IMPROVEMENTS IN INSTRUMENTS FOR MEASURING ANGLES AND DIS- TANCES, APPLICABLE TO NAUTICAL AND OTHER PURPOSES
Year: 1834

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JANET
TAYLOR, of East Street, Red Lion Square, in the County of Middlesex, send
greeting.
WHEREAS His present most Excellent Majesty King William the Fourth,
by His Letters Patent under the Great Seal of Great Britain, bearing date
at Westminster, the Twenty-seventh day of March, in the fourth year of Ilis
reign, did, for Ilimself, His heirs and successors, give and grant unto me, the
said Janet Taylor, Elis especial licence, full power, sole privilege and authority,
that I, the said Janet Taylor, my exors, adiñors, and assigns, or such others
as I, the said Janet Taylor, my exors, adñiors, or assigns, should at any time
agree with, and no others, from time to time and at all times during the term
of years therein expressed, should and lawfully might make, use, exercise, and
vend, within England, Wales, and the Town of Berwick-upon-Tweed, my
Invention of IMPROVEMENTS IN INSTRUMENTS FOR MEASURING ANGLES AND DIS-
TANCES, APPLICABLE TO NAUTICAL AND OTHER PURPOSES;" in which said Letters
Patent is contained a proviso that 1, the said Janet Taylor, shall cause a
particular description of the nature of my said Invention, and in what
manner the same is to be performed, to be inrolled in His said 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 thereunto had, will more fully and at large appear.
NOW KNOW YE. that in compliance with the said proviso, 1, the said
Janet Taylor, do hereby declare the nature of my said Invention, and the
manner in which the same is to be performed, are fully described and

page_text: Luke is to say
moves.
DESCRIPTION OF THE DRAWING.
Figure represents an entire instrument constructed according to and with
my improvements. Figures 2 and 8 are parts thereof shown separately, and
Figure 4 is a plan. In each of these Figures the same letters indicate similar
parts. A is a rod and handle, by which the instrument is held when taking
observations, (see Figure 1). B is a circular ring, to the poles of which the rod
A is fixed. C is a semicircular graduated scale, moving on joints or hinges at
the pole of the circular ring B, and is consequently capable of assuming any
angle thereto. The semicircular scale C is shown separately at Figure 3. D
is a semicircular stay to the ring B, (see Fig. 1,) and within which the scale C
E is another semicircular graduated scale affixed at the top of the
instrument in such manner that the centre of the circle of which it is the half
is in a right line with the poles of the circular ring B, and this semicircular
graduated scale E is affixed at right angles to the circular ring B. In Figures
1 and 4. F is an indicator revolving on a centre at the point G; at the end of
this indicator is an oblong rectangular opening, through which may be seen
part of the scale E. It will be seen in Figure 1, there is a strap or plate
attached to the end of the indicator F, by which strap the indicator is made
to embrace the outer edge of the scale E, and is also made steady at the time
of moving it from side to side. q is a connecting piece of brass attached at one
end to the indicator F, and at the other end to the semicircular C, and its use
is to move them together, so that the graduated scale u, v, determines the
angle formed by any movement of semicircle C with B. II is a tangent screw,
similar to the corresponding screw in sextants. I is a clamp or set screw.
J is a nonins, sliding in a groove formed in the moving semicircular scale C.
Figure 8, on which nonius is a graduated scale, as shown in that Figure. K
is a nonius sliding in a groove, in that part of the circular ring B. on which is
a graduated scale a, b, beginning at a, with o, and ending at 6 with 90°, sce
Figure 2, which is a separate view of one half of the circular ring B; and
this nonius is also graduated as shown at Figure 2. The semicircular scale C
is graduated in two directions, commencing at o at the point c, and ending
respectively at 90", at the points and c. The semicircular scale E is
graduated into three scales f, g, h. The one at f commencing at o, at the
point f, and ending at 180° at the point f. g, h, are scales graduated in
opposite directions to 18°, commencing respectively at o, in the middle of

page_text: the scale E. From u to v, on the shelving plane or bevelled edge of the
indicator F, is a graduated scale commencing with o at the point v, to
correspond with the scale f, as shewn in Figure 4; and from w to æ, on a
similar shelving plane, is another graduated scale, to correspond with the scales
g and h, the graduation commencing ato in the centre, as shown in Figure 4.
In Figure 1 there are shown glasses for taking observations, though these
form no part of the Invention, they being added to the instrument, for the
purpose of rendering the quadrant and sectant unnecessary; their positions are
shown by the Drawing.
Having now described the various parts of the instrument and the manner
of combining the same, I now propose to describe the manner of using it in
ascertaining or measuring angles and distances. I will suppose that it is
desired to discover the hour angle at any time of the day. Let the latitude be
51° 32', north, the nonius K is slided along the groove and set so that the
point o comes opposite that degree (viz. 51° 32') on the graduated scale a, b.
The nonius J, on the graduated scale C, is then to be slided and set to the
declination of the sun, as shown in the usual tables (say 23° 28' north). The
altitude of the sun is then taken by observation, in the usual manner; the
compliment of the altitude is to be measured off by a pair of compasses on the
graduated scale C; that is, supposing this compliment to be 59° 20' it is
measured off by stepping one leg of the compass at o, and opening out the
other leg, till its point comes to 59° 20' on the scale. Having thus measured
the compliment, the scale C is to be moved to such a position that the com-
pliment taken by the pair of compasses will be equal to the distance between
the two degrees marked on the graduated scales C and B, that is in such a
position that the point of one of the legs of the compasses shall touch the point
at 51° 32' north, marked by the nonius K, and the point of the other leg of
the compasses will touch the point 23° 28' north, marked by the nonius J.
The indicator is then to be fixed by the set serew, and at the point o, on the
plate u, v, the hour required will be indicated, the result being 4° 38' 40".
I will now suppose that it is desired to ascertain a distance between two
given points. Let the difference of longitude between two places be 11° 6.
The indicator F is to be affixed by the set or clamp screw to that point on
the scalef; the nonius J to the point 49° 58' north, and the nonius K to the
point 33" 3' north, these being their latitudes. The distance between these
two points 49° 58' and 33° 3' will be the distance required, and which on
being taken by a pair of compasses, the point of each leg being respectively placed
at o, on the two nonius J, K, will give the distance sailed in degrees, which
on placing one legof the compasses on the point o, on the scale C, and observing
where the other touches, it will be found to be 18° 48', the distance required.

page_text: I will now point out the manner of ascertaining the difference of longi-
tude, which it will be evident will be the reverse of the preceding problem.
The noniuses J, K, are to be set respectively to the two latitudes, and the
distance sailed in degrees is to be taken by a pair of compasses, and the scale C
is to be moved till the two points of the compass touch respectively the points
o, on the two noniuses; the difference of longitude will be found on the scale E
at the point o, on the part 1, 2, of the indicator F.
It will be evident from the above description that most, if not all, problems
relating to spherical triangles may be worked by this instrument, for on observ-
ing the nature of its construction, it will be seen to represent an hemisphere
consisting of the circle B, with a semicircle E affixed to it at right angles,
and the semicircular scale C, moveable to any angle; and that in virtue of
the capacity of the scale C to assume any angle with B, a true representation
of any proposed spherical triangle may be attained by accurately marking the
angles or sides given, when those required will be obtained without calculation.
Having now described the nature of my Invention, and the manner of using
the same, I would have it understood, that I lay no claim to the parts
separately; but I do hereby declare, that I confine my claim of Invention to
the giving to the scale C the property of assuming any angle with reference
to the scale (a, b) on the ring B, when the same is combined with the seale E,
and used for the purpose of ascertaining or measuring angles and distances,
as above described.
In witness whereof, I, the said Janet Taylor, have hereunto set my
hand and seal, this Twenty-fifth day of September, in the fifth year
of the reign of our Sovereign Lord William the Fourth, and in the
year of our Lord One thousand eight hundred and thirty-four.