An Improved Sketching Protractor.
Year: 1890

page_text: Date of Application, 10th Apr., 1890
Complete Specification Left, 4th July, 1890-Accepted, 16th Aug., 1890
PROVISIONAL SPECIFICATION.
An Improved Sketching Protractor.
I JOHN FORMBY, of Formby Hall, near Liverpool in the County of Lancashiro,
Gentleman, do hereby declare the nature of this invention to be as follows:-
This invention relates to a certain improved arrangement of protractor for sketching
purposes. By the term protractor I mean a flat instrument of ivory, wood or metal
bearing upon its surfaces scales for the mensuration of angles distances etc., and also
various other useful collateral information relative to its practical use.
The object of my improved arrangement is to provide an instrument having a clear
and condensed arrangement of all the scales useful for practical purposes determinable
at sight, and thus the occurence of errors and delays will be obviated while greater
confidence and speed in his work will be ensured to the user.
In such instruments as usually arranged there are generally different scales marked
in yards of which one is on the front of the protractor. This arrangement when
working with any different scale causes great liability to error especially in rapid
work, while the marking in yards also is itself a source of error when using a scale
which has to be obtained by multiplication or division from that given: I therefore
provide a simple decimal division for all scales as being less liable to error.
A further objection is that the number of scales is very limited and the information
scanty, while only the single normal scale of horizontal equivalents is marked, there-
fore if different scales be required say large ones for fortification work
apparatus must be carried.
-
other
I will explain my invention with reference to the accompanying drawings in which
figure 1 is the front and figure 2 the back side of the instrument.
Referring first to the front side figure 1. The "protractor" or angle measurer is
arranged in the usual way, the degrees radiating from the centre of the top side A
around sides B C D. On the same surface along the side A is arranged an universal
scale of 22nds a, sub-divided at its left end & into 44th, the factors of eleven and
twenty two giving a direct decimal scale of yards for all scales of inches to a mile. A
special feature in my arrangement of this scale is the marking of the main sub-divisions
with small cross lines or dots a aa for the better and more rapid guiding of the eye,
for example such an eye guide is placed at the centre of the protractor, 90°, and
at every half and quarter inch on the main 22nds scale c, and on the sub-
divided 44ths a¹.
=
Occupying the central space of the front side below the scales ar¹ are arranged two
scales A A2, the upper one A¹ being 25000. 2:5344 inches to a mile, and the lower
one A² being 20000 = 3.168 inches to a mile, these scales are arranged with parallel
scales of German Schritt, English yards, and French mètres : almost all German and
French war map scales being simple factors or multiples of these two-thus French
or German scales can be translated at sight into English measures of yards, or a
scale may be constructed by having the representative fractions which are also
indicated.
Figure 1 clearly illustrates the arrangement combination and grouping of all the
above described improvements.
Referring now to the arrangement of the back surface of the instrument illustrated
in figure 2.
There are arranged in a convenient manner and position a number of scales
including one of French millimètres and also different scales of horizontal equivalents
(hereinafter referred to by the letters H. E.) commonly used in English, French
and German war maps, with useful information from which any such scal: may be
constructed. Looking at figure 2 reversed on the right end E are two scales, e ol
TD 01

page_text: 30ths, and e¹ of 9ths of an inch. Along the top side F are three scales each two
inches in length and arranged in order from right to left, of which represents 12ths,
f16ths and f2 20ths of inches. On the left end G is a scale g of 50ths, and on
the top side E to the right is a short scale h one inch long of 35ths. Below
scale is placed a scale of ths and below scale f2 is a scale of ths each less
than two inches long. Below these two scales f³ and f is a scale of millimètres.
It will be noticed that the scales e e¹ on E are devisible by 3, those on F by 4, on
by 5, and on H by 7-on the inches are all marked with a cross or dot a au
on the lines, as hereinabove described. The length of each scale is immaterial so long as
the main divisions of inches can be read clearly and uninterruptedly throughout, for
the actual small divisions are generally only required for the sinall end of any scale
to be put on paper.
Reversing the figure on the side H is marked at h¹ the normal scale of H. E. (as
at present authorised) to 20°, but divided into 3rds and ths for the first 10°, and
s for the remainder. This gives greater flexibility so that either the same vertical
interval (V. I.) may be used for other scales than six inches to a mile, or other V. I.
may be used for the six inch scale. Below this scale is given the rule N for finding
the V. I. for other scales using the normal scale; and immediately below N is given
the rule N for constructing tables of H. E. Below this is a scale ² of H. E. for a
four inch scale V. 1. 25 feet. Below this is a German scale h³ of H. E. showing
the usual V. I. for the scales on figure 1; and finally below this scale is a French
scale of H. E. showing the usual V. I. for the same scales.
Although in the foregoing specification I have set forth definite groupings and
combinations of my improved arrangement of scales rules and relative information
upon a protractor I wish it to be understood I do not confine my improvements within
such very narrow limits, as the said arrangements groupings and combinations may
be transposed or varied the essential features however whereby the best results may
be produced remaining substantially the same.
Dated this 10th In: 1000
COMPLETE SPECIFICATION.
An Improved Sketching Protractor.
I JOHN FORMBY, of Formby Hall, near Liverpool, in the County of Lancashire,
Gentleman, 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 :-
This invention relates to a certain improved arrangement of protractor for sketching
purposes. By the term protractor 1 mean a flat instrument of ivory wood or metal
bearing upon its surfaces scales for the mensuration of angles distances etc.; and also
various other useful collateral information relative to its practical use.
The object of my improved arrangement is to provide an instrument having a
clear and condensed arrangement of all the scales useful for practical purposes
determinable at sight, and thus the occurrence of errors and delays will be obviated
while greater confidence and speed in his work will be ensured to the user.
In such instruments as usually arranged there are generally different scales marked
in yards of which one is on the front of the protractor. This arrangement when
working with any different scale causes great liability to error especially in rapid
work, while the marking in yards also is itself a source of error when using a scale
which has to be obtained by multiplication or division from that given: I therefore
provide a simple decimal division for all scales of inches to a mile as being less liable
to error.
A further objection is that the number of scales is very limited, therefore if more
be required say large ones for fortification work-other apparatus must be carried,

page_text: while only the single normal scale of horizontal equivalents is marked, and
information is scanty.
I will explain my invention with reference to the drawings filed with my provisional
specification in which figure 1 is the front and figure 2 the back side of the instrument,
and also in reference to the sheet filed with this specification which illustrates different
methods of notation of the protractor which I also use.
Referring first to the front side figure 1. The "protractor" or angle measurer may
be arranged in known manners, the degrees radiating from the centre of the top side Á
around sides B CD and being notated either as illustrated in figures 1 or 4: 1 con-
sider however the method of notation illustrated in figure 4 to be novel-herein the
centre line is marked 360° on the outer row of figures and 180° on the inner, the
outer row running from 280° to 80° the inner from 100° to 260° along the sides BCD,
the figures of the inner row along the side C, being inverted as shown. On the
same surface as the protractor along the side A is arranged an universal scale of
22nds x, the factors of eleven and twenty two giving a direct decimal scale of yards
for all scales of inches to a mile. This is illustrated in figure 4. It is five inches
long so as to leave at each end a space of half an inch to the corner of the protractor
see Fig. 4, and is numbered in tens being subdivided into 44ths at each side of every
tenth line, while the fives are marked with small cross lines or dots a a a for the
better and more rapid guiding of the eye, for example such an eye guide is placed at
the centre of the protractor (which is 55 of the scale) and at every tenth line on each
side of it.
1
Occupying the central space of the front side below the scale are arranged two
scales A A2 the upper one A' being 5000 = 2.5344 inches to a mile, and the lower
one A2 being 20000 = 3.168 inches to a mile, these scales are arranged with parallel
scales of German Schritt, English yards, and French metres almost all German and
French war map scales being simple factors or multiples of these two-thus French or
German scales can be translated at sight into English measures of yards, or a scale
may be constructed, having the representative fractions which are also indicated.
:
Figures 1 and 4 clearly illustrate the arrangement combination and grouping of all
the above described improvements.
Referring now to the arrangement of the back surface of the instrument illustrated
in figure 2.
There are arranged in a convenient manner and position a number of scales including
one of French millimetres and also different scales of horizontal equivalents (hereinafter
referred to by the letters H. E.) commonly used in English, French, and German war
maps, with useful information rom which any such scale may be constructed.
Looking at figure 2 reversed on the right end E are two scales, e of 30ths, and e
of 9ths of an inch. Along the top sido are three scales each two inches in length
and arranged in order from right to left, of which represents 12ths, f¹ 16ths and
f2 20ths of inches. On the left end G is a scale g of 50ths, and on the top side H to
the right is a short scale h one inch long of 35ths. Below scale f is placed a scale f³
of ths, and below scale 2 is a scale of ths, each less than two inches long.
Below these two scales f³ and is a scale f' of millimètres.
It will be noticed that the scales e e' on E are divisible by 3, those on F by 4,
that on G by 5, and on H by 7. On F the inches are all marked with a cross or
dot aa a on the lines as hereinabove described. The length of each scale is immaterial
so long as the main divisions of inches can be read clearly and uninterruptedly through-
out, for the actual small divisions are generally only required for the small end of
any scale to be put on paper.
Reversing the figure on the side H is marked at h¹ the normal scale of H. E. (as
at present authorized) to 20°, but divided into rds and ths for the first 10°, and
s for the remainder. This gives greater flexibility so that either the same vertical
interval (V. I.) may be used for other scales than six inches to a mile, or other V. I.
may be used for the six inch scale. Below this scale is given the rule N for finding
the V. I. for other scales using the normal scale of H. E., and immediately below N
is given the rule N' for constructing tables of H. E.

page_text: Below this is a scale h² of H. E. for a four inch scale V. I. 25 feet. Below this is
a German scale 3 of H. E. showing the usual V. I. for the scales on figure 1; and
finally below this scale is a French scale h of H. E. showing the usual V. I. for the
same scales,
Although in the foregoing specification I have set forth definite groupings and
combinations of my improved arrangement of scales, rules, and relative information
upon a protractor, I wish it to be understood 1 do not confine my improvements within
such very narrow limits, as the said arrangements groupings and combinations may
be transposed or varied, the essential features however whereby the best results may
be produced remaining substantially the same.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed I declare that what I
claim is:
In an instrument such as is hereinabove described
1. The arrangement of an universal decimal scale of yards for all scales of inches to
a mile arranged on same surface as the angle protractor itself.
2. The notation or marking in figures of an angle protractor as set forth in reference
to figure 4.
3. The marking of the main points and sub-divisions of scales with small cross lines
or dots for the more rapid and accurate guidance of the eye of the operator.
4. The combination with the foreign scales arranged substantially as illustrated
of English equivalent scales arranged in parallel for translation at sight.
5. The arrangement and sub-division of the normal scale of English H. E. and
the combination therewith of French and German H. E. marked as set forth whereby
the V. I. may be applied to other scales, and with or without the formulæ for the
construction of tables of H. E.
5. The number, disposition, sub-division, notation, and general grouping of the
various scales for measurement of distances, of angles, and of H. E., and V. I.,
together with the representative fractions and formulæ for constructing same when
desired substantially as set forth and illustrated in the annexed drawings (except in
so far as they are herein before acknowledged to be known) or any mere modified or
varied arrangement thereof producing the same or a similar result.
Dated this Third day of July 1890
y ot
J. C. CHAPMAN, Fel. Inst. Patent Agents,
70, Chancery Lane, London, W., Agent for Applicant.