48 " 9. ..12:07 June 4. ..11:58 " 10. ..11:47 " 11. ..12:08 " 10. ..ll:.-i9 " 14. ..11:46 " 14. .12:00 " 14. ..12:00 " 19. ..11:45 " 17. .12:10 " 19. ..12:01 26. ..11:44 " 20. ..12:11 " 24. ..12:02 Nov. 17. ..11:45 " 23. ..12:12 " 29. ..12:03 " 22. ..11:46 " 28. .12:13 July 4. ..12:04 " 25! ..11:47 Feb. 3. ..12:14 10. ..12:05 " 29. ..11:48 " 26. ..12:13 " 10. ..12:06 Dec. 1. ..11:49 Mar. 3. ..12:12 ^ug. 11. ..12:05 " 4. ..11:50 " 8. .12:11 16. ..12:04 " 6. ..11:51 << 11. ..12:10 " 21. ..12:03 " 9. ..11:52 " 15. ..12:00 " 25. ..12:02 " 11. ..11:53 " 18. ..12:08 " 28. ..12:01 " 13. ..11:54 " 22. ..12:07 " 31. ..12:00 '* 15. ..11:55 " 25! ..12:06 Sept. 4. ..11:59 " 17. ..11:56 •' 28. ..12:05 7. ..11:58 " 19. ..11:57 .\pr. 1. ..12-04 " 10. ..11:57 " 21. ..11:58 4. ..12:03 " 12. ..11:56 " 23. ..11:59 " ..12:02 15. ..11:55 " 25. ..12:00 " 11! ..12:01 " 18. ..11:54 " 27. ..12:01 " 15. ..12:00 " 21. ..11:53 " 29. ..12:02 " 19. ..11 :.">.) " 24. ..11:52 " 31. .12:03 " 24. ..11:.^.8 " 27. ..11:51 The above table shows the variation of the sun from "mean" or clock time, by even minutes. the same place in its elliptical orbit and the correction of this by the leap years causes the ecjuation table to vary in periods of four years. The centen- nial leap years cause another variation of 400 years, etc., but these variations are less than the error in reading a dial. 18 TIME AND ITS MEASUREMENT Fig 4 — 12-Inch Modern Horizontal Sundial for Latitude 40°— 43' The reason that the table given here is convenient for setting- clocks to mean time is that a minute is as close as a dial can be read, but if you wish for greater accuracy, then the almanac, which gives the "equation of time" to a second for each day, will be better. The reason that these noon-mark dials are better than ordinary commercial dials is that they are larger, and still further, noon is the only time that any dial is accurate to sun time. This is be- cause the sun's rays are "refracted" in a variable manner by our atmosphere, but at noon this refraction takes place on a north and south line, and as that is our noon-mark line the dial reads correctly. So, for setting clocks, tl corner of your house is far ahead of tl most pretentious and expensive diall In Fig. 4 is shown a modern horizont dial without the usual confusing "orn; mentation," and in Fig. 5 it is shown S( up on the latitude of New York Cit for which it is calculated. This shew clearly why the edge EG of the sty which casts the shadow must be pal allel to the earth's axis and why a hori zontal dial must be made for the latj tude of the place where it is set ug Figure 6 is the same dial only the linej are laid out on a square dial plate, and Fig. 5 — The Earth, Showing Relation of Dial Styles to Axis Fig. 6 — Modern Sundial Set Up in Garden it will give your young scientific read- ers a hint of how to set up a dial in the garden. In setting up a horizontal dial, consider only noon and set the style, or 12 o'clock line, north and south as described above for noon-mark dials. A whole issue of I'opular Mechanics could be filled on the subject of dials and even then only give a general out- line. Astronomy, geography, geometry, mathematics, mechanics, as w^ell as architecture and art, come in to make "dialing" a most charming scientific and intellectual avocation. TIME AND ITS MEASUREMENT 19 During the night and also in cloudy- feather the sundial was useless and '6 read that the priests of the temples nd monks of more modern times went out to observe the stars" to make guess at the time of night. The most rominent type after the shadow de- ices was the "water clock" or "clepsy- ra," but many other methods were sed, such as candles, oil lamps and in Dmparatively late times, the sand lass. The fundamental principle of all ater clocks is the escape of water from vessel through a small hole. It is i^ident that such a vessel would empty self each time it is filled in very nearly le same time. The reverse of this has een used as shown in Fig. 7, which ;presents the "time-boy" of India. He ts in front of a large vessel of water nd floats a bronze cup having a small Die in its bottom in this large vessel, nd the leakage gradually lowers this jp till it sinks, after which he fishes up and strikes one or more blows on as a gong. This he continues and a ide division of time is obtained, — hile he keeps awake ! The most interesting of all water ocks is undoubtedly the "copper jars ropping water," in Canton, China, here I saw it in 1897. Referring to le simple line sketch, which I make om memory. Fig. 8, and reading four hinese characters downwards the anslation is "Canton City." To the ft and still downwards, — "Hon-woo- L-low," which is, — "Copper jars drop- ng water." Educated Chinamen in- irm me that it is over 3,000 years old and had a weather vane. As they speak of it as "the clock of the street arch" this would look quite probable ; since the little open building, or tower in Fig. 7 — "Time-Boy" of India Fig. 8 — "Hon-woo-et-low" or "Copper Jars Dropping Water" — Canton, China which it stands is higher than surround- ing buildings. It is, therefore, reason- ably safe to state that the Chinese had a zueathcr and time station over 1,000 years before our era. It consists of four copper jars partially built in masonry forming a stair-like structure. Com- mencing at the top jar each one drops into the next downward till the water reaches the solid bottom jar. In this lowest one a float, "the bamboo stick," is placed and indicates the height of the water and thus in a rude way gives the time. It is said to be set morning and evening by dipping the water from jar 4 to jar 1, so it runs 12 hours of our time. What are the uses of jars 2 and 3, since the water simply enters them and drips out again? No information could be obtained, but I venture an ex- planation and hope the reader can do better, as we are all of a family and there is no jealousy. When the top jar is filled for a 12-hour run it would drip out too fast during the first six hours 20 TIME AND ITS MEASUREMENT and too slow during tl e second six hours, on account of the varying "head" of water. Now, the spigot of jar 2 could be set so that it would gain water during the first six hours, and lose dur- ing the second six hours and thus equal- ize a little by splitting the error of jar 1 in two parts. Similarly, these two errors of jar 2 could be again split by jar 3 making four small variations in lowest jar, instead of one large error in the flow of jar 1. This could be ex- tended to a greater number of jars, another jar making eight smaller errors, etc., etc. But I am inclined to credit our ancient Chinese inventor with the sound reasoning that a human attend- ant, being very fallible and limited in his capacity, would have all he could properly do to adjust four jars, and that his record would average better than it would with a greater number. Remember, this man lived thousands of years before the modern mathemati- cian who constructed a bell-shaped vessel with a small hole in the bottom, and proportioned the varying diameter in such a manner that in emptying itself the surface of the water sank equal distances in equal times. The sand glass, Fig. 9, ])oetically called the "hour glass," belongs to the water-clock class a n d the sa n d flows from one bulb into the other, but it gives no subdivisions of its period, so if you are using one running an hour it does not give you the half hour. The sand glass is still in use by chair- men, and when the oldest inhabitant gets on his feet, I always advise setting a 20-minute glass "on him." In the "Tower of the Winds" at Athens, Greece (Fig. 10), we have a later "weather bureau" station. It is Fig. 9 — Modern Sand Glass or "Hour Glass" Fig. 10 — "Tower of the Winds" — Athens, Greece attributed to the astronomer Androni cos, and was built about 50 B. C. It i: octagonal in plan and although 27 f1 in diameter and 44 ft. high, it looks lik^ a sentry box when seen from one o the hills of Athens. It had a bronz^ weather vane and in later times sun dials on its eight sides, but all thes are gone and the tower itself is only ; dilapidated ruin. In making the draw ing for this cut, from a photograph o the tower, I have sharpened th weathered and chipped corners of th stones so as to give a view nearly lik the structure as originally built ; bu nothing is added. Under the eaves i has eight allegorical sculptures, repre senting wind and weather. Artists stat^ that these sculptures are inferior a compared with Grecian art of an olde period. But the most interesting par is inside, and here we find curiou passages cut in solid stone, and socket which look as if they had containe( metal bearings for moving machinery Circumstantial evidence is strong tha it contained a complicated water clocl TIME AND ITS MEASUREMENT 21 ,which could have been kept running Iwith tolerable accuracy by setting it daily to the dials on the outside. Prob- ably during- a few days of cloudy weather the clock would "get off quite a little," but business was not pressing in those days. Besides, the timekeeper would swear by his little water wheel, anyway, and feel safe, as there was no higher authority wearing an American watch. Some very interesting engravings of Japanese clocks and a general explana- tion of them, as well as a presentation of the Japanese mental attitude to- wards "hours" and their strange method of numbering them may be ex- pected in the next chapter. CHAPTER II JAPANESE CLOCKS Chinese and Japanese divisions of the day. — Hours of vary- ing length.— Setting clocks to length of daylight.— Curved line dials. — Numbering hours bacWards and strange reasons for same. — Daily names for sixty day period. — Japanese clock movements practically Dutch. — Japanese astronomical clock. — Decimal numbers very old Chinese. — Original ver- tical dials founded on "bamboo stick" of Chinese clepsydra. — Mathematics and superstition. — Mysterious disappear- ance of hours 1 , 2, 3.— Eastern mental attitude towards time. — Japanese methods of striking hours and half hours. CHAPTER II The ancient methods of dividing day and night in China and Japan become more hazy as we go backwards and the complications grow. The three circles in Fig. 1 (Chapter 1) are all taken from Japanese clocks, but the in- terpretation has been obtained from Chinese and Japanese scholars. The Japanese obtained a great deal from the Chinese, in fact nearly everything relating to the ancient methods of time keeping and the compiling of calen- dars. I have not been able to find any Chinese clocks constructed of wheels and pinions, but have a number of Jap- anese. These have a distinct resem- blance to the earlier Dutch move- ments, and while made in Japan, they are practically Dutch, so far as the "works'" are concerned, but it is easy to see from the illustrations that they are very Japanese in style and ornamenta- tion. The Dutch were the leaders in opening Japan to the European nations and introduced modern mathematics and clocks from about 1590 A. D. The ancient mathematics of Japan came largely from China through Corea. In Fig. 11 are given the Japanese figures beside ours, for the reader's use as a key. The complete day in Japan was the clocks are set, as the days vary in length, so that six o'clock is sunrise and sunset. The hour numerals on Fig. 12 are on little plates which are mov- able, and are shown set for a long day and a short night. In Fig. 13 they are set for short days and long nights. The narrow plates shown in solid black are the half-hour marks. In this type the hand is sta- tionary and always points straight upward. The dial rotates, as per arrow, once in a full day. This style of dial is shown on complete clocks. Fig. 14 being a weight clock and Fig. 15 a spring clock with chain and fusee. The hours are 9 to 4 and the dials rotate to make them read backwards. The six hours of daylight are 6, 5, 4, 9, 8, 7, 6 and the same for night, so these hours average twice as long as ours. Note that nine is ^'^- ^^ mid-dav and mid-night, and as these -^ 1 ^ 2 = 3 \3 4 i 5 6 -b 7 A 8 K 9 + 10 ± 11 ± 12 Fig. 12 Fis Japanese Dials Set for Long and Short Days divided into twice six hours; that is, do not change by long and short days six for daylight and six for night, and they are stationary on the dial, as you 26 TIME AND ITS MEASUREMENT can and easily see by comparing Figs. 13 13, which are the same dial set for Fig. 14 — Japanese Striking Clock with Weight and Short Pendulum different seasons. Between these ex- tremes the dial hours are set as often as the owner wishes ; so if he happens to correspond with our ''time crank" he will set them often and dispute with his neighbors about the time. Figure IG shows a clock with the hour numerals on a vertical series of movable plates and it is set for uniform hours wdien day and night are equal at the equinox. The ornamental pointer is fastened to the weight through the vertical slit, plainly visible in illustration, and in- dicates the time as it descends. This clock is wound up at sunset, so the six on the top of the dial is sunset the same as the six on the bottom. Figure 17 shows how this type of dial is set for long and short days and ex- plains itself, but will become plainer as we proceed. This dial is virtually a continuation of the old method of marking time by the downward mo- tion of the water in the clepsydras and will be noticed later. Figure 18 represents a clock which is a work of art and shows great re- finement of design in providing for the varying lengths of days. The bar lying across the dial is fastened to the weight through the two slits running the whole length of the dial. On this cross bar is a small pointer, which is mo\'al)le by the fingers, and may be set to any one of the thirteen vertical lines. The numerous characters on the top space of dial indicate the dates on which the pointer is to be set. This clock is wound up at sunset, and it is easy to see that as the little pointer is set towards the right, the night hours at the top of the dial become shorter and the day hours longer on the lower part. The left edge of the dial gives the hours, reading down- Fig. 15 — Japanese Striking Clock with Spring, Fusee and Balance wards, and as the pointer touches any one of the curved lines the hour is TIME AND ITS MEASUREMENT 27 iad at the left-hand end. The curved lies formed of dots are the half-hours. liie right-hand edge of the dial has lie "twelve horary characters" which 11 be explained later. For dividing ^e var3ang" days into six hours' sun- ine it would be difficult to think of rmore artistic and beautiful invention can this. It is a fine example of great jigenuity and constant trouble to op- ate a system which is fundamentally jrong according to our method of uni- ;rm hours at all seasons. Clocks living these curved lines for the vary- ig lengths of days — and we shall find I em on circular dials as we go on — lUst be made for a certain latitude, nee the days vary more and more as )U go farther from the equator. This ill become plain when you are re- inded that a Japanese clock at the [uator would not need any adjust- ent of hour numerals, because the lys and nights are equal there all the iSLT. So after such infinite pains in irming these curved lines the clock only good in the latitude for which was made and must not be carried 3rth or south ! Our clocks are correct om pole to pole, but all clocks must ? set to local time if they are carried ist or west. As this is a rather scinating phase of the subject it ight be worth pointing out that if )u go north till you have the sun up r a month in the middle of summer — id there are people living as far up . that — the Japanese system would icome absurd and break down ; so ere is no danger of any of our polar :peditions carrying Japanese clocks. Figure 19 shows a very fine clock which the dial is stationary and the md moves just as on our dials. This )ur hand corresponds to the single md of the old Dutch clocks. When e Japanese reached the point of con- dering the application of minute and cond hands to their clocks they found at these refinements would not fit eir old method and they were com- ;lled to lay aside their clocks and ke ours. On this dial, Fig. 19, nine noon, as usual, and is on top side of al. Hand points to three quarters past seven, that is, a quarter to six, near sunset. Between the bell and the Fig. 16 — Japanese Clock with Vertical Dial, Weight and Bal- ance. Fig. 18 — Japanese Clock with Vertical Dial Having Curved Lines, Weight and Balance. top of the clock body two horizontal balances, having small weights hung on them, are plainly shown, and the clock has two verge escapements — one connected with each balance, or "fo- liot." Let us suppose a long day com- ing to a close at sunset, just as the hand indicates. The upper balance, which is the slow one, has been swinging back- wards and forwards measuring the long hours of the day. When the clock strikes six, at sunset, the top balance is thrown out of action and the lower one, which is the fast one. 28 TIME AND ITS MEASUREMENT is thrown into action and measures the short nis:ht hours. At sunrise this is swr* SET. ^•^ 6.< ^2^" 5-< ^> 4- < -C?^^ 9 c ^> 8 C :^> 7 ^ :^ 6. C ^^t: fj '" 6-. < .c -V tvj^-^ B.C "r 7. C ^ ^•. C - ^ 'H^*'lHre^.' 5<^ <^ >5. <^ >^ X 5 9. ^^Ca) 5 8. c(^ >7- >5: c^^^^ >4. ffi^Cf ^v^ >9. 8. cCV) :>7. ~ ~^^'\^ >6. Fig. 17 — Japanese Vertical Dials thrown out and the top one in again to measure the next day's long hours. As the days vary in length, the bal- ances, or foliots, can be made to swing faster or slower by moving the weights inwards or outwards a notch or two. The balance with small weights for regulation is the oldest known and was used in connection with the verge es- capement, just as in this clock, by the Dutch about 1364. All the evidence I can find indicates that the Japanese clocks are later than this date. In de- sign, ornamentation and methods for marking varying days, however, the Japanese have shown great artistic taste and inventiveness. It is seen that this dial in addition to the usual six hours, twMce over, has on the out- side circle of dial, the "twelve horary branches" called by the Japanese the "twelve honorary branches," thus in- dicating the whole day of tw^elve Jap- anese hours, six of them for dav and six for night. By this meai they avoided repeating the same hou for day and night. When it pointed out that these "twelve horai branches" are very old Chinese, v are not in a position to boast aboi our twenty-four hour system, becaui these branches indicate positive' whether any given hour is day or nigh When we print a time table in tl twenty-four hour system so as to g' rid of our clumsy A. M. and P. M., v are thousands of years behind the Ch nese. More than that, for they g( the matter right without any sue pressure as our close running trail have brought to bear on us. The; branches have one syllable names ar the "ten celestial stems" have also oi syllable names, all as shown on Fi 20. Refer now to Fig. 21 where t\^ disks are shown, one having tl "twelve horary branches" and tl other the "ten celestial stems." The; disks are usually put behind the di so that one "branch" and one "sten can be seen at the same time throug two openings. The clock moves the; disks one step each night, so that new pair shows each day. Runnir in this manner, step by step, you wi find that it takes sixty moves, that sixty days, to bring the same pa around again. Each has a sing syllable name, as shown on Fig. 2 and we thus get sixty names of tv\ S3'llables by reading" them together i the left. The two openings may 1 seen in the dials of Figs. 15 and 1 So the Japanese know exactlv wli; day it is in a period of sixty whic they used in their old calendars. The; were used by the Chinese over foi thousand years ago as the names < a cycle of sixty years, called the "se: agenary." The present Chinese yet 4 006 is YU-KI which means the ye; 46 of the 76th "sexagenarv." That i 76X60+46=4,606. ^In Fig. 20, ^^ read TSU-KIAH, or the first year, you will make two disks like Fie. S and commence with TSU-KIAH an move the tw^o together you will coir to YU-KI on the 46th move. Bt there is another way which you migl TIME AND ITS MEASUREMENT 29 xe better, thus : Write the twelve tranches," or syllables, straight down- ards, continuously five times; close ;■ the right, write the ten "stems" six mes. Now you have sixty words of vo syllables and the 46tli, counting Dwnwards, will be YU-KI. Besides, Siis method gives you the whole sixty iames of the "sexagenary" at one view. ilways read left, that is, pronounce :ie "stem" syllable first. ' Calendars constitute a most inter- isting and bewildering part of time measuring. We feel that we have set- led the matter by determining the imgth of the year to within a second if time, and keeping the dates cor- 3ctly to the nearest day by a leap year very fourth and every fourth century, stablished by Pope Gregory XIII in 588, and known as the "Gregorian 'alendar." In simple words, our "al- lanac" is the "Gregorian." We are 1 the habit of saying glibly that any ear divisible by four is a leap year, ut this is far from correct. Any year eaving out the even hundreds, which 3 divisible by four is a leap year. Iven hundreds are leap when divisible ly four.'''"This explains why 1900 was , common year, because, ig hundreds 3 not divisible by fouf"; 2000 will be . leap begause .20 hundreds is divisible •y four;' therefore 2100, 2200 and 300 will be common years and 2400 . leap, etc., to 4000 which must be nade common, to keep things straight, n spite of the fact that it is divisible •y four^both in its hundreds and thou- ands. But for practical purposes, dur- ng more than two thousand years to ome, we may simplify the rule to: '^ears and even hundreds divisible by our are leaps. But great confusion till exists as a result of several coun- ries holding to their own old methods, rhe present Chinese year has 384 days, .3 months and 13 full moons. Com- )ared with our 1909 it begins on Jan- lary 21st and will end on February 8, .910. Last year the China-Japan cal- endar had 12 months, or moons, but LS that is too short they must put in in extra every thirtieth month. We )nly allow the error to reach one day and correct it with our leap years, but they are not so particular and let the Figr. 19— Japanese Striking Clock with Two Balances and Two Escapements; Dial Stationary, Hand Moves error grow till they require another "moon." The Old Testament is full of moons, and even with all our "mo- dernity" our "feasts" and holy days are often "variable" on account of being mixed up with moons. In Japan the present year is the 42nd of Meiji, that is, the 42nd of the present Emperor's reign. The present is the Jewish 5669. These and others of varying lengths overlap our year in different degrees, so that in trade matters great confusion exists. The Chinese and Japanese publish a trade almanac in parallel columns with ours to avoid this. It is easy to say that we ought to have a uniform calendar all over the world, but the same remark applies just 30 TIME AND ITS MEASUREMENT as much to money, weights, measures, and even to language itself. Finally, the difficulty consists in the facts that 3- TSU. I Ipp KIAH I ft CHou 2 g ym. 3 ^ &HEN § S SSU. 6 ^ wu. 7 ^'vVVEi. 8 ^ SHEW. 9 g YU. 10 ^ HAl. 12 S YIN. 2 f^ PING. 3 T TiNG. 4 /^ WL/. 5 B Kl. 6 ^ SIN. 8 ^ JEN. 9 ^y^ KWEI. 10 Fig. 20— Key to "12 Horary Branches" and "10 Celestial Stems there are not an even number of days in a year — or in a moon — or moons in a year. "These many moons" is a survival in our daily speech of this old method of measuring by moons. Just a little hint as to the amount of superstition still connected with "new moon" will be enough to make clear the fact that we are not yet quite so "enlightened" as we say we are. While our calendar, or almanac, may be con- sidered as final, we must remember that custom and religion are so mixed up with the matter in the older coun- tries of the East that they will change very slowly. Strictly, our "era" is ar- bitrary and Christian ; so we must not expect nations which had some astro- nomical knowledge and a working cal- endar, thousands of years before us, to change suddenly to our "upstart" methods. In Fig. 23 we have the dial of a very complicated astronomical clock. This old engraved brass dial did not photograph well, so I made a copy by hand to get clean lines. Commencing at the centre, there is a small disk, FJ, numbered from 1 to 30, giving days of the moon's age. The moon rises at A and sets at AA, later each day, of course. Her age is shown by the num- ber she touches on disk B, as this disk advances on the moon one number each day. Her phases are shown the motion of a black disk over t face; so we have here three motio for the moon, so differentiated as show phase, ascension and age. Si further, as she is represented on t dial when below the horizon, it c be seen Avhen she will rise, and "moc light" parties may be planned, Ji outside the moon's course is an a nulus having Japanese numbers 1 12, indicating months. 'Note the i curring character dividing the mont in halves, which means "middle," ai is much used. If you will careful read these numbers you will find character where one would come ; t\ means "beginning" or "primary" ai is often used instead of one. The clo hand is the heavy arrow and swee the dial once in a whole day, sar direction as our clocks. This circ of the months moves along with tl hand, but a little faster, so as to ga one number in a month. As shown ( the figure it is about one week into tl sixth month. Next outward is tl broad band having twelve curved lin for the hours ending outwardly in ring divided into 100 parts, mark( off in tens by dots. These curved lin^ are numbered with the Japanese m merals for hours which you must no be able to read easily. These hoi lines, and the dotted lines for ha hours, are really the same as the sirn lar lines on Fig. 18 which you no understand. As the hand sweeps tl ^ o l^g^f o s \^ ^/ \^ "%"/ \^ R^ MLJb^ Fig. 21— "12 Horary Branches" and "10 Celestial Stems" as Used in Clocks dial daily it automatically moves ou1 ward a little each day, so it shorten the nights and lengthens the dayj just as previously explained for Fig 18. But there is one difference, fo you will notice that the last nigh TIME AND ITS MEASUREMENT 31 our, on which the arrow hand now lands, is longer than the other night ours before it, and that it is divided ;ito three by the dotted lines. The last '^ay hour, on le left of dial, 3 a 1 s o long n d divided n t o three ["hat is, while [ll the dials reviously de- jicribed have tqual hours iOr any given jay, or night, fhis dial has a fist long hour n each case, divided into hree instead if the usual lalf -hours, fhis is a cu ri- als and inter- sting point laving its ori- ;'in long before locks. In the early days of the clepsy- ra in China, a certain time was allowed o dip up the water from the lowest jar, ach morning and evening about five 'clock of our time, see Fig. 8 (diap- er 1). During this operation the lepsydral was not marking time, and he oriental mind evidently considered t in some sense outside of the regular ours, and like many other things was etained till it appeared absurdly on be earlier clocks. This wonderful sat of putting an interval between wo consecutive hours has always been npossible to modern science ; yet 'resident Roosevelt performed it asily in his "constructive" interreg- uni ! Referring to the Canton clep- ydra, Fig. 8, we find that the float, or bamboo stick," was divided into 100 arts. At one season 60 parts for the ay and 40 parts for the night, grad- ally being changed to the opposite )r short days. The day hours were eaten on a drum and the night hours lown on a trumpet. Later the hour numerals were made Dial of Japanese Astronomical Clock movable on the "bamboo stick." This is virtually a vertical dial with mov- able hour plates, so their idea of time measuring at that date, was of some- thing moving up or down. This was put on the first clocks by the Japanese ; s o that the dial of Fig. 16 is sub- stantially the float of the Chinese clep- sydra. Furth- e r, in this "bamboo stick" of 100 parts, we have our present system of dec- imal numbers, so we can af- ford to be a little modest here too. Be- fore leaving Fig. 22 note the band, or annulus, of stars which moves with the month circle. I cannot make these stars match our twelve signs of the Zo- diac, but as I have copied them care- fully the reader can try and make order out of them. The extreme outer edge of the dial is divided into 360 parts, the tens being emphasized, as in our decimal scales. As we are getting a little tired of these complicated descriptions, let us branch off for a few remarks on some curiosities of Eastern time keeping. They evidently think of an hour as a period of time more specifically than we do. \^'hen we say "(i o'clock" we mean a point of time marked by the striking of the clock. We have no names for the hour periods. We must say "from 5 to 6" or "between 5 and 6" for an hour period. The "twelfth hour" of the New Testament, I under- stand to mean a whole hour ending at sunset ; so we are dealing with an oriental attitude of mind towards time. I think we get that conception 32 TIME AND ITS MEASUREMENT nearly correct when we read of the "middle watch" and understand it to mean during the middle third of the night. Secondly, why do the Japanese use no 1, 2, 3 on their dials? These numbers were sacred in the temples and must not be profaned by use on clocks, and they mentally deducted these from the clock hours, but ulti- mately became accustomed to 9. 8, T, 6, 5, 4. Thirdly, why this reading of the hours backwards? Let us suppose a toiler commencing at sunrise, or six. When he toiled one hour he felt that there was one less to come and he called it five. This looks quite logi- cal, for the diminishing numbers in- dicated to him how much of his day's toil was to come. Another explana- tion which is probably the foundation of "secondly" and "thirdly" above, is the fact that mathematics and super- stition were closely allied in the old days of Japan. If you take the num- bers 1 to 6, Fig. 23, and multiply them each into the uncanny "yeng number." or nine, vou will find that the last digits, reading downwards, give 9, 8, 7, 6, 5, 4. Stated in other words: When 1 to (> are multiplied into "three times three" the last figures are 9, 8, 7, 6, 5, 4, and i, 2, j, have disappeared; so the common ])eople were tilled with fear and awe. Some of the educated, even now, are mystified by the strange results produced by using three and nine as factors, and scientific journals often give space to the matter. We know^ that these results are produced by the simple fact that nine is one less than the "radix" of our decimal scale of numbers. Nine is sometimes called the "indestructible number," since adding the digits of any of its powers gives an even number of nines. But in those days it was a mystery and the common people feared the mathe- maticians, and I have no doubt the shrewd old fellows took full advantage of their power over the plebeians. In Japan, mathematics was not cleared of this rubbish till about 700 A. D. On the right-hand side of Fig. 23 are given the animal names of the hours, so the dav and nieht hours could not be mistaken. In selectiti the rat for night and the Iwrse for d;i thev showed good taste. 1 heir fori 1X9= 9 tV f^AT ^icVt 2X9 = 18 A OK, 2An 3X9 = 27 -t TIGER tAKl 4 X 9 = 36 K H^REioAH 5X9=45 iCMBm G X 9 = 54 CHSHaKElOW 1X9=9 tlHO(?SBNOON 2X9= 18 A SHLtP 2?K 3X9 = 27 t m^w^ 4X9=36 iy COCK^P./^. 5X9=45 fL Doa m (BX9-.S-4 Cs6OAf\10P(v\ Fig. 23 — Use of "Yeng Number" and Animal Names of Hours noon was "before horse" and the afternoon "after horse." Japane clocks are remarkable for variety, looks as if they were always made order and that the makers, probab urged by their patrons, made extren efforts to get in wonderful motioi and symbols relating to astronomy ar astrology. Anyone examining abo fifty of them would be likely to co elude that it was almost hopeless understand them all. Remember, th is the old Japanese method. Near all the clocks and watches I saw Japan were American. It will now 1 necessary to close this chapter with few points on the curious striking Japanese clocks. In those like Figs. 14, 15, 19, tl bell and hammer can be seen. In tl type of Fig. Ki, the whole strikir mechanism is in the weight. In fac the striking part of the clock is tl weight. On each of the plates, havii the hour numerals, Fig. 16, a pin pr jects inwards and as the weight co taining the striking mechanism, d scends, a little lever touches these at lets off the striking just when tl pointer is on the hour numeral. Kee ing this in mind, it is easy to see th the clock will strike correctly wh( the hour is indicated by the pointe TIME AND ITS MEASUREMENT 33 ') matter how the hour plates are set 'r long- or short days. Similar pins oject inwards from movable plates 1 Figs. 12, 13, 14, 15, so they strike irrectly as each hour plate comes to e top just under the point of the ced hand. In Fig. 19, the striking is t off by a star wheel just as in old utch clocks. Clocks like Figs. 18- ; do not strike. In all cases the hours e struck backwards, but the half- )urs add another strange feature, he odd numbered hours, 9, 7, 5, are llowed b}^ one blow at the half hour; id the even hours, 8, 6, 4 by two blows, stated altogether — d, 8, ^ 7, e, 5, 4,. ere the large figures are the hours id the small ones the half-hours. Only one bell is used, because there being no one and two among the hours, the half-hours cannot be mistaken. This is not all, for you can tell what half hour it is within two hours. For example, suppose you know approxi- mately that it is somewhere between 9 and 7 and you hear the clock strike 2, then you know it is half past 8. See the large and small figures above. This is far superior to our method of one at each half-hour. By our method the clock strikes one three times consecutively, between 12 and 2 o'clock and thus mixes up the half hours with one o'clock. Some in- teresting methods of striking will be explained in the third chapter when we deal with modern time keeping. CHAPTER III MODERN CLOCKS DeVick's clock of 1 364. — Original "verge" escapement. — "Anchor" and "dead beat" escapements. — "Remontoir" clock. — The pendulum. — Jeweling pallets. — Antique clock with earliest application of pendulum. — Turkish watches. — Correct designs for public clock faces. — Art work on old watches. — Twenty-four hour watch. — Syrian and Hebrew hour numerals. — Correct method of striking hours and quarters.— Design for twenty-four hour dial and hands.^ — Curious clocks. — Inventions of the old clockmakers. CHAPTER III Public Dial by James Arthur Fig. 24 Dial of Philadelphia City Hall Clock Modern clocks commence with De V^ick's of 1364 which is the first un- questioned clock consisting of toothed A^heels and containing the funda- nental features of our present clocks. References are often quoted back to ibout 1000 A. D., but the words trans- ated "clocks" were used for bells and lials at that date ; so we are forced to consider the De Vick clock as the first ill more evidence is obtained. It has )een pointed out, however, that this :lock could hardly have been invented ill at once ; and therefore it is probable hat many inventions leading up to it lave been lost to history. The part of L clock which does the ticking is called he "escapement" and the oldest form mown is the "verge," Fig. 25, the date )f which is unknown, but safely 300 rears before De Vick. The "foliot" s on the vertical verge, or spindle, vhich has the pallets A B. As the oliot swings horizontally, from rest to ■est, we hear one tick, but it requires wo of these single swings, or two icks, to liberate one tooth of the es- ape wheel ; so there are twice as many ticks in one turn of the escape wheel as it has teeth. We thus see that an es- capement is a device in which some- thing moves back and forth and allows the teeth of an "escape wheel" to es- cape. While this escapement is, in some respects, the simplest one, it has always been difficult to make it plain in a drawing, so I have made an efifort to explain it by making the side of the wheel and its pallet B, which is nearest the eye, solid black, and farther side and its pallet A, shaded as in the figure. The wheel moves in the direc- tion of the arrow, and tooth D is very near escaping from pallet B. The tooth Fig. 25 — Verge Escapement C on the farther side of wheel is mov- ing left, so it will fall on pallet A, to be 38 TIME AND ITS MEASUREMENT in its turn liberated as the pallets and foliot svvino- back and forth. It is easy ■CORO. WEIGHT. Fig. 26— De Vick's Clock of 1364 to see that each tooth of the wheel will give a little push to the pallet as it es- capes, and thus keep the balance swinging. This escapement is a very poor time-keeper, but it was one of the great inventions and held the field for about 600 years, that is, from the days when it regulated bells up to the "onion" watches of our grandfathers. Scattered references in old writings make it reasonably certain that from about 1,000 to 1,300 bells were struck by machines regulated with this verge escapement, thus showing that tin striking part of a clock is older thar the clock itself. It seems strange to u; to say that many of the earlier clocks were strikers, only, and had no dials oi hands, just as if you turned the face o: your clock to the wall and depended or the striking for the time. Keeping this action of the verge escapement in minq we can easily understand its applica- tion, as made by De Vick, in Fig. 26 where I have marked the same pallet.' A B. A tooth is just escaping from pal- let r> and then one on the other side o: the wheel will fall on pallet A. Foliot verge and pallets form one solid piec( which is suspended by a cord, so as tc enable it to swing with little friction For the purpose of making the motion; very plain I have left out the dial anc framework from the drawing. Th( wheel marked "twelve hours," and th( pinion which drives it, are both outsid( the frame, just under the dial, and art drawn in dash and dot. The axle o this twelve-hour wheel goes througl the dial and carries the hand, whicl" marks hours only. The winding pinior and wheel, in dotted lines, are in side the frame. Now follow th( "great wheel" — "intermediate" — "es Fig. 27 — Anchor Escapement cape wheel" and the two pinions, all ir solid lines, and you have the "train' TIME AND ITS MEASUREMENT 39 .vliich is the principal part of all clocks. This clock has an esca])ement, wheels, )inions, dial, hand, weight, and wind- .AVf^ square. We have only added the ;i'pendulum, a better escapement, the minute and second hands in over 500 lyears ! The "anchor" escapement, Fig. i37, came about 1680 and is attributed tto Dr. Hooke, an Englishman. It gets its name from the resemblance of the ipallets to the flukes of an anchor. This ^anchor is connected to the pendulum •and as it swings right and left, the 'itecth of the escape wheel are liberated, one tooth for each two swings from rest to rest, the little push on the pal- lets A B, as the teeth escape, keeping the pendulum going. It is astonishing how many, even among the educated, think that the pendulum drives the clock! The pendulum must always be driven by some power. This escapement will be found in nearly all the grandfather clocks in connection with a seconds pendulum. It is a good time-keeper, runs well, wears well, stands some rc^ugh hand- ling and will keep going even when pretty well covered with dust and cob- webs ; so it is used more than all the numerous types ever invented. Figure ing a strip of steel ; but it is not the best form, as the acting surfaces of the Fig. 28 — American Anchor Escapement 28 gives the general American form of the "anchor" which is made by bend- Fig. 29 — Dead Beat Escapement pallets are straight. It is, therefore, inferior to Fig. 27 where the acting surfaces are curved, since these curves give an easier "recoil." This recoil is the slight motion backzvards which the escape wheel makes at each tick. The "dead beat" escapement is shown in Fig. 29, and is used in clocks of a high grade, generally with a seconds pendu- lum. It has no recoil as you can easily see that the surfaces O O on which the teeth fall, are portions of a circle around the center P. The beveled ends of these pallets are called the impulse surfaces, and a tooth is just giving the little push on the right-hand pallet. It is found in good railroad clocks, watch- makers' regulators and in many astro- nomical clocks. These terms are merely comparative, a "regulator" be- ing a good clock and an "astronom- ical," an extra good one. Figure 30 gives the movement of a "remontoir" clock in which the dead beat shown is used. The upper one of the three dia!-. indicates seconds, and the lever which crosses its center carries the large wheel on the left. This wheel makes the left end of the lever heavier than the right, and in sinkino- it drives the clock for one min- 40 TIME AND ITS MEASUREMENT ute, but at the sixtieth second it "re- mounts" by the action of the clock weight ; hence the n a m e, "remon- toir." Note here that the big weight does not directly drive the clock ; it only re- winds it every minute. The min- utes are shown on the dial to the right and its hand j u m p s forward one minute at each sixtieth sec- ond as the lever remounts; so if you wish to set your watch to this clock the proper way is to set it to the even minute "on the jump." The hour hand is on the dial to the left. By this re- mounting, or re- winding, the clock receives the same amount of driving- force each min- ute. The complete clock is shown in Fig. 31, the large w e i g h t which does the rewinding each minute being plainly visible. The pendulum is com- pensated with steel and aluminum, so that the rate of the clock may not be influenced by hot and cold weather. Was built in 1901 and is the only one I can find room for here. It is fully described in "Machinery," New York, for Nov., 1901. I have built a consider- able number, all for experimental pur- poses, several of them much more complicated than this one, but all dif- fering from clocks for commercial pur- poses. Pallets like O O in Fig. 29 are often made of jewels; in one clock I used agates and in another, running thirteen months with one winding, I used pallets jeweled with diamonds. Fig, 31 Remontoir Clock by James Arthur This is done to avoid friction and wea Those interested in the improveme of clocks are constantly striving afl^ light action and small driving weight' Conversel}^ the inferior clock has heavy weight and ticks loud. Th "gravity escapement" and others giv ing a "free" pendulum action would ri quire too much space here, so we mui be satisfied with the few successfi ones shown out of hundreds of inver tions, dozens of them patented. Th pendulum stands at the top as a tim measurer and was known to the ai cients for measuring short periods f time just as musicians now use tli metronome to get regular beats. Ga ileo is credited with noticing its regulj beats, but did not apply it to clock although his son made a partially su( cessful attempt. The first mathemat cal investigation of the pendulum we made by Fluyghens about 1670, and li is generally credited with applying to clocks, so there is a "Huyghens clock with a pendulum instead of tb foliot of De Vick's. Mathematical!; the ItMiger and heavier the pendului Fig. 30 — Remontoir Clock Movement the better is the time-keeping, bi nature does not permit us to carry an} thing- to the extreme ; so the difficult TIME AND ITS MEASUREMENT 41 ,of finding- a tower high enough and iSteady enough, the cumbersomeness of weight, the elasticity of the rod, and many other difficulties render very .long and heavy pendulums impractic- able beyond about 13 ft. which beats once in two seconds. "Big Ben" of Westminster, London, has one of this length weighing 700 lb. and measuring, over all, 15 ft. It runs with an error under one second a week. This is surpassed only by some of the astronomical clocks which run sometimes two months within a second. This wonderful time- keeping is done with seconds pendu- lums of about 39 in., so the theoretical advantage of long pendulums is lost in the difficulties of constructing them. Fractions are left out of these lengths as they would only confuse the ex- planations. At the Naval observatory in AVashington, D. C, the standard clocks have seconds pendulums, the rods of which are nickel steel, called "Invar," which is little influenced by changes of temperature. These clocks are kept in a special basement, so they stand on the solid earth. The clock room is kept at a nearly uniform tem- perature and each clock is in a glass C3dinder exhausted to about half an at- mosphere. They are electric remon- toirs, so no winding is necessary and thev can be kept sealed up tight in their glass cylinders. Nor is any ad- justment of their pendulums neces- sary, or setting of the hands, as the cor- rection of their small variations is efifected by slight changes in the air pressure within the glass cylinders. When a clock runs fast they let a little air into its cylinder to raise the resist- ance to the pendulum and slow it down, and the reverse for slow. Don't forget that we are now considering variations of less than a second a week. The clock room has double doors, so the outer one can be shut before the inner one is opened, to avoid air cur- rents. Visitors are not permitted to see these clocks because the less the doors are opened the better ; but the Commander will sometimes issue a special permit and detail a responsible assistant to show them, so if you wish to see them, you must prove to him that you have a head above your shoul- Fig. 32 — Antique Clock, Entirely Hand-Made ders and are worthy of such a great favor. The best thing the young student could do at this point would be to grasp the remarkable fact that the clock is not an old machine, since it covers only the comparatively short period from 1364 to the present day. Compared with the period of man's history and inventions it is of yester- dav. Strictly speaking, as we use the word clock, its age from De Vick to the modern astronomical is only about 42 TIME AND ITS MEASUREMENT 540 years. If we take the year 1660, we find that it represents the center of Fig. 33 — Antique Clock, Entirely Hand-Made modern improvements in clocks, a few years before and after that date in- cludes the pendulum, the anchor and dead beat escapements, the minute and second hands, the circular balance and the hair spring, along with minor im- provements. Since the end of that period, which we may make 1700, no fundamental invention has been added to clocks and watches. This 1)ecomes impressive when we remember that the last 200 years have produced more inventions than all previous known history — but only minor improvements in clocks ! The application of electric- ity for winding', driving", or regulatinc clocks is not fundamental, for the time- keeping is done by the master clod with its pendulum and wheels, just aE bv any grandfather's clock 200 years (lid. This broad survey of time meas- uring does not permit us to go into minute mechanical details. Those wishing to follow up the subject would require a large "horological library" — and Dr. Eliot's five-foot shelf would be altogether too short to hold the books. A good idea of the old church clocks may be obtained from Fig. 32 which is one of my valued antiques. Tradition has followed it down as the "English Blacksmith's Clock." Ic has the very earliest application of the pendulum. The pendulum, which I have marked b}' a star to enable the reader to find it, is less than 3 in. long and is hung on the verge, or pallet axle, and beats 222 per minute. This clock may be safely ])ut at 230 years old, and contains noth- ing invented since that date. \\'heels are cast brass and all teeth laboriously filed out by hand. Pinions are solid with the axles, or "stafifs," and also filed Fig. 36— Double-Case Watch of Repousse Work out by hand. It is put together, gener- ally by mortise, tenon and cotter, but TIME AND ITS MEASUREMENT 43 Fig. 34— Triple-Case Turkish Watches has four original screws all made by :nd with the file. How did he thread e holes for these screws? Probably ade a tap by hand as he made the rews. fJut the most remarkable ature is the fact that no lathe was ed in forming- any part — all staffs, nions and pivots being filed by hand, lis is simply extraordinary when it is tinted out that a little dead center the is the simplest machine in the Drld, and he could have made one in 5s than a day and saved himself ;eks of hard labor. It is probable at he had g^reat skill in hand work d that learning to use a lathe would ve been a great and tedious effort for m. So we have a complete striking 3ck made by a man so poor that he d only his anvil, hammer and file. le weights are hung- on cords as thick an ordinary- lead pencil and pass er pulleys having spikes set around em to prevent the cords from slip- n^. The weig-hts descend 7 ft. in 12 airs, so they must be pulled up — not :)und up — twice a cfay. The single lur hand is a work of art and is cut rough like lace. Public clocks may still be seen in Europe with only one hand. Many have been puzzled by finding- that old, rudely made clocks often have fine dials, but this is not re- markable when we state that art and engraving- had reached a high level be- fore the days of clocks. It is worthy of Fig. 38 — Watch Showing Dutch Art Work note that clocks in the early days were generally built in the form of a church 44 TIME AND ITS MEASUREMENT tower vvitli the bell under the dome and Figs. 38, 33 show a good example. It is highly ])rol)able that the maker of given it up at this point, so the secon« and fifths seconds came easily. The first watches, about 1500, hi Fig. 35— Triple-Case Turkish Watch this clock had access to some old church clock — a wonderful machine in those days — and that he laboriously copied it. It strikes the hours, only, by the old "count wheel" or "locking- plate" method. Between this and our modern clocks appeared a type show- ing quarter hours on a small dial under the hour dial. No doubt this was at that time a great advance and looked like cutting time up pretty fine. As the hand on the quarter dial made the cir- cuit in an hour the next step was easy. by simply dividing the circle of quar- ters into sixty minutes. The old fel- lows who thought in hours must have the foliot and verge escapement, and i some early attempts to govern tli foliot a hog's bristle was used as spring. E}^ putting a ring around tli ends of the foliot and adding the ha: spring of Dr. Hooke, about 1640, w have the verge watches of our granc fathers. This balance wheel and ha: spring stand today, but the "lever" ei capement has taken the place of th verge. It is a modification of the dea beat. Fig. 39, by adding a lever to th anchor, and this lever is acted on b the balance, hence the name "leve watch." All this you can see by oper ing your watch, so no detailed exph TIME AND ITS MEASUREMENT 45 :ion is necessary. Figure 34 shows Cromwell wore an immense triple-case triple-cased Turkish watches with A.atch of this kind, and the poor plebe- -oe escapements, the one to the left ians who were permitted to examine 37 — Watches Showing Art Work ing shown partly opened in Fig. 35. le watch with its inner case, includ- y the glass, is shown to the right, lis inner case is complete with two iges and has a winding hole in the ck. The upper case, of "chased" )rk. goes on next, and then the third, outer case, covered with tortoise ell fastened with silver rivets, g;oes outside the other two. When all ree cases are opened and laid on the ble, they look like a heap of oyster ells, but they go easily together, rming the grand and dignified watch own to the left in Fig. 34. Oliver such a magnificent instrument were favored ! Our boys' watches costing one dollar keep much better time than this type of watch. Comparing the Syrian dial, Fig. 42, wnth that on Fig. 35, it is evi- dent that the strange hour numerals on both are a variation of the same characters. These, so-called, "Turk- ish watches" were made in Europe for the Eastern trade. First-class samples of this triple-case type are getting scarce, but I have found four, two of them in Constantinople. Figure 36 shows the double-case style, called 46 TIME AND ITS MEASUREMENT "pair cases," the outer case thin silver, the figures and ornaments l:)eing- ham- mered and punched up from the inside Fig. 39 — Antique Watch Cock and called "repousse." Before we leave the old watches, the cjuestion of art work deserves notice, for it looks as if ornamentation and time-keeping- varied inversely in those days — the more art the worse the watch. I pre- sume, as they could not make a good time-keeper at that date, the watch- maker decided to give the buyer some- thing- of great size and style for his money. In Fig-. 37 foiir old movements are shown, and there is no doubt about the art, since the work is purely indi- vidual and no dies or templates used. In examining" a large number of these watches. I have never found the art work on an}- two of them alike. Note the grotesque faces in these, and in Fig. 39 which is a fine example of pierced, engraved work. Figure 38 is a fine example of pierced work with animals and flowers carved in relief. Figure 40 is a "Chinese" watch but made in Europe for the Chinese mar- ket. In Fig. 41 we have what remains of a quarter repeater with musical at- tachment. Each of the 24 straight gongs, commencing with the longest one, goes a little nearer the center of the large wdieel, so a circle of pins set in the wheel for each gong, or nol and there is plenty of room for sever; tunes ^\ hich the wearer can set ofif pleasure. Figure 43 is a modern wati with Hebrew hour numerals. Figu 14 is a modern 24-hour watch used c some railroads and steamship lines, have a pretty clean-cut recollection ( Due event in connection with the 2- Imur system, as I left Messina betwee 18 and ID o'clock on the night of tl earthquake! Dials and hands const tute an important branch of the snl ject. The general fault of hands is th: they are too much alike; in many ii stances they are the same, exceptir that the minute hand is a little longi than the hour. The dial shown on tl left of Fig. 24 was designed by me f( a public clock and can be read twice ; far away as the usual dial. Just wl \^'e should make the worst dials ar hands for public clocks in the Unit( States is more than I can find out, f( there is no possible excuse, since tl "spade and pointer" hands have bee known for generations. Figure 45 offered as a properly designed dial fi watches and domestic clocks, havir flat-faced Gothic figures of modera height, leaving a clear center in tl dial, and the heav}^ "spade" hour har "Chinese" Watch reaching only to the inner edges of tl figures. For public clocks the Arab TIME AND ITS MEASUREMENT 47 iimerals are the worst, for at a dis- Hince they look Hke twelve thumb larks on th.e dial ; while the flat-faced toman remain distinct as twelve clear iarks. ! Do you know that you do not read a tiiblic clock by the figures, but by the .osition of the hands? This was dis- i)vered long ago. Lord Grimthorp id Due with twelve solid marks on the al and also speaks of one at the thena?um Club, both before lS(i!). ihe Philadelphia City Hall clock has ials of this kind as shown on right ide of Fig. 24. It has also good hands id can be read at a great distance, er}' few persons, even in Philadel- aia, know that it has no hour nunier- s on its dials. Still further, there is 3 clock in the tower, the great hands sing" moved every minute by air pres- ire which is regulated by a master ock set in a clock room down below here the walls are 10 ft. thick. Call :id see this clock and you will find that le City Hall officials sustain the good ame of Philadelphia for politeness, -enerally, we give no attention to the our numerals, even of our watches, as le following" proves. When you have iken out your watch and looked at the me, for yourself, and put it back in our ]:)Mcket, and when a friend asks yourself, you did not read hours and minutes, but only got a mental impres- g. 41 — Musical Watch, Repeating Hours and Quarters le time you take it out again to find le time for him ! Why? Because, for Fig. 42 — Syrian Dial sion from the position of the hands ; so we only read hours and minutes when we are called on to proclaim the time. We must find a little space for strik- ing- clocks. The simplest is one blow at each hour just to draw attention to the clock. Striking the hours and also one blow at each half hour as well as the quarter double blow, called "ting tong" quarters, are too well known to need description. The next stage after this is "chiming quarters" with three or more musical gongs, or bells. One of the best strikers I have has three trains, three weights and four bells. It strikes the hour on a large bell and two minutes after the hour it strikes it again, so as to give you another chance to count correctly. At the first quarter it repeats the last hour followed by a musical chord of three bells, which we will call one triple blozv: at the second quarter the hour again and two triple iilows and at the third quarter, the hour again and three triple blows. Suppose a sample hour's striking from four o'clock, this is what you hear, and there can be no mistake. "Four" and in two minutes "four" — "four and one quarter" — -"four and two quarters" — -"four and three quarters," and the same for all other hours. This is definite, for the clock proclaims the 48 TIME AND ITS MEASUREMENT hour, or the hour and so much past. It can be set silent, but that only stops it from striking- automatically, and blow on a small bell ; at the half hour it strikes the last hour over again or the small bell ; at the third quarter il Fig. 43 — Hebrew Numerals whether so set or not, it will repeat by pulling' a cord. You awake in the night and pull the cord, and then in mellow musical tones, almost as if the clock were speaking, you hear — "four and two quarters." This I consider a perfect striking clock. It is a large movement of fine w^orkmanship and was made in the department of the Jura, Erance. When a clock or watch only repeats, I consider the old "five- minute repeater" the best. I used this, method in a clock which, on pulling the cord, strikes the hour on a large bell and if that is all it strikes, then it is less than five minutes past. If more than five minutes past it follows the hour by one blow on a small bell for every five minutes. This gives the time within five minutes. It is fully described and illustrated in "Machin- ery," New York, for March, 1905. Just one more. An old Dutch clock which I restored strikes the hour on a large bell ; at the first quarter it strikes one Fig. 44— 24-Hour Watch strikes one IjIow on the large Ijell. But this in spite of its great ingenuity, only gives definite information at the houi and half hour. Of curious clocks there is no end, sc I shall just refer to one invented b}; \Mlliam Congreve, an Englishman, over one hundred years ago, and ofter coming up since as something new. A plate about 8 in. long and 4 in. wide has a long zigzag groove crosswise, This plate is pivoted at its center sc either end can be tipped up a little. A ball smaller than a boy's marble will roll back and forth across this plate till it reaches the lower end, at whicli point it strikes a click and the main- spring of the clock tips the plate the other way and the ball comes slowl}; back again till it strikes the disk at the other end of the plate, etc. Every time the plate tips, the hands are moved a little just like the remontoir clock al- ready described. Clocks of this kind are often used for deceptive purposes TIME AND ITS MEASUREMENT 49 nd those ignorant of mechanics are eceived into the belief that they see erpettial motion. The extent to which lodern machine builders are indebted D the inventions of the ancient clock- laker, I think, has never been appreci- ted. In its earlier stages the clock was al- lost the only machine containing Dothed gearing, and the "clock tooth" ; still necessary in our delicate ma- hines. It is entirely different from our tandard gear tooth as used in heavy lachines. The clock-makers led for a )ng time in working steel for tools, prings and wearing surfaces. They Iso made investigations in friction, earings, oils, etc., etc. Any one re- toring old clocks for amusement and leasure will be astonished at the high- lass mechanics displayed in them— early always by unknown inventors, lere is an example: The old clock- laker found that when he wished to rill a hole in a piece of thick wire so s to make a short tube of it, he could nly get the hole central and straight y rotating the piece and holding the rill stationary. By this method the rill tends to follow the center line of rotation ; and our great guns as well as our small rifles are bored just that way to get bores which will shoot straight. Fig. 45 — Domestic Dial by James Arthur The fourth and last chapter will deal with the astronomical motions on which our time-keeping is founded, our present hour zones of time, and close with suggestions for a universal time svstem over the whole world. CHAPTER IV ASTRONOMICAL FOUNDATION OF TIME Astronomical motions on which our time is founded. — Reasons for selectmg the sidereal day as a basis for our 24-hour day. — Year of the seasons shorter than the zodiacal year. — Precession of the equinoxes." — Earth's rotation most uniform motion known to us. — Time Stars and Transits. — Local time.— The date line. — Standard time. — Beginning and ending of a day— Proposed universal time. — Clock dial for universal time and its application to business. — Next great improvement in clocks and watches indicated. — Auto- matic recording of the earth's rotation. — Year of the seasons as a unit for astronomers.^ — General conclusions. \ CHAPTER IV The mystery of time encloses all lings in its folds, and our grasp of its ifinite bearings is measured by our mitations. As there are no isolated cts in the Universe, we can never get ) the end of our subject; so we know ily what we have capacity to absorb. 1 considering the foundation on which 1 our time measuring is based, we ■e led into the fringe of that Elysian ild of science — astronomy. A sci- ice more poetical than poetry — more larming than the optimistic phanta- es of youth. That science which aves our imagination helpless ; for its cts are more wonderful than our ex- emest mental flights. The science of istness and interminable distances hich our puny figures fail to express, rhe stars sang together for joy," ight almost be placed in the category : facts ; while the music of the spheres .ay now be considered a mathematical lality. Our time keeping is inevitably jsociated with these motions, and we lUst select one which has periods not )0 long. That is, no continuous mo- on could be used, unless it passed )me species of milestones which we )uld observe. Consequently, our ocks do not — in the strict sense — leasure time ; but are adjusted to '■vide periods which they do not deter- line. We are constantly correcting leir errors and never entirely suc- ked in getting them to run accu- itely to periods of time which exist itirely outside of such little things 5 men and clocks. So a clock is stter as it approximates or bears a ;gular relation to some motion in iture. The sidereal clock of the as- onomer does run to a regular motion ; nt our 24-hour clocks do not, as we lall see later. Now consider the year, r the sun's apparent motion in the odiac, from any given star around to le same one again. This is altogether )o long to be divided by clocks, as we innot make a clock which could be depended on for anywhere near a year. The next shorter period is that of a "moon." This is also a little too long, is not easily observed, and requires all sorts of corrections. Observations of the moon at sea are so difficult and sub- ject to error that mariners use them only as a last resort. If a little freedom of language is permissible, I would say that the moon has a bad character all around, largely on account of her long association with superstition, false the- ology and heathen feasts. She has not purged herself even to this day! The ancients were probably right when they called erratic and ill-balanced persons "luny." Now we come to the day and find that it is about the right practical length — but what kind of a day? As there are five kinds we ought to be able to select one good enough. They are : — 1st. The solar day, or noon to noon by the sun. 2nd. An imaginary sun moving uni- formly in the ecliptic. 3rd. A second imaginary sun mov- ing uniformly parallel to the equator at all seasons of the year. 4th. One absolute rotation of the earth. 5th. One rotation of the earth meas- ured from the node, or point, of the spring equinox. The difference between 1st and 2nd is that part of the sun's error due to the elliptical orbit of the earth. The other part of the sun's error — and the larger — between 2nd and 3rd is that due to the obliquity of the eclip- tic to the equator. The whole error between 1st and 3rd is the "equation of time" as shown for even minutes in the first chapter under the heading, "Sun on Noon Mark 1909." Stated simply, for our present pur- pose, 1st is sundial time, and 3rd our 24-hour clock time. This 3nd day is therefore a refine- ment of the astronomers to separate 54 TIME AND ITS MEASUREMENT the two principal causes of the sun's error, and I think we ought to handle it cautiously, or my friend, Professor Todd, might rap us over the knuckles for being presumptuous. This 5th day is the sidereal day of the astronomers and is the basis of our time, so it is entitled to a little atten- tion. I shall confine "sidereal day" to this 5th to avoid confusion with 4th. If you will extend the plane of the equator into the star sphere, you have the celestial equator. When the center of the sun passes through this plane on his journey north, in the Spring, we say, "the sun has crossed the line." This is a distant point in the Zodiac which can be determined for any given year by reference to the fixed stars. To avoid technicalities as much as possible we will call it the point of the Spring equinox. This is really the point which determines the common year, or year of the seasons. Using popular language, the seasons are marked by four points, — Spring equi- nox — longest day: Autumnal equinox — shortest day. This would be very simple if the equinoctial points would stay in the same places in the star sphere ; but we find that they creep westward each year to the extent of 50 seconds of arc in the great celestial circle of the Zodiac. This is called the precession of the equinoxes. The year is measured from Spring equinox to Spring equinox again ; but each year it comes 50 seconds of arc less than a full revolution of the earth around the sun. Therefore if wc measured our year by a full revolution we would displace the months with reference to the seasons till the hot weather would come in January and the cold weather in Jwly in about 13,000 years; or a complete revolution of the seasons back to where we are, in 2G,000 years. Leaving out fractions to make the illustration plain, we have: — il) . %0 degrees of Zodiac ^ ,^ ^^ ^^^^^^ .SO seconds of arc (2) 1 day of time 35^ seconds (3) 1 y ear of time 20% minutes (4) 3% seconds days in a year = 26.000 years = 26.000 years — T- of a second , All * Aiiproximate In (1) we see that a "precession" ^ 50 seconds of arc will bring the Sprir equinox around in 26,000 years. In (2) we see, as 50 seconds of a represents the distance the earth w rotate in 3 1/3 seconds, a difference one day will result in 26,000 yeai That is since the clock regulated by tl stars, or absolute rotations of the eart would get behind 3 1/3 seconds p year, it would be behind a day 26,000 years, as compared with a ; dereal clock regulated by the Sprii equinoctial point. In (3) we see that as 50 seconds arc is traversed by the earth, in i annual revolution, in 20 1/3 minut( a complete circle of the Zodiac will made in 26,000 years. In (4) we see that as the differen between the year of the seasons and t Zodiacal year is 3 1/3 seconds of t' earth's rotation, it follows that if t\ is divided by the number of days in year we have the amount which sidereal day is less than 4th, or an abs lute rotation of the earth. That is, ai meridian passes the Spring equinocti point 1/110 of a second sooner than t time of one absolute rotation. The four equations are all founded on t precession of the equinoxes, and a simply different methods of stating Absolutely and finally, our time is re" lated by the earth's rotation : b strange as it may appear, we do n take one rotation as a unit. As shov above, we take a rotation to a moval point which creeps the 1/110 of a secoi daily. r)Ut after all, it is the unifoi rotation which governs. This is t one "dependable" motion which has n been found variable, and is the mc easily observed. When we rememb that the earth is not far from being heavy as a ball of iron, and that : surface velocity at the equator is aho 17 miles per minute, it is easy to foru conception of its uniform motic Against this, however, we may pla the friction of the tides, forcing up mountain ranges, as well as mining a: building skyscrapers — all tending slow it. Mathematicians moving in t ethereal regions of astronomy lead TIME AND ITS MEASUREMENT 55 conclude that it must become gradu- illy slower, and that it is slowing; but he amount may be considered a van- shing quantity even compared with the miallest errors of our finest clocks ; so or uncounted generations past — and to ;ome — we may consider the earth's •otation uniform. Having now found 1 uniform motion easily observed and )f convenient period, why not adopt it IS our time unit? The answer has )een partially given above in the fact ;hat we are compelled to use a year, neasured from the Spring equinoctial )oint, so as to keep our seasons in )rder ; and therefore as we must have ;ome point where the sidereal clocks md the meantime clocks coincide, we ake the same point, and that point is he Spring equinox. Now we have hree days : — 1st. A sidereal day 1/110 of a sec- )nd less than one rotation of the earth. 2nd. One rotation of the earth in 23 lours, 56 minutes and 4 seconds, nearly, )f clock time. ord. One mean time clock day of 24 lours, which has been explained pre- dously. Now, isn't it remarkable that our 24- lour day is purely artificial, and that lothing in nature corresponds to it? )ur real day of 24 hours is a theoretical lay. Still more remarkable, this theo- etical day is the unit by which we ex- »ress motions in the solar system. A Linar month is days — hours — minutes —and seconds of this theoretical day, nd so for planetary motions. And still nore remarkable, the earth's rotation i^hich is itself the foundation is ex- iressed in this imaginary time ! This 3oks like involution involved, yet our 4-hour day is as real as reality ; and the nan has not yet spoken who can tell ;Ahether a mathematical conception, ustained in practical life, is less real han a physical fact. Our legal day of iractical life is therefore deduced from he day of a fraction less than one earth otation. In practice, however, the mall ditiference between this and a otation is often ignored, because as he tenth of a second is about as near s observations can be made it is evi- dent that for single observations 1/110 of a second does not count, but for a whole year it does, and amounts to 3 1/3 seconds. Now as to the setting of our clocks. W hile the time measured by the point of the Spring equinox is what we must find it is found loy noting the transits of fixed stars, because the relation of star time to equinoctial time is known and tabulated. Remember we cannot take a transit of the equinoctial point, because there is nothing to see, and that nothing is moving! But it can be observed yearly and astronomers can tell where it is, at any time of the year, by calculation. The stars which are preferred for observation are called "time stars" and are selected as near the celestial equator as possible. The earth's axis has a little wabbling mo- tion called "nutation" which influences the apparent motion of the stars near the pole ; but this motion almost dis- appears as they come near the equator, because nutation gives the plane of the equator only a little "swashplate" mo- tion. The positions of a number of "time stars" with reference to the equi- noctial point, are known, and these are observed and the observations aver- aged. The distance of any time star from the equinoctial point, in time, is called its "right ascension." Astrono- mers claim an accuracy to the twentieth part of a second when such transits are carefully taken, but over a long period, greater exactness is obtained. Really, the time at which any given star passes the meridian is taken, in practical life, from astronomical tables in the Nauti- cal Almanacs. Those tables are the result of the labors of generations of mathematicians, are constantly sub- ject to correction, and cannot be made simple. Remember, the Earth's rota- tion is the only uniform motion, all the others being subject to variations and even compound variations. This very subject is the best example of the broad fact that science is a constant series of approximations ; therefore, nothing is exact, and nothing is permanent but change. But you say that mathematics is an exact science. Yes. but it is a logical abstraction, and is therefore only 56 TIME AND ITS MEASUREMENT the universal solvent in physical sci- ence. With our imaginary— but real — time unit of 24 hours we are now ready to consider "local time." Keeping the above explanation in mind, we may use the usual language and speak of the earth rotating in 34 hours clock time ; and since motion is relative, it is per- missible to speak of the motion of the sun. In the matter of the sun's appar- ent motion we are compelled to speak of his "rising," "setting," etc., because language to express the motion in terms of the earth's rotation has not been invented yet. For these reasons we will assume that in Fig. 47 the sun is moving as per large arrow and also that the annulus, half black and half white, giving the 24 hours, is fastened to the sun by a rigid bar, as shown, and moves around the earth along with him. In such illustrations the sun must al- ways be made small in proportion, but this rather tends to plainness. For simplicity, we assume that the illus- tration represents an equinox when the sun is on the celestial equator. Im- agine your eye in the center of the sun's face at A, and you would be look- ing on the meridian of Greenwich at 12 noon ; then in one hour you would be looking on 15° west at 12 noon ; but this would bring 13 o'clock to Green- wich. Continue till you look down on New York at 12 noon, then it is 17 o'clock at Greenwich (leaving out fractions for simplicity) etc. If you will make a simple drawing like Fig. 47 and cut the earth separate, just around the inside of the annulus, and stick a pin at the North Pole for a center, you may rotate the earth as per small arrow and get the actual motion, but the result will be just the same as if you went by the big arrow. We thus see that every instant of the 24 hours is represented, at some point, on the earth. That is, the earth has an in- finity of local times ; so it has every conceivable instant of the 24 hours at some place on the circle. Suppose we set up 1,440 clocks at uniform distances on the equator, then they would be about 17 miles apart and dififer by min- utes. Now make it 86,400 clocks, they would be 1,500 feet apart and differ by seconds. With 864,000- clocks the)/ would be 150 feet apart and vary by tenths of seconds. It is useless to ex- tend this, since you could always im- agine more clocks in the circle ; thus es^ tablishing the fact that there are ar infinity of times at an infinity of place; always on the earth. It is necessary tc ask a little patience here as I shall us( this local time and its failure later ir our talk. Strictly, local time has nevei been used, because it has been founc impracticable in the affairs of life This will be plain when we draw atten tion to the uniform time of London which is Greenwich time ; yet thi British Museum is 30 seconds slow o Greenwich, and other places in Londoi even more. This is railroad time fo Great Britain ; but it is 20 minutes tO( fast for the west of England. This le( to no end of confusion and clocks wer often seen with two minute hands, on to local and the other to railroad time This mixed up method was followed b; "standard time," with which we are al pretty well acquainted. Simply, stand ard time consists in a uniform time fo each 15° of longitude, but this is theo retical to the extreme, and is not evei approached in practice. The first zon commences at Greenwich and as that i near the eastern edge of the Britisl Islands, their single zone time is fas at nearly all places, especially the wes coast of Ireland. When we follo^ these zones over to the United State we find an attempt to make the middl of each zone correct to local time, s at the hour jumping points, we pas from half an hour slow to half an hou fast, or the reverse. We thus see tha towns about the middle of these fou United States zones have sunrise an sunset and their local day correct, bu those at the eastern and western edge average half an hour wrong. As a cor sequence of this disturbance of th working hours depending on the ligh of the day, many places keep two set of clocks and great confusion result; Even this is comprehensible ; but it i a mere fraction of the trouble and corr f TIME AND ITS MEASUREMENT 57 plication, because the hour zones are not separated by meridians in practice, but by zig-zag lines of great irregular- ity. Look at a time map of the United States and you will see the zones divided by lines of the wildest irregu- larity. Now question one of the bright- est "scientific chaps" you can find in one of the great rail- road offices whose lines touch, or enter, Canada and Mexico. Please do not tell me what he said to you ! So great is the confusion that no man under- stands it all. The amount of wealth destroyed in printing time tables, and failing to ex- plain them, is immense. The amount of human life de- stroyed by premature death, as a result of wear and tear of brain cells is too sad to con- template. And all by attempt- ing the impossible ; for local time, even if it zvas reduced to hourly periods is not compat- ible with any continental sys- tem of time and matters can only get worse while the at- tempt continues. For the present, banish this zone sys- tem from your mind and let us consider the beginning and ending of a day, using strictly local time. A civil, or legal, day ends at the instant of 24 o'clock, midnight, and the next day commences. The time is con- tinuous, the last instant of a day touching the first instant of the next. This is true for all parts of the earth ; but something in addition to this happens at a certain meridian called the 'date line." Refer again to Fig. 47 which is drawn with 24 meridians representing hours. As we are taking Greenwich for our time, the meridians are num- bered from 0°, on which the observa- tory of Greenwich stands. When you visit Greenwich you can have the pleas- ure of putting your foot on "the first meridian," as it is cut plainly across the pavement. Degrees of longitude are numbered east and west, meeting just opposite at 180°, which is the "date line." Our day begins at this line, so far as dates are concerned ; but the local day begins everywhere at midnight. Let us start to go around the world from the date line, westward. When we arrive at 90° we are one quarter apparen r MOTION OF TME SUN. ^'DNI GV^"^ Fig. 47 — Local Time — Standard Time — Beginning and Ending of the Day around and it takes the sun 6 hours longer to reach us. At 0° (Greenwich) we are half around and 12 hours ahead of the sun motion. At 90° west, three quarters, or 18 hours, and when back to 180° we have added to the length of all days of our journey enough to make one day ; therefore our date must be one day behind. Try this example to change the wording: — Let us start from an island B, just west of the date line. These islanders have their 24- hour days, commencing at midnight, like all other places. As we move west- ward our day commences later and 58 TIME AND ITS MEASUREMENT later than theirs, as shown above. Sup- pose we arrive at the eastern edge of the 180° line on Saturday at 12 o'clock, but before we cross it we call over to the islanders, — what day is it? We would get answer, "Sunday ;" because all our days have been longer, totplling one day in the circuit of the globe. So if we step over the line at 12 o clock Saturday, presto, it is 12 o'clock Sun- day. It looks like throwing out 24 hours, but this is not so, since we have lived exactly the same number of hours and seconds as the islanders. In this supposition we have all the dates, how- ever, but have jumped half of Saturday and half of Sunday, which equals one day. In practice this would not have been the method, for if the ship was to call at the island, the captain would have changed date on Friday night and thrown Saturday out, all in one piece, and would have arrived on their Sun- day ; so his log for that week would have contained only 6 days. It is not necessary to go over the same ground for a circuit of the globe eastward, but if you do so you will find that you shorten your days and on arri\'ing at the date line would have a day too much ; so in this case you would double a date and have 8 days in that week. In both cases this is caused by com- pounding your motion with that of the sun ; going with him westward and lengthening your days, or eastward meeting him and shortening them. Figure 47 shows Greenwich noon, we will say on Monday, and at that in- stant, Monday only, exists from to 24 o'clock on the earth ; but the next in- stant, Tuesday begins at 180° B. In one hour it is noon of Monday at 15° West, and midnight at 165° East; so Tuesday is one hour old and there is left 23 hours of Monday. Monday steadily declines to as Tuesday steadily grows to 24 hours ; so that, except at the instant of Greenwich noon, there are always two days on the world at once. If we said that there are ahvays two days on the world at once, we could not be contradicted ; since there is no conceivable time be- tween Monday and Tuesday; it is an instantaneous change. As we cannol conceive of no time, the statement thai there is only one day on the earth at Greenwich noon is not strictly per- missible. Since there are always twc dr^ys on the world at once let us sup- pose that these two are December 31st and January 1st; then we have tzuc years on the world at once for a period of 24 hours. Nine years ago we had the 19th and 20th centuries on the world at once, etc. As a mental exer- cise, you may carry this as far as you please. Suppose there was an impas^ able sea w^all built on the 180° meri- dian, then there would be two days or the world, just as explained above but, practically, there would be no date line, since in sailing west to this wal we would "lengthen our days," anc then shorten them the same amouni coming around east to the other side o; the wall, but would never jump oi double a date. This explanation is founded, as it ought to be, on uniforn local time, and is the simplest I car give. The date line is fundamentall) simple, but is difficult to explain. Wher it is complicated by the standard time — or jumping hour system — and alsc with the fact that some islands coun' their dates from the wrong side of th( line for their longitudes, scientific para doxes arise, such as having three date; on the world at once, etc. ; but as thes< things are of no more value than wast ing time solving Chinese puzzles, the) are left out. Ships change date on the nearest night to the date line ; but i they are to call at some island port ir the Pacific, they may change eithei sooner or later to correspond with it; date. Here is a little Irish date line wi' printed for the first time, — I was tell ing my bright friend about turning ir on Saturday night and getting up foi breakfast on Monday morning. "Oh,' said he, "I have known gentlemen to dc as good as that without leaving Ne-w York City !" As what is to follow relates to the growing difficulties of local time and t proposed method of overcoming them let us recapitulate : — 1st. Local time has never been kept TIME AND ITS MEASUREMENT 59 and the difficulties of using- it have in- creased as man advanced, reaching a climax of absurdity on the advent of the railroad ; so it l3roke down and be- came impractical. 3nd. To make the irregular disorder of local time an orderly confusion, the "standard time" — jumping by hours- — ■ has helped a little, but only because we can tell how much it is wrong at any given place. This is its only advantage over the first method, where we had no means of knowing what to expect on entering any new territory. That is, we have improved things by throwing out local time to the extent of an hour. My proposal is to throw local time out totally and establish one, invari- able, universal time. Greenwich time being most in use now, and meridians numbered from it, may be taken in pref- erence to any other. Still another rea- son is that the most important time- keepers in modern life — ship's chrono- meters — are set to Greenwich time. Universal time — no local time — only local day and night. Our 24-hour sys- tem is all right, so do not disturb it, as it gets rid of A.M. and P.M. and makes the day our unit of time. Our railroad time now throws out local time to the extent of one hour ; but I propose to throw it out entirely and never change the clock hands from Greenwich time. The chronometers do that now, so let us conduct all business to that time. Now refer to Fig. 46, in which Greenwich is taken as universal time. The annulus, half white and half black, indicates the average day and night, and is a separate ring in the dial which can be set so that "noon" is on the meridian of the place, as shown for four places in the illustration. It is the same dial in all four cases set to local day and night. Strictly, the local time conception is dropped and the local day left for regulating working and sleep- ing time. All business would have the same time. In traveling east we would not have the short hours ; or west, the long hours. All clocks and watches would show the same time as ship's chronometers do now. The only change would be the names of the hours for the parts of the local day. This is just the difficulty, for we are so accus- tomed to associate a certain number, as seven, with the morning and breakfast time. Suppose breakfast time in Lon- don is 7 o'clock, then according to the local day it would be 12 o'clock break- fast time in New York; but in both cases it would be the same time with reference to the local daylight. Let it be distinctly understood that our associa- tion of 12 o'clock with noon is not nec- essary. The Japanese called it "horse" and "nine" — the ancient Romans, the New Testament writers, and the Turks called it the "sixth hour" — the astrono- mers now call it 24 o'clock, and the Chinese represent it by several char- acters ; but, in all cases, it is simply the middle of the day at any place. By the proposed universal time, morning, noon, and evening would be — at any given place — the same hours. There would be no necessity of establishing legal noon with exactness to the meri- dian, because that would only regulate labor, meals, etc., and would not touch universal time. This is an important part of the proposal and is worth elabor- ating a little. Sections in manufactur- ing districts could make their working hours correspond at pleasure and no confusion would result. That is, local working hours to convenience but by the same universal time. Note how perfectly this would work in traveling, — you arrive in Chicago from the effete east and your watch corresponds all along with the railroad clocks. As you leave the station you glance up at the clock and see that Chicago noon is 17.30, so you set the day and night ring of your watch to match the same ring on the clock, but no disturbance of the hands. As you register at the hotel you ask, — dinner? and get answer, 24.30— then breakfast, 12.30. These questions are necessary now, so I do not add complication here. When you arrive in a strange city you must ask about meals, business hours, theater hours, "doors open" hours, etc., etc. ; so all this remains the same. Let us put the matter forcibly, — while we count days, or dates, something must 60 TIME AND ITS MEASUREMENT vary with east and west ; I propose the fixing of hours for business and sleep to suit each locality, but an invariable time. Get rid of the idea that a certain number, as 7 o'clock, represents the age of the day at all places. See how this would wipe out the silly proposal to "save daylight" by setting the clock back and forward. Suppose workmen commenced at 12.30 in New York; for the long summer days make it 11.30, but no change in universal time. As this is the only difference from our pre- sent time system, keep the central con- ception, firmly, — universal time — local day and night. Suppose Chicago decided that "early to bed and early to rise" was desirable ; then it could establish its legal noon as 17.30, which would be about 20 min- utes early for its meridian. You could do business with Chicago for a lifetime and not find this out, unless you looked up the meridian of Chicago and found that it was 17.50 o'clock. None of the railroads or steamship lines of the city would need to know this, except as a matter of scientific curiosity, for the time tables would all be printed in uni- versal time. For hiring labor, receiving and delivering goods, etc., they would only need to know Chicago business hours. To state the matter in different words, — Chicago would only need to decide what portion of the universal 24 hours would suit it best for its day and which for its night, and if it decided, as supposed above, to place its working day forward a little to give some day- light after labor, nothing would be dis- turbed and only the scientific would ever know. Certainly, "save daylight," but do not make a fool of the clock! Having shown the great liberty which localities could take without touching the working of the system, the same remarks apply to ultra-scientific locali- ties. A city might establish its noon to the instant ; so it is possible — even if a little improbable — that the brilliant and scientific aldermen of New York might appoint a commission with proper campfollowers and instrument bearers to determine the longitude of the city to the Nth of a second and tell us where we "are at." The glory of this achievement — and especially its total cost — would be all our own and incorruptible time would be untouched ! We thus see that great local freedom and great accuracy are alike possible. With our present system, accuracy in local time is impracticable and has never even been attempted, and is con- fusion confused since we added the rail- road hour jumps. Why did we nurse this confusion till it has become almost intolerable? Because man has always been a slave to mental associations, and habits. Primitive man divided the local day into parts and gave them names and this mental attitude sticks to us after it has served its day. The ad- vantages of universal time could hardly be enumerated, yet we can have them all by dropping our childish associa- tion of 7 o'clock with breakfast time! Another example, — you visit a friend for a few days and on retiring the first night you ask "what is your breakfast hour" — "8 o'clock." You have to ask this question and recollect the answer. Now tell me what difference it would make if the answer had been 13 o'clock? None whatever, unless, perhaps, that is, you do not like thirteen ! You ask, how about ships? Ships now carry universal time and only change the clock on deck to please the simple minded passengers. How about the date line? No change whatever, so long as we use dates which means num- bering local days. It is useless multi- plying examples; all difficulties disap- pear, as if by magic, the moment we can free our minds of local time and the association of the same hour with the same portion of the day at all places. The great interest at present mani- fested in the attempts to reach the North Pole calls for some consideration of universal time in the extreme north. Commencing at the equator, it is easy to see that the day and night ring, Fig. 4fi, would represent the days and nights of 12 hours at all seasons. As we go north, however, this ring represents the average day and night. When we reach the Polar Circle, still going north, the daily rising and setting of the sun grad- p TIME AND ITS MEASUREMENT 61 ually ceases till we reach the great one- year day at the Pole, consisting of six months darkness and six months light. Let us now assume that an astronom- ical observatory is established here and the g"reat equatorial placed pre- cisely on the pole. At this point, local time, day and night, and the date line, al- most cease to have a meaning. For this very reason universal time would be the only practical method ; there- hours within five seconds ! At the pole the day would commence at the same instant as at some assumed place, and the day and night ring would represent working and sleeping as at that place. Suppose this observatory to be in tele- graphic communication with New York, then it would be best for the at- tendants to set their day and night to New York, so as to correspond with its business hours. Many curious supposi- Fig. 46— Universal Time Dial Set for Four Places fore, it more than stands the test of be- ing carried to the extreme. Universal time would regulate working and sleep- ing here the same as at all other places. Strictly local time in this observatory would be an absurdity, because in walking around the telescope (pole) you would be in all instants of the 24 'tions might be made about this polar observatory with its "great night" and equally "great day." It is evident that to keep count of itself it would be com- pelled to note dates and 24-hour days to keep in touch with us; so it would be forced to adopt the local day of some place like New York. This choice 62 TIME AND ITS MEASUREMENT would be free, because a polar observa- tory would stand on all the meridians of the earth at once. We are now in a position to consider the next possible — and even probable — improvement in our clocks and watches. To minimize the next step it might be well to see what we can do now. Clocks are often regulated by electric impulses over wires. Electricians in- form me that they can do this by wire- less ; but that owing to the rapid atten- uation of the impulses it cannot be done commercially, over great distances. In the history of invention the first step was io do something and then find a way of doing it cheaply enough for general use. So far as I know, the watch in the wearer's pocket has not yet been regulated by wireless ; but I am willing to risk the statement that the editor of Popular Mechanics can name more than one electrician who can do this. A watch to take these impulses might be larger than our present watches, but it Avould not stay larger and would ultimately become much smaller. You know what has happened since the days of the big "onions" described in the third chapter, Fig. 34 ; so get your electric watch and make it smaller at your leisure. We have made many things commercially practicable, which looked more revolutionary than this. Now throw out the mainspring, wheels, pinions, etc., of our watches and reduce the machinery part to little more than dial and hands and do the driving by wireless, say, once every minute. I feel certain that I am restraining the scientific imagination in saying that the man lives among us who can do this. I repeat, that we now possess the ele- mentary knowledge — which if collated and applied — would produce such a watch. Now I have a big question to ask — the central note of interrogation in this little scientific conversation with you, — does the man live who can make the earth automatically record its rotation? Do not be alarmed, for I am prepared to make a guess as to this possibility. A direct mechanical record of the earth's rotation seems hopeless, but let us see what can be done. You are aware that some of the fixed stars have a distinct spectrum. It is not unreasonable tc suppose that an instrument could be made to record the passage of such a star over the meridian. Ah. but you say, there is no mechanical force in this. Dc not hurry, for we have long been ac- quainted with the fact that things which, apparently, have no force car be made to liberate something which manifests mechanical force. We could now start or stop the greatest steam en- gine by a gleam of sunlight, and some day we might be able to do as much h^ the lately discovered pressure of light 'Jhat is, we can now liberate the great- est forces by the most infinitesimal, b} steps ; the little force li1:)erating out greater than itself, and that one an- other still greater. A good example i^ the stopping of an electric train, frorr a distance, by \^ ireless. The standarc clock in Philadelphia, previously re- ferred to, is a delicate instrument anc its most delicate part, having the leasi force, moves a little valve every min- ute, and by several steps liberates th( air pressure, 200 feet higher in the tower, to move the four sets of greai hands. I am not traveling beyond th( record when I say that the invisible actinic rays could be used to liberate i great force; therefore what is there un reasonable in the supposition that th( displacement of the sodium line in th( spectrum of a star might be made tc record the earth's rotation? So I sa} to the electrician — the optician — tht photographer — the chemist and the me chanic, — get together and produce thii watch. Permit me, with conventiona and intentional modesty, to nam( the new timepiece Chroncosmic. Foi pocket use, it would be Cosmic zuatch In the first chapter I allowed to the year 2,000 for the production of thi; watch, but it is likely we will not nee to wait so long. Having stated my proposal for uni versal time as fully as space will per- mit and given my guess as to the com- ing cosmic watch, let us in this closm^ paragraph indulge in a little mental ex- ercise. Suppose we copy the old time TIME AND ITS MEASUREMENT 6a lecturer on astronomy and "allow our iiinds to penetrate into space." Blessed 36 his memory, he was a doer of good. How impressive as he repeatedly dropped his wooden pointer, and lo ! [t always moved straight to the floor ; thus triumphantly vindicating univer- sal gravitation ! ! ! We can think of a time system which ivould discard months, weeks and days. What is the meaning of the financial almanac in which the days are num- bered from 1 to 365 or 366? Simply a step in the right direction, azvay from Uie months and zvecks, so that the dis- tance between any two dates may be Been at a glance. We would really be setter without months and weeks. Now let us consider the year of the seasons as a unit — long since proposed by the astronomers — and divide it into 3,000 :hrons. Clocks regulated by star tran- sits, as at present, would divide this decimally, the fourth place being near snough to make the new pendulums of :onvenient length. This would throw 3Ut months, weeks and days, local time and the date line. Each of these chrons ivould represent the same time in the year, permanently. For example, i64.6731 would mark to a dixmillieme- :hron (a little more than one second) :he point reached in the year ; while the date does not, as I have shown in the irst chapter. But you still object that his is a great number of figures to use 11 fixing a point in the year. Let us ■,ee what it takes to fix a point in the /ear now, August 24th, 11-16-32 P. M., Vf7C' York standard time. A pretty long .tory, but it does not fix the point of ihe year even then ; for it would re- quire the assistance of an astronomer ^o fix such a point in any giz'cn year, lay 1909. But 464.6731 would be iternally right in absolute time of the easons, and has only one meaning, /ith no qualifications for any year /hatever. I believe the astronomers hould use a method something like lis. Ah, but there is a difficulty in pplying this to the affairs of daily life ;hich looks insurmountable. This is lused by the fact that the day and year 'e incommeasurable. One of them cannot be exactly expressed in terms of the other. They are like the diagonal and side of a square. The day is now the unit and therefore the year has an interminable fraction ; conversely, if we make the year the unit, then the day becomes an endless fraction. This brings us face to face with the local day which we ignored in our scientific year unit. We must regulate our labors, in this world, to day and night and, with the year unit, the chrons would bear no fixed relation to day and night, even for two days in succession. So the year unit and absolute time must be left to the astronomers ; but the day unit and the uniform world day of Mii- z'crsal time as explained in connection with Fig. 46 I offer as a practical sys- tem. I am satisfied that all attempts to measure the year and the day by the same time yard stick must fail and keep us in our present confusion. There- fore separate them once for all time. Brought down to its lowest terms my final proposal is : — 1st. An equinoctial year unit for the astronomers, divided somewhat as sug- gested, but no attempt to make the divisions even approximate to days and hours. This would fix all astronomical events, absolutely. A variation in the length of the year would not disturb this system, since the year itself would be the unit. In translating this astro- nomical, or year unit time, into clock time, no difficulties w^ould be added, as compared with our present translation of sidereal time into clock time. Deal with the year unit and day unit sepa- rately and convert them mutually when necessary. 2nd. A universal mean time day of 24 hours, as now kept at Greenwich, all human business being regulated by this time. Dates and the date line as well as leap years all being retained as at present. 3rd. Weight and spring clocks and watches to be superseded by the cosmic clocks and watches regulated by wire- less impulses from central time sta- tions, all impulses giving the same in- variable time for all places. 64 TIME AND ITS MEASUREMENT 4th. Automatic recording of the earth's rotations to determine this time. To avoid any possibility of misunder- standing, I would advise never count- ing a unit till it is completed. We do this correctly with our hours, as we understand 24 o'clock to be the same as o'clock. But we do not carry this out logically, for we say 34.30. How can this be so, since there is nothing more than 24 o'clock? It ought to be simply 30 minutes, or hour 30 min- utes. How can there be any hour when a new day is only 30 minutes old? This brings up the acrimonious con- troversy, of some years ago, as to whether there was any "year one." One side insisted that till one year was com- pleted there could only be months and days. The other side argued that the "year one" commenced at and that the month and date showed how much of it had passed. Test yourself, — is this the year 1909, of which only 8 months have passed ; or is it 1909 and 8 months more? Regarding the centuries there appears to be no difference of opinion that 1900 is completed, and that we are in the 20th century. But can you tell whether we are 8 years and 8 months into the 20th century or 9 years and 8 months? It ought to be, logically 1909 years complete and 8 months of the next year, which we must not count till it is completed. Take a carpenter's rule, we say V4, in. — i/o in. — % in., but do not count an inch till we complete it. When the ancients are quoted, — "about the middle of the third hour" there is no mistake, because that means 21/2 hours since sunrise. If we said the 1909th year that would be definite too, and mean some distance into that year. Popular language states that Green- wich is on the "first meridian" ; strictly, it is on the zero meridian, or 0°. These matters are largely academic and I do not look on them as serious subjects of discussion ; but they are good thought producers. Bidding you good-bye, for the present, it micht be permissible to state that this conversational article on Time was intended to be readable and somewhat instructive ; but especially to indicate the infinity of the subject, that thought and investigation might be encouraged. 82 8 L-^ I .^^ -^ce. \> ,v ..- * '^ S^" "^^. ''5-2 s^%. v>^n 'X^^"-^ '^^. c>' ^^" ■'^>. 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