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While writing, the news has come that another Zeppelin has dropped three bombs on Ostend, the casualty list being one dog. Two unexploded projectiles were found on a field near Waeragheim. These were probably thrown from the same airship. They show how constantly missile throwing from a moving airship may fail to come near the mark. There is no doubt that to hit particular objects aimed at from airships is by no means an easy matter. Success would seem to require considerable training in this particular method of warfare. The late Colonel Moedebeck, in his well-known pocket-book of aëronautics, makes the following remarks on the throwing of balloon missiles:—
We may assume that, if handled skilfully, the object aimed at will be hit very exactly. We must distinguish between the throw when the airship is at rest and that when it is in motion. In throwing out while at rest, which is only possible when the airship can travel against the wind, the following points must be considered:—
(a) The height of the object.—This may be accurately determined from the contour lines on the map, or from a determination of its normal barometric height. Both must be done before starting.
(b) The height of the airship above the object.—The barometric height is read and reduced to normal conditions. The difference in heights as found from (b) and (a) gives the height above the object.
(c) The velocity of the wind.—May be read on an anemometer in the airship, or determined beforehand by captive balloons.
(d) The time of fall.—Given by the law of gravitation from the determination under (b).
The height of fall = h = gt²/2.
Whence the time of fall t = √(2h/g).
(e) The resistance of the air. R = (γ/g)Fv².
(f) The leeway.—The longer the fall, and the lighter and larger the falling body, the stronger is the drift. For known missiles, the drift for different heights and wind velocities may be determined practically.