“Smyth is credited for noting another anomaly in the Queen's Chamber—there were flakes of white mortar exuding from stone joints inside the shaft. Analysis of the mortar found it to be plaster of paris—gypsum (calcium sulfate). Smyth also described this chamber as having a foul odor, which caused early visitors to the chamber to beat a hasty retreat, and it was assumed that tourists were relieving themselves, though the way Smyth described this chamber, few people stayed long enough to do so. However, as I will make clear, this odor may not have been the result of unhygienic conditions but of the chemical process that once occurred in the Queen's Chamber.
One of the greatest mysteries of this chamber has been the salt encrustation on the walls. It was up to one-half-inch thick in places, and Petrie took it into account when he made measurements of the chamber. The salt also was found along the Horizontal Passage and in the lower portion of the Grand Gallery. How did salt come to build up on the walls?”