Knowledge aids joy by discipline, by increasing the sphere of enjoyment, by showing us in animals, in plants, for example, what life is, how our own is related to theirs, showing us, in fact, our position, responsibilities and debts among the other inhabitants of the earth. Pursued out of doors where those creatures, moving and still, have their life and their beauty, knowledge is real. The senses are invited there to the subtlest and most delightful training, and have before them an immeasurable fresh field, not a field like that of books, full of old opinions, but one with which every eye and brain can have new vital intercourse. It is open to all to make discoveries as to the forms and habits of things, and care should be taken to preserve the child from the most verbose part of modern literature, that which repeats in multiplied ill-chosen words stale descriptions of birds and flowers, etc., coupled with trivial fancies and insincere inventions. Let us not take the study, the lamp and the ink out of doors, as we used to take wild life--having killed it and placed it in spirits of wine--indoors. Let us also be careful to have knowledge as well as enthusiasm in our masters. Enthusiasm alone is not enthusiasm. There must, at some stage, be some anatomy, classification, pure brain-work; the teacher must be the equal in training of the mathematician, and he must be alive, which I never heard was a necessity for mathematicians. But not anatomy for all, perhaps; for some it might be impossible, and a study of colours, curves, perfumes, voices--a thousand things--might be substituted for it.