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UNITED STATES ATENT OFFICE.
VALENTINE IIARTGROVES SMITH, OF SIERLY, TEXAS.
PLOTTER.
SPECIFICATION forming part of Letters Patent No. 448,685, dated liarch 24, 1891.
Application filed September 11, 1890. Serial No. 364,611. (No model.)To all wVhons it mCay coTcerun:
Be it known that l,VALENTINE IIARTGROVES
SirITH, a citizen of Sherly, in the county of
Hopkins and State of Texas, have invented
5 certain new and useful Improvements in Sur-
veying-Instruments; and I do hereby declare
the following to be a full, clear, and exact de-
scription of the invention, such as will enable
others skilled in the art to which it appertains
io to make and use the same.
My invention relates to an improvement in
surveying-instruments, and has for its object
to produce a simple device whereby certain
information can be obtained without the ne-
15 cessity of auxiliary calculations.
A further object is to produce a simple in-
strument whereby bearings may be found
showing latitude and departure of courses,
lengths of angular lines, and square surface
20 contained in a triangle.
With these objects in view the invention
consists in certain novel features of construe-
tion and combinations and arrangements of
parts, as hereinafter set forth, and pointed
25 out in the claims.
The accompanying drawing represents a
plan view of my improved apparatus.
A represents a plate, of any suitable mate-
rial, on which the quadrant of a circle is
30 marked, having the degrees from 0 to 90
marked thereon. Within the segment is lo-
cated a square or right angle B3, the end of
said square extending to the radii a b, and
the apex of said square or triangle B touch-
35 ing the mark indicating forty-five degrees on
the periphery of the quadrant. A second are
c is drawn within the first or outer are, this
are passing through the square, as represented
on the drawing. At the point where the radii
40 meet a needle C is pivoted, and is adapted to
mark the radius of the inner as well as the
outer are of the quadrant, the portion of the
needle between the two arcs being graduated,
as explained farther on. The radius of the in-
45 ner are is intended to represent a unit of any
measure, and when the radius is extended in
length all the other lines are extended or sup-
posed to be extended in like manner. The
two tangents produced by the square or right
50 angle B are each divided into one hundred
equal parts. Whenever the radius is ex-
tended, it changes the value of these equalparts. If the radius is multiplied by one
thousand, the unit of measure being yards
or any other unit, the tangent-lines will also 55
be multiplied, and then each division on
the tangent-lines will represent ten yards or
whatever measure may be used. The inner
are is graduated the same as the tangent-
lines and is intended to represent, as the nee- 6o
die is turned from one degree to another
around the arc, the length of the sine and
cosine of the degree which corresponds to lati-
tude and departure of courses. The distance
on the end of the needle that is graduated is 65
equal to the distance the needle exceeds the
radius of the inner are. Suppose, now, that
E F equals one thousand units. The distance
from F to G equals one hundred units. E and
G are two stations between which the line is 70
to be run. Now consider the line marked
"radius" increased one thousand times and
equal to E F. The tangent-line is extended
in like manner. The station G is on tangent-
line, which line represents one thousand units 75
divided into one hundred equal parts, the
value of each of these parts equaling ten
units, and then ten of the divisions on tan-
gent-line would equal the distance between
F and G, one hundred units. The compass is 80o
placed at E and set to run an east and west
or north and south line, and the compass cited
will be on the line represented by E F. Place
the needle of the instrument on the line
marked "radius" at the extremity of the arc- 85
and turn said needle until it passes over ten
divisions of the tangent-line. Next count
the degrees the needle has passed on the are,
note this number, change the compass the
same number of degrees, turn the compass 90
cited to the right until the compass-needle
passes over this number of degrees, and then
the compass-sights will be on station G. This
will give the correct bearing to G without cal-
culations, and in the same manner other bear- 95
ings may be found. The graduations on the
forward end of the needle are the same as the
divisions on the tangent-lines, and when the
needle is at forty-five degrees it divides each
are in the center and is the length of a line ioo
drawn from corner to corner of the square.
By turning the needle around the are either
way and observing the divisions on the nee-
dle between the inner are and tangent-line,
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Smith, Valentine Hartgroves. Plotter., patent, March 24, 1891; [Washington D.C.]. (https://texashistory.unt.edu/ark:/67531/metapth172643/m1/2/: accessed June 30, 2024), University of North Texas Libraries, The Portal to Texas History, https://texashistory.unt.edu.; crediting UNT Libraries Government Documents Department.