Shortly afterwards, Pallier left Zinder with 300 riflemen to make a reconnaissance of the route to
Lake Chad, but was forced by a mutiny among his men to make a premature return to the city. The soldiers had threatened to kill him if he didn't immediately take them back to Zinder and promise to send them back to
French Sudan. Consequently, it was decided at Zinder to split the expedition, with 300 riflemen, Lt. Pallier, Dr. Henric and two French
NCOs leaving immediately for French Sudan while the remaining 270 riflemen (who had pledged to continue the mission for another year) put themselves under the command of Lt.
Paul Joalland. Klobb's former officer, Lt.
Octave Meynier, became Joalland's second and the expedition became known as the . Joalland and Meynier remained for some time in Zinder to pacify the area; the
sarki (king or sultan) Amadou was killed on September 15 during a skirmish, which brought Zinder's territory under full control. This freed the two French officers to leave Zinder on October 3 to continue with their reconnaissance. They took 170 men and a cannon, while 100 men were left behind to secure the city under the command of Sergeant Bouthel, who was awaiting the Foureau-Lamy mission that was heading towards Zinder from
Algiers across the
Sahara, and which arrived in November. In January 1900 Foureau and
Lamy left Zinder, moving south-east towards the Komadugu Yobe River. They followed this river east to
Lake Chad, north around the western and northern shores of the lake and then south along its eastern shore. Here they encountered Joalland who had travelled north, up the east side of the lake, to meet them. The united expeditions, now under the overall command of Lamy, returned south to Joalland's base camp on the right bank of the
Chari River, near where it enters Lake Chad from the south. The joint expedition conquered
Kousséri in April 1900; shortly afterwards, on April 21, they were joined by a third expedition, the
Gentil Mission, that had entered the area from the Congo and been awaiting them for some time in the region of Lake Chad. The following day, in the
battle of Kousséri, this combined force totally defeated
Rabih az-Zubayr's forces, and Rabih was killed in the fight, his empire crumbling with him. This event meant that the original expedition had now accomplished all its main aims, that is, surveying the lands of Northern
Nigeria and
Niger (contributing to a clearer Franco-British
delimitation of the colonial borders), uniting with the Foureau-Lamy mission and destroying Rabih's empire, which permitted the institution in September by the French government of the military territory of Chad. Having achieved their goals, Joalland and Meynier left Chad and returned to
French Sudan and the
Niger River by November. Joalland, the doctor Henric and the other French officers, due to the military success of the campaign, were able to avoid
court-martial. Both Joalland and Meynier went on to have successful careers, and become generals. ==Reactions in France==