THE chronology of Egypt is an inexact science; and must so remain, in the absence of far more data than are at present available. The primary evidence lies in records, scattered over many centuries, from which must be inferred the use of several calendars and of a seasonal year with a special definition. These records prior, at any rate, to the period of the Eighteenth Dynasty are open to more than one interpretation. The solution of the chronological problem therefore lies in finding that interpretation in each case which will produce concordance; so that the resulting inferences will afford a conclusion which is logical, acceptable, and consistent with all the evidence at present known, such as old chronological records partially preserved, monumental records, and the conclusions drawn from other archaeological remains. To aid in this study, it is necessary to invoke the assistance of astronomers, numismatists, historians of other peoples, and other experts.
The question may be asked, indeed has been asked, whether it is credible that a people whose writing was in its infancy at the opening of dynastic history should be capable of astronomical observations and computations. The primary answer is that there is ample evidence that they actually did make surprisingly accurate observations. It is unnecessary to offer conjectures as to the method adopted for observation of an equinox, since the only reasonable inference from the evidence is that they knew the length of a year measured from autumn equinox to autumn equinox within one or two minutes. Such accuracy could be attained only by the use of records which showed the interval which had elapsed between autumn equinoxes, for example, 100 years apart. It was perhaps the very fact that the science of writing was in its infancy which accounts for