A NEW AND IMPROVED APPARATUS FOR MEASURING DISTANCES, ALTITUDES, AND ANGLES
Year: 1868

page_text: ETTERS PATENT to Henri Adrien Bonneville, of the British and
Foreign Patent Offices, 10, Sackville Strect, Piccadilly, in the
County of Middlesex, and 18, Chaussée d'Antin, Paris, in the
Empire of France, Patent Agent, for the Invention of "A NEW AND
IMPROVED APPARATUS FOR MEASURING DISTANCES, ALTITUDES, AND ANGLES."**
-A communication from Charles Auguste Constantin Eckhold,
residing at Alexandria. in the Kingdom of Egypt.
Scaled the 29th January 1869, and dated the 10th December 1868.
COMPLETE SPECIFICATION filed by the said Henri Adrien Bonneville
at the Office of the Commissioners of Patents, with his Petition.
and Declaration, on the 10th December 1868, pursuant to the 9th
Section of the Patent Law Amendment Act, 1852.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HENRI
ADRIEN BONNEVILLE, of the British and Foreign Patent Offices, 10,
Sackville Street, Piccadilly, in the County of Middlesex, and 18,
Chaussée d'Antin, Paris, in the Empire of France, Patent Agent, send
greeting.

page_text: WHEREAS I am in possession of an Invention for "A NEW AND
IMPROVED APPARATUS FOR MEASURING DISTANCES, ALTITUDES, AND ANGLES,"
a communication from Charles Auguste Constantin Eckhold, a person
resident at Alexandria, in the Kingdom of Egypt, and have petitioned
Her Majesty to grant unto me, my executors, administrators, and assigns,
Her Royal Letters Patent for the same, and made solemn Declaration
that it is a communication.
NOW KNOW YE, that I, the said Henri Adrien Bonneville, do hereby
declare that the following Complete Specification, under my hand and
seal, fully describes and ascertains the nature of the Invention, and the
manner in which the same is to be performed, reference being had
to the accompanying Drawings, and to the letters marked thereon, that
is to say:
The Invention communicated to me relates to a new and improved.
apparatus for measuring the bases of triangulation, horizontal or oblique
distances, altitudes, and angles.
In Fig. 1 of the accompanying Drawings a represents a graduated
circle giving by means of a vernier the ten seconds of horizontal angles;
b, a glass moving in a plane perpendicular to-the-circle; c, another glass
fixed by the support k in the vertical plane of the glass upon the
circle a; d, a powerful microscope closely connected with the glass b ;
f, a very sensitive level resting on a ruler of a determinate length;
h, a scale fixed vertically at the extremity of the said ruler in the plane
of the optic axis of the microscope and divided into half millimetres
(the millimetres are alone marked with a figure comprised between one
and a hundred); i, a micrometrical screw joined to the lower part of the
scale giving the 1000 of a millimetre of the scale read on the graduated
circle of the screw; g, another very sensitive level, which may be applied
on the glass and serving to determine its horizontal position. Several
other organs and accessories, such as nut screws, counterweights, .level
keys, are represented in Fig. 1, as needful to obtain an efficient working.
In addition to the apparatus as being. necessary for its working, Fig. 2
represents a sight, not graduated, of an invariable length, 3 metres, for
instance, terminated at each extremity by a white line m, m', on a dark
background.

page_text: order the more readily to understand its mode of working and
appreciate the advantages resulting from its use, an example may he
be given Suppose the horizontal distance between any two giv
points has to be determined. First, the sight, as in all geodesic
operations, should be placed and vertically held upon one of the point
then the apparatus should be placed upon the other point by means
the level, and with the help of the nut screws the apparatus is dispos
in a horizontal plane. The glass is then pointed upon the white line
of the sight, and the glass fixed with the pressure screw. The scale
inclination of the glass is then read with the microscope. The magi
fying power of the microscope allows of reading only one figure
the scale at the same time. Suppose the figure read be 67 (millimetre
besides the indeterminate fraction comprised between that division a
the horizontal thread of the microscope. This fraction may be exact
estimated by means of the micrometer; for instance, let the fracti
read on the circle be 2035. This number is thereupon written down
the right of 67 already noted, which gives
This operation is identically repeated for the line m' of the
sight; suppose the number found be
-
"
the operation by means of the apparatus is terminated, as the
necessary data for calculating the distance are found. It is
now merely necessary to find the difference between these two
numbers, which is
and to divide 6,000,000 (a number constantly the same for all
other cases) by the difference found, which gives
which is the horizontal distance souglit.
6720
6094
626
95
This will be better understood by referring to the Fig. 3 of t
accompanying Drawings. Suppose the sight to be at m, m', o bei
the point around which the glass pivots, AB is the difference foun
62035. Let a horizontal line be drawn by the point o, the line AB bei
extended to H, and the line m, m', to D, AB and m, m', are perpen
cular to oD. In like triangles, oAH and omD we have the proporti
OH
AB
0-20 x 3
whence oD=0-0062635
0-6
0-0062635
6,000,000
62,635
=95-79.
In the foregoing example, the sight is supposed to be placed on o
point and the apparatus on another. That is not the only manner
operating; there are two other ways, the one by placing the appara
in a line with the two points, the other by placing it outside such a lin
either way a sight must be placed upon both the points. In the fi

page_text: for measuring inclined planes; the Figure required for effecting the
reckoning is given by the formula (see Fig. 2) m'D=
mm'x BH
AB that
is to say, three times the difference of the averages on the sight,
divided by the difference with the horizontal line. Measurements may
be obtained with great accuracy for distances of 100 or less; they
may be reckoned to the fraction of a millimetre, and for longer
distances where the apparatus now in use cannot be employed the
utmost accuracy may be obtained. This accuracy results, 1°, from
the fact that in disposing the apparatus there is no necessity to centre
the optical axis; 2°, that the operator ever has in view the same lincs
of the sight; 3°, that no hesitation arises in the readings, as in self-
registering sights, for which it is necessary to have recourse to estimates.
Levelling on uneven ground with ordinary levels is both long and
costly, the distances measured being necessarily very short, and the
operations being multiplied as the inclined plane is more rapid, whilst
the above apparatus allows of levelling points situate at very great
distances and very much out of the horizontal line. It offers therefore,
even as a level, advantages which are not to be found in the apparatus
in use up to the present day.
Having thus fully described and ascertained the nature of the said
Invention, and the manner of carrying the same into effect, what I
claim is a new and improved apparatus for measuring distances, altitudes,
and angles, substantially in the manner herein-before fully set forth and
described and illustrated in the accompanying Drawings.
In witness whereof, I, the said Henri Adrien Bonneville, have
hereunto set my hand and seal, this Ninth day of December,
in the year of our Lord Eighteen hundred and sixty-eight.