THE SAFE GUIDENCE OF SHIPS AT SEA, LIFE AND PROPERTY
Year: 1885

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HENRY JOB, Retired Master Mariner, of 45 years of experience, as a Sailor,
5 years of which as Mate and 31 as Master, Residing at 73 Devonshire' Street,
Monk wearmouth Sunderland in the County of Durham, do hereby declare the
nature of my invention for THE SAFE GUIDENCE OF SHIPS AT SEA, LIFE AND
PROPERTY to be as follows:-
That my Invention is based on the true principle of the true North Pole of the
World. That I am the sole Inventor of this improved Mariners, from which
no variation can be produced from Bearings of the Sun, or any other heavenly
object by the following method, viz. First, take a set of Observations of the
Sun or a Star, and at each Observation take the Bearings of the Sun by a common
Sight Vane Compass, and at the same time note down the time when each Observa-
tion were taken as near as possible take three sets of Observations and then add
the sets of Suns Altitudes togather, and then divide the same by three, then the
Mean or Average of the Altitudes, and so on withe the Sun's Bearings and times,
Then take the first set of Observations in the morning, and on the same day in
the afternoon, Then find the variation in the morning and found in the afternoon,
add those two variations, found (by the rules laid down for that purpose) togather,
then take the half, you then have no variation, then find the number of degrees
found of variations by the morning set, say 26 degrees, and by the afternoon set,
say, 28 degrees (for they do differ), add those togather, and then half them, then
with this half the number of degrees found, apply it to the Needle Point, so ineny
degrees from its original point, on the Compass Card, towards the West, if the
variation is westerly, the Magnetic Compass then is transfered into a true
North Polar Compass, with the Card at all times and places, pointing to the
true North Pole of the World, and will continue to do so and will work with
the true North, as laid down with the true North all the World over as already
been tested, whether the variation is East or West, and it requires no adjustments
whatever, and local attraction as no effect on it outside of 2 feet range all round
and therefore I claim for it an Universal Patent, and that all the present Magnetic
Compasses could be made a true Polar Compass with little cost.

page_text: Improved Mariners' Compass.
I, HENRY JOB, Retired Master Mariner of 73 Devonshire Street, Monkwear-
mouth, Sunderland in the County of Durham, 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:—
This Invention relates to certain improvements in or applicable to Mariner's
compasses, the principal object of the Invention being to cause the North point
of the compass card at all times and in all geographical places in all latitutes
and longitudes of the Earth to point to the terrestrial North pole, and to work
with the true North as laid down on Charts, without liability of Easterly or
Westerly declination or variation from the true Meridian, and consequently
without needing subsequent allowance or adjustment therefor, and without being
liable to deviation caused by any local attraction situated beyond a radius of
about two feet around the compass.
The improvements are applicable to existing magnetic polar compasses at little
cost, and will be hereinafter described as applied thereto in converting such
magnetic polar compasses into true terrestrial polar compasses.
In carrying the Invention into effect, I cause the needle to be set in a peculiar
relation to the compass card, and determine this relation by proceeding as
follows:-
In both the morning and afternoon of the same day about the same time (pre-
ferably three to four hours) before and after midday, I take at about equal intervals
of time two, three or more sets of observations of the sun by an ordinary sight
vane compass, and note down the time of taking each set of observations, and
ascertain from existing means giving such information the declination of the sun
at the time of observation.
I then take the morning and afternoon sets of observations, separately, but
proceed with them both alike as follows:-
I add the sets of the sun's altitudes together, and divide the product by the
number of the sets of observations, and thus obtain the mean or average altitude,
I also add together and similarly proceed with the sets of the sun's bearings, and
with the noted times of observation, respectively.
Taking the ascertained average of the Sun's altitudes as a basis, I then proceed
(in the manner hereinafter set out and which will be well understood by mariners)
as regards the morning set of observations to ascertain the Sun's true Azimuth
East, and the variation of the magnetic or compass bearings therefrom, and as
regards the afternoon set of observations to ascertain the Sun's true Azimuth
West, and the variation of the magnetic or compass bearings therefrom.

page_text: I then add together the variations thus found, and divide the product by two,
and obtain a quotient of degrees in accordance with which in relation to its
original position, and on the side on which the variation is at the place of taking
such observations, I apply the North pointing end of the needle to the compass
card, and thereby convert the magnetic polar compass in which variation has
always to be allowed for into a true North or terrestrial polar compass in which
variation does not require to be allowed for.
The following is an example of a complete set of observations and calculations
taken at Sunderland for finding the said variations in the forenoon, and in the
afternoon, half the product of which variations is to be applied to the needle as
hereinbefore stated.

page_text: Having now particularly described and ascertained the nature and objects
of my said Invention, and in what manner the same is to be performed, I declare
that what I claim is
1. The combination in mariner's compasses, of a magnetic needle or pointer with
a compass-card in such a manner or set in such relation thereto as to cause the
North point of the compass-card at all times and in all places to point truly to
the Terrestrial North Pole, substantially as hereinbefore described.
2. The herein before described improved method of producing such improved or
terrestrial polar mariner's compass.