“That these water-clocks however were then scarce, as well as in the following centuries, we have reason to conclude from their being so little spoken of in the writings of those periods. In the ancient customs of the monastery of St. Viton, at Werden[1061], written as is said in the tenth century, no mention of them occurs; and the monks regulated their prayers by the crowing of the cock; for it is said, ‘Cum lucem ales nunciaverit, dabuntur omnia signa in resurrectione Domini nostri,’ &c. I find as little mention of them in the eleventh century, even in passages where they could not have been omitted, had they been known. Thus, in a little work by Pet. Damiani, De Perfectione Monachorum, where the author speaks of the significator horarum, he does not so much as allude to a clepsydra. That the reader may know what he means by significator horarum, I shall here quote his own words: ‘He could not find time for idle fables, nor hold long conversations, nor finally could he trouble himself about what was done by the laity, but always intent on the duties of his office, always provident, always anxious, he felt a desire to construct a voluble sphere that should never stop, should show the passage of the stars and the flight of time. He also had a custom of singing to himself whenever he wished to have a notion as to the quantity of time; that, whenever the brightness of the sun or the position of the stars was obscured by the weather he might form a certain time-measurer by the quantity of psalmody he had accomplished[1062].’
“Some ascribe the invention of our modern clocks to Gerbert, who, in the tenth century, was raised to the pontifical chair at Rome, under the name of Sylvester II., and who was reckoned to be the first mathematician and astronomer of his time[1063]. This opinion however is supported only by mere conjecture, and appears to be false from the account of Dithmar, who says, ‘Gerbert, on being expelled from his country, sought the emperor Otho, and after a long conversation with him, made the time-piece in Magdeburg, constructing it correctly by taking as guide the polar star[1064].’ No mention is made here of wheels or weights, and this horologium seems to have been a sun-dial, which Gerbert fixed up by observing the polar star. It appears, indeed, that Gerbert was acquainted with no other kind of horologia; for those who speak of his book De Astrolabio, in which he explains the method of constructing dials for various latitudes, produce no further proofs[1065]. Some, according to the testimony of Kircher, consider this horologium to have been a portable dial, which showed the hour when properly set by the help of a needle touched with a magnet; but even this opinion is not warranted by the words of Dithmar.
“The anonymous author of the Life of William, abbot of Hirshau[1066], who lived in the eleventh century, and who was a very learned man for his time, says, ‘Naturale horologium ad exemplum cælestis hæmispherii excogitasse.’ Though this passage is so short, that no idea can be formed from it of the construction of the machine, it is evident that it alludes neither to a sun-dial nor to a water-clock, but to some piece of mechanism which pointed out the hours and exhibited the motion of the earth and other planets. As more frequent mention of horologia occurs afterwards, and as, in speaking of them, expressions are used which cannot be applied to sun-dials or water-clocks, I am induced to think that the invention of our clocks belongs to this period. In the Constitutiones Hirsaugienses, or Gengebacenses, of the same William, it is said of the sacristan, ‘eum horologium dirigere et ordinare.’ In the like manner Bernardus Monachus, a writer of the same century, says, in the Ordo Cluniacensis, ‘apocrisiarium horologium dirigere et diligentius temperare.’ The same author, in the Ancient Customs, &c. of the Monastery of St. Victor, at Paris, written also about the same time, says that the registrar (matricularius), the sacrist’s companion, ought ‘horas canonicas nocte et die ad divinum celebrandum custodire, signa pulsare, horologium temperare.’
“The unequal hours then in use rendered this regulating of the horologia necessary. The days and the nights consisted of twelve hours each; but were sometimes shorter and sometimes longer. The reason of this is explained in the sixty-fourth chapter of the before-mentioned Customs, where it is said, ‘From the solstice of summer to the solstice of winter, the time-piece is regulated thus: as much as that space of night which precedes the matins gradually increases according to the increments of the nights through the several months, it, slowly increasing, makes that space in the winter solstice which is before matins to that which follows, twice. On the contrary, from the winter solstice to that of spring it is thus regulated: it decreases that space which it had got in advance according to the decrease of the nights through the several months, until scarcely decreasing, it at length in the summer solstice passes over in the same time that space which is before matins and that which follows[1067].’ Such was the regulating of the horologia, and I much doubt whether it could be applied to water-clocks.
“These horologia not only pointed out the hours by an index, but emitted also a sound. This we learn from Primaria Instituta Canonicorum Præmonstratensium[1068], where it is ordered that the sacristan should regulate the horologium and make it sound before matins to awaken him. I dare not however venture thence to infer, that these machines announced the number of the hour by their sound, as they seem only to have given an alarm at the time of getting up from bed. I have indeed never yet found a passage where it is mentioned that the number of the hour was expressed by them; and when we read of their emitting a sound, we are to understand that it was for the purpose of wakening the sacristan to morning-prayers. The expression ‘horologium cecidit,’ which occurs frequently in the before-quoted writers, I consider as allusive to this sounding of the machine. Du Cange, in my opinion, under the word horologium, conceives wrongly the expression ‘de ponderibus in imum delapsis,’ because the machine was then at rest, and could rouse neither the sacristan nor any one else whose business it was to beat the scilla.
“I shall now produce other testimony which will serve further to confirm what I have here said of the origin of clocks. Calmet, in his Commentary on the Regulæ S. Benedicti, quotes from a book on the usages of the Cistercians, three passages which I shall give as he has translated them, because I have not access at present to the original. ‘We read,’ says he, ‘in chap. 21 of the first part of their Customs, compiled about the year 1120, that the bells will not be sounded for any service, not even for the clock, from the mass of Holy Thursday, to that of Holy Saturday; and in chap. 114, the sacristan is ordered to regulate the clock that it may strike and wake him during winter before matins or before the nocturns; and in chaps. 68 and 114, that when the brethren have risen too early the sacristan give notice to him who reads the last lesson to continue it until the clock strikes, or till signal be made to the reader to leave off[1069].’
“The use of these machines must have been continued from that period, for we find them mentioned in the thirteenth century, in the commentary of Bernardus Cassinensis (Bernard of Cassino) on the unpublished Regulæ S. Benedicti, from the eighth chapter of which Martene gives the following quotation: ‘But the eighth hour being already come, there was sufficient interval,—from the middle of the night, when he who had care of the clock rose to strike it and to light the lamps of the church which might have gone out on account of the length of the night, and to ring the bells in order to wake the sleeping brothers,—that he was able to get through half the eighth hour before the brothers had risen[1070].’ It is said also in the Chronicon Mellicense, in Du Cange, ‘Some one, deputed by the superior who had the care of the striking clock, struck; and also carried light to all the cells[1071].’
“As all arts are at first imperfect, it is observed of these clocks that they sometimes deceived; and hence, in the Ordo Cluniacensis Bernardi Mon., the person who regulated the clock is ordered, in case it should go wrong, ‘ut notet in cereo, et in cursu stellarum vel etiam lunæ, ut fratres surgere faciat ad horam competentem.’ The same admonition is given in the Constitutiones Hirsaugienses.
“From what has been said I think it is sufficiently apparent that clocks moved by wheels and weights began certainly to be used in the monasteries in Europe, about the eleventh century. I do not, however, think that Europe is entitled to the honour of this invention; but that it is rather to be ascribed to the Saracens, to whom we are indebted for most of the mathematical sciences. This conjecture is supported by the horologium, which, as Trithemius tells us, was sent by the sultan of Egypt, in the year 1232, to the emperor Frederic II. ‘In the same year,’ says he, ‘the Saladin of Egypt sent by his ambassadors as a gift to the emperor Frederic a valuable machine of wonderful construction worth more than five thousand ducats. For it appeared to resemble internally a celestial globe in which figures of the sun, moon, and other planets formed with the greatest skill moved, being impelled by weights and wheels, so that performing their course in certain and fixed intervals they pointed out the hour night and day with infallible certainty; also the twelve signs of the zodiac with certain appropriate characters, moved with the firmament, contained within themselves the course of the planets[1072].’
“The writers of this century speak in such a manner of clocks that it appears they must, at that period, have been well-known. Gulielmus Alvernus, disputing against those who deny the existence of the soul, after producing various arguments, thus obviates one which might be used against him. ‘Neither,’ says he, ‘do the motions of those clocks which are moved by water or weights give you uneasiness, both kinds of which move but for a short and moderate time, require frequent repair, the arranging of their parts, and the perfect skill of the astronomer who has a thorough knowledge of his art. But in the bodies of animals and vegetables the motive power is entirely internal, which moderates and regulates the movements of their parts and renders it in all ways perfect[1073].’ And Dante, the Italian poet, says[1074],