AN IMPROVED MADE OR MOUNTING MARINE CHRONOMETERS
Year: 1856

page_text: LETTERS PATENT to Edward Daniel Johnson, of Wilmington Square,
in the County of Middlesex, Watchmaker, for the Invention of "AN
IMPROVED MADE OR MOUNTING MARINE CHRONOMETERS
"1
Sealed the 8th July 1856, and dated the 9th May 1856.
PROVISIONAL SPECIFICATION left by the said Edward Daniel Johnson
at the Office of the Commissioners of Patents, with his Petition, on the
9th May 1856.
I; EDWARD DANIEL JOHNSON, of Wilmington Square, in the County of
Middlesex, Watchmaker, do hereby declare the nature of the said Invention
for AN IMPROVED MODE OF MOUNTING MARINE CHRONOMETERS, to be as follows:-
The object of this Invention is to neutralize any magnetic polarity that may
exist in the balance of marine chronometers. This I propose to effect by
causing the chronometer to revolve slowly on its own vertical axis. The
gimbals which carry the chronometer I mount within a ring of brass, that rests
on three or more flanged rollers, mounted loosely on axles fixed to the sides of
the chronometer box. The bearing surfaces of the said rollers are covered
with vulcanized india-rubber, and the whole is kept in its place by brass clamps,
projecting over the ring but without touching it. One of these rollers has its
flange cut into teeth, and has a spring similar to the spring of a watch attached
to it, arranged to drive, it in the direction required. The before-mentioned

page_text: teeth are used to drive a small train of wheels and escapement, so arranged as
to allow the roller to advance at such a rate as desired, the bearing surface of"
the roller producing corresponding motion by friction of contact in the ring
carrying the said chronometer.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Edward Daniel Johnson in the Great Seal Patent Office
on the 8th November 1856.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, EDWARD
DANIEL JOHNSON, of Wilmington Square, in the County of Middlesex, Watch-
maker, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Eighth day of May, in the year of our Lord
One thousand eight hundred and fifty-six, in the nineteenth year of Her
reign, did, for Herself,. Her heirs and successors, give and grant unto me, the
said Edward Daniel Johnson, Her special licence that I, the said. Edward
Daniel Johnson, my executors, administrators, and assigns, or such others
as I, the said Edward Daniel Johnson, my executors, administrators, and
assigns, should at any time agree with, and no others, from time to time and
at all times thereafter during the term therein expressed, should and lawfully
night make, use, exercise, and vend, within the United Kingdom of Great
Britain and Ireland, the Channel Islands, and Isle of Man, an Invention for
"AN IMPROVED MODE OF MOUNTING MARINE CHRONOMETERS," upon the con-
dition (amongst others) that. I, the said Edward Daniel Johnson, by an
instrument in writing under my hand and seal, should particularly describe
and ascertain the nature of the said Invention, and in what manner the
same was to be performed, and cause the same to be filed in the Great Seal
Patent Office within six calendar months next and immediately after the
date of the said Letters Patent.
: NOW KNOW. YE,. that I, the said Edward Daniel Johnson, do hereby
declare the nature of my said Invention, and in, what manner the same
is to be performed, to be particularly described and ascertained in and by the
following statement, reference being had to the Drawing hereunto annexed,
and to the letters and figures marked thereon (that is to say):-
The object of this Invention of an improved mode of mounting marine
chronometers is to neutralize any magnetic polarity that may exist in the

page_text: balance of marine chronometers. This object I propose to effect by causing
the chronometer to revolve slowly on its own vertical axis. In carrying out the
Invention, the gimbals which support or carry the chronometer in the case are
connected to or mounted within a ring of brass, that rests on three or more
flanged rollers, mounted loosely on axles fixed to the sides of the chronometer
box. The bearing surfaces of these flanged rollers are covered with vulcanized
india-rubber, and the brass ring is kept in its place on the rollers by brass
clamps, secured, to the sides of the box, and projecting over the ring but
without touching it. On the spindle of one of these rollers is a toothed wheel,
which gears into and drives a pinion, and an arrangement of wheelwork,
similar to the movement of a watch. This wheelwork or clock movement is
provided with an escapement, and is driven by a spring similar to the spring of
a watch. The spring barrel is on the axle of the driving wheel, which is also
the spindle of one of the wheels that support the gimbals of the chronometer,
and it is arranged to drive the clock or watch movement and carry round the
chronometer in the required direction; the train of wheels and escapement are
so arranged as to allow the roller to advance at such a rate as may be
considered advisable, say, for instance, to carry the chronometer round on its
axis one or more times in every twelve or twenty-four hours, the bearing
surface of the roller which actuates the gimbals of the chronometer producing
a corresponding motion by friction of contact in the ring carrying the said
chronometer.
In order, however, that my Invention and the mode-of carrying out the same
may be clearly understood, I have shewn various views of my improved mode
of mounting chronometers.
Fig. 1 is a perspective view of a chronometer in its box, with my improve-
ments adapted thereto, a part of one of the sides being broken away to shew
the mechanism for actuating the gimbals; Fig. 2 is a plan view of the chro-
nometer box; Fig. 3 is a longitudinal vertical section of the same.
The sides of the box are shewn at a, a, a, a. The chronometer bis mounted
in gimbals c, c, in the ordinary way, as seen in Fig. 1; but the outer ring d of
the gimbals, instead of being hung upon centres attached to the sides of the
box, is placed upon rollers e, e, e, e, Figures 2 and 3. These rollers turn on
spindles fixed to the box, and one of them carries a spring barrel f and a large
toothed wheel g, which drives the pinion h with the escapement and train of
wheels belonging thereto; the head of the spindle of the spring barrel f is
made square, and passes through the side of the box, where there is a keyhole
for the admission of a key, whereby the clock or watch movement is wound up.

page_text: The ring is kept in its place on the rollers e, e, by the brass arms i, i, under
which it moves.
Having now described my Invention of "An Improved Mode of Mounting.
Marine Chronometers," and the means of carrying the same into effect, I claim
mounting the chronometer in a ring or other suitable contrivance, to which a
slow rotary motion is given for the purpose of carrying the chronometer round
on its own vertical axis, as above described.'
In witness whereof, I, the said Edward Daniel Johnson, have hereunto
set my hand and seal, the Eighth day of November, in the year of our
Lord One thousand eight hundred and fifty-six.
Witness,
J. W. MOFFATT,
66, Chancery Lane.
E. D. JOHNSON. (L.S.)