One of the major pressures of T V has been to encourage the "teaching machine." In fact, these devices are adaptations of the book in the direction of dialogue. These teaching machines are really private tutors, and their being misnamed on the principle that produced the names "wireless" and "horseless carriage" is another instance in that long list that illustrates how every innovation must pass through a primary phase in which the new effect is secured by the old method, amplified or modified by some new feature.