Abstract: Apparatus is described for placement in a borehole in the earth, which enables the generation of closely controlled seismic waves from the borehole. Pure torsional shear waves are generated by an apparatus which includes a stator element fixed to the borehole walls and a rotor element which is electrically driven to rapidly oscillate on the stator element to cause reaction forces transmitted through the borehole walls to the surrounding earth. Logitudinal shear waves are generated by an armature that is driven to rapidly oscillate along the axis of the borehole relative to a stator that is clamped to the borehole, to cause reaction forces transmitted to the surrounding earth. Pressure waves are generated by electrically driving pistons that press against opposite ends of a hydraulic reservoir that fills the borehole. High power is generated by energizing the elements at a power level that causes heating to over 150.degree. C.

Abstract: This invention is conerned with conveyors using reciprocating flights to convey material along the length of the conveyor. The conveyor consists essentially of a bed of articulated plates, a track constraining a chain adjacent a first longitudinal edge of the bed, spaced flights attached to the chain and located to extend across the bed and means for reciprocating the chain along the track. The chain is preferably made of rigid members of substantially uniform cross-section and the flights are shaped bars having one end adapted to be pivotally attached to the chain and are reduced in their height towards their free ends with the trailing edges of each flight tapered downwardly towards their bottom surfaces and inclined towards the leading edges at their free ends which ends are chamfered.