Holland is sinking with respect to sealevel and the ocean is encroaching on its shores. Dikes are built to protect the land, and from generation to generation they have been raised higher and higher until now fields and meadows lie five or ten yards below the level of the ocean. The sinking has progressed variably, yet without complete interruption, since the beginning of local history, and the measurements of a thousand years indicate that it ranges from 0.09 to 0.75 of a meter per century, the more exact measurements since 1732 giving a mean of 0.26 of a meter for each hundred years. No horizontal movement of the terrestrial crust has been detected in connection with this vertical movement.
In 1819 a severe earthquake devastated the delta of the Five Rivers in western India, and throughout an immense area the quaking land . . .