ully and accurately traced
from the station in the vicinity of Houlton where the labors of the year
1840 terminated to a point 4 miles north of the St. John River in the
vicinity of the Grand Falls, being a distance of 81 miles from the
monument. The timber has been removed along this line to a width
necessary for its accurate prolongation and for the requisite
astronomical observations at various points upon it, and a correct
profile, or vertical section, has also been obtained by means of the
spirit level the whole of the distance above mentioned.

Besides the astronomical observations necessary to obtain and continue
the due north direction upon this line, numerous magnetic observations
have also been made at a number of points upon it, in order to show the
physical causes which must operate to produce serious discrepancies
between a meridian line properly traced and such a one as has actually
separated the jurisdiction of the two Governments since the attempt in
the years 1817 and 1818 to define and mark this portion of the boundary
under the provisions of the treaty of Ghent, although no portion of that
line was ever ratified or made binding upon the parties to the treaty.

Upon this portion of the survey there have been chained, including
measured offsets to the old line and to other important points, 85
miles.

Four hundred and fifty-two transit observations of heavenly bodies have
been made, aided by three excellent chronometers, for the determination
of the true meridian direction, most of which also served for the
computation of the correct time.

For the determination of the longitude of this meridian west of the
Royal Observatory of Greenwich and the latitudes of four important
points upon it there were made eighty-five complete sets of astronomical
observations, including altitudes of the sun and stars and the meridian
transits of the moon and moon-culminating stars.

The number of barometric observations made upon the line and in its
vicinity is 5,767; besides which there were made at Calais, for
comparison with the level of mean tide on the St. Croix, 1,336 similar
observations.

There have been determined in altitude above or below the level of the
monument, by means of the spirit level, 1,716 points, and the altitudes
of 1,816 other points have been similarly observed in order to verify
the altitude of the monument above the level of mean tide at Calais.

For the determination of the magnetic va