An Improved Instrument for Measuring Distances on a Chart, and also when so required, for use as a Protractor and as a Station Pointer.
Year: 1892

page_text: Date of Application, 30th Sept., 1892
Complete Specification Left, 15th June, 1893-Accepted, 5th Aug., 1893
PROVISIONAL SPECIFICATION.
An Improved Instrument for Measuring Distances on a Chart, and
also when so required, for use as a Protractor and as a Station
Pointer.
I, JOHN WILSON GILLIE Nautical Instrument Maker of the New Quay North
Shields in the County of Northumberland, do hereby declare the nature of this
invention to be as follows:-
Distances are usually measured on a chart by means of a pair of compasses.
When a ship's position at sea, after having been calculated from astronomical
observations, has to be laid down on a chart, two pairs of compasses are generally
used, one pair to mark off the distance in latitude from the nearest parallel of
latitude and one pair to measure the distance in longitude from the nearest meridiau.
I propose to use a thin rectangular sheet of xylonite or other similar material about
ten inches by five, or other suitable dimensions, the edges of which are cut perfectly
straight and the corners perfectly square. In using such a sheet so prepared for
laying down a ship's position, the distance in longitude would be measured along
one of the short sides of the sheet from one of the corners to a mark made with a
pencil on the border of the sheet, the distance in latitude from the same corner to
another pencil mark made on the border of one of the long sides; the sheet would
then only require to be laid on the chart with the first-mentioned pencil mark on the
meridian and the second pencil mark on the parallel, from which the distances were
in each case respectively measured, when the corner before spoken of would
indicate the ship's position which could then be marked on the chart with a pencil
in the usual way, thereby enabling positions to be more conveniently and
expeditiously laid down on a chart than has been possible heretofore.
To enable the aforesaid transparent sheet to be used for measuring distances
directly, when the scale to which the chart is drawn is known, I mark upon it two
scales of tenths of an inch, one down the centre of the sheet parallel to and equi-
distant from the two longer sides, the other along the border of one of the shorter
sides which I shall hereafter call the bottom side.
When the before described transparent sheet is required for measuring angles, I
mark degrees along the borders of the two longer sides of the aforesaid sheet and
along the border of the short side opposite to that just described as the bottom
side. When the sheet is also used for marking off a ship's position or measuring
distances in the ways before described, I place the degree marks about an eighth
of an inch from the edges of the sheet in order that they may not interfere with
any pencil marks which may require to be made on the borders of the said sheet.
I make the degree marks very short in order that they may take up as little room
on the sheet as possible and so leave the greater portion of the sheet free and clear
from markings, thereby enabling the depths and character of soundings taken to be
pencilled on the sheet and compared with the corresponding depths &c. laid down
on the chart and seen through the sheet if so desired. The centre from which the
degrees are drawn I prefer to make the centre of the short side before described as
the bottom side. By means of these degree marks I make it possible for the
before described transparent sheet to be used as an instrument not only for
measuring distances but also as a protractor and as a station pointer, for the angles
which the legs of a station pointer are used to indicate may be indicated on the
aforesaid sheet by means of lines ruled with a straightedge and pencil, and the
sheet may then be used in the same way as a station pointer is used, the ship's
position being finally pricked off by inserting the point of a pencil in a small hole

page_text: which is drilled through the centre, from which the degrees are drawn on the bottom
side of the sheet.
For the cheap production of this before-described transparent sheet, I find it.
convenient to make some or all of the markings on the sheet by means of a suitable
die, slightly heated laid on the sheet and pressed upon it by means of a screw or
weight.
Dated this 29th day of September 1809
.
COME LEIE SPECIFICATION.
An Improved Instrument for Measuring Distances on a Chart, and
also when so required, for use as a Protractor and as a Station
Pointer.
I, JOHN WILSON GILLIE, Nautical Instrument Maker, of the New Quay
North Shields, in the County of Northumberland 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 :-
Distances are usually measured on a chart by means of compasses or dividers.
When a ship's position at sea, after having been calculated from astronomical
observations has to be laid down on a chart, two pairs of compasses are generally
used, one pair to mark off the distance in latitude from the nearest parallel of
latitude and one pair to measure the distance in longitude from the nearest meridian;
but, according to my invention, I use a sheet or strip of thin xylonite or similar
material with one or both surfaces slightly roughened to receive the mark of a
pencil. I prefer to roughen the surface by means of fine emery paper and I prefer
to use what is known as a copying pencil for marking the surface. I prefer to make
the sheet rectangular and about ten inches long and five inches wide, the edges
being accurately straight and the corners accurately square. In using such a sheet
so prepared for laying down a ship's position, the distance in longitude would be
measured along one of the short sides from one of the corners to a mark made with
a pencil on the border of the sheet, the distance in latitude from the same corner
to another pencil mark made on the border of one of the long sides, the sheet then
only requires to be laid on the chart with the first mentioned pencil mark on the
meridian and the second pencil mark on the parallel from which the distances were
in each case respectively measured, when the corner before spoken of will indicate
the ship's position, which can then be marked on the chart with a pencil in the
usual way, thereby enabling positions to be more conveniently and expeditiously
laid down on a chart, than has been possible heretofore. By altering the dimen-
sions of the sheet and making it longer and narrower, it may be made capable of
being used for measuring distances on a chart, which would be beyond the stretch
of ordinary dividers or compasses. When it is desired to use the before described
sheet for the purpose of measuring distances directly, that is without referring to
the printed scale of miles or degrees at the side of the chart, I mark upon the
before described sheet two scales of tenths of an inch, one down the centre midway
between the two longer sides, the other along the border of one of the shorter sides
which I hereafter call the bottom side, so that when the scale of the chart is known,
the distances may be read off directly from the aforementioned scales.
When the before described sheet is required for use as a protractor or station
pointer, I mark degrees along the borders of the two longer sides and along the
border of the short side opposite to that just described as the bottom side.
I place the degree marks about an eighth of an inch from the edges of the sheet
in order that they may not interfere with any pencil marks, which may have to be
made ou the extreme borders. I prefer to make the degree marks very short, in
order that they may take up as little room on the sheet as possible and so leave the
greater portion of the sheet free and clear from markings, thereby enabling the

page_text: depths and character of soundings taken (to be pencilled if so desired) upon
the sheet, and compared with the corresponding depths laid down on the chart and
seen through the sheet. The centre from which the degrees are drawn, I prefer to
make the centre of the bottom side. By means of these degree marks, I make it
possible for the before described sheet to be used as an instrument not only for
measuring distances, but also as a protractor and as a station pointer, for the angles
which the legs of a station pointer are used to indicate may be indicated on the
aforesaid sheet by means of lines ruled with a straightedge and a pencil, and the
sheet may then be used in the same way as a station pointer, the ship's position
being finally pricked off by inserting the point of a pencil in a small hole, which is
drilled through the sheet through the centre from which the degrees are drawn.
When my invention is intended to be used only for measuring distances on a
chart, the sheet or strip may be cut from white opaque xylonite or ivorine, but
when it is also desired to be used as a station pointer, I cut the sheet out of the best
transparent xylonite.
For the cheap production of the before described sheets, I find it convenient to
make some or all of the markings on the sheet by means of a suitable die, pressed
upon the sheet by means of a screw, lever or weight.
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) A rectangular sheet or a strip of thin xylonite or similar material, with one
or both surfaces slightly roughened, so as to be capable of receiving the mark of a
pencil; used in measuring distances on a chart.
(2) A sheet of xylonite or similar material with one or both surfaces roughened
so as to receive the mark of a pencil, marked with a scale of degrees round three
sides, for use as a station pointer and protractor.
(3) In the manufacture of protractors out of xylonite or similar material for
use as station pointers on a chart the use of a die for producing the markings or
divisions required.
Dated this 14th day of June 1893.
JOHN WILSON GILLIE,