234 THE MONTESSORI METHOD
lowest." Then placing the two extreme pieces side by side she may take them out of the line and compare the bases, showing that they are equal. From the extremes she may proceed as before, selecting each time the two remaining pieces most strongly contrasted.
With the third solid inset, the directress, when she has arranged the pieces in gradation, calls the child's attention to the first one, saying, " This is the largest," and to the last one, saying, " This is the smallest." Then she places them side by side and observes how they differ both in height and in base. She then proceeds in the same way as in the other two exercises.
Similar lessons may be given with the series of graduated prisms, of rods, and of cubes. The prisms are thick and thin and of equal length. The rods are long and short and of equal thickness. The cubes are big and little and differ in size and in height.
The application of these ideas to environment will come most easily when we measure the children with the an-thropometer. They will begin among themselves to make comparisons, saying, " I am taller,— you are thicker." These comparisons are also made when the children hold out their little hands to show that they are clean, and the directress stretches hers out also, to show that she, too, has clean hands. Often the contrast between the dimensions of the hands calls forth laughter. The children make a perfect game of measuring themselves. They stand side by side; they look at each other; they decide. Often they place themselves beside grown persons, and observe with curiosity and interest the great difference in height.
Form. When the child shows that he can with security distinguish between the forms of the plane gRometric in-