The Alleguash was ascended in the month of October in bateaux and canoes from its mouth to its source in Lake Telos, a distance of about 94 miles. The river and its lakes were coursed by a compass, the distances estimated, and the projection resulting therefrom corrected before being placed upon the map by means of astronomical observations at eight intermediate points between its mouth and its source. The lakes were triangulated by means of magnetic bearings as far as was practicable, in order to obtain their widths and general contour. In the vicinity of Chamberlain Lake use has also been made of a recent survey of Mr. Parrott, a surveyor in the employ of the State of Maine, to whom we acknowledge ourselves indebted for the aid which this portion of his valuable labors furnished us. Between the head of Lake Telos and Webster Pond, one of the sources of the East Branch of the Penobscot, there is a portage of only 1 mile and a half. This, together with a small cut or canal, made in 1841 to connect the waters of Lake Telos with those of Webster Pond, enabled the party which made this survey to proceed with their boats and baggage down the Penobscot to Bangor, where they and their surplus stores were disposed of. A survey of the river St. John was made in the month of September with the chain and compass from the mouth of Fish River to the intersection of the meridian of the monument at the source of the St. Croix with the St. John. This survey was afterwards extended eastward to the Grand Falls, in order to connect with the astronomical station established there, and westward to the mouth of the Alleguash, embracing a distance of 87 miles. The islands were all surveyed, and the channels on either side of them sounded. The commissioner, having had other duties assigned him in reference to the question of boundary, did not take the field in person until September. Between the middle of that month and the middle of December he was occupied in performing the field duties assigned him by the Department of State. The party conducted by him in person made the astronomical observations for the determination of the latitude and longitude of the Grand Falls of the St. John, and of the mouths of the Grand, Green, Madawaska, Fish, and St. Francis rivers, all tributary to the St. John. The same party also made a survey of the river St. Francis from its mouth to the outlet of Lake St. Francis, a distance of 81 miles. This river was coursed by means of a compass, and whenever the nature of the shores would permit the distances from bend to bend were either measured with a chain or paced. Through the greater part of the stream, however, the impediments offered by the thick and small growth near the shores rendered this degree of minuteness impracticable and a resort to estimating the distances by the eye, well practiced by previous actual measurements, became necessary.