Abstract: A fixed tank is disposed in the sea adjacent a floating solar still, with a flexible conduit extending between a lower portion of the tank and the interior of the still. A one-way check valve disposed in the lower portion of the tank permits sea water to enter the tank and fill it as the tide rises. As the tide lowers, water flows from the tank through a restriction in the conduit to the solar still.

Abstract: A long plastic film roll is manufactured in situ for covering an agricultural, athletic or other field. A plurality of short plastic film rolls are supported on drivable rollers, which in turn are mounted on a plurality of spaced trucks extending along the width of the field. The axes of the film rolls are parallel, but alternate rolls are staggered with every other roll being disposed either forwardly or rearwardly of the adjacent rolls. The roll ends overlap and, as the trucks move longitudinally down the field to lay down the film, the overlapping edges of the film are sealingly joined together as they leave their respective rolls and just before being laid down.

Abstract: A flexible pick-up conduit is connected to a source of vacuum for picking up leaves and the like. The conduit is mounted to an assembly which includes at least three longitudinally expandable accordian-like tubular control members normally extending parallel to the conduit. Pressurized air flows through the control members, and the relative air flow therethrough is selectively variable, as by a proportioning valve, thereby causing the tilt angle of the conduit and its mouth to change. A momentarily actuatable piston functions through a valve control plate to increase or decrease the expansion of the control members so as to lengthen or shorten the conduit without changing its angular disposition.