Abstract: A device for encapsulating seeds in a gel. A nozzle with dual vertical, rectilinear, concentric tubes--i.e., an inner tube and an outer tube--is supplied with gel that is fed into the outer tube. The gel goes down the outer tube to an outlet from the inner tube, so that a meniscus of gel is stretched across the outlet. Singulated seeds are fed into an inlet of the inner tube, so that each seed--and only one--drops down upon a meniscus of gel. A slight puff of air is caused to pass down the inner tube and slightly inflate the meniscus upon which a seed has dropped. More gel is fed, to cause the meniscus to separate from the outlet and form a drop of gel with a seed inside, which drops down into a fixative bath that causes the gel to set.

Abstract: Especially for use in agricultural machines such as lettuce harvesters having a maturity tester thereon, there is provided a radiation source such as Americium 241 sealed in a capsule at atmospheric pressure. The capsule is disposed in a plunger movable in an evacuated chamber between a first position in alignment with a passage having a window permeable by radiation to the outside and a second position in which the capsule is out of alignment with the passage. A pressure responsive switch monitors the pressure in the chamber and affords an alarm if the chamber pressure rises.

Abstract: For use with lettuce heads growing in double rows between furrows, there is provided a wheeled cart having a body adapted to be drawn along a furrow and carrying a radiant energy detector and an indicator, printer or readout for the detector, as well as a power supply and auxiliary equipment for the indicator and detector. One or a pair of outrigger bodies are articulated to and movable toward and away from the cart body. Each outrigger body runs between the lettuce heads in one of the double rows on opposite sides of the furrow. A source of radiant energy is located in one or both outrigger bodies and beams through the lettuce heads to the detector. Except when away from the cart body in operating position, the energy source is or the sources are shielded to block release of radiant energy. The source and detector locations may be interchanged.