Horologium

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Horologium   the Pendulum Clock

SUBJECT AREA: Horology

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Huygens was born into a cultured and privileged class. His father, Constantijn, was a poet and statesman who had wide interests. Constantijn exerted a strong influence on his son, who was educated at home until he reached the age of 16. Christiaan studied law and mathematics at Ley den University from 1645 to 1647, and continued his studies at the Collegium Arausiacum in Breda until 1649. He then lived at The Hague, where he had the means to devote his time entirely to study. In 1666 he became a Member of the Académie des Sciences in Paris and settled there until his return to The Hague in 1681. He also had a close relationship with the Royal Society and visited London on three occasions, meeting Newton on his last visit in 1689. Huygens had a wide range of interests and made significant contributions in mathematics, astronomy, optics and mechanics. He also made technical advances in optical instruments and horology.

Despite the efforts of Burgi there had been no significant improvement in the performance of ordinary clocks and watches from their inception to Huygens's time, as they were controlled by foliots or balances which had no natural period of oscillation. The pendulum appeared to offer a means of improvement as it had a natural period of oscillation that was almost independent of amplitude. Galileo Galilei had already pioneered the use of a freely suspended pendulum for timing events, but it was by no means obvious how it could be kept swinging and used to control a clock. Towards the end of his life Galileo described such a. mechanism to his son Vincenzio, who constructed a model after his father's death, although it was not completed when he himself died in 1642. This model appears to have been copied in Italy, but it had little influence on horology, partly because of the circumstances in which it was produced and possibly also because it differed radically from clocks of that period. The crucial event occurred on Christmas Day 1656 when Huygens, quite independently, succeeded in adapting an existing spring-driven table clock so that it was not only controlled by a pendulum but also kept it swinging. In the following year he was granted a privilege or patent for this clock, and several were made by the clockmaker Salomon Coster of The Hague. The use of the pendulum produced a dramatic improvement in timekeeping, reducing the daily error from minutes to seconds, but Huygens was aware that the pendulum was not truly isochronous. This error was magnified by the use of the existing verge escapement, which made the pendulum swing through a large arc. He overcame this defect very elegantly by fitting cheeks at the pendulum suspension point, progressively reducing the effective length of the pendulum as the amplitude increased. Initially the cheeks were shaped empirically, but he was later able to show that they should have a cycloidal shape. The cheeks were not adopted universally because they introduced other defects, and the problem was eventually solved more prosaically by way of new escapements which reduced the swing of the pendulum. Huygens's clocks had another innovatory feature: maintaining power, which kept the clock going while it was being wound.

Pendulums could not be used for portable timepieces, which continued to use balances despite their deficiencies. Robert Hooke was probably the first to apply a spring to the balance, but his efforts were not successful. From his work on the pendulum Huygens was well aware of the conditions necessary for isochronism in a vibrating system, and in January 1675, with a flash of inspiration, he realized that this could be achieved by controlling the oscillations of the balance with a spiral spring, an arrangement that is still used in mechanical watches. The first model was made for Huygens in Paris by the clockmaker Isaac Thuret, who attempted to appropriate the invention and patent it himself. Huygens had for many years been trying unsuccessfully to adapt the pendulum clock for use at sea (in order to determine longitude), and he hoped that a balance-spring timekeeper might be better suited for this purpose. However, he was disillusioned as its timekeeping proved to be much more susceptible to changes in temperature than that of the pendulum clock.

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1) Religion: book of hours, horologium, hour-book

2) Christianity: breviary, prayer-book

1) General subject: clockmaker, horologer, horologist, watch repairer, watch-maker, watchmaker

2) Church: horologium

(gen. dags, dat. degi; pl. dagar), m.

1) day;

at kveldi skal dag leyfa, at eventide shall the day be praised;

dagr kemr upp í austri, sezt í vestri, the day rises in the east, sets in the west;

öndverðr dagr, the early day, forenoon;

miðr dagr, midday;

hallandi dagr, declining day;

at kveldi dags, síð dags, late in the day;

sannr sem dagr, true as day;

í dag, today;

á (or um) daginn, during the day;

sama dags, the same day;

annan dag, the next day;

annars dag, another day;

hindra dags, the day after, tomorrow;

dag frá degi, hvern dag frá öðrum, from day to day;

dag eptir dag, day after day;

nótt ok dag, night and day;

dögunum optar, more times than there are days, over and over again;

á deyjanda degi, on one’s death-day;

2) pl., days, times;

ef aðrir dagar (better days) koma;

góðir dagar, happy days;

3) esp. pl., lifetime;

á dögum e-s, um daga e-s, in the days of, during or in the reign of;

eptir minn dag, when I am dead (gaf honum alla sína eign eptir sinn dag);

mátti hann eigi lengr gefa en um sína dagi, than for his lifetime;

ráða (taka) e-n af dögum, to put to death.

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m., irreg. dat. degi, pl. dagar: [the kindred word dœgr with a vowel change from ó (dóg) indicates a lost root verb analogous to ala, ól, cp. dalr and dælir; this word is common to all Teutonic dialects; Goth. dags; A. S. dag; Engl. day; Swed.-Dan. dag; Germ. tag; the Lat. dies seems to be identical, although no interchange has taken place]

I. a day; in different senses:

1. the natural day:—sayings referring to the day, at kveldi skal dag leyfa, at eventide shall the day be praised, Hm. 80 ; allir dagar eiga kveld um síðir; mörg eru dags augu, vide auga; enginn dagr til enda tryggr, no day can be trusted till its end; allr dagr til stefnu, Grág. i. 395, 443, is a law phrase,—for summoning was lawful only if performed during the day; this phrase is also used metaph. = ‘plenty of time’ or the like: popular phrases as to the daylight are many—dagr rennr, or rennr upp, and kemr upp, the day rises, Bm. 1; dagr í austri, day in the east, where the daylight first appears; dagsbrún, ‘day’s brow,’ is the first streak of daylight, the metaphor taken from the human face; lysir af degi, it brightens from the day, i. e. daylight is appearing; dagr ljómar, the day gleams; fyrir dag, before day; móti degi, undir dag, about daybreak; komið at degi, id., Fms. viii. 398; dagr á lopti, day in the sky; árla, snemma dags, early in the morning, Pass. 15. 17; dagr um allt lopt, etc.; albjartr dagr, hábjartr d., full day, broad daylight; hæstr dagr, high day; önd-verðr d., the early day = forenoon, Am. 50; miðr dagr, midday, Grág. i. 413, 446, Sks. 217, 219; áliðinn dagr, late in the day, Fas. i. 313; hallandi dagr, declining day; at kveldi dags, síð dags, late in the day, Fms. i. 69. In the evening the day is said to set, hence dag-sett, dag-setr, and dagr setzt; in tales, ghosts and spirits come out with nightfall, but dare not face the day; singing merry songs after nightfall is not safe, það kallast ekki Kristnum leyft að kveða þegar dagsett er, a ditty; Syrpuvers er mestr galdr er í fólginn, ok eigi er lofat at kveða eptir dagsetr, Fas. iii. 206, Ísl. Þjóðs. ii. 7, 8: the daylight is symbolical of what is true or clear as day, hence the word dagsanna, or satt sem dagr, q. v.

2. of different days; í dag, to-day, Grág. i. 16, 18, Nj. 36, Ld. 76, Fms. vi. 151; í gær-dag, yesterday; í fyrra dag, the day before yesterday, Háv. 50; í hinni-fyrra dag, the third day; annars dags, Vígl. 23, Pass. 50. I; hindra dags, the hinder day, the day after to-morrow, Hm. 109; dag eptir dag, day after day, Hkr. ii. 313; dag frá degi, from day to day, Fms. ii. 230; hvern dag frá öðrum, id., Fms. viii. 182; annan dag frá öðrum. id., Eg. 277; um daginn, during the day; á dögunum. the other day; nótt ok dag, night and day; liðlangan dag, the ‘life-long’ day; dögunum optar, more times than there are days, i. e. over and over again, Fms. x. 433; á deyjanda degi, on one’s day of death, Grág. i. 402.

β. regu-dagr, a rainy day: sólskins-dagr, a sunny day; sumar-dagr, a summer day; vetrar-dagr, a winter day; hátíðis-dagr, a feast day; fegins-dagr, a day of joy; dóms-dagr, the day of doom, judgment day, Gl. 82, Fms. viii. 98; hamingju-dagr, heilla-dagr, a day of happiness; gleði-dagr, id.; brúðkaups-dagr, bridal-day; burðar-dagr, a birthday.

3. in pl. days in the sense of times; aðrir dagar, Fms. i. 216; ek ætlaða ekki at þessir dagar mundu verða, sem nú eru orðnir, Nj. 171; góðir dagar, happy days, Fms. xi. 286, 270; sjá aldrei glaðan dag (sing.), never to see glad days.

β. á e-s dögum, um e-s daga eptir e-s daga, esp. of the lifetime or reign of kings, Fms.; but in Icel. also used of the lögsögumaðr, Jb. repeatedly; vera á dögum, to be alive; eptir minn dag, ‘after my day,’ i. e. when I am dead.

γ. calendar days, e. g. Hvíta-dagar, the White days, i. e. Whitsuntide; Hunda-dagar, the Dog days; Banda-dagr, Vincula Petri; Höfuð-dagr, Decap. Johannis; Geisla-dagr, Epiphany; Imbru-dagar, Ember days; Gang-dagar, ‘Ganging days,’ Rogation days; Dýri-dagr, Corpus Christi; etc.

4. of the week-days; the old names being Sunnu-d. or Drottins-d., Mána-d., Týs-d., Öðins-d., Þórs-d., Frjá-d., Laugar-d. or Þvátt-d. It is hard to understand how the Icel. should be the one Teut. people that have disused the old names of the week-days; but so it was, vide Jóns S. ch. 24; fyrir bauð hann at eigna daga vitrum mönnum heiðnum, svá sem at kalla Týrsdag Óðinsdag, eðr Þórsdag, ok svá um alla vikudaga, etc., Bs. i. 237, cp. 165. Thus bishop John (died A. D. 1121) caused them to name the days as the church does (Feria sccunda, etc.); viz. Þriði-d. or Þriðju-d., Third-day = Tuesday, Rb. 44, K. Þ. K. 100, Ísl. ii. 345; Fimti-d., Fifth-day—Thursday, Rb. 42, Grág. i. 146, 464, 372, ii. 248, Nj. 274; Föstu-d., Fast-day = Friday; Miðviku-d., Midweek-day = Wednesday, was borrowed from the Germ. Mittwoch; throughout the 12th and 13th centuries, however, the old and new names were used indiscriminately. The question arises whether even the old names were not imported from abroad (England); certainly the Icel. of heathen times did not reckon by weeks; even the word week (vika) is probably of eccl. Latin origin (vices, recurrences). It is curious that the Scandinavian form of Friday, old Icel. Frjádagr, mod. Swed.-Dan. Fredag, is A. S. in form; ‘Frjá-,’ ‘Fre-,’ can hardly be explained but from A. S. Freâ-, and would be an irregular transition from the Norse form Frey. The transition of ja into mod. Swed.-Dan. e is quite regular, whereas Icel. ey (in Frey) would require the mod. Swed.-Dan. ö or u sound. Names of weekdays are only mentioned in Icel. poems of the 11th century (Arnór, Sighvat); but at the time of bishop John the reckoning by weeks was probably not fully established, and the names of the days were still new to the people. 5. the day is in Icel. divided according to the position of the sun above the horizon; these fixed traditional marks are called dags-mörk, day-marks, and are substitutes for the hours of modern times, viz. ris-mál or miðr-morgun, dag-mál, há-degi, mið-degi or mið-mundi, nón, miðr-aptan, nátt-mál, vide these words. The middle point of two day-marks is called jafn-nærri-báðum, in modern pronunciation jöfnu-báðu, equally-near-both, the day-marks following in the genitive; thus in Icel. a man asks, hvað er fram orðið, what is the time? and the reply is, jöfnubáðu miðsmorguns og dagmála, half-way between mid-morning and day-meal, or stund til (to) dagmála; hallandi dagmál, or stund af ( past) dagmálum; jöfnu-báðu hádegis og dagmúla, about ten or half-past ten o’clock, etc. Those day-marks are traditional in every farm, and many of them no doubt date from the earliest settling of the country. Respecting the division of the day, vide Pál Vídal. s. v. Allr dagr til stefnu, Finnus Johann., Horologium Island., Eyktamörk Íslenzk (published at the end of the Rb.), and a recent essay of Finn Magnusson.

II. denoting a term, but only in compounds, dagi, a, m., where the weak form is used, cp. ein-dagi, mál-dagi, bar-dagi, skil-dagi.

III. jis a pr. name, Dagr, (freq.); in this sense the dat. is Dag, not Degi, cp. Óðinn léði Dag (dat.) geirs síns, Sæm. 114.

COMPDS: dagatal, dagsbrun, dagshelgi, dagsljós, dagsmark, dagsmegin, dagsmunr.

1) half-past three o’clock, p. m. (var þat nær e. dags);

2) time of three hours (þá er þógn hafði verit nær hálfa e.).

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eykð, f. three or half-past three o’clock P. M.; many commentaries have been written upon this word, as by Pal Vídalín Skýr., Finn Johnson in H. E. i. 153 sqq. note 6, and in Horologium, etc. The time of eykð is clearly defined in K. Þ. K. 92 as the time when the sun has past two parts of the ‘útsuðr’ (q. v.) and has one part left, that is to say, half-past three o’clock P. M.: it thus nearly coincides with the eccl. Lat. nona (three o’clock P. M.); and both eykt and nona are therefore used indiscriminately in some passages. Sunset at the time of ‘eykð’ is opposed to sunrise at the time of ‘dagmál,’ q. v. In Norway ‘ykt’ means a luncheon taken about half-past three o’clock. But the passage in Edda—that autumn ends and winter begins at sunset at the time of eykt—confounded the commentators, who believed it to refer to the conventional Icel. winter, which (in the old style) begins with the middle of October, and lasts six months. In the latitude of Reykholt—the residence of Snorri—the sun at this time sets about half-past four. Upon this statement the commentators have based their reasoning both in regard to dagmál and eykt, placing the eykt at half-past four P. M. and dagmál at half-past seven A. M., although this contradicts the definition of these terms in the law. The passage in Edda probably came from a foreign source, and refers not to the Icel. winter but to the astronomical winter, viz. the winter solstice or the shortest day; for sunset at half-past three is suited not to Icel., but to the latitude of Scotland and the southern parts of Scandinavia. The word is also curious from its bearing upon the discovery of America by the ancients, vide Fb. l. c. This sense ( half-past three) is now obsolete in Icel., but eykt is in freq. use in the sense of trihorium, a time of three hours; whereas in the oldest Sagas no passage has been found bearing this sense,—the Bs. i. 385, 446, and Hem. l. c. are of the 13th and 14th centuries. In Norway ykt is freq. used metaph. of all the four meal times in the day, morning-ykt, midday-ykt, afternoon-ykt (or ykt proper), and even-ykt. In old MSS. (Grág., K. Þ. K., Hem., Heið. S.) this word is always spelt eykð or eykþ, shewing the root to be ‘auk’ with the fem. inflex. added; it probably first meant the eke-meal, answering to Engl. lunch, and thence came to mean the time of day at which this meal was taken. The eccl. law dilates upon the word, as the Sabbath was to begin at ‘hora nona;’ hence the phrase, eykt-helgr dagr (vide below). The word can have no relation to átta, eight, or átt, plaga coeli. At present Icel. say, at eykta-mótum, adv. at great intervals, once an eykt, once in three hours.

I. half-past three; þá er eykð er útsuðrs-átt er deild í þriðjunga, ok hefir sól gengna tvá hluti en einn ógenginn, K. Þ. K. 92; net skal öll upp taka fyrir eykð, 90; helgan dag eptir eykð, 88; ef þeir hafa unnit á eykð, 94; enda skal hann undan honum hafa boðit fyrir miðjan dag en hinn skal hafa kosit at eykþ, Grág. i. 198; ok á maðr kost at stefna fyrir eykþ ef vill, 395; í þat mund dags er tók út eyktina, Fms. xi. 136; eptir eykt dags, rendering of the Lat. ‘vix decima parte diei reliqua,’ Róm. 313; þeir gengu til eyktar, ok höfðu farit árla morguns, en er nón var dags, etc., Fs. 176; at eykð dags þá kómu heim húskarlar Barða. Ísl. ii. 329; nú vættir mik at þar komi þér nær eykð dags, 345; var þat nær eykð dags, 349; var hón at veraldligu verki þangat til er kom eykð, þá fór hón til bænar sinnar at nóni, Hom. (St.) 59.

COMPDS: eykðarhelgr, eyktarstaðr, eykðartíð.

II. trihorium; en er liðin var nær ein eykt dags, Bs. i. 446; at þat mundi verit hafa meir en hálf eykt, er hann vissi ekki til sín, 385; þessi flaug vanst um eina eykð dags, Hem. (Hb.)

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clock

clocks

horologe

horologium

timekeeper

timepiece

timepieces

timer

timers

watch

watches

ănăphŏrĭcus, a, um, adj., = anaphorikos.

In astronomy, adjusted according to the rising of the stars:

horologium,

Vitr. 9, 9.—

In medicine, bringing up blood, spitting blood, Firm. Math. 3, 13.