Abstract: 1. In a mechanism for sweeping a pressure controlled mine arranged within a ody of water comprising a plurality of water entraining devices, each of said devices comprising a pair of pressure plates, a plurality of bracing members for maintaining the pressure plates of each pair in predetermined fixed space relation with respect to each other, a plurality of flexible tension members interconnecting said pairs of pressure plates whereby the plates are adapted to cause the water entrained between said plates to be moved sufficiently to reduce the pressure of the water adjacent the mine to a predetermined value as the mechanism travels over the mine, and means for causing movement of said mechanism above the mine.

Abstract: 1. In a pressure responsive mine having a casing and an arming and firing rcuit therein, a pressure responsive device mounted in the casing and exposed to the pressure of the sea water, a second pressure responsive device mounted in the casing, a fluid connection between the first and second pressure responsive devices, a third pressure responsive device mounted in the casing, a restricted fluid pressure responsive connection between the second and third pressure responsive devices, and a circuit making and breaking device positioned in the restricted connection between the second and third pressure responsive devices and connected in the arming and firing circuit.

Abstract: Prior art shows multiple element optical means for image format reversal located between the front and rear elements of the large aperture primary lens of a snapshot type three dimensional (3-D) camera. Described herein are improvements in the prior art image format reversal means and the use of multiple element format reversal means in other positions not shown in the prior art. Also described are 3-D cameras which use new and different type of multiple image format reversal elements having superior characteristics.