Fecha de publicación: 04/09/1919 Fuente: WIPO "pollen" 131,706. Pollen, A. H., and Landstad, H. F. Aug. 20, 1918. Addition to 127,032. Sights and methods of sighting. - Consists in providing the aircraft navigating apparatus described in the parent Specification with adjustable cam-shaped fore-sights 114 whereby the proper moment for the release of a bomb may be determined. The sights 114 are carried on the guide 10 through which the pivot X passes and are adapted to rotate about an axis 124, a pointer 109 thereon being set to the altitude of the aircraft on a scale 101. The contour of the cams is arranged to give the necessary angular advance of the line of sight at various altitudes between definite speed limits, and the bomb is released when the target is seen on the edge of the cams through back-sights 111 carried by the arm 5. Pointers b, c, fixed respectively to the bracket carrying the bar 2 and to the bracket base, when in juxta-position, indicate that the first-named bracket is parallel with the longitudinal axis of the aircraft. The compass is mounted on the arm 5 with its axis coinciding with that of the pivot Y. Drift wires 7 may be carried by the arm 5 situated on each side thereof in the plane of the cams 114, and the arm is graduated to represent speed with respect to the ground or in terms of time required to cover a certain distance on the ground, the reading point being at the pivot X. A pointer 20 overlapping the compass allows the instrument to be used in dark or foggy weather.