length. This stick is known as Jacob’s staff, as shown
in figure 15-38. For rough work, you may ignore the
use of a stick and merely use the height of your eye
above the ground in your normal standing position.
The hand level is used for checking grade during
the rough or early part of a construction project and is
not used at distances greater than about 50 feet or even
lesser distances if an accuracy of more than 2 or 3
tenths is required.
DUMPY LEVEL
The dumpy level (fig. 15-39) has its telescope
rigidly attached to the level bar, which supports an
adjustable, highly sensitive level vial. The cross hairs
are brought into focus by rotation of the eyepiece and
the focusing knob. The telescope can be exactly
trained on the level rod by lightly tightening the
azimuth clamp and manipulating the azimuth tangent
screw. Depending on atmospheric conditions, the
dumpy level can be used to measure vertical distances
accurately at distances of 300 feet or less. When used
for alignment, it is accurate at distances up to 1,000
feet.
SELF-LEVELING LEVEL
The self-leveling level (fig. 15-40) is a precise,
time-saving leveling instrument and is equipped with
a small bull’ s-eye level and three leveling screws. The
leveling screws, which are on a triangular foot plate,
are used to center the bubble of the bull’ s-eye level.
The line of sight automatically becomes
horizontal and
bubble remains
remains horizontal as long as the
approximately centered. A prismatic
Figure 15-40.—Self-leveling level.
15-23
