In 1818–19 he was in lower Nubia, beyond the Cataracts of the Nile. In 1820 he joined the expedition of the French consul general and explorer Bernardino Drovetti to the oasis of Siwa in the Libyan Desert, where the oracle of Ammon had been consulted by Alexander the Great but to which no modern European had penetrated; his drawings illustrated the "Voyage à l'Oasis de Syouah", published by E. Jomard (1823). Within a few months he travelled with the Italian Alessandro Ricci to Sinai: the party left Cairo and followed the peninsula's eastern coast, passing through the Wells of Moses, Wadi Gharandel and Khazne Firaoun, to arrive at Maghara, where they made copies of the hieroglyphic inscriptions. Their intention to reach Petra was foiled by the insecurity of the area, but in returning to Cairo they passed through Sarbout el-Khadem and sketched its monuments. This first trip to Sinai enabled him to establish contacts with the Bedouin and prepare himself for the successful trip to Petra finally undertaken with Léon de Laborde in 1828.