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. Yet in Joseph's well, the partition of rock between the pit and the passage way, and the uniform inclination of the latter, seem to have been ascertained with equal precision as if the whole had been constructed of cut stone on the surface. Was the pit or the passage formed first, or were they simultaneously carried on, and the excavated masses from both borne up the latter 1 The extreme thinness of the partition justly excited the astonishment of M. Jomard, whose account of the well is inserted in the 2d volume of Memoirs of Napoleon's great work on Egypt. It is, according to M. Jomard, but sixteen centimetres,, or about six inches, thick ! It must have required singular care to, leave and preserve so small a portion, while excavating the rock from both sides of it. It would seem no stronger, in proportion, than sheets of pasteboard placed on edge, to support one end of the stairs of a modern built house, for it must be borne in mind, that the massive roof of the spiral passage next the well, has nothing but this film of rock to support it, or to prevent such portions from falling as are loosened by fissures,, or such as from changes in the direction of the strata, are not firmly united to the general mass.