Improvements on
Year: 1774

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOSHUA
LOVER MARTIN, of Fleet Street, London, Optician, send greeting.
WHEREAS His most Excellent Majesty King George the Third, by His
Letters Patent under the Great Seal of Great Britain, bearing date the
Twenty-fifth day of November, in the fifteenth year of His reign, did give
and grant unto me, the said Joshua Lover Martin, His especial license
that I, the said Joshua Lover Martin, during the term therein expressed,
should and lawfully might use, exercise, and vend, within England, Wales,
and Town of Berwick-upon-Tweed, and also in all His Majesty's Colonies
and Plantations abroad, my Invention and capital Improvements on "A
CERTAIN INSTRUMENT COMMONLY CALLED HADLEY'S QUADRANT, OR SEA OCTANT
AND SEXTANT;" in which said Letters Patent there is contained a proviso
obliging me, the said Joshua Lover Martin, under my hand and seal, to cause
a particular description of the nature of my said Invention and Improvements,
and how the same is to be used, to be inrolled in His Majesty's High Court
of Chancery within four calendar months after the date of the said recited

page_text: Letters Patent, as in and by the same, relation being thereunto had, may
more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
Joshua Lover Martin, do hereby declare that my said Invention and Improve-
ments on a certain Instrument called Hadley's Quadrant, or Sea Octant and 5
Sextant, is described in the Plan thereof hereunto annexed.
In witness whereof, I, the said Joshua Lover Martin, have hereunto
set my hand and seal, this Twenty-third day of March, One thousand
seven hundred and seventy-five.
A DESCRIPTION of the JMPROVEMENTS FOR ADJUSTING the GLASSES, and
rendering the Use of the Octant and Sextant more easy, viz. :—
An alidade of brass M & N, fixed upon the index of the octant or sextant,
and moveable about the same center, as shewn by the copper-plate Figures. A
pin passing through the whole in the common center of the octant. The brass
case or frame which holds the index glass D is placed upon the head or
circular plate of the alidade at M & O, moveable by an axis at each end, and
on the back side of the brass frame D is also fixed, on the same plate, the
brass pillar O, through which the adjusting screw passes that rectifies or adjusts
the glasses in the horizontal position. At the lower end of the alidade N is
fixed the other adjusting screw, which is fastned to the index by a peice of
brass or other metal on either side at L or R, as may be found most convenient.
This screw is to adjust the index glass of the octant or sextant in altitude.
The horizon glass E is screwed fast to the brass block T, which is fastned to
its proper position by a screw on the back side; in the same manner the back
observation glass F is fixed to its proper angle with the index glass. There
are two brass caps to screw over the heads of the adjusting screws P and R,
to prevent their being moved by accident after adjusted. The new handle,
with a joint at the top and a pin at the other end to take out at pleasure, to
fasten it in a perpendicular position to the plane of the octant or sextant, or any
other oblique position as may be found most convenient for use. There are
likewise a number of small brass, ivory, or ebony pins or hobs fixed on the
back side of the graduated arch or limb S, for the greater convenience of
moving the index of the sextant or octant when used in a horizontal and oblique
position.

page_text: AND BE IT REMEMBERED, that on the Twenty-third day of March,
in the year of our Lord 1775, the aforesaid Joshua Lover Martin came before
our said Lord the King in His Chancery, and acknowledged the Specification
aforesaid, and all and every thing therein contained and specified, in form
above written. And also the Specification aforesaid was stampt according to
the tenor of the Statute made in the sixth year of the reign of the late King
and Queen William and Mary of England, and so forth.
Inrolled the Twenty-third day of March, in the year of our Lord One
thousand seven hundred and seventy-five.