SECOND CLASS OF CONDITIONS MODIFYING EFFECTS
SHOCK—FIRST ASPECT OF RUINED TOWNS.
This disposes, by anticipation, of the third class of modifying conditions. As respects the second, nothing is more remarkable and puzzling to an unpractised observer, who enters a town situated upon tolerably level ground, than the apparent caprice by which the fall of the buildings is characterized. He finds one whole side of a street cleared down; turning into the next, within a few hundred feet, he needs be on the watch, to discover any signs of injury. Further on, whole districts of streets have disappeared, and one heap of rubbish, stones, and beams occupies their place; yet, not far off, long lines of houses are but fissured. In some large streets the houses are down here and there, in the most irregular order, some of the very loftiest stand pretty safely—some of the humblest are in dust.
These abrupt changes from safety to destruction are still more remarkable, if the town, in place of resting upon the plain, or on pretty level ground, occupy the summit and flanks of some "colline," or conoidal hill. Here, perhaps, at one side of a line passing over the crest of the hill, nearly everything is demolished; at the other, little damage has been done. Until by the help of such observations as have