with cold, nor in summer, when everything is parched and withered by the heat; nor yet in autumn, when the vital force of all creatures declines with the sun’s declining rays, and a new winter with hostile mien is approaching; but in spring, when the sun brings back life and strength to all. Again, the process consists of several steps. While it is yet cold the bird conceives the eggs and warms them inside its body, where they are protected from the cold; when the air grows warmer it lays them in its nest, but does not hatch them out until the warm season comes, that the tender chicks may grow accustomed to light and warmth by degrees.
8. Imitation.—In the same way the gardener takes care to do nothing out of season. He does not, therefore, plant in the winter (because the sap is then in the roots, preparing to mount and nourish the plant later on); nor in summer (when the sap is already dispersed through the branches); nor in autumn (when the sap is retiring to the roots once more); but in spring, when the moisture is beginning to rise from the roots and the upper part of the plant begins to shoot. Later on, too, it is of great importance to the little tree that the right time be chosen for the various operations that are needful, such as manuring, pruning, and cutting. Even the tree itself has its proper time for putting forth shoots and blossoms, for growing, and for coming to maturity.
In the same manner the careful builder must choose the right time for cutting timber, burning bricks, laying foundations, building, and plastering walls, etc.
9. Deviation.—In direct opposition to this principle, a twofold error is committed in schools.
(i) The right time for mental exercise is not chosen.
(ii) The exercises are not properly divided, so that all advance may be made through the several stages needful, without any omission. As long as the boy is still a child he cannot be taught, because the roots of his understanding are still too deep below the surface. As soon as he becomes old, it is too late to teach him, because the intellect
