Improvements in Apparatus for Finding the True Points of the Compass, and Correcting Errors and Deviations by the Use of Chronometers or other Time Pieces with which Special Indications are Employed.
Year: 1895

page_text: Date of Application, 23rd Apr., 1895
Complete Specification Left, 9th Jan., 1896-Accepted, 18th Apr., 1896
PROVISIONAL SPECIFICATION.
Improvements in Apparatus for Finding the True Points of the
Compass, and Correcting Errors and Deviations by the Use
of Chronometers or other Time Pieces with which Special
Indications are Employed.
I, FRANCIS WILLIAM ENGELBACH of Llanwern West Dulwich Gentleman,
do hereby declare the nature of this invention to be as follows :-
I attach to the circumference of the dial plate of a chronometer or other time
keeper a movable indicator so arranged that it can be readily shifted round the
outside face of such dial plate. The chronometer need not be an expensive one
but must be altered from time to time so as to indicate ships or local time if at the
place where it is desired to ascertain the true points of the compass the time is
not the same as Greenwich time.
In the case of a ship I prefer to place such chronometer on a movable base
close to the standard compass of such ship in a position allowing the faces of
the chronometer and compass to be compared together.
When checking the compass by my invention I move the chronometer round
until the direct ray or line of the sun falls exactly on the point of the hour-hand
of such chronometer. I then shift the moving indicator precisely halfway between
the hour-hand and noon (or twelve) marked on the dial. The indicator will then
point to the exact South irrespective of all magnetic interference or the presence
of other disturbing influences such as large masses of iron whether afloat or on
shore owing to which many vessels have been lost through their compasses
becoming deranged as has been notably the case off the coast of Bilbao.
The position of a ship at sea is at present practically obtained by observation
of the sun at noon but this very often cannot be obtained owing to the state of
the weather at the time and the latitude remains unknown together with the exact
position of the ship and no means remain of checking any error however great
in the compasses.
By my invention if the sun is only visible-even if only dimly-for one minute
during the day-the true points of the compass can be determined-and for this
purpose the ship's compass should be checked each watch if possible.
I attach directions to the above effect to each chronometer.
I also employ watches for discovering the points of the compass-with or
without attaching the indicator already described and I mark the letter "S"
against 12 o'clock on the dial plate and place instructions in a suitable place on
the watch to the following effect-
Half way
"Hold the watch so that the hour-hand points direct to the sun.
between the hour hand and "S" is south."
The foregoing directions apply to northern latitudes. If south of the equator
the foregoing indications equally apply but the result will be to determine the
true north instead of the true south.
The vital importance of thus marking watches for explorers travellers soldiers
and sailors who have often to take to their boats without a compass is obvious.
Dated this 23rd day of April 1895.

page_text: F
Improvements in Apparatus for Finding the True Points of the
Compass, and Correcting Errors and Deviations by the Use
of Chronometers or other Time Pieces with which Special
Indications are Employed.
I, FRANCIS WILLIAM ENGELBACH of Llanwern Park Road West Dulwich,
Gentleman, do hereby declare the nature of this invention and in what manner
the same is to be performed to be particularly described and ascertained in and
by the following statement :-
According to my invention in addition to the usual hour and minute hands
I attach or add to the dial plate of a chronometer or other time keeper a moving
indicator or supplemental hand or one so arranged that it can be readily shifted
round the outside face of such dial plate. The chronometer need not be an
expensive one, but must be altered from time to time, so as to indicate ships or
local time, if, at the place where it is desired to ascertain the points of the compass,
the time is not the same as Greenwich time.
In the case of a ship I prefer for example to place such chronometer on a
movable base close to the standard compass (of such ship) in a position allowing
the faces of the chronometer and compass to be compared together, and I may
provide the chronometer with folding sights whereby the instrument may be
adjusted to position as hereafter described with great accuracy when required.
When checking the compass by my invention I move the chronometer round
until the direct ray or line of the sun falls exactly on the point of the hour hand of
such chronometer. I then shift, either forward or backward, according to whether
it is A.M. or P.M. the indicator or supplemental hand placing it precisely half way
between the hour hand and noon (or twelve) marked on the dial. The indicator
or supplemental hand will then point to the South irrespective of all magnetic
interference or the presence of other disturbing influences, such as large masses of
iron whether afloat or on shore owing to which many vessels have been lost
through their compasses becoming deranged as has been notably the case off the
coast of Bilbao.
When constructing the apparatus with a moving indicator or supplemental hand,
I attach the latter to a suitable spindle of the timepiece and so arrange the
movement of such time piece that this moving indicator or supplemental hand shall
revolve round the face or dial plate in exactly half the time taken by the hour
hand the moving indicator being so set that both it and the hour hand shall point
direct to 12 o'clock on the dial plate at the same time. When I require to
ascertain the points of the compass I turn the face of the time piece as previously
stated so that the hour-hand is pointing direct to the sun; the moving indicator or
supplemental hand is then pointing south in northern latitudes or vice versa north
in southern latitudes. I generally attach in some convenient part of the time piece
short directions and when the timepiece is for use as above-by preference to the
stand upon which it is mounted.
The position of a ship at sea is at present practically obtained by observation of
the sun at noon but this very often cannot be obtained owing to the state of the
weather at the time and the latitude remains unknown, together with the exact
position of the ship and no means remain of checking any error however great in
the compasses.
By my invention--if the sun is only visible-even if only dimly-for one minute
during the day-the points of the compass can be determined and for this purpose
the ships compass should be checked each watch.
I attach directions to the above effect to each chronometer.

page_text: I also employ watches for discovering the points of the compass-with the
indicators already described and I mark the letter "S" against 12 o'clock on the
dial plate and place instructions in a suitable place on the watch to the following
effect.
"Place the indicator half way between the hour hand and "S" hold the watch
so that the hour hand points direct to the sun and the indicator points to the
south."
The foregoing directions apply to northern latitudes-if south of the equator the
foregoing indications equally apply, but the result will be to determine the north
instead of the south.
The vital importance of thus marking watches for explorers, travellers, soldiers,
and sailors, who have often to take to their boats without a compass, is obvious.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :
1. An apparatus for finding the points of the compass, composed of or consisting
of, a chronometer or watch set to ships or local time, in combination with an
adjustable rotary index, or indicator or supplemental hand whereby upon the
chronometer or watch being placed so that the hour hand points to the sun and
upon the indicator being moved half way between the hour hand and noon
(twelve o'clock), the said index or indicator points south if in northern latitudes
and north if in southern latitudes.
2. An apparatus for finding the points of the compass composed of or consisting
of a chronometer or watch in combination with a rotary and adjustable outer ring,
carrying a pointer, index, or equivalent composed arranged and acting substantially
as and for the purposes hereinbefore described.
3. An apparatus for finding the points of the compass composed of or consisting
of a chronometer or watch set to ships or local time, in combination with a
revolving or rotary index actuated by chronometric or watch mechanism to move
in the same direction as the clock hands, at half the speed of the hour hand, and
set so that the indicator and the hour hand coincide at twelve o'clock (noon)
whereby upon the chronometer or watch being placed so that the hour hand points
to the sun the index will then be pointing south in northern latitudes and north in
southern latitudes substantially as and for the purposes set forth.
Dated this 9th day of January 1896.
F. W. ENGELBACH.