At Assuân the course of the river is broken by the first cataract, where its waters rush between numberless more or less diminutive islands, the most famous of which is the island of Philæ above and Elephantine in front of Assuân. In the shape it has reached us Manetho's work is of comparatively little assistance, on account of its chronology, which seems to be hopelessly mixed up, besides being grossly exaggerated; and it must be used with the greatest caution. These scholars, however, paved the way for the present generation of Egyptologists, of the German school especially, who have at last succeeded in placing the chronology of ancient Egypt on a firm basis. Steindorff's "Outline of the History of Egypt" in Baedeker's "Egypt" (6th ed., 1908), with the exception of the year 408, the last of the Twenty-seventh Dynasty and first of the Twenty-eighth, which we copy from Maspéro, "Guide to the Cairo Museum" (Cairo, 1903, p. Manetho, who, as a rule, does not seem to have been much better informed than we are, resorts in such cases to traditions, strongly tinged with legend, which were in the keeping of the priests and belonged, very likely, to the same stock as most of those related by Heroditus on matters that could not fall under his personal observation.
The final velocity is a few percent of the speed of light or about 50 million miles per hour.The analyzing and switching magnets select the mass of the radionuclide of interest, further reducing the intensity of neighbouring stable isotopes.The ions are slowed down and come to rest in propane gas.As they stop, electrons are knocked off the gas atoms. As far as Edfu (Appollinopolis Magna) the valley is rather narrow, rarely as much as two or three miles wide. Besides a few short notices, the epitome contains nothing but names and figures showing the duration of each reign and dynasty. We cannot enter here upon even a cursory analysis, much less a discussion, of the various systems of Egyptian chronology. Evidently, in some cases the lack of information on some periods, which must have been very momentous ones in the political life of Egypt, should be attributed to the disappearance of monuments of an historical character, or to the fact that such monuments have not yet been discovered; it is very likely, however, that in many cases no historical evidence was ever handed down to posterity.
From Napata the Nile continues for a while in the southwest direction which it follows from Abu-Hamed, but soon assumes is ordinary sinuous course to the north, describing two great principle curves one to the west down to Wâdi Halfa, just below the second cataract, Soleb being the westernmost point, then another to the east as far as Assiût (Lycopolis), Assuân forming its apex, or easternmost point. Judging from that epitome, the work of Manetho was divided into three parts, the first of which contained the reigns of the gods and demi-gods (omitted in the African recension) and eleven dynasties of human kings; the second, eight dynasties of such kings; the third, twelve (the last one added after Manetho's death). Although their interest lies chiefly in another direction, yet we may glean from them occasional chronological data for the times during which these two writers lived. Accession of Menes and beginning of the dynasties 3400-2980 B. We know little or nothing of the peoples they battled with, nor can we detect the political reasons which brought about the rise and fall of the several dynasties.
The table above gives the half life (time it takes for half of the atoms to decay; see here) and the detection limit (value for the atom ratio of the radionuclide to stable nuclide measured for a “blank” sample that contains a negligible amount of the radionuclide).
Decay products of some of these radioactive nuclides (10Be, 26Al, 129I) have also been detected in meteorites and other extraterrestrial materials.
In addition, they eliminate molecules completely by selecting only the highly charged ions that are produced in the terminal stripper.
Highly charged molecules are unstable since they are missing the electrons that bind the atoms together.
There are still lots of molecules and isobars (isotopes of neighboring elements having the same mass) that must be removed by more magnets after the accelerator.