Remembering a Causal Process Represented by Levers

For the present experiment we have used two models which resemble each other in the static state, but represent two distinct causal mechanisms. The first model, which we shall call B (blue match-box), is rigid and held in position by a slide; when the handle a is pushed up, the whole model moves in a vertical direction (see Figure 38, 11). Model R (topped by a red match-box), on the other hand, is fixed to the board by a central bolt, and its three segments are connected by two screws: when the handle a is pushed up, the segments b and c move down (Figure 38, IV).