1As 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.
2We 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.
3Besides 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.
4In 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.
5If 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.
6These 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.
7Valleys in the midst of mountains receive a very large proportion of rain, and from the closeness of their woods, as well 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 not probably 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.