Note 151
From Chapter 50 of the Decline & Fall

The Greeks and Latins have invented and propagated the vulgar and ridiculous story, that Mahomet's iron tomb is suspended in the air at Mecca Laonicus Chalcondyles, de Rebus Turcicis, l. iii. p. 66), by the action of equal and potent loadstones (Dictionnaire de Bayle, MAHOMET, Rem. EE. FF.). Without any philosophical inquiries, it may suffice, that,
1. The prophet was not buried at Mecca; and,
2. That his tomb at Medina, which has been visited by millions, is placed on the ground(Reland, de Relig. Moham. l. ii. c. 19, p. 209 - 211. Gagnier, Vie de Mahomet, tom. iii. p. 263 - 268.).