DEFLECTION SCALE.
Q. Describe the deflection scale and explain its use.
A. The deflection scale is used to determine azimuth corrections for mortars. After the "set-forward point" has been obtained, the plotter sets the gun-arm on it and by means of the indicator determines the zone, range, and elevation of the target. The operator reads the straight azimuth from the gun-azimuth scale and gets the zone and elevation from the plotter. He then sets the elevation scale-pointer at the given elevation, turns crank moving small azimuth pointer to the azimuth he obtained from gun-arm scale; then by referring to the large azimuth scale-pointer he reads the corrected gun-azimuth, which he sends to the pits together with zone and elevation. Should it become necessary to make a correction for drift, turn the deflection-scale knob, either to right or left, as the case may be, as 3 = normal. (See Fig. 83.)
Note.—This apparatus depends upon the fact that the drift is the same for the same elevation in every zone except the eighth. In this zone the instrument cannot be used as now constructed.
WARSHIPS.
Q. State the general appearance, average length, beam, draft, speed, tonnage, thickness of belt and deck armor of battleships, armored cruisers, protected cruisers, torpedo-boat destroyers, and torpedo boats.
A. See Table "A."
Q. Point from Figs. 84 and 85 the following: