A NEW OR IMPROVED NAUTICAL INSTRUMENT OR INSTRUMENTS, APPLICABLE ESPECIALLY AMONGST OTHER PURPOSES TO THOSE OF GREAT CIRCLE SAILING
Year: 1850

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, EDWARD
DAVID ASHE, late of Brompton, in the County of Middlesex, but now residing
at Quebec, in Lower Canada, Lieutenant in Her Majesty's Navy, send
greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Royal Letters Patent bearing date at Westminster, the Fourteenth day of
November (1850), in the fourteenth year of Her reign, did, for Herself,
Her heirs and successors, give and grant unto me, the said Edward David
Ashe, my exors, adññiors, and assigns, Her especial licence, full power, sole
privilege and authority, that I, the said Edward David Ashe, my exors,
admors, and assigns, and every of them, by myself or themselves, or by my
and their deputy or deputies, servants or agents, or such others as I, the
said Edward David Ashe, my exors, admors, and assigns, should at any
time agree with, and no others, from time to time and at all times there-
after during the term of years therein expressed, should and lawfully might
make, use, exercise, and vend, within that part of Her Majesty's United
Kingdom of Great Britain called England, Her Dominion of Wales, and
Town of Berwick-upon-Tweed, my Invention of "A NEW OR IMPROVED
NAUTICAL INSTRUMENT OR INSTRUMENTS, APPLICABLE ESPECIALLY AMONGST OTHER
PURPOSES TO THOSE OF GREAT CIRCLE SAILING;" in which Letters Patent is con-
tained a proviso obliging me, the said Edward David Ashe, to particu-
larly describe and ascertain the nature of the said Invention, and in what
manner the same is to be performed, by an instrument in writing under my

page_text: hand and seal, and cause the same to be enrolled in Her Majesty's High
Court of Chancery within six calendar months next and immediately after the
date of the said in part recited Letters Patent, as in and by the same,
reference being thereto had, will more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
Edward David Ashe, do hereby declare that the nature of my said Invention,
and in what manner the same is to be performed, are fully set forth and
ascertained in and by the present Specification or explanation thereof, reference
being had to the Drawings hereunto annexed.
My Invention has reference to the production of an instrument or instru-
ments applicable to nautical purposes, and more especially to those of great
circle sailing, that is, sailing in a course which will form an arc of a great
circle on the globe, such being the shortest course. I therefore construct
such instrument or instruments with the view to indicate with facility and
sufficient accuracy the course of a ship on the great circle between any two
places, either at setting out on a voyage, or at any given period thereof, the
said instrument or instruments being also applicable to the purposes of ascer-
taining the true bearing of the sun or other heavenly body, by their amplitudes
or an azimuth. This instrument is not to supersede the necessity of ascer-
taining the place of the ship by observation in the usual manner; but that
being done, the course of the ship on the great circle, thence.to.the destina-
tion, may be shewn by using the said instrument, as herein-after set forth and
described. With these views and intentions I construct such instrument or
instruments, so that against an ordinary mariner's compass card or other simi-
larly divided circle may be indicated the course requisite to be steered, which
is effected by means of a graduated curved limb or are held against two
graduated semicircular curved limbs or arcs duly adjusted with regard to
each other, and to a point representing the zenith, the two latter arcs being
hinged or jointed together at their extremities or poles, and capable of adjust-
ment to various angles thereat, clamps or fastenings being furnished for
holding the former limb or are in the requisite positions.
And having thus set forth and ascertained the nature of my said Invention,
I will proceed to describe and ascertain in what manner the same is to be
performed as hereafter followeth, reference being had to the Drawings hereto
annexed.
Figures 1 and 2. represent front and side elevations respectively of an
instrument constructed according to my Invention; Figure 3 a plan; Figure
4 a partial side elevation, with face plate removed in order to shew the
construction of certain parts; Figure 5 is a vertical section through the line

page_text: Z, Z, in Figure 4, the pinion which is represented in the latter Figure being.
removed. The remaining Figures shew details of construction of some of the
parts,, which may easily be identified, as similar letters of reference are
employed to denote corresponding parts in the several Figures. a is a foot or
pedestal supporting a circular ring b, which I call the fixed meridian. At by
is a pin for indicating the zenith by means of plates c, c, on either side of
it.; the pedestal a also supports the block or piece d, which has a curved face
on its under side. e is a mariner's compass card resting on a pillar supported
by the fixed parts attached to the pedestal. f is a semicircular rack having
an edge bar or flange on either side of the teeth, the upper or inner curved
face of each of which flanges bear against the correspondingly curved face of
the block d, and is kept close up against it by means of two, edge bar pieces
9, 9, which press against the lower or outer face of the said flanges. _h is a
pinion gearing with the rack .f, and having a handle * on its axis for turning
it. and are a pair of semicircular limbs or arcs, which I denominate
moveable meridians; these are hinged or jointed at their. extremities or poles
to the rack f, and also to earch other. 7. is a small wheel attached to one of
the moveable meridians, but not to the other. m is a pinion supported in a
frame connected to the rack; it gears with the wheel 1, and is for the purpose
of setting the moveable meridians at any required angle with regard to each
other, and for turning them round on their axes after being so set and
clamped. is a clamping screw at one pole or extremity for fixing them after
being set to the required angle. o is a limb or arc, which. I denominate the
course circle. This is supported in two sliding clamps p, p, one on either of
the moveable meridians. These clamps can be set to any required position on
their moveable meridians, so as to hold the course circle up to and closely
against the inner edges of the faces of the said meridian. In order that this
accurate fitting may be insured, the adjusting face of the course circle and
edges of moveable meridians are fitted spherically to each other. The moveable
meridians and the course circle are graduated, on their faces to degrees and.
parts of a degree of the circle. The course circle has also two indices q, q,
which slide in a groove, as shewn, for the purposes of adjusting the course
circle. to the moveable meridians, and making the position of the ship,
according to the progress made..
Another instrument or modification of the foregoing instrument is .con
structed (as illustrated by Fig. 6) by fitting outside the semicircular rack (and
horizontally with regard to the zenith) a circular ring graduated similarly to
the mariner's compass card, and which.I denominate the compass ring; or by
adapting what is known as the "wooden horizon" of, the common.globe

page_text: similarly graduated, and by using a course circle outside the moveable
meridians, their outer edges and its under face being fitted spherically to cach
other, and both its faces being graduated to degrees and parts of a degree of
the circle, and in place of a compass card adopting a globe, the pillar being
removed and the globe supported on its axis.or poles connected to the extre
mities or poles of the moveable meridians. In this instrument .it will be
necessary to make the axis and the handle of the pinion m removeable, or
otherwise capable of clearing the compass ring just mentioned (as for instance
by making the said handle similar to a watch key and fitting on the end of
the axis. The above arrangements will render the instrument of great service
for the
purposes of instruction.
The mode of using the instrument or instruments above described is this:
-To determine the great circle course, the moveable meridians are to be
opened so as to form such an angle. with each other as corresponds with the
difference of longitude between the two places; this is measured. on the course
circle when placed against the equator or middle of each of the separated
moveable meridians. These are then to be fixed at such angle by means of
the clamping screw n at the pole. If the vessel be bound to the eastward,
the course circle is next to be placed with the index q at zero against that
part of the edge of the meridian i which denotes the latitude of place at
starting, and another portion of the course circle against that part of the edge
of the meridian k which denotes the latitude of the place bound to. The
clamps p, p, are to be used to fix the course circle in this position, which will
then represent that of the particular great circle which cuts through both
places. If the vessel is bound to the westward, the instrument will require to
be adjusted in a reverse order with regard to the meridians i and k and the
course circle, whilst the index q placed at its zero is to be adjusted to the
meridian k. On bringing the position of the vessel at starting under the
zenith by means of the pinions h and m, the required course will be indicated
on the compass card, or on the compass ring where that is adopted, by a line
on the centre of the non-adjusting face of the course circle, and as the vessel
proceeds the index is to be moved onwards in its groove according to the
distance travelled measure on the said course circle, and as often as this is
done and the index is brought under the zenith, the requisite course will be
indicated in the same manner.
For the convenience of illustration red lines
are adopted to exemplify the movement of some of the parts. To find the
true bearing of a heavenly body, if by an amplitude, then bring the latitude of
the place measured on one meridian under the zenith, and the place where the
declination of the observed body measured on the other meridian cuts the

page_text: horizon measured by the compass card (or compass ring when adopted) will
indicate the true bearing. If by an. azimuth adjust the course circle to the
moveable meridian with its zero coinciding with the latitude of the place
(measured) on one meridian, and the observed body's zenith distance
measured on the course circle coinciding with the body's declination measured
on the other median, then bring the zero under the zenith, when the course
indicated against the compass card (or the compass ring, if adopted) will be
the true bearing of the observed body.
Having now described the nature of my said Invention, and in what manner
the same is to be performed, I declare that I do not claim any of the parts
above stated separately and unconnectedly, but I declare that what I claim in
respect thereof. is the new or improved instrument or instruments, the nature
and character whereof is herein-before particularly described and ascertained
as required by the aforesaid Letters Patent; it being understood that I do not
confine myself to the precise details set forth, provided the particular nature
and character of the before-described Invention be retained and used.
In witness whereof, I, the said Edward David Ashe, have hereunto set
my hand and seal, the Fourth day of March, One thousand eight
hundred and fifty-one.
This is the Specification referred to in the Affidavit of Edward Smith, sworn
before me, this Seventh day of May 1851..
J. JEFFERSON.
Edward Smith, of No. 3, New Burlington Street, in the County of
Middlesex, Gentleman, maketh oath and saith, that he is well acquainted
with the manner and character of the handwriting of W. C. Meredith,
Esquire, a Judge of the Superior Court for Lower Canada, at Quebec, in
Her Majesty's said Province of Lower Canada. And this Deponent further

page_text: Judge
safth, that the name or signature W. C. Meredith, with the addition "
of the Superior Court for Lower Canada," set, subscribed, or written upon or
endorsed on the Specification marked A. hereunto annexed, and dated the
Fourth day of March, One thousand eight hundred and fifty-one, and pur-
porting to be executed by Edward David Ashe, whereby it is stated that the
said Specification was acknowledged by the said Edward David Ashe before
the said W. C. Meredith, on the said Fourth day of March, One thousand
eight hundred and fifty-one, at Quebec aforesaid, is of the proper handwriting
of the said W. C. Meredith, and that the said Judge at the time of 'the
setting or subscribing his name on the said Specification in manner above
stated, was and now is, to the best of the knowledge and belief of this Deponent,
a Judge of the Superior Court for Lower Canada..