Abstract: A device for controlling the flow of water between an irrigation ditch and an adjacent field. A conduit having a first end opening into the irrigation ditch and a second end opening into the field to be irrigated. The cover is pivotally attached to the first end of the conduit by means of a "J"-shaped hinge. A handle is provided on the exterior of the cover and can be engaged by a manually-held instrument to pivot the cover to a position above the conduit where it will rest due to the configuration of the hinge part. The conduit is positioned relative to the irrigation ditch such that the first end is recessed inwardly of one side wall of the ditch and extends below the bottom wall of the ditch.

Abstract: Disclosed is a test system primarily designed for free field testing of the hearing of an individual utilizing phase modulation to reduce or eliminate the production of standing waves thereby permitting accurate determination of pure tone hearing acuity. The test system consists of an audio signal source which may be the continuous or pulsed sine wave output of an audiometer, audio frequency signal generator, audio oscillator, or tape recorder wherein said stimulus signal is applied to a phase modulator. The phase modulator may be either an electronic or mechanical device or any combination thereof for periodically shifting the phase of the stimulus signal a predetermined amount. The phase modulated signal may be applied directly to an acoustic transducer or transducers if of sufficient amplitude or it may be amplified by an audio amplifier or amplifiers prior to such application.

Abstract: Spectacle cleaning apparatus including resilient nose piece supporting means, two pairs of cooperating opposed rotatable brushing means located on either side of said nose piece supporting means, positioning means for changing the spacing between respective brushing means of each pair, drive means for rotating each brushing means, connecting means operatively connecting said drive means with said resilient nose piece supporting means to continuously change the position of said supporting means as said brushing means are rotated, and holding means to maintain the nose piece of spectacles against said supporting means as the position of said supporting means changes.