Fifty years elapsed from the visits of the Verendryes to the next important exploration of North Dakota. In November 1797 David Thompson, an English geographer in the employ of the Hudson's Bay Company, was sent out to survey the boundary and visit the company posts. It was an unusually cold winter, and the party suffered intensely during the 68-day journey. They explored along the Assiniboine and Souris Rivers and the west edge of the Turtle Mountains, then turned southwest to the Missouri, where they visited the Mandans, and Hidatsa. Thompson in his journal has given a thorough account of the homes, manners, food, dress, and agricultural activities of these Indians. He noted that, while their villages were much alike, the Mandans were a more courteous and better behaved group. Called "the greatest practical land geographer in history," Thompson later helped survey the boundary line between Canada and the United States in accordance with the Treaty of 1818. In commemoration of his exploration of this State a monument has been erected to him, in the shape of a large masonry sphere, at Verendrye (_see Tour 7_). The same year that Thompson explored central North Dakota, Charles Chaboillez, a fur trader, came to Pembina to establish the first North West Company post within the present boundaries of this State. Both the Hudson's Bay and the XY Companies established posts in the same vicinity in 1801, and with three great companies in deadly competition, life at Pembina was colorful and dangerous. Excusing their own lack of scruples on the grounds of competition, the companies bought furs with liquor, giving rum to the Indians until they agreed to sell or until they were too stupefied to know when the pelts were taken from them. Three years after the establishment of Chaboillez's post, Alexander Henry, a partner in the North West Fur Company, built a post on the Red River near the mouth of Park River, and shortly afterward moved down to the mouth of the Pembina. He made frequent trips to the Grandes Fourches (Grand Forks) and established depots there and in the Hair Hills, or Pembina Mountains. On one occasion he made a trip to the Missouri to visit the Mandans, and his journal says of their farming methods: "The whole view was agreeable and had more the appearance of a country inhabited by a civilized nation than by a set of savages." Liquor flowed freely at the Henry post. Traders found it profitable to deal with Indians who were in a drunken stupor. Henry's journal gives evidence that brawls were an everyday occurrence. One entry reads: "Feb. 9, 1806. Men and women have been drinking a match for three days and nights, during which it has been drink, fight--drink, fight--drink, and fight again--guns, axes, and knives their weapons--very disagreeable." Henry left Pembina in 1808 for the Saskatchewan River.