The astronomer, after spending a few weeks in making up his notes and surveys, determined to go eastward and undertake the survey of the Red River. On February 26th, 1798, he started with three French Canadians and an Indian guide. Six dogs drew three sleds laden with baggage and provisions. The company soon reached the sand hills, then called the Manitou Hills, from some supposed supernatural agency in their neighbourhood. Sometimes on the ice, and at other times on the north shore of the Assiniboine to avoid the bends of the river, the party went, experiencing much difficulty from the depth of the snow. At length, after journeying ten days over the distance of 169 miles, the junction of the Assiniboine and Red River, at the point where now stands the city of Winnipeg, was reached. There was no trading post here at the time. It seems somewhat surprising that what became the chief trading centre of the company, Fort Garry, during the first half of this century should, up to the end of the former century, not have been taken possession of by any of the three competing fur companies. Losing no time, Thompson began, on March 7th, the survey, and going southward over an unbroken trail, with the snow three feet deep, reached in seven days Pembina Post, then under the charge of a leading French trader of the company, named Charles Chaboillez. Wearied with a journey of some sixty-four miles, which had, from the bad road, taken seven days, Thompson enjoyed the kind shelter of Pembina House for six days. This house was near the forty-ninth parallel and was one of the especial points he had been appointed to determine. He found Pembina House to be in latitude 48 deg. 58´ 24´´ N., so that it was by a very short distance on the south side of the boundary line. Thompson marked the boundary, so that the trading post might be removed, when necessary, to the north side of the line. A few years later, the observation taken by Thompson was confirmed by Major Long on his expedition of 1823, but the final settlement of where the line falls was not made till the time of the boundary commission of 1872. Pushing southward in March, the astronomer ascended Red River to the trading post known as Upper Red River, near where the town of Grand Forks, North Dakota, stands to-day. Here he found J. Baptiste Cadot, probably the son of the veteran master of Sault Ste. Marie, who so long clung to the flag of the Golden Lilies.