An interesting proof of the earth's rotation on its axis has recently been found.
"In a paper in the _Proceedings_ of the Vienna Academy (June, 1908) by Herr Tumlirz, it is shown mathematically that if a liquid is flowing outwards between two horizontal discs, the lines of flow will be strictly straight only if the discs and vessel be at rest, and will assume certain curves if that vessel and the discs are in rotation, as, for example, due to the earth's rotation. An experimental arrangement was set up with all precautions, and the stream lines were marked with coloured liquids and photographed. These were in general accord with the predictions of theory and the supposition that the earth is rotating about an axis."[77]
In a book published in 1905 entitled _The Rational Almanac_, by Moses B. Cotsworth, of York, the author states that (p. 397), "The explanation is apparent from the Great Pyramid's Slope, which conclusively proves that when it was built the latitude of that region was 7°·1 more than at present. Egyptian Memphis now near Cairo was then in latitude 37°·1, where Asia Minor now ranges, whilst Syria would then be where the Caucasus regions now experience those rigorous winters formerly experienced in Syria." But the reality of this comparatively great change of latitude in the position of the Great Pyramid can be easily disproved. Pytheas of Marseilles--who lived in the time of Alexander the Great, about 330 B.C.--measured the latitude of Marseilles by means of a gnomon, and found it to be about 42° 56'-1/2. As the present latitude of Marseilles is 43° 17' 50", no great change in the latitude could have taken place in over 2000 years.[78] From this we may conclude that the latitude of the Great Pyramid has _not_ changed by 7°·1 since its construction. There is, it is true, a slow diminution going on in the obliquity of the ecliptic (or inclination of the earth's axis), but modern observations show that this would not amount to as much as one degree in 6000 years. Eudemus of Rhodes--a disciple of Aristotle (who died in 322 B.C.)--found the obliquity of the ecliptic to be 24°, which differs but little from its present value, 23° 27'. Al-Sufi in the tenth century measured the latitude of Schiraz in Persia, and found it 29° 36'. Its present latitude is 29° 36' 30",[79] so that evidently there has been no change in the latitude in 900 years.
