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Extending transversely of the stock or body portion 5
is a shaft 14 upon which is mounted for rotation
a pointer or index finger 15, the latter being
movable over the face of a graduated dial 16 seated
in a suitable recess 17 formed in one side of said
stock or body portion. The pointer 15 is provided
with oppositely disposed indicating fingers 17´,
the lower one of which is weighted, as indicated at
18, so as to always maintain said pointer in
a vertical position regardless of the angle or inclination
of the stock. The dial 16 consists of a plate
of metal, cardboard or other suitable material upon
which are printed, stamped or otherwise represented
a plurality of circles arranged concentric with the shaft
14 and divided by division lines 19 into
quarter circles or quadrants, as shown. The inner
circle 20 is divided by radial lines into seventy-six
equal spaces representing inches on the circumference
of a circle while the outer circle 21 is divided
by similar radial lines into degrees, each quarter
circle or quadrant representing ninety degrees. The
upper right-hand quadrant 22 is graduated from
left to right and indicates the height of the perpendicular
in inches per slant foot in any elevation and the adjacent
quadrant 23 graduated from right to left and indicates
the number of inches in the base for each slant foot in
the hypotenuse. The lower quadrants 24 and
25 are graduated to indicate the same measurements
as the upper quadrants 22 and 23 only the
lower quadrants are numbered in whole numbers and decimals
per foot for every five degrees thereby enabling the operator
to more readily see the fractions of an inch per foot.
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The upper left-hand quadrant 26 is graduated
from right to left and is used for ascertaining the height
or altitude of a perpendicular from a known base,
at a desired grade, and also the length of the slant
line or hypotenuse if the length of the base or the height
of the perpendicular are known. The adjacent upper
left-hand quadrant 27, which is also graduated
from right to left, indicates the number of inches
in the slant line or hypotenuse to every foot in the base.
Thus for example if the grade is nine inches per horizontal
foot the index finger of the dial will point to the numeral
9 on the quadrant 26 and to the numeral
15 on the quadrant 27, thus indicating
that to every foot in the base there are fifteen inches
in the slant line hypotenuse. In further explanation
of the use of the quadrants 26 and 27 let
us say that it is desired to know the height of a perpendicular
fifty feet from a given point, if the grade is nine
inches to the foot. In this case elevate the instrument
until the index finger points to the numeral 9
on the quadrant 26 and then sight over the level
or through the longitudinal recess therein and the height
of the perpendicular will be 50x9 or 37 feet 6 inches.
Again, let us say the height of the perpendicular
is known, as well as the base and it is desired to
ascertain the length of the slant line or hypotenuse.
Place the instrument at an incline and sight to the top
of the perpendicular and if, for instance, the
index finger points to the numeral 9 on the quadrant
26, it will also point to the numeral 15
on the adjacent quadrant 27 thus indicating that
to every horizontal foot (in this case fifty feet)
there are fifteen inches in the slant line or hypotenuse
thus making the slant line 50x15 or 62 feet 6 inches.
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