Page:Popular Science Monthly Volume 78.djvu/245

Rh the speaker in the introductory summary. If there is any doubt in this matter, it is for the speaker skilfully to devise a plan by which difficult or novel matters shall not be too soon or too rapidly presented.

Especial care should be taken regarding the use of local names in regional descriptions. It is of no avail, it is indeed confusing to an audience, if a speaker uses the name of an unknown village as a means of indicating the locality of some natural feature, such as a cliff, or a bay. The speaker may truly, by the frequent mention of the local names of distant places, show a great familiarity with that aspect of his subject, but he will at the same time show little comprehension of the small value which such names have for his hearers. Names that are generally known, such as Apennines, Nile, Titicaca, may of course be used without introduction, as guides to smaller features in their neighborhood; but it would be a mistake to say that near Brisighella the valley of the Lamone is of incised meandering form, for few hearers can be assumed to know where so unimportant a village and so small a river lie. Local features, natural or artificial, should therefore be first introduced in terms of their relation to large natural features; and only when thus properly located should their names be added. Furthermore, if allusion may be here made to a relatively trivial matter, the speaker should not indicate the location of the features that he mentions by pointing to a map and saying "here" or "there"; the pointing stick says that; the speaker should say something more by giving the verbal equivalent of the pointer's indication; for example, "at the western base of the mountain range," or "on the southern shore of the lake." Similarly, such phrases as "on this side" or "in that direction" should be replaced by "on the northeastern side," and "in the same direction as that of the river flow."

May we not imagine a student, already practised in narration and induction, in analysis and classification, and now returned from a journey in classic lands, standing near a map of Italy and a diagram of his district, and saying to his hearers: Conceive a subdued range of deformed limestones in the back country, where several rivers, flowing through transverse valleys, emerge upon a lowland which they cross southwestward towards the sea; and then upon this lowland conceive a series of four large volcanoes to be built up, each some thirty or forty kilometers in diameter, but of moderate height and gentle slope, so that they form a series about 150 kilometers in length from northwest to southeast. After growth by eruption, the summits of all the cones are destroyed by engulfment, which forms calderas holding lakes in three of the cones, but in the fourth (southeastemmost) volcano the caldera is filled again by new eruptions. At the same time, consequent drainage erodes shallow radial furrows, which submaturely dissect the gentle outer slopes of the cones. The rivers from the mountainous back country are now obstructed; they turn along the depression