Of this, examples were found in the Val di Diano and elsewhere, and are mentioned in loco.
4th. Places situated along the line of mountain ranges, which are also in the line or nearly so of the wave-path, are more or less protected, when situated near sudden enlargements of the mountain mass, and the contrary; and places situated beyond the remote or free-lying end, of a mountain range which has gradually or abruptly diminished to the plain, are severely handled.
Just as in a line of ivory balls, the somewhat analogous illustration adduced by Humboldt, where the last (or free lying) ball, is caused to fly off from the others, by the stroke of the moving ball, given to the first, and transmitted through the other. If all the balls be of equal size, all will have equal range of motion, but if the last ball be a large one, in relation to the striking ball, its range of motion will be smaller, and if a small one, larger; and this too whether the large or small ball, be at the remote extremity, or be interposed in the range anywhere.
Examples of this exalted effect are found, at Spinazzola and Canosa, which received the wave, transmitted from the free-lying northern and eastern extremity, of the great east and west Apennine, branching into furcations at Palazzo (Map A). Saponara, Padula, Lauria, Lagonegro, Sapri, with Ascoli in the extreme north, belong to the same category; while examples of the reduction of effect, due to the sudden entrance of the wave to greatly increased masses, have been remarked and the action explained, (Part II.) at various points, but more particularly for the district, between Balvano and Baraggiano.
