Abstract: An improved microprocessor-controlled sonar depth sounder, which is automatically operative to detect and lock to the bottom of a body of water, fill in the display below the detected bottom, change display scales in response to the detected bottom going off-scale, and reformat the entire display in response to a scale change. A memory is provided for storing target data up to the operable depth limits of the device, thereby allowing display reversing and display expansion or "zoom" of a predetermined portion of the display selected by a zoom cursor. The zoom or cursor is variably positionable at different depths. The device employs an improved variable sensitivity amplifier. Also disclosed is an improved water-resistant switch construction for marine electronic equipment.

Abstract: An improved microprocessor-controlled sonar depth sounder, which is automatically operative to detect and lock to the bottom of a body of water, fill in the display below the detected bottom, change display scales in response to the detected bottom going off-scale, and reformat the entire display in response to a scale change. A memory is provided for storing target data up to the operable depth limits of the device, thereby allowing display reversing and display expansion or "zoom" of a predetermined portion of the display selected by a zoom cursor. The zoom or cursor is variably positionable at different depths. The device employs an improved variable sensitivity amplifier. Also disclosed is an improved water-resistant switch construction for marine electronic equipment.

Abstract: A dispersing method and apparatus for metering the dispersing of dry particulate material into a liquid. The apparatus includes a supply container and a metering and dispersing assembly having a clog-preventer with a hub and a plurality of radially extending arms with a rim. Passages are formed between the arms for the passage of dry material. Any large agglomerates that may be formed from the dry material are supported by these arms above the passages to prevent clogging. A dispensing rod capable of vertical movement is positioned within a bore in the hub, and controls the vertical movement of the downwardly inclined dispersing surface attached to the lower end of the rod. The dispersing surface receives the particulate material from the bottom opening, and carries it substantially laterally from the bottom opening to be dispersed into the liquid.