pr.1. 1. THE ancestors of the Greeks have appointed such great honours for the famous athletes who are victorious at the Olympian, Pythian, Isthmian, and Nemean games, that they are not only greeted with applause as they stand with palm and crown at the meeting itself, but even on returning to their several states in the triumph of victory, they ride into their cities and to their fathers' houses in four-horse chariots, and enjoy fixed revenues for life at the public expense. When I think of this, I am amazed that the same honours and even greater are not bestowed upon those authors whose boundless services are performed for all time and for all nations. This would have been a practice all the more worth establishing, because in the case of athletes it is merely their own bodily frame that is strengthened by their training, whereas in the case of authors it is the mind, and not only their own but also man's in general, by the doctrines laid down in their books for the acquiring of knowledge and the sharpening of the intellect.
pr.1. Nobilibus athletis, qui Olympia, Pythia, Isthmia, Nemea vicissent, Graecorum maiores ita magnos honores constituerunt, uti non modo in conventu stantes cum palma et corona ferant laudes, sed etiam, cum revertantur in suas civitates cum victoria, triumphantes quadrigis in moenia et in patrias invehantur e reque publica perpetua vita constitutis vectigalibus fruantur. cum ergo id animadvertam, admiror, quid ita non scriptoribus eidem honores etiamque maiores sint tributi, qui infinitas utilitates aevo perpetuo omnibus gentibus praestant. id enim magis erat institui dignum, quod athletae sua corpora exercitationibus efficiunt fortiora, scriptores non solum suos sensus, sed etiam omnium, ⟨cum⟩ libris ad discendum et animos exacuendos praeparant praecepta.
pr.2. 2. What does it signify to mankind that Milo of Croton and other victors of his class were invincible? Nothing, save that in their lifetime they were famous among their countrymen. But the doctrines of Pythagoras, Democritus, Plato, and Aristotle, and the daily life of other learned men, spent in constant industry, yield fresh and rich fruit, not only to their own countrymen, but also to all nations. And they who from their tender years are filled with the plenteous learning which this fruit affords, attain to the highest capacity of knowledge, and can introduce into their states civilized ways, impartial justice, and laws, things without which no state can be sound.
pr.2. Quid enim Milo Crotoniates, quod fuit invictus, prodest hominibus aut ceteri, qui eo genere fuerunt victores, nisi quod, dum vixerunt ipsi, inter suos cives habuerunt nobilitatem. Pythagorae vero praecepta, Democriti, Platonis, Aristotelis ceterorumque sapientium cotidiana perpetuis industriis culta non solum suis civibus, sed etiam omnibus gentibus recentes et floridos edunt fructus. e quibus qui a teneris aetatibus doctrinarum abundantia satiantur, optimos habent sapientiae sensus, instituunt civitatibus humanitatis mores, aequa iura, leges, quibus absentibus nulla potest esse civitas incolumis.
pr.3. 3. Since, therefore, thee great benefits to individuals and to communities are due to the wisdom of authors, I think that not only should palms and crowns be bestowed upon them, but that they should even be granted triumphs, and judged worthy of being consecrated in the dwellings of the gods. Of their many discoveries which have been useful for the development of human life, I will cite a few examples. On reviewing these, people will admit that honours ought of necessity to be bestowed upon them.
pr.3. Cum ergo tanta munera ab scriptorum prudentia privatim publiceque fuerint hominibus praeparata, non solum arbitror palmas et coronas his tribui oportere, sed etiam decerni triumphos et inter deorum sedes eos dedicandos iudicari. Eorum autem cogitata utiliter hominibus ad vitam explicandam e pluribus singula paucorum uti exempla ponam, quae recognoscentes necessario his tribui honores oportere homines confitebuntur.
pr.4. 4. First of all, among the many very useful theorems of Plato, I will cite one as demonstrated by him. Suppose there is a place or a field in the form of a square and we are required to double it. This has to be effected by means of lines correctly drawn, for it will take a kind of calculation not to be made by means of mere multiplication. The following is the demonstration. A square place ten feet long and ten feet wide gives an area of one hundred feet. Now if it is required to double the square, and to make one of two hundred feet, we must ask how long will be the side of that square so as to get from this the two hundred feet corresponding to the doubling of the area. Nobody can find this by means of arithmetic. For if we take fourteen, multiplication will give one hundred and ninety-six feet; if fifteen, two hundred and twenty-five feet.
pr.4. Et primum Platonis e multis ratiocinationibus utilissimis unam, quemadmodum ab eo explicata sit, ponam. locus aut ager paribus lateribus si erit quadratus eumque oportuerit duplicare, quod opus fuerit genere numeri, quod multiplicationibus non invenitur, eo descriptionibus linearum emendatius reperitur. est autem eius rei haec demonstratio. quadratus locus, qui erit longus et latus pedes denos, efficit areae pedes c. si ergo opus fuerit eum duplicare id est pedum CC item e paribus lateribus facere, quaerendum erit, quam magnum latus eius quadrati fiat, ut ex eo CC pedes duplicationibus areae respondeant. id autem numero nemo potest invenire. namque si XIIII constituentur, erunt multiplicati pedes CXCVI, si XV, pedes CCXXV.
pr.5. 5. Therefore, since this is inexplicable by arithmetic, let a diagonal line be drawn from angle to angle of that square of ten feet in length and width, dividing it into two triangles of equal size, each fifty feet in area. Taking this diagonal line as the length, describe another square. Thus we shall have in the larger square four triangles of the same size and the same number of feet as the two of fifty feet each which were formed by the diagonal line in the smaller square. In this way Plato demonstrated the doubling by means of lines, as the figure appended at the bottom of the page will show.
pr.5. Ergo quoniam id non explicatur numero, in eo quadrato, longo et lato pedes X quod fuerit, linea ab angulo ad angulum diagonios perducatur, uti dividantur duo trigona aequa magnitudine, singula areae pedum quinquagenûm, ad eiusque lineae diagonalis longitudinem locus quadratus paribus lateribus describatur. ita quam magna duo trigona in minore quadrato quinquagenûm pedum linea diagonio fuerint designata, eadem magnitudine et eodem pedum numero quattuor in maiore erunt effecta. hac ratione duplicatio grammicis rationibus ab Platone, uti schema subscriptum est in ima pagina, explicata est.
pr.6. 6. Then again, Pythagoras showed that a right angle can be formed without the contrivances of the artisan. Thus, the result which carpenters reach very laboriously, but scarcely to exactness, with their squares, can be demonstrated to perfection from the reasoning and methods of his teaching. If we take three rules, one three feet, the second four feet, and the third five feet in length, and join these rules together with their tips touching each other so as to make a triangular figure, they will form a right angle. Now if a square be described on the length of each one of these rules, the square on the side of three feet in length will have an area of nine feet; of four feet, sixteen; of five, twenty-five.
pr.6. Item Pythagoras normam sine artificis fabricationibus inventam ostendit, et quod magno labore fabri normam facientes vix ad verum perducere possunt, id rationibus et methodis emendatum ex eius praeceptis explicatur. namque si sumantur regulae tres, e quibus una sit pedes III, altera pedes IIII, tertia pedes V, eaeque regulae inter se compositae tangant alia aliam suis cacuminibus extremis schema habentes trigoni, deformabunt normam emendatam. ad eas autem regularum singularum longitudines si singula quadrata paribus lateribus describantur, quod erit trium latus, areae habebit pedes VIIII, quod IIII,XVI, quod V erit,XXV.
pr.7. 7. Thus the area in number of feet made up of the two squares on the sides three and four feet in length is equalled by that of the one square described on the side of five. When Pythagoras discovered this fact, he had no doubt that the Muses had guided him in the discovery, and it is said that he very gratefully offered sacrifice to them. This theorem affords a useful means of measuring many things, and it is particularly serviceable in the building of staircases in buildings, so that the steps may be at the proper levels.
pr.7. Ita quantum areae pedum numerum duo quadrata ex tribus pedibus longitudinis laterum et quattuor efficiunt, aeque tantum numerum reddit id unum ex quinque descriptum. id Pythagoras cum invenisset, non dubitans a Musis se in ea inventione monitum, maximas gratias agens hostias dicitur his immolavisse. ea autem ratio, quemadmodum in multis rebus et mensuris est utilis, etiam in aedificiis scalarum aedificationibus, uti temperatas habeant graduum librationes, est expedita.
pr.8. 8. Suppose the height of the story, from the flooring above to the ground below, to be divided into three parts. Five of these will give the right length for the stringers of the stairway. Let four parts, each equal to one of the three composing the height between the upper story and the ground, be set off from the perpendicular, and there fix the lower ends of the stringers. In this manner the steps and the stairway itself will be properly placed. A figure of this also will be found appended below.
pr.8. Si enim altitudo contignationis ab summa coaxatione ad imum libramentum divisa fuerit in partes tres, erit earum quinque in scalis scaporum iusta longitudine inclinatio. ⟨quare⟩ quam magnae fuerint inter contignationem et imum libramentum altitudinis partes tres, quattuor a perpendiculo recedant et ibi conlocentur inferiores calces scaporum. ita si erunt temperatae, ⟨libratae⟩ et graduum ipsarum scalarum erunt conlocationes. item eius rei erit subscripta forma.
pr.9. 9. In the case of Archimedes, although he made many wonderful discoveries of diverse kinds, yet of them all, the following, which I shall relate, seems to have been the result of a boundless ingenuity. Hiero, after gaining the royal power in Syracuse, resolved, as a consequence of his successful exploits, to place in a certain temple a golden crown which he had vowed to the immortal gods. He contracted for its making at a fixed price, and weighed out a precise amount of gold to the contractor. At the appointed time the latter delivered to the king's satisfaction an exquisitely finished piece of handiwork, and it appeared that in weight the crown corresponded precisely to what the gold had weighed.
pr.9. Archimedis vero cum multa miranda inventa et varia fuerint, ex omnibus etiam infinita sollertia id, quod exponam, videtur esse expressum. nimirum Hiero enim Syracusis auctus regia potestate, rebus bene gestis cum auream coronam votivam diis inmortalibus in quodam fano constituisset ponendam, manupretio locavit faciendam et aurum ad sacomam adpendit redemptori. is ad tempus opus manu factum subtiliter regi adprobavit et ad sacomam pondus coronae visus est praestitisse.
pr.10. 10. But afterwards a charge was made that gold had been abstracted and an equivalent weight of silver had been added in the manufacture of the crown. Hiero, thinking it an outrage that he had been tricked, and yet not knowing how to detect the theft, requested Archimedes to consider the matter. The latter, while the case was still on his mind, happened to go to the bath, and on getting into a tub observed that the more his body sank into it the more water ran out over the tub. As this pointed out the way to explain the case in question, without a moment's delay, and transported with joy, he jumped out of the tub and rushed home naked, crying with a loud voice that he had found what he was seeking; for as he ran he shouted repeatedly in Greek, “Εὕρηκα, εὕρηκα.”
pr.10. Posteaquam indicium est factum dempto auro tantundem argenti in id coronarium opus admixtum esse, indignatus Hiero se contemptum esse neque inveniens, qua ratione id furtum reprehenderet, rogavit Archimeden, uti in se sumeret sibi de eo cogitationem. tunc is, cum haberet eius rei curam, casu venit in balineum, ibique cum in solium descenderet, animadvertit, quantum corporis sui in eo insideret, tantum aquae extra solium effluere. idque cum eius rei rationem explicationis ostendisset, non est moratus, sed exsiluit gaudio motus de solio et nudus vadens domum ⟨uni⟩versis significabat clara voce invenisse, quod quaereret; nam currens identidem graece clamabat εὕρηκα εὕρηκα.
pr.11. 11. Taking this as the beginning of his discovery, it is said that he made two masses of the same weight as the crown, one of gold and the other of silver. After making them, he filled a large vessel with water to the very brim, and dropped the mass of silver into it. As much water ran out as was equal in bulk to that of the silver sunk in the vessel. Then, taking out the mass, he poured back the lost quantity of water, using a pint measure, until it was level with the brim as it had been before. Thus he found the weight of silver corresponding to a definite quantity of water.
pr.11. Tum vero ex eo inventionis ingressu duas fecisse dicitur massas aequo pondere, quo etiam fuerat corona, unam ex auro et alteram ex argento. cum ita fecisset, vas amplum ad summa labra implevit aquae, in quo demisit argenteam massam. cuius quanta magnitudo in vasum depressa est, tantum aquae effluxit. ita exempta massa quanto minus factum fuerat, refudit sextario mensus, ut eodem modo, quo prius fuerat, ad labra aequaretur. ita ex eo invenit, quantum pondus argenti ad certam aquae mensuram responderet.
pr.12. 12. After this experiment, he likewise dropped the mass of gold into the full vessel and, on taking it out and measuring as before, found that not so much water was lost, but a smaller quantity: namely, as much less as a mass of gold lacks in bulk compared to a mass of silver of the same weight. Finally, filling the vessel again and dropping the crown itself into the same quantity of water, he found that more water ran over for the crown than for the mass of gold of the same weight. Hence, reasoning from the fact that more water was lost in the case of the crown than in that of the mass, he detected the mixing of silver with the gold, and made the theft of the contractor perfectly clear.
pr.12. Cum id expertus esset, tum auream massam similiter pleno vaso demisit et ea exempta, eadem ratione mensura addita invenit ex aquae numero sextantum minore, quanto minus magno corpore eodem pondere auri massa esset quam argenti. postea vero repleto vaso in eadem aqua ipsa corona demissa invenit plus aquae defluxisse in corona quam in aurea eodem pondere massa, et ita ex eo, quod fuerat plus aquae in corona quam in massa, ratiocinatus reprehendit argenti in auro mixtionem et manifestum furtum redemptoris.
pr.13. 13. Now let us turn our thoughts to the researches of Archytas of Tarentum and Eratosthenes of Cyrene. They made many discoveries from mathematics which are welcome to men, and so, though they deserve our thanks for other discoveries, they are particularly worthy of admiration for their ideas in that field. For example, each in a different way solved the problem enjoined upon Delos by Apollo in an oracle, the doubling of the number of cubic feet in his altars; this done, he said, he inhabitants of the island would be delivered from an offence against religion.
pr.13. Transferatur mens ad Archytae Tarentini et Eratosthenis Cyrenaei cogitata; hi enim multa et grata a mathematicis rebus hominibus invenerunt. itaque cum in ceteris inventionibus fuerint grati, in eius rei cogitationibus maxime sunt suspecti. alius enim alia ratione explicaverunt, quod Delo imperaverat responsis Apollo, uti arae eius, quantum haberent pedum quadratorum, id duplicarentur, et ita fore uti, qui essent in ea insula, tunc religione liberarentur.
pr.14. 14. Archytas solved it by his figure of the semicylinders; Eratosthenes, by means of the instrument called the mesolabe. Noting all these things with the great delight which learning gives, we cannot but be stirred by these discoveries when we reflect upon the influence of them one by one. I find also much for admiration in the books of Democritus on nature, and in his commentary entitled Χειρόκμητα, in which he made use of his ring to seal with soft wax the principles which he had himself put to the test.
pr.14. Itaque Archytas cylindrorum descriptionibus, Eratosthenes organica mesolabi ratione idem explicaverunt. cum haec sint tam magnis doctrinarum iucunditatibus animadversa et cogamur naturaliter inventionibus singularum rerum considerantes effectus moveri, multas res attendens admiror etiam Democriti de rerum natura volumina et eius commentarium, quod inscribitur Χειροκμήτων, †in quo etiam utebatur anulo signaretur amolcie est expertus.
pr.15. 15. These, then, were men whose researches are an everlasting possession, not only for the improvement of character but also for general utility. The fame of athletes, however, soon declines with their bodily powers. Neither when they are in the flower of their strength, nor afterwards with posterity, can they do for human life what is done by the researches of the learned.
pr.15. Ergo eorum virorum cogitata non solum ad mores corrigendos, sed etiam ad omnium utilitatem perpetuo sunt praeparata, athletarum autem nobilitates brevi spatio cum suis corporibus senescunt. itaque neque cum maxime sunt florentes neque posteritati hi, quemadmodum sapientium cogitata hominum vitae, prodesse possunt.
pr.16. 16. But although honours are not bestowed upon authors for excellence of character and teaching, yet as their minds, naturally looking up to the higher regions of the air, are raised to the sky on the steps of history, it must needs be, that not merely their doctrines, but even their appearance, should be known to posterity through time eternal. Hence, men whose souls are aroused by the delights of literature cannot but carry enshrined in their hearts the likeness of the poet Ennius, as they do those of the gods. Those who are devotedly attached to the poems of Accius seem to have before them not merely his vigorous language but even his very figure.
pr.16. Cum vero neque moribus neque institutis scriptorum praestantibus tribuantur honores, ipsae [autem] per se mentes aeris altiora prospicientes memoriarum gradibus ad caelum elatae aevo inmortali non modo sententias sed etiam figuras eorum posteris cogunt esse notas. itaque, qui litterarum iucunditatibus instinctas habent mentes, non possunt non in suis pectoribus dedicatum habere, sicuti deorum, sic Ennii poetae simulacrum; Accii autem carminibus qui studiose delectantur, non modo verborum virtutes sed etiam figuram eius videntur secum habere praesentem [esse].
pr.17. 17. So, too, numbers born after our time will feel as if they were discussing nature face to face with Lucretius, or the art of rhetoric with Cicero; many of our posterity will confer with Varro on the Latin language; likewise, there will be numerous scholars who, as they weigh many points with the wise among the Greeks, will feel as if they were carrying on private conversations with them. In a word, the opinions of learned authors, though their bodily forms are absent, gain strength as time goes on, and, when taking part in councils and discussions, have greater weight than those of any living men.
pr.17. Item plures post nostram memoriam nascentes cum Lucretio videbuntur velut coram de rerum natura disputare, de arte vero rhetorica cum Cicerone, multi posterorum cum Varrone conferent sermonem de lingua latina, non minus etiam plures philologi cum Graecorum sapientibus multa deliberantes secretos cum his videbuntur habere sermones, et ad summam sapientium scriptorum sententiae corporibus absentibus vetustate florentes cum insunt inter consilia et disputationes, maiores habent, quam praesentium sunt, auctoritates omnes.
pr.18. 18. Such, Caesar, are the authorities on whom I have depended, and applying their views and opinions I have written the present books, in the first seven treating of buildings and in the eighth of water. In this I shall set forth the rules for dialling, showing how they are found through the shadows cast by the gnomon from the sun's rays in the firmament, and on what principles these shadows lengthen and shorten.
pr.18. Itaque, Caesar, his auctoribus fretus sensibus eorum adhibitis et consiliis ea volumina conscripsi, et prioribus septem de aedificiis, octavo de aquis, in hoc de gnomonicis rationibus, quemadmodum de radiis solis in mundo sunt per umbras gnomonis inventae quibusque rationibus dilatentur aut contrahantur, explicabo.
1.1. 1. IT is due to the divine intelligence and is a very great wonder to all who reflect upon it, that the shadow of a gnomon at the equinox is of one length in Athens, of another in Alexandria, of another in Rome, and not the same at Piacenza, or at other places in the world. Hence drawings for dials are very different from one another, corresponding to differences of situation. This is because the length of the shadow at the equinox is used in constructing the figure of the analemma, in accordance with which the hours are marked to conform to the situation and the shadow of the gnomon. The analemma is a basis for calculation deduced from the course of the sun, and found by observation of the shadow as it increases until the winter solstice. By means of this, through architectural principles and the employment of the compasses, we find out the operation of the sun in the universe.
1.1. Ea autem sunt divina mente comparata habentque admirationem magnam considerantibus, quod umbra gnomonis aequinoctialis alia magnitudine est Athenis, alia Alexandriae, alia Romae, non eadem Placentiae ceterisque orbis terrarum locis. itaque longe aliter distant descriptiones horologiorum locorum mutationibus. umbrarum enim aequinoctialium magnitudinibus designantur analemmatorum formae, e quibus perficiuntur ad rationem locorum et umbrae gnomonum horarum descriptiones. ἀνάλημμα est ratio conquisita solis cursu et umbrae crescentis ad brumam observatione inventa, e qua per rationes architectonicas circinique descriptiones est inventus effectus in mundo.
1.2. 2. The word “universe” means the general assemblage of all nature, and it also means the heaven that is made up of the constellations and the courses of the stars. The heaven revolves steadily round earth and sea on the pivots at the ends of its axis. The architect at these points was the power of Nature, and she put the pivots there, to be, as it were, centres, one of them above the earth and sea at the very top of the firmament and even beyond the stars composing the Great Bear, the other on the opposite side under the earth in the regions of the south. Round these pivots (termed in Greek πόλοι) as centres, like those of a turning lathe, she formed the circles in which the heaven passes on its everlasting way. In the midst thereof, the earth and sea naturally occupy the central point.
1.2. Mundus autem est omnium naturae rerum conceptio summa caelumque sideribus et stellarum cursibus conformatum. id volvitur continenter circum terram atque mare per axis cardines extremos. namque in his locis naturalis potestas ita architectata est conlocavitque cardines tamquam centra, unum a terra inmani ⟨spatio⟩ in summo mundo ac post ipsas stellas septentrionum, alterum trans contra sub terra in meridianis partibus, ibique circum eos cardines orbiculos circum centra uti in torno perfecit, qui graece π ́ολοι nominantur, per quos pervolitat sempiterno caelum. ita media terra cum mari centri loco naturaliter est conlocata.
1.3. 3. It follows from this natural arrangement that the central point in the north is high above the earth, while on the south, the region below, it is beneath the earth and consequently hidden by it. Furthermore, across the middle, and obliquely inclined to the south, there is a broad circular belt composed of the twelve signs, whose stars, arranged in twelve equivalent divisions, represent each a shape which nature has depicted. And so with the firmament and the other constellations, they move round the earth and sea in glittering array, completing their orbits according to the spherical shape of the heaven.
1.3. His natura dispositis ita, uti septentrionali parte a terra excelsius habeat altitudinem centrum, in meridiana autem parte in inferioribus locis subiectum a terra obscuretur, tunc etiam per medium transversa et inclinata in meridiem [circuli de] lata zona XII signis est conformata. eorum species stellis dispositis XII partibus peraequatis exprimit depictam ab natura figurationem. itaque lucentia cum mundo reliquisque sideribus ornatu circum terram mareque pervolantia cursus perficiunt ad caeli rotunditatem.
1.4. 4. They are all visible or invisible according to fixed times. While six of the signs are passing along with the heaven above the earth, the other six are moving under the earth and hidden by its shadow. But there are always six of them making their way above the earth; for, corresponding to that part of the last sign which in the course of its revolution has to sink, pass under the earth, and become concealed, an equivalent part of the sign opposite to it is obliged by the law of their common revolution to pass up and, having completed its circuit, to emerge out of the darkness into the light of the open space on the other side. This is because the rising and setting of both are subject to one and the same power and law.
1.4. Omnia autem visitata et invisitata temporum necessitate sunt constituta. ex quis sex signa numero supra terram cum caelo pervagantur, cetera sub terram subeuntia ab eius umbra obscurantur. sex autem ex his semper supra terram nituntur. quanta pars enim novissimi signi depressione coacta versatione subiens sub terram occultatur, tantundem eius contraria e conversationis necessitate suppressa rotatione circumacta trans locis patentibus ex obscuris egreditur ad lucem; namque vis una et necessitas utrimque simul orientem et occidentem perficit.
1.5. 5. While these signs, twelve in number and occupying each one twelfth part of the firmament, steadily revolve from east to west, the moon, Mercury, Venus, the sun, as well as Mars, Jupiter, and Saturn, differing from one another in the magnitude of their orbits as though their courses were at different points in a flight of steps, pass through those signs in just the opposite direction, from west to east in the firmament. The moon makes her circuit of the heaven in twenty-eight days plus about an hour, and with her return to the sign from which she set forth, completes a lunar month.
1.5. Ea autem signa cum sint numero XII partesque duodecumas singula possideant mundi versenturque ab oriente ad occidentem continenter, tunc per ea signa contrario cursu luna, stella Mercurii, Veneris, ipse sol itemque Martis et Iovis et Saturni ut per graduum ascensionem percurrentes alius alia circumitionis magnitudine ab occidente ad orientem in mundo pervagantur. luna die octavo et vicesimo et amplius circiter hora caeli circumitionem percurrens, ex quo signo coeperit ire, ad id signum revertendo perficit lunarem mensem.
1.6. 6. The sun takes a full month to move across the space of one sign, that is, one twelfth of the firmament. Consequently, in twelve months he traverses the spaces of the twelve signs, and, on returning to the sign from which he began, completes the period of a full year. Hence, the circuit made by the moon thirteen times in twelve months, is measured by the sun only once in the same number of months. But Mercury and Venus, their paths wreathing around the sun's rays as their centre, retrograde and delay their movements, and so, from the nature of that circuit, sometimes wait at stopping-places within the spaces of the signs.
1.6. Sol autem signi spatium, quod est duodecuma pars mundi, mense vertente vadens transit; ita XII mensibus XII signorum intervalla pervagando cum redit ad id signum, unde coeperit, perficit spatium vertentis anni. ex eo, quem circulum luna terdecies in XII mensibus percurrit, eum sol eisdem mensibus semel permetitur. Mercurii autem et Veneris stellae circa solis radios uti per centrum eum itineribus coronantes regressus retrorsus et retardationes faciunt, etiam stationibus propter eam circinationem morantur in spatiis signorum.
1.7. 7. This fact may best be recognized from Venus. When she is following the sun, she makes her appearance in the sky after his setting, and is then called the Evening Star, shining most brilliantly. At other times she precedes him, rising before daybreak, and is named the Morning Star. Thus Mercury and Venus sometimes delay in one sign for a good many days, and at others advance pretty rapidly into another sign. They do not spend the same number of days in every sign, but the longer they have previously delayed, the more rapidly they accomplish their journeys after passing into the next sign, and thus they complete their appointed course. Consequently, in spite of their delay in some of the signs, they nevertheless soon reach the proper place in their orbits after freeing themselves from their enforced delay.
1.7. Id autem ita esse maxime cognoscitur ex Veneris stella, quod ea, cum solem sequatur, post occasum eius apparens in caelo clarissimeque lucens vesperugo vocitatur, aliis autem temporibus eum antecurrens et oriens ante lucem lucifer appellatur. ex eoque nonnumquam plures dies in ⟨uno⟩ signo commorantur, alias celerius ingrediuntur in alterum signum. itaque quod non aeque peragunt numerum dierum in singulis signis, quantum sunt moratae prius, transiliendo celerioribus itineribus perficiunt iustum cursum. ita efficitur, uti, quod demorentur in nonnullis signis, nihilominus, cum eripiant se ab necessitate morae, celeriter consequantur iustam circumitionem.
1.8. 8. Mercury, on his journey through the heavens, passes through the spaces of the signs in three hundred and sixty days, and so arrives at the sign from which he set out on his course at the beginning of his revolution. His average rate of movement is such that he has about thirty days in each sign.
1.8. Iter autem in mundo Mercurii stella ita pervolitat, uti trecentesimo et sexagensimo die per signorum spatia currens perveniat ad id signum, ex quo priore circumlatione coepit facere cursum, et ita peraequatur eius iter, ut circiter tricenos dies in singulis signis habeat numeri rationem.
1.9. 9. Venus, on becoming free from the hindrance of the sun's rays, crosses the space of a sign in thirty days. Though she thus stays less than forty days in particular signs, she makes good the required amount by delaying in one sign when she comes to a pause. Therefore she completes her total revolution in heaven in four hundred and eighty-five days, and once more enters the sign from which she previously began to move.
1.9. Veneris autem, cum est liberata ab inpeditione radiorum solis,XXX diebus percurrit signi spatium. quod minus quadragenos dies in singulis signis patitur, cum stationem fecerit, restituit eam summam numeri in uno signo morata. ergo totam circinationem in caelo quadringentesimo et octogensimo et quinto die permensa iterum init signum, ex quo signo prius iter facere coepit.
1.10. 10. Mars, after traversing the spaces of the constellations for about six hundred and eighty-three days, arrives at the point from which he had before set out at the beginning of his course, and while he passes through some of the signs more rapidly than others, he makes up the required number of days whenever he comes to a pause. Jupiter, climbing with gentler pace against the revolution of the firmament, travels through each sign in about three hundred and sixty days, and finishes in eleven years and three hundred and thirteen days, returning to the sign in which he had been twelve years before. Saturn, traversing the space of one sign in twenty-nine months plus a few days, is restored after twenty-nine years and about one hundred and sixty days to that in which he had been thirty years before. He is, as it appears, slower, because the nearer he is to the outermost part of the firmament, the greater is the orbit through which he has to pass.
1.10. Martis vero circiter sexcentesimo octogensimo tertio siderum spatia pervagando pervenit eo, ex quo initium faciendo cursum fecerat ante, et in quibus signis celerius percurrit, cum stationem fecit, explet dierum numeri rationem. Iovis autem placidioribus gradibus scandens contra mundi versationem, circiter CCCLX diebus singula signa permetitur, et consistit post annum XI et dies CCCXIII et redit in id signum, in quo ante XII annos fuerat. Saturni vero, mensibus undetriginta et amplius paucis diebus pervadens per signi spatium, anno nono et vicensimo et circiter diebus CLX, in quo ante tricensimo fuerat anno, in id restituitur, ex eoque, quo minus ab extremo distat mundo, tanto maiorem circinationem rotae percurrendo tardior videtur esse.
1.11. 11. The three that complete their circuits above the sun's course do not make progress while they are in the triangle which he has entered, but retrograde and pause until the sun has crossed from that triangle into another sign. Some hold that this takes place because, as they say, when the sun is a great distance off, the paths on which these stars wander are without light on account of that distance, and so the darkness retards and hinders them. But I do not think that this is so. The splendour of the sun is clearly to be seen, and manifest without any kind of obscurity, throughout the whole firmament, so that those very retrograde movements and pauses of the stars are visible even to us.
1.11. Ei autem, qui supra solis iter circinationes peragunt, maxime cum in trigono fuerint, quod is inierit, tum non progrediuntur, sed regressus facientes morantur, doneque [cum idem] sol de eo trigono in aliud signum transitionem fecerit. id autem nonnullis sic fieri placet, quod aiunt solem, cum longius absit abstantia quadam, non lucidis itineribus errantia per ea sidera obscuritatis morationibus inpedire. nobis vero id non videtur. solis enim splendor perspicibilis et patens sine ullis obscurationibus est per omnem mundum, ut etiam nobis appareant, cum faciant eae stellae regressus et morationes. ergo si tantis intervallis nostra species potest id animadvertere, quid ita divinitatibus splendoribusque astrorum iudicamus obscuritates obici posse?
1.12. 12. If then, at this great distance, our human vision can discern that sight, why, pray, are we to think that the divine splendour of the stars can be cast into darkness? Rather will the following way of accounting for it prove to be correct. Heat summons and attracts everything towards itself; for instance, we see the fruits of the earth growing up high under the influence of heat, and that spring water is vapourised and drawn up to the clouds at sunrise. On the same principle, the mighty influence of the sun, with his rays diverging in the form of a triangle, attracts the stars which follow him, and, as it were, curbs and restrains those that precede, not allowing them to make progress, but obliging them to retrograde towards himself until he passes out into the sign that belongs to a different triangle.
1.12. Ergo potius ea ratio nobis constabit, quod, fervor quemadmodum omnes res evocat et ad se ducit, ut etiam fructus e terra surgentes in altitudinem per calorem videmus, non minus aquae vapores a fontibus ad nubes per arcus excitari, eadem ratione solis impetus vehemens radiis trigoni forma porrectis insequentes stellas ad se perducit et ante currentes veluti refrenando retinendoque non patitur progredi, sed ad se regredi in alterius trigoni signum [esse].
1.13. 13. Perhaps the question will be raised, why the sun by his great heat causes these detentions in the fifth sign from himself rather than in the second or third, which are nearer. I will therefore set forth what seems to be the reason. His rays diverge through the firmament in straight lines as though forming an equilateral triangle, that is, to the fifth sign from the sun, no more, no less. If his rays were diffused in circuits spreading all over the firmament, instead of in straight lines diverging so as to form a triangle, they would burn up all the nearer objects. This is a fact which the Greek poet Euripides seems to have remarked; for he says that places at a greater distance from the sun are in a violent heat, and that those which are nearer he keeps temperate. Thus in the play of Phaethon, the poet writes: καίει τὰ πόρρω τἄγγυθεν δ' εὔκρατ' ἔχει.
1.13. Fortasse desiderabitur, quid ita sol quinto a se signo potius quam secundo aut tertio, quae sunt propiora, facit in his fervoribus retentiones. ergo, quemadmodum id fieri videatur, exponam. eius radii in mundo uti trigoni paribus lateribus formae lineationibus extenduntur. id autem nec plus nec minus est ad quintum ab eo signo. igitur si radii per omnem mundum fusi circinationibus vagarentur neque extentionibus porrecti ad trigoni formam linearentur, propiora flagrarent. id autem etiam Euripides, Graecorum poeta, animadvertisse videtur. ait enim, quae longius a sole essent, haec vehementius ardere, propiora vero eum temperata habere. itaque scribit in fabula Phaethonte sic: καίει τὰ πόρρω, τἄγγυθεν δ' εὔκρατ' ἔχει.
1.14. 14. If then, fact and reason and the evidence of an ancient poet point to this explanation, I do not see why we should decide otherwise than as I have written above on this subject. Jupiter, whose orbit is between those of Mars and Saturn, traverses a longer course than Mars, and a shorter than Saturn. Likewise with the rest of these stars: the farther they are from the outermost limits of the heaven, and the nearer their orbits to the earth, the sooner they are seen to finish their courses; for those of them that have a smaller orbit often pass those that are higher, going under them.
1.14. Si ergo res et ratio et testimonium poetae veteris id ostendit, non puto aliter oportere iudicari, nisi quemadmodum de ea re supra scriptum habemus. Iovis autem inter Martis et Saturni circinationem currens maiorem quam Mars, minorem quam Saturnus pervolat cursum. item reliquae stellae, quo maiore absunt spatio ab extremo caelo proxumamque habent terrae circinationem, celerius ⟨pervagari⟩ videntur, quod quaecumque earum minorem circinationem peragens saepius subiens praeterit superiorem.
1.15. 15. For example, place seven ants on a wheel such as potters use, having made seven channels on the wheel about the centre, increasing successively in circumference; and suppose those ants obliged to make a circuit in these channels while the wheel is turned in the opposite direction. In spite of having to move in a direction contrary to that of the wheel, the ants must necessarily complete their journeys in the opposite direction, and that ant which is nearest the centre must finish its circuit sooner, while the ant that is going round at the outer edge of the disc of the wheel must, on account of the size of its circuit, be much slower in completing its course, even though it is moving just as quickly as the other. In the same way, these stars, which struggle on against the course of the firmament, are accomplishing an orbit on paths of their own; but, owing to the revolution of the heaven, they are swept back as it goes round every day.
1.15. Quemadmodum, si in rota, qua figuli utuntur, inpositae fuerint septem formicae canalesque totidem in rota facti sint circum centrum imo adcrescentes ad extremum, in quibus hae cogantur circinationem facere, verseturque rota in alteram partem, necesse erit eas contra rotae versationem nihilominus adversus itinera perficere, et quae proximum centrum habuerit, celerius pervagari, quaeque extremum orbem rotae peragat, etiamsi aeque celeriter ambulet, propter magnitudinem circinationis multo tardius perficere cursum: similiter astra nitentia contra mundi cursum suis itineribus perficiunt circumitum, sed caeli versatione redundationibus referuntur cotidiana temporis circumlatione.
1.16. 16. The reason why some of these stars are temperate, others hot, and others cold, appears to be this: that the flame of every kind of fire rises to higher places. Consequently, the burning rays of the sun make the ether above him white hot, in the regions of the course of Mars, and so the heat of the sun makes him hot. Saturn, on the contrary, being nearest to the outermost limit of the firmament and bordering on the quarters of the heaven which are frozen, is excessively cold. Hence, Jupiter, whose course is between the orbits of these two, appears to have a moderate and very temperate influence, intermediate between their cold and heat. I have now described, as I have received them from my teacher, the belt of the twelve signs and the seven stars that work and move in the opposite direction, with the laws and numerical relations under which they pass from sign to sign, and how they complete their orbits. I shall next speak of the waxing and waning of the moon, according to the accounts of my predecessors.
1.16. Esse autem alias stellas temperatas, alias ferventes, etiamque frigidas haec esse causa videtur, quod omnis ignis in superiora loca habet scandentem flammam. ergo sol aethera, qui est supra se, radiis exurens efficit candentem, in quibus locis habet cursum Martis stella; itaque fervens ab ardore solis efficitur. Saturni autem, quod est proxima extremo mundo tangit⟨que⟩ congelatas caeli regiones, vehementer est frigida. ex eo Iovis, cum inter utriusque circumitiones habeat cursum, a refrigeratione caloreque earum medio convenientes temperatissimosque habere videtur effectus. De zona XII signorum et septem astrorum contrario opere ac cursu, quibus rationibus et numeris transeunt e signis in signa, et circumitum eorum, uti a praeceptoribus accepi, exposui; nunc de crescenti lumine lunae deminutioneque, uti traditum est nobis a maioribus, dicam.
2.1. 1. ACCORDING to the teaching of Berosus, who came from the state, or rather nation, of the Chaldees, and was the pioneer of Chaldean learning in Asia, the moon is a ball, one half luminous and the rest of a blue colour. When, in the course of her orbit, she has passed below the disc of the sun, she is attracted by his rays and great heat, and turns thither her luminous side, on account of the sympathy between light and light. Being thus summoned by the sun's disc and facing upward, her lower half, as it is not luminous, is invisible on account of its likeness to the air. When she is perpendicular to the sun's rays, all her light is confined to her upper surface, and she is then called the new moon.
2.1. Berosus, qui ab Chaldaeorum civitate sive natione progressus in Asia etiam disciplinam Chaldaicam patefecit, ita est professus: pilam esse ex dimidia parte candentem, reliqua habere caeruleo colore. cum autem cursum itineris sui peragens subierit sub orbem solis, tunc eam radiis et impetu caloris corripi convertique candentem propter eius proprietatem luminis ad lumen. cum autem ea vocata ab solis orbi superiora spectent, tunc inferiorem partem eius, quod candens non sit, propter aeris similitudinem obscuram videri. cum ad perpendiculum ea sit ad eius radios, totum lumen ad superiorem speciem retineri, et tunc eam vocari primam.
2.2. 2. As she moves on, passing by to the east, the effect of the sun upon her relaxes, and the outer edge of the luminous side sheds its light upon the earth in an exceedingly thin line. This is called the second day of the moon. Day by day she is further relieved and turns, and thus are numbered the third, fourth, and following days. On the seventh day, the sun being in the west and the moon in the middle of the firmament between the east and west, she is half the extent of the firmament distant from the sun, and therefore half of the luminous side is turned toward the earth. But when the sun and moon are separated by the entire extent of the firmament, and the moon is in the east with the sun over against her in the west, she is completely relieved by her still greater distance from his rays, and so, on the fourteenth day, she is at the full, and her entire disc emits its light. On the succeeding days, up to the end of the month, she wanes daily as she turns in her course, being recalled by the sun until she comes under his disc and rays, thus completing the count of the days of the month.
2.2. Cum praeteriens vadat ad orientis caeli partes, relaxari ab impetu solis extremamque eius partem candentiae oppido quam tenui linea ad terram mittere splendorem, et ita ex eo eam secundam vocari. cotidiana autem versationis remissione tertiam, quartam in dies numerari. septimo die, ⟨cum⟩ sol sit ad occidentem, luna autem inter orientem et occidentem medias caeli teneat regiones, quod dimidia parte caeli spatio distet a sole, item dimidiam candentiae conversam habere ad terram. inter solem vero et lunam cum distet totum mundi spatium et lunae orienti sol trans contra sit ad occidentem, eam, quo longius absit, a radiis remissam XIIII die plena rota totius orbis mittere splendorem, reliquosque dies decrescentia cotidiana ad perfectionem lunaris mensis versationibus et cursu a sole revocationibus subire sub rotam radiosque eius, et ita menstruas dierum efficere rationes.
2.3. 3. But Aristarchus of Samos, a mathematician of great powers, has left a different explanation in his teaching on this subject, as I shall now set forth. It is no secret that the moon has no light of her own, but is, as it were, a mirror, receiving brightness from the influence of the sun. Of all the seven stars, the moon traverses the shortest orbit, and her course is nearest to the earth. Hence in every month, on the day before she gets past the sun, she is under his disc and rays, and is consequently hidden and invisible. When she is thus in conjunction with the sun, she is called the new moon. On the next day, reckoned as her second, she gets past the sun and shows the thin edge of her sphere. Three days away from the sun, she waxes and grows brighter. Removing further every day till she reaches the seventh, when her distance from the sun at his setting is about one half the extent of the firmament, one half of her is luminous: that is, the half which faces toward the sun is lighted up by him.
2.3. Uti autem Aristarchus Samius mathematicus vigore magno rationes varietatis disciplinis de eadem ⟨re⟩ reliquit, exponam. non enim latet lunam ⟨non⟩ suum propriumque habere lumen, sed esse uti speculum et ab solis impetu recipere splendorem. namque luna de septem astris circulum proximum terrae in cursibus minimum pervagatur. ita quot mensibus sub rotam solis radiosque uno die, antequam praeterit, latens obscuratur. cum est cum sole, nova vocatur. postero autem die, quo numeratur secunda, praeteriens ab sole visitationem facit tenuem extremae rotundationis. cum triduum recessit ab sole, crescit et plus inluminatur. cotidie vero discedens cum pervenit ad diem septimum, distans a sole occidente circiter medias caeli regiones, dimidia lucet, et eius quae ad solem pars spectat, ea est inluminata.
2.4. 4. On the fourteenth day, being diametrically across the whole extent of the firmament from the sun, she is at her full and rises when the sun is setting. For, as she takes her place over against him and distant the whole extent of the firmament, she thus receives the light from the sun throughout her entire orb. On the seventeenth day, at sunrise, she is inclining to the west. On the twenty-second day, after sunrise, the moon is about mid-heaven; hence, the side exposed to the sun is bright and the rest dark. Continuing thus her daily course, she passes under the rays of the sun on about the twenty-eighth day, and so completes the account of the month. I will next explain how the sun, passing through a different sign each month, causes the days and hours to increase and diminish in length.
2.4. Quarto autem decumo die, cum in diametro spatio totius mundi absit ab sole, perficitur plena et oritur, cum sol sit ad occidentem, ideo quod totum spatium mundi distans consistit contra et impetu solis totius orbis in se recipit splendorem. septumo decumo die cum sol oriatur, ea pressa est ad occidentem. vicensimo et altero die cum sol est exortus, luna tenet circiter caeli medias regiones, et id quod spectat ad solem, id habet lucidum reliquis obscura. item cotidie cursum faciendo circiter octavo et vicensimo die subit sub radios solis, et ita menstruas perficit rationes. Nunc, ut in singulis mensibus sol signa pervadens auget et minuit dierum et horarum spatia, dicam.