Vitruvio - De Architectura - Book VIII


1. Thales, the Milesian, one of the seven wise men, taught that water was the original cause of all things. Heraclitus maintained the same of fire: the priests of the magi, of water and fire. Euripides, a disciple of Anaxagoras, called by the Athenians the dramatic philosopher, attributed it to air and earth; and contended that the latter, impregnated by the seed contained in the rain falling from the heavens, had generated mankind and all the animals on the earth; and that all these, when destroyed by time, returned to their origin. Thus, such as spring from the air, also return into air, and not being capable of decay, are only changed by their dissolution, returning to that element whereof they first consisted. But Pythagoras, Empedocles, Epicharmus, and other physiologists, and philosophers, maintained that there were four elements, air, fire, water, and earth; and that their mixture, according to the difference of the species, forms a natural mould of different qualities. 

2. We must recollect, that not only from these elements, are all things generated, but that they can neither be nourished, nor grow without their assistance. Thus bodies cannot live without abundance of air; that is, without its being furnished for inspiration and respiration in considerable quantity. So, also, if a body do not possess a due proportion of heat, it can neither be endued with animal spirits nor a strong constitution, nor will the hardness of its food be duly attenuated: and if the members of the body are not nourished by the fruits of the earth, they will waste, because deprived of the mixture of that element with them. 

3. Lastly, animals deprived of moisture, from want of water dry up, and are bloodless and parched. Divine Providence as made those things neither scarce nor dear which are necessary for mankind, as are pearls, gold, silver, and the like, which are neither necessary for the body nor nature; but has diffused abundantly, throughout the world, those things, without which the life of mortals would be uncertain. Thus, if a body be deficient in spirit, the deficiency is supplied by the air. The power of the sun, and the discovery of fire, are always ready to assist us, and render life more certain. The fruits of the earth also, furnishing nourishment even to excess, feed and support animals continually. Water is of infinite utility to us, not only as affording drink, but for a great number of purposes in life; and it is furnished to us gratuitously. 

4. Hence the priests of the Egyptian worship teach, that all things are composed of water; and when they cover the vase with water, which is borne to the temple with the most solemn reverence, kneeling on the earth, with their hands raised to heaven, they return thanks to divine goodness for its creation. 

Chapter 1 

1. As it is the opinion of physiologists, philosophers and priests that all things proceed from water, I thought it necessary, as in the preceding seven books rules are laid down for buildings, to describe in this the method of finding water, its different properties, according to the varied nature of places, how it ought to be conducted, and in what manner it should be judged of; inasmuch as it is of infinite importance, for the purposes of life, for pleasure, and for our daily use. This will be easily accomplished if the springs are open and flowing above ground. If that be not the case, their sources under ground are to be traced and examined. In order to discover these, before sunrise one must lie down prostrate in the spot where he seeks to find it, and with his chin placed on the ground and fixed, look around the place; for the chin being fixed, the eye cannot range upwards farther than it ought, and is confined to the level of the place. Then, where the vapours are seen curling together and rising into the air, there dig, because these appearances are not discovered in dry places. [A plowed field of brown earth with thick fumes rising from it.] 

2. We should also consider the nature of the place when we search for water. In clay, the vein of water is small, the supply little, and not of the best flavour; and if in low places, it will be muddy and ill tasted. In black earth, only tricklings and small drops are found, which, collected from the winter rain, subside in compact hard places, and are of very excellent flavour. In gravel, the veins are small and variable, but they are exceeding well flavoured. In the strong, common and red sands, the supply is to be depended on with more certainty, and is of good taste. In red stone, abundance and that of good quality may be obtained, if it do not filter away and escape through the pores. At the feet of mountains, and about flinty rocks the supply is copious and abundant; it is there cold and more wholesome. In champaign countries, the springs are salt, gross, tepid, and unpleasant, except those, which percolating from the mountains beneath the surface, issue forth in the plains, where, especially when shadowed by trees, they are as delicious as those of the mountains themselves. 

3. Besides the above signs for ascertaining in what places water may be found, are the following: when a place abounds with the slender bulrush, the wild willow, the alder, the withy, reeds, ivy, and other plants of a similar sort, which neither spring up nor flourish without moisture. For these plants usually grow about lakes, which, being lower than the other parts of a country, receive both the rain water and that of the district, through the winter, and, from their size, preserve the moisture for a longer period. On these, however, we must not rely. But in those districts and lands, no lakes being near, where the plants in question grow spontaneously, there we may search.4. In places where these signs do not appear, the following plan must be adopted. Dig a hole three feet square, and at least five feet deep, and in it, about sunset, place a brazen or leaden basin, or larger vessel, if one be at hand. It must be rubbed over with oil inside and inverted, and the upper part of the excavation is to be covered with reeds or leaves; on these the earth is to be thrown. On the following day let it be opened, and if the inside of the vase be covered with damp and drops of water, water will be there found. 

5. If the vase placed in the pit be of unburnt clay, having been covered as above directed, when uncovered it will be damp, and perhaps destroyed by the moisture. A fleece of wool being placed in the same pit, if, on the following day, water can be expressed from it, the existence of water in the place is indicated, and that in abundance. Also, if a trimmed lamp full of oil be lighted, and placed in the covered pit, and on the following day it be not exhausted, but still retain unconsumed some of the wick and oil, and present a humid appearance, it shows that water will be found there, inasmuch as heat invariably draws the moisture towards it. Moreover, if in such place a fire be made on the ground, and the ground, when heated, throw out cloudy vapours, water will be found in it. 

6. These experiments having been made, and the requisite indications being manifest, a well is to be sunk on the spot; and if the head of the spring be found, many other wells are to be dug round about it, and, by means of under-cuttings, connected with it so as to concentrate them. The spring-heads, however, are chiefly to be sought in mountains and northern districts, because, in those situations, they are generally sweeter, more wholesome, and more copious, on account of their being sheltered from the rays of the sun, of the trees and shrubs in those places being in greater abundance, and of the sun’s rays coming obliquely on them, so that the moisture is not carried off. 

7. Valleys in the midst of mountains receive a very large proportion of rain, and from the closeness of their woods, as well as from the shade which the trees afford, added to the snow, which so long remains on them, allow it to percolate through their strata, and thus arrive at the foot of the mountain, when, issuing forth, it becomes the source of a river. On the contrary, in a champaign country, much water will probably not be found; or if it should, it will not be wholesome, because the great power of the sun, unobstructed by shade, attracts and carries off all humidity from the plains; and were even the water to appear, the air would attract and dissipate the lightest, subtlest, and wholesomest parts, and leave the heaviest, most unpleasant, and most unwholesome in the spring. 

Chapter 2 

1. Water collected from showers possesses wholesome qualities, because it consists of the lightest and most subtle particles of all springs, which, cleansed by the action of the air, and loosened by the tempests, descend upon the earth: and the reason why showers do not fall so often upon plains as they do on mountains or their vicinity is, because the vapours ascending from the earth at sunrise, to whatever part of the heavens they incline, drive the air before them, and, being in motion, receive an impetus from the air which rushes after them. 

2. The air rushing on, and driving in every direction the vapour before it, creates gales, and blasts, and eddies of wind. Hence the winds, wherever they travel, extract from springs, rivers, marshes, and from the sea, when heated by the sun, condensed vapours, which rise and form clouds. These, borne up by the winds when they come against the sides of mountains, from the shock they sustain, as well as from storms, swell, and, becoming heavy, break and disperse themselves on the earth.3. The vapours, clouds, and exhalations which rise from the earth, seem to depend on its retention of intense heat, great winds, cold moisture, and its large proportion of water. Thus when, from the coolness of the night, assisted by the darkness, winds arise, and clouds are formed from damp places, the sun, at its rising, striking on the earth with great power, and thereby heating the air, raises the vapours and the dew at the same time. 

4. A corroboration of this may be seen in a hot bath; for it is absurd to suppose that there can be a spring above its ceiling; and yet that, when warmed by the heated air from the furnace, attracts the moisture from the pavement, whence it is carried up to the vaulting of the ceiling, where it hangs. For hot vapours always ascend, and at first, from their lightness, do not fall down, but as soon as condensed, their gravity prevents buoyancy, and they drop on the heads of the bathers. In the same manner the atmospheric air, when warmed by the sun, raises the moisture from all places, and gathers it to the clouds: for the earth acted upon by heat, drives out its moisture, as heat drives out perspiration from the human body. 

5. This is manifest from the winds, among which, those that blow from the coldest quarters, as the north, and the north-east, bring dry and pure air, but the south and other winds, which blow from the direction of the sun’s course, are very damp, and always bring showers with them, because they reach us heated by the torrid regions, and imbibing vapours from the countries they pass over, transport them to the northern quarters. 

6. That this is the case, is evident from an inspection of the sources of rivers, as marked in geographical charts; as also from the descriptions of them, wherein we find that the largest, and greatest number are from the north. First, in India, the Ganges and Indus spring from Mount Caucasus: in Syria, the Tigris and Euphrates: in Asia, and especially in Pontus, the Borysthenes, Hypanis and Tanaïsame: in Colchis, the Phasis: in France, the Rhô ne: in Belgium, the Rhine: southward of the Alps, the Timavus and Po: in Italy, the Tiber: in Maurusia, which we call Mauritania, the river Dyris, from Mount Atlas, which, rising in a northern region, proceeds westward to the lake Heptabolus, where, changing its name, it is called the Niger, and thence from the lake Heptabolus, flowing under barren mountains, it passes in a southern direction, and falls into the marsh Coloe, which encircles Meroe, a kingdom of the southern Ethiopians. From this marsh turning round near the rivers Astasoba, Astabora, and many others, it passes through mountains to the Cataract, and falling down towards the north it passes between Elephantis and Syene and the Thebaic Fields in Egypt, where it receives the appellation of the Nile. 

7. That the source of the Nile is in Mauritania, is certain, because on the other side of the Mount Atlas are other springs whose course is towards the western ocean, in which are found the ichneumon, the crocodile, and other animals and fishes of a similar nature, the hippopotamus excepted. 

8. Since, therefore, all the large known rivers in the world seem to flow from the north, and towards the land of Africa, because those are in the southern regions under the sun’s course, where there is little moisture, and but few springs and rivers, it follows that those sources which are in the north and north-east, are much better than others, unless they run over a sulphureous, aluminous, or bituminous soil, for their quality is thereby changed, and whether hot or cold, their water is then of bad smell and taste. It is not that water, by its nature, is hot, but when cold, it is heated by running over a hot soil, and issues warm from the earth through the different pores: it does not, however, long remain in that state, but soon becomes cold; whereas, if it were naturally hot, it would not so soon grow cool; for it does not lose its taste, smell, and colour, which, from the purity of its nature, remain unchanged and discoloured.

Chapter 3 

1. There are some hot springs from which water of an excellent flavour is procured, so pleasant to the taste, that it is inferior neither to that of the fountains of the Camenæ nor of the Martian aqueduct. These are naturally so, on the following account. When fire is generated under ground, and the soil is heated all round, either from abundance of alum, bitumen, or sulphur, the hot vapour ascends to the upper parts, and, if there are therein springs of sweet water affected by its spreading through the pores, they grow hot, without injury to the flavour. 

2. There are also cold springs whose smell and taste are bad. These arise in the lower subterranean places, then pass through hot districts, and afterwards continuing their course for a considerable distance, are cold when they rise to the surface, and of a vitiated taste, smell, and colour. Such is the river Albula, in the Tiburtine way: such are the cold fountains in the lands of Ardea, both of a similar smell, which is like sulphur: such, also, are found in other places. But these, though cold, seem, nevertheless, to boil: for, falling from a high place on to a heated soil, and acted on by the meeting of the water and fire, they rush together with great violence and noise; and, apparently inflated by the violence of the compressed air, they issue boiling from the spring. Among them, however, those whose course is not open, but obstructed by stones or other impediments, are, by the force of the air through the narrow pores driven up to the tops of hills. 

3. Hence, those who think they have found springs at such a height as the tops of hills, are mistaken when they dig their wells. For as a brazen vase, not filled to the brim, but about two- thirds full of water, with a cover thereon, when subjected to the great heat of a fire communicates that heat to the water, this, from its natural porosity, receiving the heat and swelling out, not only fills the vase, but, raising the cover by the force of the steam, increases and boils over. If the cover be taken away, the steam passes off to the open air, and the water subsides. In the same manner, when springs are forced through narrow channels, the pressure of the air drives the bubbles of the water to the top; but as soon as they come into wide open channels, the pores of the liquid having vent, it subsides and returns to its natural level. 

4. All hot springs are, therefore, medicinal; because boiling in the soils through which they pass, they acquire many virtues. Thus sulphureous waters restore, by their heat, those suffering under nervous complaints, by warming and extracting the vitious humours of the body. If any member of the body, either from paralysis or other malady, become useless, aluminous waters warm it, and introducing, through the open pores, the opposing power of heat, restore it, and thus it immediately regains its former strength. Bituminous waters, taken inwardly, act as purgatives, and are excellent for the cure of inward complaints. 

5. There is a species of cold nitrous spring like that at Pinna a city of the Vestini, at Cutilium, and other similar places, which, when taken, purges, and in its passage through the bowels, diminishes schrophulous tumours. In those places where gold, silver, iron, brass, lead, and other similar substances, are excavated, very copious springs are found. These, however, are very pernicious. Indeed they produce effects contrary to those of the hot springs which emit sulphur, alum, and bitumen: for when taken inwardly, passing through the intestines, they affect the nerves and joints, and produce hard swellings on them. Hence the nerves are contracted by the swelling, in the direction of their length, and thus induce the cramp or the gout, because the vessels become saturated with gross hard particles. 

6. But there is a species of water, which, when not clear, has a foam, like a flower, swimming on its surface, of a colour similar to that of purple glass. It is known at Athens more particularly, and, from the places and springs in which it is found, it is conducted to the city and to the Piræus; but, on the account of the cause above-mentioned, no one drinks it, though it is in use for washing and other purposes. They, therefore, to avoid its ill effects, drink the well water. The Troezenians are not able to escape this evil; for they have no other sort of water, except that of Cybdelus. Hence, in their city, all or at least the greatest part, of the inhabitants are affected with diseases in the feet. At Tarsus, a city of Cilicia, there is a river whose name is Cydnus, in which, if gouty persons steep their feet, they receive relief from it. 

7. There are, moreover, many other sorts of water, which have particular properties, as the Himera, in Sicily, which, when it departs from its source, is divided into two branches. That branch which flows towards Ætna, passing through a country of sweet humidity, is exceedingly soft; the other, its course being through land where salt is dug, has a salt taste. At Parætonium, also, and on the road to the temple of Ammon, and at Casium in Ægypt, there are marshy lakes containing so much salt, that it congeals on them. In many other places the springs, rivers and lakes, which run near salt-pits, are therefrom rendered salt. 

8. Others, running over veins of fat earth, issue forth impregnated with oil: as at Soloe, a city of Cilicia, a river called Liparis, in which those that swim or wash, are, as it were, anointed by the water. In Ethiopia, also, there is a lake which anoints those that swim therein; and in India there is another, which, when the sky is clear, emits a great quantity of oil. At Carthage there is a spring, on the surface of which swims an oil of the smell of cedar dust, with which they anoint cattle. In the island of Zacynthus, and about Dyrrachium and Apollonia, are springs which throw up a great quantity of pitch with the water. The vast lake at Babylon, called the Asphaltic pool, contains floating bitumen, with which, and with bricks of baked earth, Semiramis built the wall round Babylon. At Joppa, also, in Syria, and in Numidian Arabia, are lakes of immense size, yielding large masses of bitumen, which are taken away by the inhabitants of the neighbourhood. 

9. This is not, however, surprising; for in that spot there are many quarries of hard bitumen: hence, when the water bursts out from this bituminous earth, it carries it therewith; and having come forth, the bitumen is separated from it and deposited. In Cappadocia, on the road between Mazaca and Tuana, there is a considerable lake, in which, if a piece of reed or any other substance be cast, and taken out on the following day, it will be found to have been turned into stone; but the part out of water will not have changed its quality. 

10. In the same manner, at Hierapolis, in Phrygia, a large head of hot water boils up, and is conducted by ditches round the gardens and vineyards. At the end of a year the ditches become incrusted with stone; and hence, making yearly cuts to the right and left, they carry off the incrustations, and use them for building field walls. This circumstance, as it appears to me, would naturally happen, if, in these spots, and in the land about, there be a juice or moisture whose nature is similar to that of rennet. For then, when this coagulating power issues forth from the earth, through the springs, congelation takes placed by the heat of the sun and air, as is seen in salt-pits. 

11. Some springs are exceedingly bitter, from the bitterness of the juices of the earth; as the river Hypanis in Pontus, which, for the first forty miles from its source, is of very sweet flavour; but at a spot one hundred and sixty miles from its mouth, a very small spring falls into it, after which the whole body of the river becomes bitter; and this because the water flows through that sort of earth and veins from whence red lead is procured. 

12. These different flavours are dependent on the quality of the earth, as in the case of fruits. For if the roots of trees, of vines, or of other plants, did not produce fruit according to the quality of the earth and the nature of the moisture, the same sort of fruit would, in all places and countries, possess the same flavour. Whereas we see, that, in the island of Lesbos the Protyran wine is made, in Mæonia the katakekaumenivth (Catakecaumenitan), in Lydia the Melitan, in Sicily the Mamertine, in Campania the Falernian, at Terracina and Fundi the Cæcuban; and in many other places a vast variety of sorts, of different qualities; which could not be the case, but that the moisture of the earth, penetrating the roots with the particular flavour it possesses, nourishes the tree, and, rising to the top of it, imparts to the fruit the flavour of the place and species. 

13. For if the soil and its moisture did not vary, not only would the reeds and rushes of Syria and Arabia be odoriferous, and the shrubs yield pepper, frankincense, and myrrh; nor would the laser grow only in Cyrene, but in all countries and in all places would the same sort of plants grow. For the varieties that are found in different situations and countries arise from the different climates, and the power of the sun, sometimes at a less and at other times at a greater distance; the effects of which are perceived, not only on the moisture of the earth, but on cattle and flocks. And these circumstances could not occur, if in every country the quality of the land did not depend on the sun’s power. 

14. In Boeotia on the rivers Cephisus and Melas, in Lucania on the Crathis, in Troy on the Xanthus, and on the springs and rivers of the Clazomenians, Erythræans, and Laodiceans, the cattle, about the time of bearing, at the proper season of the year, are daily driven to drink; and though themselves of a white colour, in some places they bring forth young of a brown colour, in others of dark brown, and in others of a black colour. Thus the property of a beverage, when it enters the body, communicates thereto its quality, of whatever sort that may be. Hence in the plains of Troy, on the banks of its river, from the flocks and cattle being yellow, the Trojans are said to have called the river Xanthus. 

15. Some sorts of water are mortal in their effects: these receive their quality from the poisonous nature of the lands through which they flow. Such is said to be the Neptunian spring at Terracina, of which those who thoughtlessly drank, lost their lives; hence the antients are said to have stopped it up: and in the country of the Cychri, in Thrace, there is a lake, of which not only those who drink, but those who bathe therein die. In Thessaly, also, flows a spring which no cattle will drink, nor even approach: near it a shrub grows, which bears a purple flower. 

16. So, in Macedonia, where Euripides is interred, from the right and left of his tomb two streams unite: on one of them travellers usually halt to refresh themselves, on account of the excellence of the water: no one, however, approaches the stream on the other side of the monument, because its effects are said to be mortal. In Arcadia, also, the Nonacrian region contains extremely cold water, which drops from the mountains and rocks. It is called water of the Styx (Stugo`V u{dwr); which neither silver, brass, nor iron vessels will hold, because it bursts and destroys them. Nothing preserves or contains it but the hoof of a mule: indeed it is said to have been conveyed, by Iolaus the son of Antipater, to the province where Alexander was, and to have been the cause of his death. 

17. In the Cottian Alps is a water which those who taste instantly die. In the Faliscan territory, on the Via Campana, and in the Cornetan division is a grove wherein a spring rises, containing bones of snakes, lizards, and other reptiles. There are other springs whose water is acid, as are those of the Lyncestis, and in Italy, of the Velinus and of the Campana near Theanum, and in many other places, which, when drank, have the effect of dissolving the stone which forms in the bladder. 

18. This seems to arise from an acrid and acid moisture being under the earth, from which the waters acquire their acridity; and when introduced into the system, dissolve that with which they come in contact whether generated by deposition or concretion. That acids will have this effect, is clear, from the experiment on an egg, whose shell, when kept therein for some time, will be softened and dissolve. Lead, also, which is very flexible and heavy, if placed in a vessel and covered with acid, and there left open, will be dissolved, and become white lead. 

19. In the same way brass which is more solid by nature, if treated in the same way, will dissolve, and become verdigrease; and even pearls and flint-stones, which neither iron nor fire can destroy, when submitted to its action, are dissolved and dissipated by an acid. With these facts before our eyes, we may fairly argue, that calculous disorders may be cured by acids, on account of their acridity. 

20. Some springs appear to be mixed with wine; as that in Paphlagonia, which, when taken, inebriate as wine. At Æqui, in Italy, and in the territory of the Medulli on the Alps, there is a species of water, the use of which produces swellings of the neck. 

21. In Arcadia, at the well-known city of Clitorium, is a cave flowing with water, of which those who drink become abstemious. At the spring is an epigram inscribed on stone, in Greek verses, to the following effect: that it is not fit for bathing, and also that it is injurious to the vine, because, near the spot, Melampus cured the daughters of Proteus of their madness, and restored them to reason. The epigram is as follows: 

Rustic, by Clitor’s stream who takest thy way, Should thirst oppress thee in the noon of day Drink at this fount, and in the holy keep Of guardian Naiads place thy goats and sheep. But dip not thou thy hand, if wine inflame, Lest e’en the vapour chill thy fever’d frame; Fly thou my sober spring. Melampus here Cleansed the mad Proetides, what time the seer Arcadia’s rugged hills from Argos sought, With purifying power my stream was fraught. 

22. There is also in the island of Chios, a fountain, of which those who imprudently drink become foolish; and thereover is inscribed an epigram to the following purport; that though the water of the fountain might be pleasant to the taste, yet he who drank of it would lose his senses. The lines are thus: Sweet drops of cooling draught the spring supplies, But whoso drinks, his reason petrifies. 

23. At Susa, the capital of Persia, there is a fountain, at which those who drink lose their teeth. On this also is written an epigram, stating that the water was excellent for washing, but that if drank it caused the teeth to fall out of their sockets. The verses are as follow: 

A dreaded spring you see, Yet if their hands, good stranger, Folks choose to wash, they’re free To do so without danger; But if from your long lip, Or only from its tip Into your hollow venter This liquor pure should enter, Your tools for munching meat Straight on the ground will tumble, And leave their empty seat For toothless jaws to mumble. 

24. The quality of the water, in some places, is such, that it gives the people of the country an excellent voice for singing, as at Tarsus, Magnesia, and other countries. In Africa there is a city called Zama, which king Juba surrounded with double walls, and built a palace there; about twenty miles from which, is the town of Ismuc, whose territory is of vast extent. Though Africa is the nursing mother of wild animals, and especially of serpents, in that territory none breed, and if any are brought there they immediately die; and if earth from this place be removed to another, it has the same effect. This sort of earth is also found in the Balearic Isles, where, as I have heard, it has even a more extraordinary quality. 

25. C. Julius, the son of Masinissa, to whom the town and territory belonged, fought under Cæsar the elder. Lodging in my house, our daily intercourse led us to discuss subjects of philology. On an occasion, talking on the power of water and its virtues, he assured me that in the above territory there were springs of the same sort, and that persons born there had excellent voices for singing; and that on this account persons went to the transmarine market to buy male and female slaves, whom they coupled for the purpose of procuring progeny, not only of excellent voice, but of great beauty. 

26. Thus has nature exhibited variety in every thing, except the human body, which in every instance consists of earth; but therein are many sorts of fluids, as blood, milk, perspiration, urine, and tears. Wherefore, if in so small a portion of earth such variety exists, it is not surprising, that in the whole world an infinite variety of liquids are found, through the veins of which a spring of water passing, becomes impregnated with their quality before arriving at its head. Hence so many fountains of different sorts, arising, as well from the diversity of their situations, as from the quality of the countries, and the properties of the soils. 

27. Of some of these things I have been an eye-witness; of others I have read in Greek books, whose authors are Theophrastus, Timæus, Posidonius, Hegesias, Herodotus, Aristides, and Metrodorus, who, with the greatest care and accuracy have described how the properties of places and the virtues of different waters, depend on the various climates of the earth. From these I have borrowed and copied into this book all that I thought necessary respecting the varieties of water, whereby, from the directions given, persons can more readily choose springs from which they may conduct water to cities and states, inasmuch as nothing is more necessary than water. 

28. For such is the nature of all animals, that if they do not receive a supply of grain, they can subsist on fruits, flesh, or fish, or something of those sorts; but without water, neither the body of an animal, nor even food itself can be raised, preserved, nor provided. The utmost diligence and labour, therefore, should be used in choosing springs, on which the health of mankind depends. 

Chapter 4 

1. The trial and proof of water are made as follows. If it be of an open and running stream, before we lay it on, the shape of the limbs of the inhabitants of the neighbourhood should be looked to and considered. If they are strongly formed, of fresh colour, with sound legs, and without blear eyes, the supply is of good quality. Also, if digging to a fresh spring, a drop of it be thrown into a Corinthian vessel made of good brass, and leave no stain thereon, it will be found excellent. Equally good that water will be, which, after boiling in a cauldron, leaves no sediment of sand or clay on the bottom. 

2. So if vegetables are quickly cooked over the fire in a vessel full of this water, it shews that the water is good and wholesome. Moreover, if the water itself, when in the spring is limpid and transparent, and the places over which it runs do not generate moss, nor reeds, nor other filth be near it, every thing about it having a clean appearance, it will be manifest by these signs, that such water is light and exceedingly wholesome. 

Chapter 5 

1. I shall now describe how water is to be conveyed to houses and cities, for which purpose levelling is necessary. This is performed either with the dioptra, the level (libra aquaria), or the chorobates. The latter instrument is however the best, inasmuch as the dioptra and level are often found to be incorrect. The chorobates is a rod about twenty feet in length, having two legs at its extremities of equal length and dimensions, and fastened to the ends of the rod at right angles with it; between the rod and the legs are cross pieces fastened with tenons, whereon vertical lines are correctly marked, through which correspondent plumb lines hang down from the rod. When the rod is set, these will coincide with the lines marked, and shew that the instrument stands level. 

2. But if the wind obstructs the operation, and the lines are put in motion, so that one cannot judge by them, let a channel be cut on top of the rod five feet long, one inch wide, and half an inch high, and let water be poured into it; if the water touches each extremity of the channel equally, it is known to be level. When the chorobates is thus adjusted level, the declivity may be ascertained. 

3. Perhaps some one who may have read the works of Archimedes will say that a true level cannot be obtained by means of water, because that author says, that water is not level, but takes the form of a spheroid, whose centre is the same as that of the earth. Whether the water have a plane or spheroidal surface, the two ends of the channel on the rod right and left, when the rod is level, will nevertheless sustain an equal height of water. If it be inclined towards one side, that end which is highest will not suffer the water to reach to the edge of the channel on the rule. Hence it follows, that though water poured in may have a swelling and curve in the middle, yet its extremities to the right and left will be level. The figure of the chorobates will be given at the end of the book. If there be much fall, the water will be easily conducted, but if there be intervals of uneven ground, use must be made of substructions. 

Chapter 6 

1. Water is conducted in three ways, either in streams by means of channels built to convey it, in leaden pipes or in earthen tubes, according to the following rules. If in channels, the structure must be as solid as possible, and the bed of the channel must have a fall of not less than half a foot to a length of one hundred. These channels are arched over at top, that the sun may strike on the water as little as possible. When they are brought home to the walls of the city a reservoir (castellum ) is built, with a triple cistern attached to it to receive the water. In the reservoir are three pipes of equal sizes, and so connected that when the water overflows at the extremities, it is discharged into the middle one, 

2. in which are placed pipes for the supply of the fountains, in the second those for the supply of the baths, thus affording a yearly revenue to the people; in the third, those for the supply of private houses. This is to be so managed that the water for public use may never be deficient, for that cannot be diverted if the mains from the heads are rightly constructed. I have made this division in order that the rent which is collected from private individuals who are supplied with water, may be applied by collectors to the maintenance of the aqueduct. 

3. If hills intervene between the city walls and the spring head, tunnels under ground must be made preserving the fall above assigned; if the ground cut through be sandstone or stone, the channel may be cut therein, but if the soil be earth or gravel, side walls must be built, and an arch turned over, and through this the water may be conducted. The distance between the shafts over the tunnelled part is to be one hundred and twenty feet. 

4. If the water is to be brought in leaden pipes, a reservoir is first made near the spring, from whence to the reservoir in the city, pipes are laid proportioned to the quantity of water. The pipes must be made in lengths of not less than ten feet: hence if they be one hundred digits wide (centenariæ), each length will weigh twelve hundred pounds; if eighty digits (octogenariæ), nine hundred and sixty pounds; if fifty digits (quinquagenariæ), six hundred pounds; if forty digits (quadragenariæ ), four hundred and eighty pounds; if thirty digits (tricenariæ), three hundred and sixty pounds; if twenty digits (vicenariæ), two hundred and forty pounds; if fifteen digits (quinumdenum ), one hundred and eighty pounds; if ten digits (denum), one hundred and twenty pounds; if five digits (quinariæ), sixty pounds. It is to be observed that the pipes take the names of their sizes from the quantity of digits in width of the sheets, before they are bent round: thus, if the sheet be fifty digits wide, before bending into a pipe, it is called a fifty-digit pipe; and so of the rest. 

5. An aqueduct which is made of lead, should be thus constructed; if there be a proper fall from the spring head to the city, and hills high enough to cause an impediment do not intervene, the low intervals must be brought to a level by means of substructions preserving the fall directed for channel aqueducts, or by means of a circuitous course, provided it be not too much about; but if there be long valleys, and when it arrives at the bottom, let it be carried level by means of a low substruction as great a distance as possible; this is the part called the venter, by the Greeks koiliva; when it arrives at the opposite acclivity, the water therein being but slightly swelled on account of the length of the venter, it may be directed upwards. 

6. If the venter were not made use of in valleys, nor the level substruction, but instead of that the aqueduct were brought to an elbow, the water would burst and destroy the joints of the pipes. Over the venter long stand pipes should be placed, by means of which, the violence of the air may escape. Thus, those without have to conduct water through leaden pipes, may by these rules, excellently regulate its descent, its circuit, the venter, and the compression of the air. 

7. It will moreover be expedient, when the level of the fall from the spring is obtained, to build reservoirs at distances of twenty thousand feet from each other, because if damage be done to any part, it will not then be necessary to take the whole work to pieces, and the defective places will be more easily found. These reservoirs, however, are not to be made on a descent, nor on the venter, nor on a rise, nor, generally speaking, in valleys, but only on plains. 

8. But if the water must be conveyed more economically, the following means may be adopted. Thick earthen tubes are to be provided, not less than two inches in thickness, and tongued at one end, so that they may fit into one another. The joints are then to be coated with a mixture of quick lime and oil, and in the elbows made by the level part of the venter, instead of the pipe, must be placed a block of red stone, which is to be perforated, so that the last length of inclined pipe, as well as the first length of the level part may be received into it. Then, on the opposite side, were the acclivity begins, the block of red stone receives the last length of the venter, and the first length of the rising pipe. 

9. Thus adjusting the direction of the tubes, both in the descents and acclivities, the work will never be dislodged. For a great rush of air is generated in an aqueduct, strong enough to break even stones, unless the water is softly and sparingly let down from the head, and unless in elbows or bending joints it be restrained by means of ligatures, or a weight of ballast. In of the respects it is similar to one with leaden pipes. When the water is first let down from the head, ashes are put in which will stop those joints not sufficiently coated. Earthen pipes have these advantages, first as to the work; next, that if damaged any one can repair it. 

10. Water conducted through earthen pipes is more wholesome than that through lead; indeed that conveyed in lead must be injurious, because from it white lead is obtained, and this is said to be injurious to the human system. Hence, if what is generated from it is pernicious, there can be no doubt that itself cannot be a wholesome body. 

11. This may be verified by observing the workers in lead, who are of a pallid colour; for in casting lead, the fumes from it fixing on the different members, and daily burning them, destroy the vigour of the blood; water should therefore on no account be conducted in leaden pipes if we are desirous that it should be wholesome. That the flavour of that conveyed in earthen pipes is better, is shewn at our daily meals, for all those whose tables are furnished with silver vessels, nevertheless use those made of earth, from the purity of the flavour being preserved in them. 

12. If there be no springs from which water can be obtained, it is necessary to dig wells, on which every care is to be bestowed, and the utmost ingenuity and discretion used in the examination of the natural indications of the circumstances thereabout, inasmuch as the different sorts of soil which are met with, are many and various. That, like every other body, is composed of four elements; first of earth itself; water, whence are the springs; heat, whence sulphur, alum, and bitumen are generated; and air, whence arise great vapours, which, piercing through the pores to the opening of wells, strike upon the excavators and suffocate them by their natural influence, so that those who do not immediately escape lose their lives. 

13. To avoid this the following method may be adopted; a lighted lamp must be lowered; if it continue to burn, a man may safely descend, but if the strength of the vapour extinguish it, then to the right and left of the well let air holes be dug, so that as it were through nostrils, the vapour may pass off. When this is done and we come to water, the well must be lined with a wall, but in such a manner as not to shut out the springs. 

14. If the soil be hard, and there be no veins of water found at the bottom, we must then have recourse to cisterns made of cement, in which water is collected from roofs and other high places. The cement is thus compounded; in the first place, the purest and roughest sand that can be had is to be procured; then work must be of broken flint whereon no single piece is to weigh more than a pound, the lime must be very strong, and in making it into mortar, five parts of sand are to be added to two of lime, the flint work is combined with the mortar, and of it the walls in the excavation are brought up from the bottom, and shaped by wooden bars covered with iron. 

15. The walls being shaped, the earth in the middle is to be thrown out as low as the foot of the walls, and when levelled, the bottom is to be covered with the same materials to the requisite thickness. If these receptacles are made in two or three divisions, so that the water may be passed from one to another, it will be more wholesome for use; for the mud in it will be thus allowed to subside, and the water will be clearer, preserve its flavour, and be free from smell; otherwise it will be necessary to use salt for purifying it. In this book I have explained to my utmost ability the virtues and varieties of waters, their use and conveyance, and how their goodness may be ascertained; in the following book I intend to describe the principles of gnomonics and the rules of dialling.


See the others books:

Nessun commento:

Posta un commento

Ti ringrazio per ogni commento, appunto, modifica o richiesta di chiarimento. Mantenendo sempre un tono civile. Ogni commento che non rispetta tali regole, sarà eliminato, sopratutto se fatto in maniera anonima. TI ricordo che cerchiamo nuovi collaboratori o appunti, per implementare il materiale presente sul sito.

Related Posts Plugin for WordPress, Blogger...