IMPROVEMENTS IN TELEMETERS OR INSTRUMENTS FOR MEASURING DISTANCES
Year: 1879

page_text: LETTERS PATENT to Herbert John Haddan, of the Firm of Herbert and
Company, Solicitors of Patents, of 67, Strand, in the City of Westminster,
Civil Engineer, for the Invention of "IMPROVEMENTS IN TELEMETERS OR
INSTRUMENTS FOR MEASURING DISTANCES." A communication from abroad
by Julius Krause, of Cassel, in the Empire of Germany.
PROVISIONAL SPECIFICATION left by the said Herbert John Haddan at the
Office of the Commissioners of Patents on the 8th April 1879.
"
HERBERT JOHN HADDAN, of the Firm of Herbert and Company, Solicitors of
Patents, of 67, Strand, in the City of Westminster, Civil Engineer. IMPROVE-
MENTS IN TELEMETERS OR INSTRUMENTS FOR MEASURING DISTANCES."
A com-
munication from abroad by Julius Krause, of Cassel, in the Empire of Germany.
The Invention consists in the combination of two telescopes placed upon a beam
or frame near the two ends of it in such a manner that one of the telescopes
remains invariably rectangular to the beam while the other may turn freely, so
that the axis of the two telescopes may be made to intersect each other in any
desired point the distance of which is to be measured, the motion of the second
telescope imparting motion to the short arm of a double armed lever of which the
longer arm carries or moves over a segment or are provided with divisions which
correspond to and indicate the various distances, for which purpose the second
telescope is fixed upon a plate at the end of a rod or tube which goes through the
interior of the beam or frame, and has its fulcrum under the centre of the first
telescope, so that the axis of the second telescope remains always at a right angle to
the radius which connects its centre with the fulcrum.
The whole instrument may be placed upon and turn horizontally round a gradu-
ated disc fixed on a standard or tripod, like a theodolite or a levelling instrument.
The telescopes are vertically movable and adjustable, and may be provided with
spirit levels.
The instrument may be constructed of metal, provided with a
compass, and is to be used for measuring distances, heights, or angles, or surveying
purposes generally.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Herbert John Haddan in the Great Seal Patent Office on the 17th
October 1879.
HERBERT JOHN HADDAN, of the Firm of Herbert and Company, Solicitors of
Patents, of 67, Strand, in the City of Westminster, Civil Engineer. " IMPROVE-
MENTS IN TELEMETERS OR INSTRUMENTS FOR MEASURING DISTANCES."
A com-
munication from abroad by Julius Krause, of Cassel, in the Empire of Germany.
By means of this new telemeter the required distance can be determined in a
simple and safe manner without any other means, and through the application of
the horizontal circle, the vertical arcs, and the compass, an instrument is constructed
by means of which in an uncommonly short time and from one point of view a
correct survey of three hundred square kilometers may be made, which is sufficient
for all general and preliminary works for military, maritime, and geographical
purposes. The new telemeter differs from the usual ones in the following points :—
No angular measurement and table are required; no vernier for the telemeter is
required, and more than one fixing and reading is unnecessary; the multiplication
of arcs offers a more correct division of the measuring scale than any other instru-
ment; the new instrument is conveniently constructed and it can easily be used
without any practice by any one having a sharp and correct eyesight. In the
annexed Drawing, B (Fig. 3) shows the three legged foot with horizontal circle
divided in / degrees, three set screws and mikrometer work H, I; C, (Fig. 1, 3),
a lattice frame supported by the alhidade A to which the central pin is fastened;
D1 and D2, two telescopes supported by the lattice frame C rectangular to its length.
The telescope D¹ with two arcs W is rigidly fastened to C by means of the frame G
carrying the vernier for W. The telescope D2 is provided with a correcting con-
trivance x (Fig. 3) for fixing it parallel with D', is movable with its frame R round
D' in such a manner that it always remains rectangular to the radius of rotation.
The fulcrum ball o (Fig. 4) coincides with the point of intersection of the longitudinal
axis of the instrument with the vertical plane through the axis of the telescope.
The adjusting plate R (Fig. 6) is provided with two slots, the larger one being
parallel with D2 for the axis of rotation T of the small telescope Z (Fig. 6), in order
to effect the movement in an unhindered manner, whilst the small slot in the
direction of the longitudinal axis is necessary for the motion of the exactly fitting
pin U; N (Figs. 1, 3, 4) represents a brass tube by means of which the turning of
the telescope D around D¹ with a constant radius of 11 m. is accurately effected,
the brass tube is arranged in such a manner that it can be made longer or shorter
by means of the slide M (Fig. 5) in order to fix the constant distance. The connec-
tion of this tube N with the ball point O (Fig. 4), as well as with the frame R is to
be seen in Fig. 5. G represents a spirit level fixed on the centre of the albidade;
E (Figs. 1, 3, 7), the distance indicator 900 millimeters long, fastened to the lattice
frame by the two screws F, is fixed on C in such a manner that its distance from T
is exactly 1000 millimeters, and that it stands rectangular to the longitudinal axis
thus parallel with D¹; Z represents a small fixing telescope, the axis of rotation T
(Fig. 6) of which is held by two steel pins V carried by the brackets S. At a
distance of 10 millimeters from T the driving pin U is firmly fastened; L is an
adjusting screw acting on the foot plate R in front of the driving pin, whilst K
represents the corresponding casing which acts on the other side of R through a
dove-tailed guide directly upon the driving pin U. By a suitable contrivance the
foot plate R can be fastened to the lattice frame C (for transport). To the new
telemeter belongs further a box compass 200 millimeters long and 100 millimeters
broad, made of hard india rubber and provided on each side with a division of 20
degrees. The box is shaped in such a manner that the compass may be placed upon
the telescope D¹. The new telemeter is used in the following manner :-(a) as

page_text: telemeter after the instrument has been adjusted on a suitable stand and
fixed horizontally by means of the three set screws and the spirit level G, the
telescope D¹ is approximately directed to the object to be observed, the fixing screw
H is then fastened whilst the more accurate adjustment is effected by means of the
mikrometer screw I. By means of the set screw L the telescope D' is now moved
until its cross wires coincide with the object viewed in an equal manner by the
telescope D'. The sliding motion of the telescope D³ moves also the driving pin U
whence the fixing telescope z, the fulcrum T of which is 100 millimeters distant
from E, describes the way travelled by U, which way is a hundred times enlarged
on the distance measurer; E represents the tangent of the multiplied arc by means
of which the required distance is ascertained through the small telescope Z. (b) as
height measurer; if the telescope D¹ is elevated in such a manner that the horizontal
thread coincides with the point to be observed, the angle is ascertained on the
vernier W up to 20 seconds, and the difference of height is then calculated from this
result and the distance found. (c) as magnet theodolite; after the horizontal
adjustment the box compass is placed on D', the magnet needle is disengaged, and
the instrument turned in such a manner that D' stands accurately in the magnetic
meridian, whence the position of the vernier of the alhidade is ascertained, the
compass is then removed, all required points on the horizon are viewed, and their
distances from the point of observation are simultaneously noted. By means of the
accurate observation of one object with the two telescopes, as above stated, angle a,
c, b, equal b, a, d, is measured directly, according to the diagram, Figure 8. The
distance a, c, =
is found from the constant distance of the two
sine. 4 b. a. d.
telescopes amounting to 1.1 m. and the measured angle. These angles and their
arcs being however very small the hundred multiplication of arcs has created a scale
which gives with greater accuracy the required distances for all angles to which
the instrument has been set and which are read off by means of the small telescope Z.
The division of this scale E is executed under the following considerations: -1. The
calculation of angles for given distances; 2, the corresponding arcs for the radius
(Fig. 6) 1100 + 10 + 10 = 1120 m. m.; 3, the division of these arcs from the
point of contact h of the ideal arc d, h, g, with the arc of the driving pin f
h, g, (diagram, Figure 9), towards both sides (T being 4 / distant from the
longitudinal axis) in order, 4, to be able to calculate the angle described by
the axis of Z during its motion towards the longitudinal axis sine ✗- h, T,
d¹,
=
h¹. d.
10.
==
h. d.
10.
1.1
5; finally, the distances from 150 to 20000 m. to be marked
on the scale were calculated by means of these angles, and the distance E, T,
1000 m
When the two telescopes are placed parallel to each other the small
telescope Z has to point exactly to the line a, b, (Figure 7).
m'
CLAIMS.
1. The enlargement of the arcs in any suitable degree, but preferably hundred
fold, by means of a movable telescope.
may be
2. The division of the scale in such a manner that the required distances
read directly without angular measurement and without the use of tables.
3. The general construction of the new instrument called "telemeter." the whole