Proportion, andth Compared with Breadth.
Year: 1885

page_text: Proportion, and Length Compared with Breadth.
THOMAS ROBERT ABLETT of 36 Wemyss Rd. Blackheath, in the county of Kent,
Inspector of Art Teaching. I Thomas Robert Ablett do hereby declare the nature
of my said invention for TRAINING THE EYE TO JUDGE (AT SIGHT) THE LENGTH
OF LINES OR SPACES, THE PROPORTION OF LINES OR SPACES ONE TO ANOTHER &
LENGTH COMPARED WITH BREADTH, to be as follows:-
My invention consists of an oblong sheath which allows a strip of wood or other
material to slide inside it up & down. Inches & proportional divisions are marked
on the strip, which can be withdrawn from the sheath to show a length equal to a
given number of inches or a length having a given proportion to the length of a
certain part of the sheath. The strip can be wholly withdrawn from the sheath
& inserted in an aperture passing through one end of it. This aperture allows the
strip to pass right through the sheath in a direction at right angles to its length.
The strip thus placed in the sheath will show a length in a horizontal direction
equal to or proportional to that of a certain part of the sheath when placed in a
vertical position or vice versa. The interior of the sheath is arranged in such a
way that the figured side of the strip will not bear on it except at its edges.

page_text: sheath. Inches and proportional divisions are marked on the strip E and this strip
can be withdrawn, in part or wholly, from the sheath A B C D so that the part
exposed at the end A. B will show a length equal to a given number of inches or a
length having a given proportion to the length of the broad black line which is
marked on the reverse face of the sheath A¹ B¹ C¹ D¹. (The bevelling of one end
of the sheath A B calls attention to the part from which the slip emerges). The
strip E can be wholly withdrawn from the sheath and then inserted in a grooved
aperture F G H I, which passes through the sheath near the end of it D C or C¹ D¹.
This grooved aperture F G H I, which is shown on the side elevation X, allows the
strip E to pass quite through the sheath in a direction at right angles to its length.
The strip placed in the grooved aperture F G H I can be made to show a length
equal to or having a certain proportion to that part of the sheath marked B J
or B J, but in a direction at right angles to it. A metal band K L M N passes
round the sheath and slides over its surface. This metal band is narrow on the
side of the sheath marked B¹ A¹ D¹ C¹ and is used to mark off, from the broad
black line, any one of the proportions which are marked on the side A B C D of
the sheath. To facilitate this method of using the metal band a slit is cut in the
centre of it on the side K L M N and this slit allows the markings on the side A B
CD of the sheath to be seen in the centre of the metal band. When the slit of
the metal band has any marking showing at its centre on the side K L M N, the
narrow part of the metal band marks off the same proportional part from the broad
black line on the side B¹ A¹ D¹ C¹..
“Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is:"
"
1. The employment of a graduated sheath, which holds a graduated slip that
slides in grooves or through a grooved aperture made in it, for the purpose of
training the eye to judge (at sight) length, proportion, and length compared with
breadth.
2. The use of a metal band, of special construction, to mark off proportions on a
broad black line.
3. The bevelling of an end of the sheath in order to show clearly the place where
the slip, emerges from that end.