MATHEMATICALL MACHINE IN TWO PARTS, FOR THE IMPROVEMENT OF ASTRONOMY AND NAVIGATION
Year: 1731

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
BUCKNALL, of the Parish of Saint Mary-le-Bow, in the County of Middlesex,
Gentleman, send greeting.
WHEREAS our Soveraigne Lord George the Second, by the grace of God
of Great Britain, France, and Ireland King, Defender of the Faith, &c., hath
by His Letters Patents under His Great Seal of Great Britain, bearing date
at Westminster, the Thirtieth day of Aprill, in the fourth year of His raigne,
granted unto me, the said William Bucknall, licence, full power, sole
priviledge and authority, that I, the said William Bucknall, my executors,
administrators, and assignes, and every of them, by myselfe and them:
selves, or by my or their deputy or deputies, servants or agents, or such
others as I, the said William Bucknall, my executors, administrators, and
assignes, should agree with (and no others) from time to time, to exercise, work,
use, and enjoy my new invented "MATHEMATICALL MACHINE IN TWO PARTS, FOR
THE IMPROVEMENT OF ASTRONOMY AND NAVIGATION," within England, Wales, and
the Towne of Berwick-upon-Tweed, to have, hold, exercise, and enjoy the
said licence, powers, priviledges, and advantages unto me, the said William
Bucknall, my executors, administrators, & assignes, for and during, and
unto the full end and term of fourteen years from the date of the said Letters
Patents, fully to be compleat and ended; in which said Letters Patents there
is a proviso in the words following (viz):-Provided also that if the said
William Bucknall doe not particularly describe and ascertain the nature of his
said Invention, and in what manner the same is to be performed, by an instru-

page_text: ment or writing under his hand and seal, to be inrolled in our High Court
of Chancery within two calendar moneths from the date of these our Letters
Patents, that then and in such case those our Letters Patents shall forthwith
cease, determine, and be utterly void to all intents and purposes, anything
herein contained to the contrary thereof in anywise notwithstanding, as by
the said recited Letters Patents (relation being thereunto had) more fully
and at large it cloth and may appear.
NOW KNOW YEE, that I, the said William Bucknall, in obedience to
His Majestie's Letters Patents have described and ascertained, and by these
Presents doe describo and ascertain, the nature of my said Invention or
new invented mathematicall machine for the improvement of astronomy or
navigation to consist of two parts.
A Description of a Mathematicall Instrument or Machine in two Parts, for
the Improvement of Astronomy and Navigation.-The first part of this
machine consists of four rings or circles made of brass, and which may be
made of any other proper metall, or of wood, and of two axis or pins passing
through the center of the whole, and when put together represent an armillary
sphere. The first or outermost ring or circle moves in a groove cut in the
next or inner circle, which inner circle is called the meridian circle, and on
this outmost ring or circle is fixed a small ring or handle to hold the instru-
ment by when used, and has a pointer fixed thereon to shew the latitude of
the place which is marked on the meridian circle. The second or next ring
or circle is called the meridian circle, and on two quarters thereof are graduated
twice ninety degrees with other subdivisions, which serve to shew the latitudo
of the place on each side the equater. The third or next ring or circle is
called the equater circle, and is fixed to the meridian by two small pins on
which it turns on an axis, and thereby when used can be sett at right angles
with the meridian circle, and on this equater are graduated the twenty-four
hours and three hundred and sixty degrees, with other subdivisions. The
fourth or innermost ring or circle is called the ecliptick circle, and moves on
the pin or axis hereafter described; and on this circle aro ingraved the days
of each moneth, the twelve signs of the zodiack, and each signo is divided into
thirty degrees, and other subdivisions, and on the center of its axis is fixed
a sight and pin, which represents the axis of the ecliptick. The axis is a brass
or other mettall pin which passes through the center of the ecliptick circle,
and serves to represent the two poles of the ecliptick; and this circle, as well
as the axis, may be taken out and put in, as occasion requires. In the nadir
of the first or outmost circle is fixed a compass box, and needle touched by the
loadstone, which shews the variačon of the compass by day and night. The

page_text: method of using the instrument is as follows:-Open the equator ring and
sett it at right angles with the meridian ring; then move the ecliptick on the
pole or axis of the ecliptick, till the middle of the equater ring cutts the
degree of that signe of the zodiack the sun is in at that time of the year; then
hold the instrument by the ring or handle, and move the first or outer circle
upon the meridian circle till the shadow from the end of the sight pin, which
is the true pole of the ecliptick, falls on the ecliptick circle or line; this done,
the shadow from the axis passing through the ecliptick sign shews the hour
of the day on the ecliptick, and the pointer of the meridian circle at the same
time shews the latitude of the place you are in, and the needle in the compass
box also at that time shews the variačon from the true poles of the world.
Then take the sun's place of departure and compare it to the sun's place shewn
on the ecliptick in this instrument, and the number of degrees and minutes
between thein is the difference of meridians. The same thing is answered by
the shadow of the moon, the instrument being placed to that shadow in the
manner as is before directed to the sun; and by comparing the moon's
apparent place at the time of this observation with the apparent place thereof
at the time of departure, the number of degrees and minutes is the difference
of meridians, all which, by inspeccon, are seen on the circle in the ecliptick.
In case the moon gives little or no shade, and you would know the time of
night by a fixed starr, this must be done by an eye-glass and object-glass fixed
att a proper focus on the axis of the poles, with cross-hairs in the focus of the
cyc-glass, so that by looking through the glass, and by moving the instru-
ment as before directed, the starr cutts the cross-hairs, the pointer from the
center of the axis gives the angle att the pole on the equator, whereby the
hour of the night is known, so that by this instrument the latitude of any
place, the hour of the day and night, the variačon of the compass, and
difference of the meridians by the sun and moon, may be known.in any part
of the world by one operation and inspection only.
The other, or second part of this machine, is only a chair or stool whereon
the observer is to stand or sit at the time of observation steady, although
the ship be moving under sail. This stool is made of two strong peices
of board or plank, about two inches thick, and eighteen or twenty inches
square, framed together by two strong peices of wood, att sixteen or seven-
teen inches distance from each other in the center of the upper board.
On the under side is fixed a box of steel, or other hard metall, turned
hollow in a concave form, with the hollow downwards; and to that box is
fitted a pin of a conick form, of steel or hard metall, placed on a strong
plank about four or five inches broad, which is to be put across the stool

page_text: in the vacancy between the two boards. The concave sockett is to rest on
the conick pin, and the plank itselfe is to rest on two stools or chairs placed
on the ship; and from the fower corners of the lower board is to go four cords
or lines, which are to unite in the center of the lower board underneath, to
which lines in their meeting in the centre is to be hung a lead, or other
weight, in proportion to the weight of the chair and of the observer; and the
chair being thus fixed, and the observer placed thereon, let the ship move as
it pleases in case it be not violent, the stool still rolling on the conick pin is,
by the weight underneath, kept always in a steady horizontall position.
In witness whereof, I hereunto sett my hand and seal, the Eighteenth
day of May, in the fourth year of His said Majestie's raigne, annor
Dñi Que thousand seven hundred and thirty-one.
ing
first legally stamped) in presence
of
THO. DUTTON.
Wч DAY.
ET MEMORANDUM, quod decimo octavo die Maij, anno suprascript
prefatus, Willielmus Bucknall venit coram dco Domino Rege in Cancellaria,
sua et recognovit Script predict, ac ofiia et singula in eodem content et spificat
in forma supradict. Necnon Script predict impress fuit secundum tenorem
Statut fact, anno Regni Regis Gulielmi et Regine Marie, &c. sexto.
1
Irr xvij die Junij A° rñi R Geo. Secundi quinto, anno D. 1781.