A Distance Measurer.
Year: 1890

page_text: Date of Application, 20th Aug., 1890
Complete Specification Left, 8th May, 1891-Accepted, 20th June, 1891
PROVISIONAL SPECIFICATION.
A Distance Measurer.
I JOHN PHILIP NOLAN of Ballinderry Tuam Co. Galway do hereby declare the
nature of this invention to be as follows:-
The combination in the focus of one telescope of scales for measuring distances
one of these scales being graduated for a base at the observing point and one, two
or more being graduated for one two or more bases at the observed point.
In the instrument described in my Patent 2886-1889 I have described a
transparent scale graduated for a known base at the observing point or station.
I now add under this present invention two other scales-marked on the same
plate of glass as the original scale these latter scales are arranged to measure
distances by the heights of objects at the observed point.
About six and eight feet are the two best heights or bases to which to graduate
these scales.
-
This combination is however a suitable improvement for other instruments which
measure distances by means of a known base at the observing point or station.
The formula used in calculating any of these scales is distance a, is to focal
length of telescope as base is to the interval between the line called the infinity
line of the scale & the mark corresponding to the distance.
My invention then consists in adding to an instrument-which measures distances
through the aid of a known base at the observing point or station-one two or more
scales, which scales will also enable such an instrument. to be used for measuring
distances through the means of heights on bases at the observed point when such
bases are available-these scales are to be placed in the focus of a telescope.
Dated this Twentieth day of August 1890.
JOHN PHILIP NOLAN.
COMPLETE SPECIFICATION.
A Distance Measurer.
I JOHN PHILIP NOLAN of Ballinderry Tuam Co. Galway Lieutenant Colonel
retired do hereby declare the nature of this invention and in what manner the
same is to be performed, to be particularly described and ascertained in and by the
following statement :—―
My invention consists in the combination of scales in the focus of a telescope used
for measuring distances.
There have been amongst other methods of measuring distances two well known
ones.
One consists in an instrument which measures distances by the aid of a fixed
base at the observing point.
The other measures distances by the aid of a base at the observed point or
station.
My invention consists in placing in the focus of a telescope of an instrument which
measures distances by means of a base at the observing point or station-a scale or
scales, suitable for measuring distances by means of a base or bases at the observed
point or station.
In my Patent 2886-1889 I have described an instrument which measures
17

page_text: distances by the aid of a base contained in the instrument and at the observing
point.
In that Patent I have described a scale photographed or inscribed on glass and
placed in the focus of a telescope used in the instrument.
Under this present invention I also photograph or inscribe on the same piece of
glass one two or more scales, suitable for measuring distances by means of a base
at the observed point.
The bases for which I prefer to graduate the scales for use in conjunction with a
base at the observed point are generally 6 feet and 8 feet.
This present invention is largely directed to introducing an improvement into
the scale of the instrument described in 2886-1889 Patent but it could also be
introduced into any cognate instrument.
The formula for the new or additional scales is the same as that for the old scale
in my Patent 2886-1889 namely
This formula is well known.
I arrange my scales by having the one for the [horizontai] base (generally
employed with instruments measuring distances by the aid of a base at the observing
point) in the centre and placing two scales for use with bases at the observed point
one on each side of the scale used with the base and at the observing point. This
might however be varied.
The advantage sought is to combine a scale suitable for measuring distances with
a base at the observing point, with scales suitably arranged for measuring distances
with bases at the observed point.
The whole of the scales are photographed or inscribed upon the same piece of
glass which is placed in the focus of a telescope of the appropriate focal length for
the scales and which is arranged as a part of an instrument for measuring distances
with a base at the observing point or station.
The drawing shows how three such scales would be marked on a thin plate of
glass.
The centre on scale A. is the scale used for observations at the observing station
it is drawn for a focal length of one yard and a base of 4 feet giving the distances
in yards.
Scales B and C are calculated for vertical bases of 8 feet and 6 feet respectively
placed at the observed point.
All the scales in the drawing are supposed to be magnified 50 times over the
true scale.
Scales A B & C are all calculated for the same focal length of telescope.
These scales could be photographed directly or almost so on the glass from the
drawing supplied.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is
(1) Adding to an instrument which measures distances by means of a base at the
observing point-which base is contained in the instrument-one or more scales for
obtaining distances with the aid of a base or bases at the observed point. These
scales being placed in the focus of a telescope.

page_text: (2) Adding one or more scales suitable for measuring distances by the aid of a
base or bases at the observed point to the instrument described in my Patent 2886
of 1889.
Dated this Eighth day of M... 1901
JOHN PHILIP NOLAN.
Applicant.