If the _solstice_ had been taken alone, the date of it would have been the same for all parts of the valley; but certainly the solstice was not taken alone, and for the obvious reason, that they wanted something to warn them of the Nile rise, and in the lower reaches of the river the rise precedes the solstice. Nor was the heliacal rising of Sirius, of which more presently, taken alone. But it was chiefly a question of the arrival of the Nile flood, and the date of the commencement of the Nile flood was by no means common to all parts of Egypt. Now it is to be gathered from the modern gauges that it takes the flood some time, as we can easily imagine, to pass down the 600 miles between Elephantine and Cairo. In the early flood, rising from, say, one cubit Aswân to six cubits, where there are many dry sandbanks, and the spreading out of the river is considerable, and there is an absence of overlapping flushes from behind, the rate goes up to fifteen days, and the _earliest_ indication of the rise may take longer still, but this is very difficult to observe. The rate in Hood is 1¾ days from Wādy Halfa to Aswân, and six days from Aswân to Rôda (941 kilometres). In very high Niles this is perhaps accelerated to five days. There is, therefore, a very great difference in time and rate between Green and Red Nile. The rise is 45 ft. at Aswân, 38 at Thebes, and 25 at Cairo. From the data obtained at the gauges named, which have been kindly forwarded to me by Mr. Garstin, the Under Secretary of State of the Public Works Department of Egypt, I have ascertained that the average time taken by the first indication of the flood to travel between Thebes and Memphis is now about nine days. It must be remembered, however, that the river-bed is now higher than formerly; the land around Thebes, according to Budge, has been raised about nine feet in the last 1,700 years. If, therefore, at each great city, such as Thebes and Heliopolis, New Year's Day depended absolutely on the arrival of the inundation, not only would the day have been uncertain, but the difference of time in the arrival of the Hood at various places along the river would represent a difference in the New Year's Days of those places, compared to which our modern differences of local time sink into insignificance, for they only touch hours of the day. The great difficulty experienced in understanding the statements generally made concerning the Nile-rise is due to the fact that the maximum flood is, as a rule, registered in Cairo upwards of forty days after the maximum at Aswân. For the following account of how this is brought about I am indebted to the kindness of Colonel Ross, R.E.:--