ordinary operation of the well the recovered liquid will accumulate to a specified head the head of liquid defines a depth at which recovery can begin from the well this head of liquid will have a certain depth in the well assume as an easy example that the head of liquid is exactly 1 000 feet below the equipment shown in fig1 the measuring wheel 40 rotates to measure the length of cable spooled into the well so that the cable can be slowed as the accumulated head is approached the motor 15 can therefore run at a relatively high speed until the bail is within about 50 feet or so at that point rotations of the measuring wheel trigger a change in motor speed the motor is preferably slowed at this juncture the weight on the cable 20 is measured the weight is measured at the dead end sensor 56 and the weight comprises only two components which are the weight of the empty bail and the weight of cable hanging over the measuring wheel the motor is slowed so that the bail then moves downwardly into the accumulated head of oil at this point the buoyancy of the empty bail reduces the weight at the dead end sensor 56 the filling rate is defined primarily by the opening 74 at the bottom of the bail the buoyancy is used to advantage as a load related signal the motor 15 is operated slowly while the reduced load is sensed on the dead sensor 56 as the bail fills the load on the cable 20 will change this load will.