Petrie, Our Inheritance, 3rd, Historical Studies II Ancient Egypt, England 1917

Sir Flides Petrie (1853-1943 of the Christian era.) Professor of Egyptology 1892-1933 and later to become professor emeritus from 1933-1942 of the world famous London University, Inventor of the gyro-compass and the “Father of Modern Archeological Methods” made extensive measurements of the Great Pyramid, especially in the Queens Chamber where he had to spend much time cleaning away salt deposits that were caked on the wall of that chamber so he could make accurate measurements. The salt that was left behind after the brackish water from the lake left inside had evaporated. However, the Queen's chamber was hundreds of feet above the valley floor, evidence that the Pyramid had once been under water.