"A spiral passage way is cut through the rock, from the surface of the ground to the chamber, independent of the well, round which it winds with so gentle a descent, that persons sometimes ride up or down upon asses or mules. It is six feet four inches

wide, and seven feet two inches high. Between it and the interior of the well, a wall of rock is left, to prevent persons falling, or even looking down into it except through certain openings, or windows, by means of which it is faintly lighted from the interior of the well by this passage the animals descend which drive the machinery that raises ;

the water from the lower shaft into the reservoir, or basin, from which it is again raised by similar machinery and other animals on the surface. In the lower shaft a path is also cut down to the water, but as no partition is left between it and the well, it is extremely perilous for strangers to descend. The water is raised in earthenware pots attached to endless chains or ropes, that as they pass over the wheel at the top, empty their contents into a trough and descend in a reversed position. " This celebrated well resembles an enormous hollow screw, the centre of which

4 PRELIMINARY ESSAY. forms the well, and the threads a winding stair-case round it. To erect of granite a flight of "geometrical" or " well-stairs," two or three hundred feet high, on the surface of the ground, would require extraordinary skill r although in the execution every aid from rules, measures,, and the light of day, would guide the workmen at every step ; but to' begin such a work at the top and construct it downward, by excavation alone, in the dark bowels of the earth,, is a more arduous undertaking, especially as deviations from the correct lines could not be corrected.