One after another Captains Lauzanne and Châteauvieux, Lieutenants Lafage and Calinon, at the head of mixed detachments of regular soldiers and Arab and Toubou auxiliaries, made their way into the wildest fastnesses of Eastern Tibesti, Borkou, and Ennedi. Captain Lauzanne, in particular, succeeded in tracking the Gourmas into the distant solitudes of Ouri, 200 miles north of Gouro, at the foot of the eastern spurs of the Tibesti, and after them their cousins the Koussadas into the very crater of Emi Koussi, till then regarded as impregnable. The fame of these two expeditions was noised abroad in the country to such an extent that by the end of the month of July the general situation of Borkou had greatly improved, and we could turn our thoughts to the consolidation of our prestige by an offensive action against the rebels of Miski, and by a junction of our troops with those of Zouar and Bardaï, the two military posts entrusted with the supervision and pacification of western and central Tibesti. =7. Exploration of Tibesti.= In the month of September 1916 I was authorized to proceed from Borkou to Tibesti for the purpose of getting in touch with the rebel tribes who intended to attack the caravans fitted out in Kanem and Wadaï for the carrying of supplies to the garrisons of Borkou and Ennedi. The garrison of Tibesti was to attempt, to the best of its ability, to co-operate with this action in such a way that the hostile bands, threatened at once on the south, the west, and the north, might either be induced to submit or else to disperse in the eastern part of the Tibestian massif, the part furthest away from the region to be traversed by our convoys of supplies. The rebels were comparatively few in number—about 2000 combatants—and divided into clans living in different regions; but they were of extreme mobility, well armed, and abundantly supplied with ammunition. Their tactics, which were very skilful, consisted in avoiding on all occasions a fight in the open, in hiding in the labyrinth of their well-nigh inaccessible rocks to fire at short range on the enemy when he passed near enough, in decamping at top speed to hide again a little further on, and so draw little groups of adversaries in the direction of death- traps, where of course well-planned ambuscades lay in wait for them. The strength of the reconnoitring detachment was forty-four black soldiers, officered by four Europeans—one of them a doctor—and accompanied by some thirty auxiliaries (guides, goumiers,[1] camel drivers, and servants). It carried food for two months, and the barrels and skins required for three days’ water. The train included about 120 camels.