Evening Republican, Volume 21, Number 83, Rensselaer, Jasper County, 16 April 1918 — Telescope and Spirit Level Part of Air Raiders’ Outfit [ARTICLE]

Telescope and Spirit Level Part of Air Raiders’ Outfit

If a bomb be dropped from an airplane 10,000 feet up, and traveling at a speed of 100 miles an hour. It reaches the ground a considerable distance ahead of the point at which it was released, and the difficulty of ' judging how to hit a particular building is enormous. A machine invented to assist the raiders has been found on a captured Gotha. The main feature, says the London Tit-Bits, is a telescope hung on gimbals and pointing through the floor of the bomber’s compartment. In connection with this is a form of spir it level which brings a bubble into the center of a glass disk when the telescope is vertical, so that the bomber knows when it is In the position that can be trusted. Below the telescope is a prism, so that the image seen is not an object directly underneath, but at any desired distance ahead, according to the angle at- whch It is set. For instance, if the airplane Is 10,000 feet up', and the speed is such that the bomb must be released half a mile from the object, the prism has to be set at an angle, of 15 degrees. Even then the calculation is liable to error, because the density of different layers, of Mr may vary.