Ten principal points have been determined in latitude and longitude by means of 115 sets of astronomical observations, aided by three good chronometers, and seventeen other points have been determined by triangulation with a portable theodolite.  Two hundred and five points have been determined in altitude by means of 1,319 barometric observations, and seventeen by means of the theodolite and spirit level.  One hundred and ninety-two observations have been made for determining the variation of the magnetic needle at three important points.

The field duties above mentioned are considered to furnish sufficient data for a correct map of the line reported upon by the late British commissioners, Colonel Mudge and Mr. Featherstonhaugh, between the St. John River and the head of the Aroostook, besides some lateral explorations of considerable extent that will have an important bearing upon this branch of the subject.  The work accomplished is full as much as could have been properly done in a single season, marked, as the last was, by an unusual drought of long continuance, which rendered it impossible to ascend, even with light canoes, some of the smaller streams, especially those forming the northwesternmost sources of the Aroostook.  These might be profitably explored another season.

2.  The division under the direction of A. Talcott has, besides verifying a part of the line of 1840 and tracing the course of Indian Stream (a branch of the Connecticut) to its source, explored and surveyed the line of highlands which extends from the Kennebec road to the Temiscouata portage, and so much of the line claimed by Great Britain as extends from the Kennebec road to the eastward as far as the head of the Aroostook River.

In the course of this survey, without counting the lines of approach or ground traveled over more than once, 703 miles have been passed over and such notes taken as will form the basis of a map.  Of these 703 miles, 335 are upon the lines respectively claimed as boundaries by the Governments of the United States and Great Britain.  In the course of these surveys, in order to the geographical determination of the position of the line, the latitudes of 54 points have been determined by means of 114 sets of altitudes of heavenly bodies, and the sets of subsidiary observations for time and for the determination of longitude by chronometers amount to 245.  The number of points at which observations have been made by barometers for the purpose of determining their altitudes is 930, of which 669 are upon the boundaries respectively claimed by the two countries.  The number of separate sets of barometric readings made at these points amounts to 1,981, while those made at the fixed stations, with which the former are to be compared, amount to 1,671.

3.  The division under the direction of J. Renwick has explored or surveyed the line of highlands from the southeastern extremity of Lake Matapediac to the vicinity of the river Du Loup, where the line of survey has been connected with that of A. Talcott.  In this survey a gap is yet left of a few miles on the western side of the valley of the Rimouski near its source.