The Motion of Earthquakes.

--Natives of those countries who have experienced many hundred earthquakes, believe the difference to be less in the greater or less duration of the shocks, or the slowness or rapidity of the horizontal oscillation, than in the alteration of motion in opposite directions.

The circular (or gyratory) earthquakes are the most rare, and at the same time the most dangerous.

In the great earthquake of Riobamba, in the province of Quito, (4th Feb., 1797), and in that of Calabria (5th Feb. and 28th March, 1783), walls were changed in direction without being overthrown; straight and parallel rows of trees were inflected, and in fields having two sorts of cultivation, one crop even took the place before occupied by the other; the latter phenomenon showing either a movement of the translation, or a mutual penetration of the different strata.

When making a plan of the ruined city of Riobamba, I was shown a place where the whole furniture of one house had been found under the remains of another; the earth had evidently moved like a fluid, in streams or currents, of which we must assume that the direction was first downward, then horizontal, and lastly again upward.

Disputes concerning the ownership of objects which had been thus carried to distances of many hundred yards were decided by the Audiencia or court of justice.--Humboldt's "Kosmos."