We shall not waste our time in noticing and refuting those fantastic explanations of the pyramids which have been given in modern times. We shall not trouble ourselves to prove that they were not observatories. Those sloping tunnels, at the bottom of which some modern writers would set unlucky astronomers to watch the passage of stars across the meridian, were hermetically sealed, and minute precautions were taken with the sole object of obstructing and concealing their entrance. The four slopes of the pyramid faced to the cardinal points, simply because the orientation of the tomb was habitual with the Egyptians; we have already explained its meaning. Still less need we occupy ourselves with the theory, which made, however, some stir in its time, that the pyramids were bulwarks by which the ancient Egyptians attempted to keep back the sand from the fertile valley of the Nile. The science of M. de Persigny was well worthy of his policy. There was in both, the same turn for fantastic invention, the same want of reflection and common sense. If such a costly barrier had been either useful or necessary it should at least have been prolonged from one end of Egypt to the other, and all the pyramids would not have been found assembled, with but few exceptions, in the neighbourhood of Memphis.[176] [176] FIALIN DE PERSIGNY, _De la Destination et de l'Utilité permanente des Pyramides d'Égypte et de Nubie contre les Irruptions sablonneuses du Désert, Développements du Mémoire adressé à l'Académie des Sciences le 14 Juillet, 1844_, suivie d'_une nouvelle interprétation de la Fable d'Osiris et d'Isis_. Paris, 1845, gr. in-8.