AN IMPROVED MECHANICAL AND MAGNETIC COMPASS
Year: 1856

page_text: LETTERS PATENT to Nicholas Doran Maillard, of Dublin, for the Inyen.
tion of "AN IMPROVED MECHANICAL AND MAGNETIC COMPASS."
PROVISIONAL SPECIFICATION left by the said Nicholas Doran Maillard
at the Office of the Commissioners of Patents, with his Petition, on tho
12th August 1856.
I, NICHOLAS DORAN MAILLARD, of Dublin, do hereby declare the nature of
the said Invention for "AN IMPROVED MECHANICAL AND MAGNETIC COMPASS," to
be as follows:-
To construct a compass according to this Invention, having formed a
suitably shaped bowl, introduce into the bottom a needle, similar to those em-
ployed in an ordinary compass, and mounted upon a pivot in the usual way; a
little above this magnetic needle extend a light bar across the centre of the
compass bowl, on this bar mount a second needle, which may be magnetised
or not, having a vertical shaft passing through the centre of it, and which has
its upper bearing on the under side of a second cross bar; this second or
upper needle works horizontally and parallel with the lower needle. On the
axle shaft of the upper needle a small grooved pulley or cog wheel is staked,
through which motion is passed to a pointer, which works on the face of an
ordinary compass card or dial, which surmounts the whole, to indicate the
action of the lower needle, by means of a band and pullies, or cog wheels, or
other convenient mechanical arrangement. When a compass constructed
according to this Invention is to be used on land, the first or common compass
needle may be dispensed with by having the other or second needle described

page_text: magnetised. This compass is to be suitably mounted in gimbels, and so forth,
in the usual way, except that, if preferred, the compass card with its pointer
may be placed vertically.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Nicholas Doran Maillard in the Great Seal Patent Office on
the 12th February 1857.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, NICHOLAS
DORAN MAILLARD, of Dublin, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing-date the Twelfth day of August, in the year of our Lord One
thousand eight hundred and fifty-six, in the twentieth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
Nicholas Doran Maillard, Her special licence that I, the said Nicholas Doran
Maillard, my executors, administrators, and assigns, or such others as I, the
said Nicholas Doran Maillard, 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 might 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
MECHANICAL AND MAGNETIC COMPASS," upon the condition (amongst others) that
I, the said Nicholas Doran Maillard, or my executors or administrators, by an
instrument in writing under my, or their, or one of their hands and seals,
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 Nicholas Doran Maillard, 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 accompanying Drawings, and
the letters and figures marked thereon (that is to say):-
This Invention consists in the use or application of a second or supple-
mentary needle, which is mounted upon a vertical shaft immediately above,
and so as work parallel with an ordinary magnetic compass needle, which is
mounted on a pivot in the bottom of the compass bowl in the ordinary way.
The vertical shaft of the upper or supplementary needle works in suitable
bearings, and which it is proposed to provide with a small groove pully, or

page_text: contrivance,
cog wheel, or any other convenient mechanical which, by means of a band
or train of wheels, actuates a pointer which works on the face of a fixed
index dial or ordinary compass card, and which index dial it is preferred to
construct vertically upon the top of the bowl (which bowl may be of the
ordinary shape, and contains the ordinary
magnetic compass needle, and also the upper or supplementary needle.
tho
When the upper needle is magnetized I reverse the poles, that is to say,
I place south or repulsive pole of the upper needle over the north or
directive pole of the lower needle, which lower needle I construct so as to have
considerably greater magnetic force than that of the upper one. If it should
be preferred, the lower or ordinary magnetic compass needle may be dispensed
with by constructing the upper or supplementary needle with a sufficient.
magnetic power to actuate the pointer of the index dial; but I prefer, in most
instances, to avail myself of the use of the ordinary magnetic compass needle,
as by that arrangement I believe there will be the least amount of friction, and
the compass will not be affected by local attraction.
so readily
A
Although I prefer to construct the index dial vertically on the top of the
compass bowl, the index dial may be constructed horizontally instead of
vertically. When that is the case, the index pointer is mounted on the upper
end of the vertical shaft of the upper needle.
That this my said Invention may be the more readily seen and understood,
I have hereunto annexed Drawings in illustration of a compass constructed
according to one of the modification of my plan; like letters and figures marked
thereon denote similar parts.
Figure 1 is an external front elevation of one of my compasses constructed
with a vertical index dial, and Figure 2 is a vertical sectional elevation
of the same.
A, the compass bowl; B, the index dial; C, index dial pointer;
D, studs formed on each side of the index dial case, by which the apparatus is
supported in gimbals in the ordinary way.
E is an ordinary compass needle, supported by and working on the point
of F, the pivot of the needle; G, the upper or supplementary needle, which is
attached to H, the vertical shaft, the lower part of which works in a jewelled
bearing, and formed in K, the supporting bar, which extends across the compass
bowl, and is fixed to the sides thereof; L, a "cock" or bracket, in which the
upper end of the verticle spindle of the needle shaft works; M is an horizontal
wheel, staked on the vertical shaft, having vertical teeth, and which works
into N, a small vertical wheel, and which works into O, a second vertical
wheel, mounted upon a horizontal spindle, which projects forward to the front
of the index dial plate (B), and upon which (C) the index pointer is mounted;
P, bracket to support the axles of the small toothed wheels (N and O); Q, two

page_text: screws, used to attach the cocks or brackets to the back of (R), the vertica!
casing surrounding the index dial, and the working part at the back thereof.
It will be readily seen by the foregoing that the power to give motion from
the upper needle to the shaft and wheelwork may be readily modified, so as to
enable the compass bowl to be placed at some distance from the index dial; for
instance, the compass bowl might be placed below the deck of a vessel, the
index dial might be upon the deck of the vessel, which can be done by elongating
the vertical shaft of the upper needle, or by means of a strap, friction pulleys.
or even in the water under the vessel, and
and
Having now fully described and ascertained the nature of this my said
Invention, and how and in what manner the same may be performed, I wish it
to be clearly understood that I do not confine myself to any precise details; but
what I claim as my Invention is,-
First, the use and application of a second or supplementary needle mounted
upon a vertical. shaft, so that the upper or supplementary needle may work
_parallel to the_lower_or ordinary magnetic compass needle, and which, second
or supplementary needle may be itself magnetized or not, and taking off the
power from the magnet or magnets to actuate a pointer travelling on the face
of a fixed index dial.
Secondly, the use of two magnetic needles, one above the other, one of
which possesses less magnetic force than the other, so as to enable me to
reverse the poles of the needles for the purpose of modifying or overcoming
local attraction.
Thirdly, the use and application of a single magnetic needle or plain steel
bar fixed upon a vertical shaft for the purpose of actuating a pointer on the
surface of a fixed index dial.
Fourthly, and lastly, the construction of compasses, substantially and in the
manner herein-before described, or any mere modification of the same.
In witness whereof, I, the said Nicholas Doran Maillard, have hereunto
set my hand and seal, this Eleventh day of February, in the year of our
Lord One thousand eight hundred and fifty-seven.
NICHOLAS DORAN (L.s.) MAILLARD.
Witness,
WILLIAM WALKER,
of 44, Castle Street, Liverpool.