A NEW OR IMPROVED INSTRUMENT FOR MEASURING DISTANCES & ALTITUDES
Year: 1863

page_text: PROVISIONAL SPECIFICATION left by Charles Thomas Boutet at the
Office of the Commissioners of Patents, with his Petition, on the
28th May 1863.
I, CHARLES THOMAS BOUTET, of Quai Mariemont, Brussels, Engineer, do
hereby declare the nature of the said Invention of "A NEW OR IMPROVED
INSTRUMENT FOR MEASURING DISTANCES & ALTITUDES," to be as follows, that is
to say:-
This instrument is based on a triangulation system, and consists of a
wooden tripod or support with moveable arms, having a table above a column
fixed on a triangle, which is mounted on the table of the tripod by means of
three screws which regulate the level of the instrument, which said column is
fixed in the centre by a strong screw with springs; at the upper part of the
column a horizontal circle is fixed for supporting the upper parts of the appa-
ratus, and a second moveable circle for the purpose of registering, and which
pivots horizontally on the first circle in the centre of the column. Two per-
fectly straight rules forming guides are fastened together, between which is
fixed a small rule divided in millimeters. At the right-hand end of the double
rule I fix perpendicularly a powerful telescope, so as to form with the rule an
angle of 90°. A sliding piece is placed on the double rule, on which it slides
by means of a parallel screw fixed between the two rules, the motion being
given by a small handle or a strong button. A small part of the rule is
attached to the sliding piece, and gives, by means of a vernier, the smallest
division of the millimeter, and moving with the sliding piece against the first

page_text: rule for dividing the divisions of the long rule. I also fix a third horizontal
graduated circle on the sliding piece, and which moves with it. In order to
give the inclination to the upper telescope a micrometric screw is adapted to
the graduated circle, and acts on the alidade. I have also a double and
divided alidade moveable at the centre of the circle, indicating the measure of
horizontal angles, and dividing the minutes of the circle by means of a vernier.
A compass is fixed between two of the arms of the graduated circle and indi-
cates the east. I fix a second telescope similar to the first on the alidade by
means of two small mountings. This telescope is moveable on its axis in a
vertical direction, and in a horizontal direction it follows the movement of the
alidade, on which it is mounted, and I fix a small arc of a graduated circle to
one of the mountings of the upper telescope. For dividing the minutes of the
arc of the circle by means of the vernier and indicating the measure of the
vertical angles, I provide a small alidade moveable with the axis of the upper
telescope, on which it is fixed. In order to put the said telescope and the
alidade in movement I adapt a screw to the other mounting of the upper tele-
scope, & the instrument is regulated by means of a portable spirit level.
For reading the divisions from the vernier, a portable magnifying glass is
provided.
The whole of the various parts of the instrument, with the exception of the
tripod, may be made of copper or of any other metal that has no influence on
the needle of the compass, the said parts being mounted by means of ordinary
screws and screws with springs, and the moveable parts are fixed at the time
of operating by means of pressure screws.