The earliest records, both of Egypt and Chaldæa, show that such an advanced state of science had been reached at the first dawn of the historical period, and we read of works on astronomy, geometry, medicine, and other sciences, written, or compiled from older treatises, by Egyptian kings of the old empire, and by Sargon I. of Accade from older Accadian works. But the monuments prove still more conclusively that such sciences must have been long known. Especially the Great Pyramid of Cheops affords a very definite proof of the progress which must have been made in geometrical, mechanical, and astronomical science at the time of its erection. If we were to believe Professor Piazzi Smyth, and the little knot of his followers who have founded what may be called a Pyramid-religion, this remarkable structure contains a revelation in stone for future ages, of almost all the material scientific facts which have been discovered since by 6000 years of painful research by the unaided human intellect. Its designers must have known and recorded, with an accuracy surpassing that of modern observation, such facts as the dimensions of the earth, the distance of the sun, the ratio of the area of a circle to its diameter, the precise determination of latitude and of a true meridian line, and the establishment of standards of measure taken, like the metre, from a definite division of the earth's circumference. It is argued that such facts as these could not have been discovered so accurately in the infancy of science, and without the aid of the telescope, and therefore that they must have been made known by revelation, and the Great Pyramid is looked upon therefore as a sort of Bible in stone, which is, in some not very intelligible way, to be taken as a confirmation of the inspiration of the Hebrew Bible, and read as a sort of supplement to it. This is of course absurd. A supernatural revelation to teach a chosen people the worship of the one true God, is at any rate an intelligible proposition, but scarcely that of such a revelation to an idolatrous monarch and people, to teach details of abstruse sciences, which in point of fact were not taught, for the monument on which they were recorded was sealed up by a casing of polished stone almost directly after it was built, and its contents were only discovered by accident, long after the facts and figures which it is supposed to teach had been discovered elsewhere by human reason. The only thing approaching to a revelation of religious import which Piazzi Smyth professed to have discovered in the Pyramid was a prediction, which is now more than ten years overdue, of the advent of the millennium in 1881.