SEQUENCE OF EXERCISES 339
Among these exercises with the solid insets, there exists the following progression from easy to difficult:
(a) The cylinders in which the pieces are of the same height and of decreasing diameter.
(b) The cylinders decreasing in all dimensions.
(c) Those decreasing only in height.
Exercises of Practical Life. To rise and be seated in silence. To walk on the line.
Sense Exercises. Material dealing with dimensions. The Long Stair. The prisms, or Big Stair. The cubes. Here the child makes exercises in the recognition of dimensions as he did in the cylinders but under a very different aspect. The objects are much larger. The differences much more evident than they were in the preceding exercises, but here, only the eye of the child recognises the differences and controls the errors. In the preceding exercises, the errors were mechanically revealed to the child by the didactic material itself. The impossibility of placing the objects in order in the block in any other than their respective spaces gives this control. Finally, while in the preceding exercises the child makes much more simple movements (being seated he places little objects in order with his hands), in these new exercises he accomplishes movements which are decidedly more complex and difficult and makes small muscular efforts. He does this by moving from the table to the carpet, rises, kneels, carries heavy objects.
We notice that the child continues to be confused between the two last pieces in the growing scale, being for a long time unconscious of such an error after he has learned to put the other pieces in correct order. Indeed