Abstract: A method and apparatus for repelling insects with compound eyes employs diffraction gratings formed in movable structures, such as conventional compact discs (CDs), to create moving diffraction patterns of light from ambient light, or light from specially provided light sources, impinging on the gratings. The CDs may be suspended in a housing or frame that may be open at its sides or closed by transparent glass or plastic walls. For open sided housings the suspended CDs may be caused to turn or twist by ambient air currents or by a motor located in the housing and connected to rotate or turn the CDs. When the housing is fully closed, the motor drive effects movement of the CDs. The resulting moving light diffraction patterns repel insects having compound eyes.

Abstract: The present invention relates to a method for imparting insect repelling qualities to the hide or skin of animals by orally administering small but effective amounts of acetate salts to the animals, preferably on a daily basis.

Abstract: A horse-drawn hitch cart has its tongue adjustably positioned laterally, by means of a clevis and plural hand-actuable locking pins, along an apertured drawbar suspended forwardly and below the floor level of the cart frame to be rotatable about a laterally-extending axis. A yoke bar is attached to the distal end of the tongue by means of a yoke ring circumscribing the tongue between two longitudinally spaced and hand-actuable stop pins preventing the ring from being disengaged from the tongue. The proximal stop pin position is adjustable to accommodate different length horses by virtue of a series of through holes defined along the tongue rearwardly of the most distal stop pin. A clutch assembly, actuable from the cart floor by means of a lever, permits a ground driven power takeoff unit to be selectively engaged quickly and easily without requiring the driver to leave his seat.