After the second observation the corrected range determined is used in setting the platen and "T" square.
See Fig. 60.
Q. How do the divisions on the azimuth-subscale and the deflection-scale of the sights compare with one another?
A. They are equal—the least reading on the former = 5 hundredths, and on the sight-scale one point or division = 5 hundredths or 3 minutes.
Q. How are the predicted range and predicted azimuth obtained?
A. It is now, under the new system of fire direction, obtained by means of the travel correction on the range correction and azimuth correction-board. If these new boards are not yet issued, the use of a range-keeper's range prediction-scale and a gunner's azimuth prediction-scale determines them at the gun. The old method was by plotting several positions of a target on the plotting-board and using a prediction-ruler, whence the predicted point was obtained.
Q. Define quadrant elevation.
A. The angle between the axis of the bore before firing and the horizontal plane. (See Figs. 63 and 64.)
Q. What is the difference between quadrant and sight elevation?