18. How is the angle of greatest range in practice affected by a change in the velocity and size of the projectile?
It seems to diminish as the velocity is increased, and as the ball is reduced. For the musket the angle of maximum range varies from 28° to 30°; and is nearly 42° for mortars.
19. Under what angle is a mortar usually fired?
Under the constant angle of 45°, and the charge is varied according to the range required.
20. What are the advantages of this practice?
Economy of ammunition; the recoil being inconsiderable, the mortar and its bed receive but little strain; the ranges are more uniform, and the effect of a slight error in the angle of fire is less than with any other.
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21. Is the mortar ever fired at any other angle than 45°?
Yes; sometimes at 60°.
22. When is the mortar fired under an angle of 60°?