ABSTRACT
THE signs for recognizing underground watercourses are given by Cassiodorus Magnus at the end of Book III in a letter of Theodoric, king of the Goths, namely, high green grasses and tall trees nearby. Ground where fresh water is not far below the surface is always favoured by an abundance of growth in particular plants: there are the bulrush, the 134light reed or cane, the stout bramble, the lissom willow, the flourishing poplar, and all the other kinds of trees, provided they rise rank and luxuriant beyond their natural height. There are other indications also to be observed in this art: when at the approach of night dry wool is laid on ground where water is suspected to be and is left there covered with an earthenware pot, then, if water is pleasingly close, in the morning the wool will be found damp. As soon as the sun becomes visible, experts carefully examine these spots and, where they observe any cloud of minute flies hovering above the soil, they joyfully promise that the object of their search will easily be found. They also add that a column of very fine steam may be seen and they know that, to whatever height it extends upwards, waters lurk below at the same depth. It is a wonderful thing that by these and other alternative signs they can foretell and accurately measure the depth at which they will come upon their objective.
Green grasses Tall trees Rush
Reed, bramble, willow, poplar
Wool
Flies
Steam
