586 THE SCIENTIFIC MONTHLY
the records we leave^ or the lack of them. Is there not a possibility tiliat the archeologists of the future will find it proportionately as difScult to obtain an accurate knowledge of our present civilization as our present archeologists have found it to learn about the past? It may be worth while to consider what our duty is in this respect to posterity.
In this discussion we may find it convenient to indicate the modern products of man's hand and brain, that have at present a permanent or recorded form, as '* works.'* Those of the past might be referred to col- lectively as " ancient works. Before we proceed further in our argu- ment, it might be well to examine the modes in which the works of miaa may be or have been destroyed. And by destruction we mean the state of ruin in which we have found many ancient works, as well as the utter ruin which leaves practically no trace or residue.
Most of the natural forces that appear to have accomplished the ruin of ancient works can be considered as being just as effective now as they have ever been. Possibly we should still consider man as an inten- tionally destructive agent, present world conditions being so closely analogous to those of the past.
The first natural agent that probably most readily suggests itself is vulcanism, with its accompanying or brother calamity, earthquake. One scarcely needs to enlarge upon the series of disasters of this character that have occurred within historic times. Nearly every year we still find that earthquakes and volcanic eruptions occasion great damage and loss of life somewhere on the earth. If a building is to withstand earth- quake, it must be exceptionally well built, and its site and foundation prepared with some care. Or, on the other hand, the buildings have to be, like those in Japan, constructed of materials that may be destroyed by other agents, if not by earthquake. Vulcanism may be terribly de- structive in several ways. One is by the burial of cities beneath great quantities of volcanic " ash," sand, lapilli, etc., as at Pompeii; another, by the flow of hot lava over and through the works of man; still another, by the swift discharge of large volumes of hot and poisonous gases, as at St. Pierre. One might almost say that more ancient ruins were caused by earthquake and vulcanism than by any other natural means.
Considering wind, water and fire, one may readily recall the known effects of these natural agents upon ancient works. Violent winds or tornadoes have doubtless visited man's habitations in the past as they have in modern times, and in their effects have been as destructive to certain structures as fire or earthquake. The Deluge of Biblical his- tory seems to have been something more than a mere tale. Even the legendary continent of Atlantis may have existed as a large island or archipelago, finally destroyed by tidal waves and seismic disturbances. Floods and deluges are prominent in the folk-lore of peoples over nearly the whole earth. We moderns have had experiences with floods, tidal waves, and the like, which have shown us the destructive power of
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