AN IMPROVED METHOD OF LIGHTING THE COMPASS COMMONLY CALLED THE BINNACLE COMPASS, USED FOR STEERING SHIPS AT SEA, AND FOR OTHER IMPROVEMENTS RELATING TO SHIPS BINNACLES
Year: 1812

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, GEORGE
DOLLOND, of Saint Paul's Church Yard, in the City of London, Optician, send
greeting.
WHEREAS His most Excellent Majesty King George the Third did, by
His Letters Patent under the Great Seal of the United Kingdom of Great
Britain and Ireland, bearing date at Westminster, the Nineteenth day of
February, in the fifty-second year of His reign, give and grant unto me, the
said George Dollond, my exors, adors, and assigns, His especial licence, full
power, sole privilege and authority, that I, the said George Dollond, my exors,
adiiors, and assigns, should and lawfully might, during the term of fourteen
years therein mentioned, make, use, exercise, and vend, within England,
Wales, and the Town of Berwick-upon-Tweed, my Invention of "AN IMPROVED
METHOD OF LIGHTING THE COMPASS COMMONLY CALLED THE BINNACLE COMPASS,
USED FOR STEERING SHIPS AT SEA, AND FOR OTHER IMPROVEMENTS RELATING TO
SHIPS BINNACLES;" in which said Letters Patent there is contained a proviso
that if I, the said George Dollond, shall not particularly describe and ascertain
the nature of my said Invention, and the manner in which the same is to be
perforined, by an instrument in writing under my hand and seal, and cause the
same to be inrolled in His said Majesty's High Court of Chancery within two
calendar months next and immediately after the date of the said Letters Patent,
that then the said Letters Patent, and all liberties and advantages whatsoever
thereby granted, shall utterly cease, determine, and become void, as in and by
the same (relation being thereunto had) may more fully and at large appear.

page_text: NOW KNOW YE, that in compliance with the said proviso, I, the said
George Dollond, do hereby declare that my said Invention is described in the
manner following, that is to say:—
It applies a lens between the eye of the steersman and the compass by
which the compass is magnified. It adds springs, &c. to the compass.
1st. There is a lantern composed of metal to which is applied a prism. This
lantern contains a lamp of the usual construction, and the prism reflects the
light upon the face of the compass. The form and position of the lantern and
the prism can be varied as circumstances may require. 2ndly. The lens that
magnifies the compass must be of such a focal length as not to confine the
steersman to a fixed distance. 3rdly. The card of the compass is so constructed
as to prevent the vibration. This is obtained by a bar or false needle placed
at right angles to the needle. The point on which the card traverses is sup-
ported by two cylinders, in the interior of which is a spiral spring, for the
purpose of preserving the point and securing the card in its place during any
violent motion of the ship, and at each axis of the gimbals is a spiral spring.
The use of these springs is to relieve the compass when the ship is greatly
agitated.
In witness whereof, I, the said George Dollond, have hereunto set my
hand and seal, the Fifteenth day of April, in the year of our Lord
One thousand eight hundred and twelve.