EVERY VISIBLE OBJECT MAY BE DRAWN AND TAKEN TO ANY SIZE, ON TRUE MATHEMATICAL PRINCIPLES, WITH GREAT ACCURACY AND FACILITY
Year: 1786

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
HENDERSON, of the City of York, Stucco Plaisterer, send greeting.
WHEREAS His most Excellent Majesty King George the Third, by His
Letters Patent under the Great Seal of Great Britain, bearing date at West-
minster, the Nineteenth day of December, in the twenty-seventh year of His
reign, hath been graciously pleased to give and grant unto me, the said
Thomas Henderson, my exors, admors, and assigns, especial license, full
power, sole privilege and authority that I, the said Thomas Henderson, my
exors, adiñors, and assigns, and every of them, by myself and themselves,
or by my and their deputy or deputies, servants or agents, or such others as
I, the said Thomas Henderson, my exors, admors, or assigns, should at any
time agree with, and no others, from time to time and at all times thereafter
during the term of years therein expressed, should and lawfully might make,
use, exercise, and vend the Invention of my father, lately deceased, discovered
by him to me, by which "EVERY VISIBLE OBJECT MAY BE DRAWN AND TAKEN TO
ANY SIZE, ON TRUE MATHEMATICAL PRINCIPLES, WITH GREAT ACCURACY AND
FACILITY," within that part of His Majesty's Kingdom of Great Britain called
England, the Dominion of Wales, and Town of Berwick-upon-Tweed, in such
manner as to me, the said Thomas Henderson, my exors, admors, and assigns,
or any of them, should in my or their discretions seem meet; and that I, the
said Thomas Henderson, my exors, adñors, and assigns, should and lawfully
might have and enjoy the whole profit, benefit, commodity, and advantage
from time to time coming, growing, accruing, and arising by reason of the
said Invention; to have, hold, exercise, and enjoy the said license, powers,
privileges, and advantages thereby granted or mentioned to be granted unto
me, the said Thomas Henderson, my exors, admňors, and assigns, for and

page_text: during and unto the full end and term of fourteen years from the date of
the said Letters Patent next and immediately ensuing, and fully to be com-
pleat and ended, according to the Statute in such case made and provided;
and whereas in the said Letters Patent there is contained a proviso or
condition that if I, the said Thomas Henderson, should not particularly
describe and ascertain the nature of the said Invention, and in what manner
the same is to be performed, by an instrument in writing under my hand
and seal, and cause the same to be inrolled in His Majesty's High Court of
Chancery within one calendar month next and immediately after the date of
the said Letters Patent, then the said Letters Patent, and all liberties and
advantages whatsoever thereby granted, should utterly cease, determine, and
become void, as in and by the said Letters Patent, relation being thereunto
had, may more fully appear.
NOW KNOW YE, that in obedience to the said Letters Patent, and to
the aforesaid proviso or condition therein mentioned, I, the said Thomas
Henderson, do by these Presents particularly describe and ascertain the
nature of the said Invention, referring to the Drawings in the margin of these
Presents, which I explain as follows:-
A, the box and instrument in perspective, as taken by another, with the
hand resting on it, as Drawing box 1st. B, the frame, which is fastned to
the box by hinges. C, the supporter to the box, which falls into a notch and
raises it to a convenient inclination. D, the upright piece, which fastens in a
mortice by a screw at the left-hand end of the box when used in drawing, as
shewn, box 2nd. E, the top piece, that screws into the upright D, as shewn,
in front of box 3rd. F 1st, the arch. F 2nd, the cylinder, made at right
angle, which fits into the top piece E, with a screw to keep it in its place,
but so as to let it have an easy movement. G, the tube, in which K, the
point of sight, is raised or depressed by means of L, a small wheel, moving on
the arch F 1. H, the joint. I, the conductor, with a small aperture, which
directs to the point of sight. K, the point of sight. L, the wheel. M, a
stay to the tube G.
N, the support of the arch F 1. O, Do. of the pencil
case, from the joint H. P, the drawing pencil. Q. The pencil case. R, the
screw by which the metal part of the instrument may be taken in pieces for
the purpose of being put in the box.
And I do declare that the said Invention is to be performed in manner
following (that is to say):
After taking the different parts of the instrument out of the box, set the box
level on a stool or table, then put the upright piece D into the mortice and
screw it tight, after which screw on the top piece E, which is turned round

page_text: in the upright piece D; then take the metal part of the instrument, which
is in two pieces, made so for the convenience of being put into the box,
and after screwing the same together, fix it into the top piece E. The
instrument being thus made ready to draw with, take hold of the pencil with
a light hand, and look with one eye through the aperture to the directing or
tracing point K, which rises and depresses upon the arch F 1, according to
the different parts of the plane you draw upon, and according as the point
of sight is moved to different parts of the object. The hand guiding the
pencil will move also, and delineate the same in the true place on the drawing
plane.
In witness whereof, I have hereunto set my hand and seal, the Sixth
day of January, in the year of our Lord Christ One thousand seven
hundred and eighty-seven, and in the twenty-seventh year of the
reign of our Sovereign Lord George the Third, by the grace of God
of Great Britain, France, and Ireland King, Defender of the Faith,
and so forth
Inrolled the Eighth day of January, in the year of our Lord One
thousand seven hundred and eighty-seven.