This first trip resulted in the discovery of emerald mines at Labarah, mentioned by Arab authors, which had been abandoned for centuries. In the excavations in the mountain Cailliaud found the lamps, crowbars, ropes, and tools used in working these mines by men in the employ of Ptolemy. Near the quarries the traveller discovered the ruins of a little town, which was probably inhabited by the ancient miners. To prove the reality of his valuable discovery he took back ten pounds' weight of emeralds to Mehemet Ali.

Another result of this journey was the discovery by the French explorer of the old road from Coptos to Berenice for the trade of India.

From September, 1819, to the end of 1832, Cailliaud, accompanied by a former midshipman named Letorzec, was occupied in exploring all the known oases east of Egypt, and in tracing the Nile to 10° N. lat. On his first journey he reached Wady Halfa, and for his second trip he made that place his starting-point. A fortunate accident did much to aid his researches. This was the appointment of Ismail Pacha, son of Mehemet Ali, to the command of an expedition to Nubia. To this expedition Cailliaud attached himself.

Leaving Daraou in November, 1820, Cailliaud arrived, on the 5th January in the ensuing year, at Dongola, and reached Mount Barka in the Chaguy country, where are a vast number of ruins of temples, pyramids, and other monuments. The fact of this district bearing the name of Merawe had given rise to an opinion that in it was situated the ancient capital of Ethiopia. Cailliaud was enabled to show this to be erroneous.

View of a Merawe temple.
(Fac-simile of early engraving.)

The French explorer, accompanying Ismail Pacha in the character of a mineralogist beyond Berber, on a quest for gold-mines, arrived at Shendy. He then went with Letorzec to determine the position of the junction of the Atbara with the Nile; and at Assour, not far from 17° N. lat., he discovered the ruins of an extensive ancient town. It was Meroë. Pressing on in a southerly direction between the 15th and 16th degrees of N. lat., Cailliaud next identified the mouth of the Bahr-el-Abiad, or White Nile, visited the ruins of Saba, the mouth of the Rahad, the ancient Astosaba, Sennaar, the river Gologo, the Fazoele country, and the Toumat, a tributary of the Nile, finally reaching the Singue country between the two branches of the river. Cailliaud was the first explorer to penetrate from the north so near to the equator; Browne had turned back at 16° 10', Bruce at 11°. To Cailliaud and Letorzec we owe many observations on latitude and longitude, some valuable remarks on the variation of the magnetic needle, and details of the climate, temperature, and nature of the soil, together with a most interesting collection of animals and botanical specimens. Lastly, the travellers made plans of all the monuments beyond the second cataract.

The Second Cataract of the Nile.

The two Frenchmen had preluded their discoveries by an excursion to the oasis of Siwâh. At the end of 1819 they left Fayum with a few companions, and entered the Libyan desert. In fifteen days, and after a brush with the Arabs, they reached Siwâh, having on their way taken measurements of every part of the temple of Jupiter Ammon, and determined, as Browne had done, its exact geographical position. A little later a military expedition was sent to this same oasis, in which Drovetti collected new and very valuable documents supplementing those obtained by Cailliaud and Letorzec. They afterwards visited successively the oasis of Falafre, never before explored by a European, that of Dakel, and Khargh, the chief place of the Theban oasis. The documents collected on this journey were sent to France, to the care of M. Jomard, who founded on them his work called "Voyage à l'Oasis de Siouah."