"But for the last half of the week it is not seen at all, and one is free to guess which day it is," I interrupted. "Then no two days of the week begin at the same hour. The first day begins with sunrise, the second two hours before sunrise, the third four hours before, and the fourth at midnight, and so on--two hours earlier each day till the week ends, when they throw in a whole night for good measure and begin the next week at sunrise again!" "Yes, that arrangement is made necessary because their Moon-day will not agree with their Sun-day in any other manner. But it is rather remarkable that the two moons agree with each other so well, the larger one making twelve revolutions while the smaller makes one, so that at the end of every week they both rise together, but on opposite sides of the horizon, which is the signal for that night to be disregarded in the count. The next week begins on the following morning, the first rising of the larger moon being disregarded, and her second rising being the one reckoned from." We were discussing this during our noon-day meal, and, when we had finished, I walked with the doctor out to the plateau, where I was supervising some important work on the Gnomons; for I had not been ten days in Kem until I attempted to buy, with my gold coins, a large amount of wheat from the Pharaoh. Through the interference and objection of Zaphnath, however, I failed utterly in getting any. But the gold had its effect just the same, and later the Pharaoh showed an evident willingness to part with anything in his possession in order to get a liberal number of the smaller coins. But I put a very high value upon the gold, comparing closely with the worth of diamonds upon Earth, and refused to part with any, until one day the wisdom of buying the Gnomons occurred to me. I considered the project carefully, and finally made him an offer of a hundred half-eagles for them. Many of the small ones had been built to watch the course of the birth-stars of his various ancestors, and these were now in a sense monuments to his dynasty. He reserved these and a small one, built to observe his own star of nativity, and finally sold me all the large important ones, upon the doctor's representation that they were no longer needed for astronomical purposes. He specified only that they must not be torn down, but that I might use them as I should see fit.