AN IMPROVED STEERING AMPLITUDE OR AZIMUTH COMPASS AND SCALE, FOR FINDING AND WORKING THE COURSE OF SHIPS AT SEA WITH GREATER CERTAINTY AND EXPEDITION THAN HATH
Year: 1805

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
SYEDS, of Fountain Stairs, Rotherhithe Wall, in the County of Surrey, Mathe-
matical Instrument Maker, send greeting.
WHEREAS His present most Excellent Majesty King George the Third,
in and by His Royal Letters Patent under the Great Seal of the United
Kingdom of Great Britain and Ireland, bearing date at Westminster, the
Seventh day of October, in the forty-fifth year of His reign, for Himself, His
heirs and successors, did give and grant unto me, the said John Syeds, my
executors, administrators, and assigns, His especial licence, full power, sole
privilege and authority, that I, the said John Syeds, my executors, adminis-
trators, and assigns, and every of them, by myself and themselves, or by my
and their deputy or deputies, servants or agents, or such others as I, the said
John Syeds, my executors, administrators, or assigns, should at any time agree
with, and no others, from time to time and at all times thereafter during the
term of years therein expressed, should and lawfully might make, use,
exercise, and vend, within that part of His said Majesty's United Kingdom
of. Great Britain and Ireland called England, His Dominion of Wales, and
Town of Berwick-upon-Tweed, my Invention of "AN IMPROVED STEERING
AMPLITUDE OR AZIMUTH COMPASS AND SCALE, FOR FINDING AND WORKING THE
COURSE OF SHIPS AT SEA WITH GREATER CERTAINTY AND EXPEDITION THAN HATH

page_text: HERETOFORE BEEN DONE;" in which said Letters Patent there is contained a
proviso obliging me, the said John Syeds, by an instrument in writing under
my hand and seal, particularly to describe and ascertain the nature of my
said Invention, and in what manner the same is to be performed, and to
cause the same to be inrolled in His said Majesty's High Court of Chancery
within one calendar month next and immediately after the date of the said
recited Letters Patent, as in and by the same Letters Patent, reference being
thereunto had, will more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso in the said
recited Letters Patent contained, I, the said John Syeds, do hereby declare that
the nature of my said Invention, and the manner in which the same is to be
performed, are particularly described and ascertained by the several Drawings,
and the description or explanation thereof, hereunto annexed.
In witness whereof, I, the said John Syeds, have hereunto set my
hand and seal, the Fourth day of November, in the forty-sixth year of
the reign of our said Sovereign Lord George Third, by the grace of God
of the United Kingdom of Great Britain and Ireland King, Defender
of the Faith, and in the year of our Lord One thousand eight hundred
and five
The advantages my improved compass carries by taking away the outside
gimboal, which is to the compasses hitherto in use suspended in the wood box,
in place of which the brass or wood box, commonly called the bowl or kettle,
being suspended in its place, for that motion of the ship called pitching not to
effect the needle suspended on the center point, prevents the line drawn in the
fore part of the compass, commonly called the lubbard's point, from being
obscured with a side light when the ship or other vessel is rolling or pressed
down to the one side by the pressure of the sails, &c., &c. The brass or wood
kettle or bowl now taking the place of the gimbol, in the inside of it is fixed a
half gimboal, suspended by two pivots in the kettle or bowl, to which the
center point is fixed, which suspends the needle and card, and prevents the
motion from disturbing the card by the rolling of the vessel. In this case there
are the four suspending points to relieve the card from being disturbed by the
motion of the ship either when pitching or rolling, or when both take place at
the same time, equal to the compasses heretofore in use, and can be fixed in
a betical, with or without the wood box, Figure 1. By suspending the kettle

page_text: in the betical, as the annexed Plan, Fig. 5, explains, it admits of the betical
being smaller than when the compass is suspended in the wood box, Fig. 1,
and the box with it put into the betical; and the smaller the betical, it is not
so cumbersome on the deck of a vessel, and less liable to damage by sea or
shot, or otherwise; which advantage, and the lubbard's point not being ob-
scured by the rolling of the ship or vessel, are objects not attained by the
compasses heretofore in use. It frequently happens, where lamps are used
over the compasses, in order that the lubbard's point shall not be obscured by
the rolling of the ship or vessel, or being pressed down to either side by the
pressure of sail or otherwise, which lamps frequently damage the compass
under it, but that inconvenience is removed by my improvemt. Heretofore,
when observing with the azimuth compass, the stop for the card was so fixed
that the observer must follow the said stop for the card with his finger,
which in a great measure took his attention from off the object he was ob-
serving or taking the bearing of, as the eye and mind must be divided, or the
finger follow the stop by guess, which was frequently attended with incon-
venience; to remove which I have added the azimuth compass a spring to
the nonius and a trigger, to which is fixed a small line made of silk, thread, or
other twine, so that the observer can hold the thread by his left hand and
govern the compass by its standard or stile in which it is suspended with his
right hand; and, when he has got his sight, by a gentle pull or jerk on the
line to the trigger, the card is stopped without the observer touching the com-
pass, which improvement may be fixed on azimuth compasses on my new
plan, or other azimuth compasses on the former plan. And to prevent the
azimuth compass from wear when not in use, in place of keeping them sus-
pended on the standards, I have adapted a notch in the standards to place the
suspending pivot into when wanted for use, and to take it therefrom and place
the compass in the bottom of the box when not wanted to be used.
The compass course, when obtained, is generally wrought by the tables of
difference of latitude and departure, after the allowance for Ice way and the
variation of the compass is made, and such allowance is most times made
by the memory; and when the navigator is fatigued, and perhaps in a
manner worn out by long duty on deck, and in bad weather, he may have
a wish at times to find the ship's place, altho' not at meridian time, and many
young navigators are at a loss to calculate the lee way and the variation of the
I have therefore invented a Scale, see Fig. 7, to work for the Ice
way, and the variation of the compass, and the set of the currents or tides, and
the difference of latitude and departure when the course and distance is given,
or the course and distance when the difference of latitude and departure is
compass;

page_text: given, or the distance and departure when the course and difference of latitude
is given, or the difference of latitude and distance when the course and
departure is given, and the miles contained in each degree of longitude from
the poles to the equator, without the assistance of a book; which Scale, being
made of wood or brass, or other proper metal with or without wood in part, is
not so liable to damage by wet, either in ship or boat, and the use of it is
easy and quick to any scafaring man that understands arithmetic, if distressed
for want of the knowledge of navigation.
Explanation of the Steering Compass.-Fig. 1. A is the left-hand side of
the wood box which contains the compass; B is the right-hand side of d°;
C is the bottom of d"; D is the fore end of d°; and E, the after end, as it
stands, and when it stands in the betical for use; F, F, is the part of the
kettle, Fig. 2, between the top and the shoulders C, C, on the pivots of do,
in two brass sockets II, II, one of which is lett into the wood box A, B, on
cach side, which suspends the kettle, and gives the fore and aft motion called
pitching; from C, C, to I is the bottom of the kettle, Fig. 2, which kettle may
be made of wood, or wood and brass or copper, or of brass or copper, or
other proper metal or material, and may be made round with a concave
bottom, or square with a flatt bottom, or squaro sides with a concave
bottom. Figure 8, M, M, is a half gimbol, suspended in the fore and aft part
of the kettle F, F, I, by its pivots P, P, which gives the motion for the rolling
of the ship; Q is the center point, fixed through a lead ballance N to the
center of the half gimbol at O, the point of which is brought on a line with
suspending gimbols G, G, and P, P, which suspends the needle S and card on
their cap R in a stationary position; K, K, is the verge that is placed on the
kettle, and receives the glass L, which is puttied or comented water-tight into
the verge, which prescrves the compass card from damps, &c. The ballance
of lead J is not wanted if the kettle or bowl, Fig. 2, is a ballance of itself,
nor the lead ballance N to the half gimboal in Fig. 2, if it ballances itself.
The verge K, K, with the glass L, will take off when wanted to do the need-
full to the card or point. The dotted line is the place for the lubbard's point,
marked in the half gimboal. Fig. 5 is a betical on a half inch scale to the
inch, where the kettle F, F, may be suspended without the box, Fig. 1. C, c,
is the lamp in the betical, the reflection of the light from it extends in the
compass according to the angle E, e; D, d, is the glass which defends the
light in the betical from the weather, and through which the light from the
lamp or candle shines on the compass. Fig. 4 is the Amplitude Compass, and
dilfers nothing from the Steering Compass, Fig. 1 and 2, only the addition
of two pins of brass A, a, with an opening in them fixed to the verge

page_text: as K, K, in order to receive the sight vanes B b, B1 b, the use of which
is to take the bearings of the sun at rising or sitting, which is called the
amplitude, or to take the bearing of any other object, which vanes are
applied to other amplitude compasses; C, c, is the cover of the box, a
deeper cover being needfull in order to lower the box out of the way of
the vanes when they are placed for taking the bearing of the sun or other
objects with.
The Scale, Fig. 7.-This scale may be a circle, or a half circle, or a quarter;
but the quarter is not so usefull as the half or the whole circle is when
easting and westing is required with northing or southing, which Scale and
index may be made of wood, or wood and brass, or brass, or any proper metal.
The cross lines in each quarter of the Scale form square miles to the number
of 60 to each quarter from the center of the pin on which the index I, N,
moves, which center is in the middle of the equator Q, Q. If the distance
exceeds 60 miles, it may be named on the Scale 2 miles to each mile in the
square lines and on the index, or 3 miles, or 4 miles, or upwards. The index
is divided into 60 miles, equal to half of the equator in miles by the square
lines, which index extends to cut the other gradations in the circles of the
Scale. The 4 circular lines are divided into 90 degrees in each quarter by a
line corresponding; from the center at 0 is 90 degrees, and marked down at
every 10 degrees to the equator Q, Q, for the use of moving or laying the
index to the course, and finding the miles of longitude to each degree of
latitude as they diminish from 60 at the equator to nothing at the poles. The
cross lines from point to point of the degrees through the circles make a
diagonal scale, dividing the degrees in 4 equal parts or 15 minutes, so that if
the index cutts all the lines in the 4 circles, then it is a degree; but if it
cutts the cross line at the first circle, it is 1 degree and 15 minutes; if the
second line, 30 minutes; if the third line, 45 minutes. The outer circles arc
the points of the compass, being 8 to cach quarter, which are marked
1, 2, 3, 4, 5, 6, 7, 8, from the equator to the poles, and back from the poles to
the equator, that they may be used both ways, which point is divided into 4
parts. The first is a short stroke for a quarter; the second, a longer stroke for
a half point; again, a short stroke for of a point, which points can be named
from the pole to the equator, or from the equator to the pole, 1, 2, 3, 4, 5,
6, 7, 8.
Problem 1st is, To work for the difference of latitude and departure when
the course and distance are given.-Admit that 90 degrees on the scale is the
north pole, and a ship sails 30 miles N.E., which is 4 points between the pole
and the equator. The difference of latitude and departure is required: Move

page_text: the Scale to 4 points between the pole and the equator, and if there is a point
and a half of variation to the west, move the index a point and a half, to the
west is 2 points N.N.E. E, the course corrected; but if there had been
leeway a point to the eastward, then the index must be moved a point from
the correction for the variation, and the course will then be 3 points, or
N.E. b. N.E. On the other hand, had the lee way been to the northward,
then the index must be moved a point to the north of the correction for
the variation, and the course will be
the course correct to be N.N.E.
distance, place the index at 2 and
cutt in the cr *lines 26 and
departure.
N. b. E. E., or 1 point; but admit
E., or 2 and points, with 30 miles
points on the Scale, at 30 miles it will
miles difference of latitude, and 14 miles
Problem 2d. To work for the course and distance, when the difference of
latitude and departure is given.-If the difference of latitude be 26 and
miles, and the departure be 14 miles, steering between the north and cast, turn
the index to cutt in the square miles northing 26 and, and casting 14 miles,
will give a N.N.E. E., or 2 and points, and on the index, against the
difference of latitude and departure, is 30 miles.
Problem 3d. To work for the course and difference of latitude when
the distance and departure are given. If the distance is 30 miles,
and the departure 14 miles, turn the index, and lett 30 miles on it
cutt 14 miles departure from line 0, and the difference of latitude will be
26 and miles, at 30 miles on the index, and the course 2 and points, or
E.
N.N.E.
Problem 4th. To work for the distance and difference of latitude, when the
course and departure are given.-If the course is N.N.E. E., which is
2 and points, and the departure is 14 miles, turn the index to 2 and
points from the north to the eastward, and at the departure 14 miles is the
difference of latitude, and the distance on the scale 30 miles.
Problem 5. To find the difference of longitude when the latitude is given.
-If a ship in north latitude 44°.. 0'0, her difference of latitude is 120 miles,
which is 2 degrees; add the half of which to the latitude, makes 45°..'00
middle latitude from the line in miles, that is, a perpendicular from 45 degrees
to the equator, and is 18 miles to the circle; substract 18 miles from 60, and
the remainder, 42 miles, is the miles of longitude to a degree in the middle
latitude between 44°..'00 and 46°.. '00, which makes 1 degree and 3 miles of
longitude.

page_text: AND BE IT REMEMBERED, that on the same Fourth day of November,
in the year above mentioned, the aforesaid John Syeds came before our Lord
the King in IIis Chancery, and acknowledged the Specification aforesaid,
and all and every thing therein contained, in form above written. And also
the Specification aforesaid was stamped according to the tenor of the Statute
in that case made and provided.