Events having the same underlying purpose, though occurring in different periods, may be arranged under one topic for review; for example, all the voyages of discovery to America may be grouped under the topic, "The Road to Cathay." (See p. 92.) In this way a comprehensive knowledge is gained. This method gives a full treatment of each topic and may be used to best advantage in connection with reviews in junior classes and occasionally as a text-book or library exercise in senior classes. 2. _Methods based on the treatment of historical facts_: Comparative, Regressive, Concentric THE COMPARATIVE METHOD By this method a comparison is made between two events, two biographies, two reigns, etc., a very useful device when applied in connection with other methods. THE REGRESSIVE METHOD In this method the pupil is expected to begin with the present and work backward; that is, to begin with institutions as they are to-day and to work back through the various steps in their progress to their present state. This method may be followed most profitably in advanced classes. In junior classes it is sufficient to refer to things as they exist to-day in order to arouse curiosity regarding the facts of history that are to be taught; for example, by the use of local material; by a visit to some place of historical interest to prepare for the story of what has occurred there in the past. (See p. 112.) THE CONCENTRIC METHOD This method, which is much used, deals in ever widening circles with the same topic or event; for example, a simple story of Champlain's life and voyages to Canada is told to Form II; the same story is considered again in Form III, but this time the different voyages are noted, the results of each investigated, and the whole summarized and memorized; again, in Form IV, but this time by the topical and comparative methods, where comparison is made of the purposes and achievements of the explorer with those of other explorers--Jacques Cartier, La Salle, etc. In this third discussion a full knowledge of Champlain's work is given. The excellence of this work lies in its review and repetition. The old or former knowledge is recalled and used in each succeeding discussion of the topic. The pupils grow gradually into fuller knowledge. 3. _Methods based on class procedure_: Oral, Text-book THE ORAL METHOD This usually takes the form of an oral presentation of the story or description of the event by the teacher, while the pupils listen and afterwards reproduce what they have heard. The narration of the story is accompanied by pictures, sketches, maps, etc., illustrative of persons, places, and facts mentioned. It may also take the "development" form, in which a combination of narrative and questioning is employed. (See pp. 66, 92.)