In order that all the expense of embalming should not be thrown away, the mummy had to be so placed that it could not be reached by the highest inundations of the river. The cemeteries were therefore established either upon a plateau surrounded by the desert, as in the case of Memphis and Abydos, or in the sides of the mountain ranges and in the ravines by which they were pierced, as at Thebes and Beni-Hassan. In the whole valley of the Nile, no ancient tomb has been discovered which was within reach of the inundation at its highest.[128] [128] RHIND describes several mummy-pits in the necropolis of Thebes which receive the water of the Nile by infiltration; but, as he himself remarks, this is because those who dug them did not foresee the gradual raising of the valley, and, consequently, of the level attained in recent ages by the waters of the Nile. It is doubtless only within the last few centuries that the water has penetrated into these tombs. (_Thebes, its Tombs and their Tenants_, p. 153.) The corpse was thus preserved from destruction, first by careful and scientific embalming, secondly by placing its dwelling above the highest "Nile." Besides this we shall see that the Egyptian architects made use of many curious artifices of construction in order to conceal the entrance to the tomb, and to prevent the intrusion of any one coming with evil intentions. All kinds of obstacles and pitfalls are accumulated in the path of the unbidden visitor, with a fertility and patient ingenuity of invention which has often carried despair into the minds of modern explorers, especially in the case of the pyramids. Mariette was fond of saying that there are mummies in Egypt which will never, in the strictest sense of the word, be brought to light. But in spite of all this pious and subtle foresight, it sometimes happened that private hate or, more often, the greed of gain, upset every calculation. Enemies might succeed in penetrating to the sepulchres of the dead, in destroying their bodies, and thus inflicting a second death worse than the first; or a thief might drag the corpse from its resting place, and leave it naked and dishonoured upon the sands, that he might, with the greater ease, possess himself of the gold and jewels with which it had been adorned. [Illustration: FIG. 87.--Mummy case from the 18th dynasty. Boulak.]