It was a peculiarity of the Hindoo mathematicians that they tried to make out that all they knew was _very old_. Modern savants appear to take the opposite stand for any little information they happen to possess. The cubit which is called the Royal Babylonian cubit and stated to measure O·5131 metre, differs so slightly from my cubit, only the six-hundredth part of a foot, that it may fairly be said to be the same cubit, and it will be for antiquaries to trace the connection, as this may throw some light on the identity of the builders of the Pyramids of Gïzeh. Few good English two-foot rules agree better than these two cubits do. While I was groping about in the dark searching for this bright needle, I tried on the plan many likely ancient measures. For a long time I worked in Memphis or Nilometric cubits, which I made 1·7126 British feet; they seem to vary from 1·70 to 1·72, and although I made good use of them in identifying other people's measures, still they were evidently not in accordance with the design; but the R.B. cubit of 1·685 British feet works as truly into the plan of the Pyramids _without fractions_ as it does into the circumference of the earth. Here I might, to prevent others from falling into one of my errors, point out a rock on which I was aground for a long time. I took the base of the Pyramid Cheops, determined by Piazzi Smyth, from Bonwick's "Pyramid Facts and Fancies" (a valuable little reference book), as 763.81 British feet, and the altitude as 486.2567; and then from Piazzi Smyth's "Inheritance," page 27, I confirmed these figures, and so worked on them for a long time, but found always a great flaw in my work, and at last adopted a fresh base for Cheops, feeling sure that Mr. Smyth's base was wrong: for I was absolutely grounded in my conviction that at a certain level, Cheops' and Cephren's measures bore certain relations to each other. I subsequently found in another part of Mr. Smyth's book, that the correct measures were 761.65 and 484.91 British feet for base and altitude, which were exactly what I wanted, and enabled me to be in accordance with him in that pyramid which he appears to have made his particular study. For the information of those who may wish to compare my measures, which are the results of an even or regular circumference without fractions, with Mr. Smyth's measures, which are the results of an even or regular diameter without fractions, it may be well to state that there are just about 99 R.B. cubits in 80 of Piazzi Smyth's cubits of 25 pyramid inches each. § 9. THE PYRAMIDS OF EGYPT, THE THEODOLITES OF THE EGYPTIAN LAND SURVEYORS. About twenty-three years ago, on my road to Australia, I was crossing from Alexandria to Cairo, and saw the pyramids of Gïzeh. I watched them carefully as the train passed along, noticed their clear cut lines against the sky, and their constantly changing relative position.