is to be viewed as a single volcanic furnace. The subterranean fire breaks forth sometimes through one and sometimes through another of these openings, which it has been customary to regard as separate and distinct volcanos. The progressive march of the subterranean fire has been here directed for three centuries from North to South. Even the earthquakes which occasion such dreadful ravages in this part of the world afford remarkable proofs of the existence of subterranean communications, not only between countries where there are no volcanos (a fact which had long been known), but also between fire-emitting openings situated at great distances asunder. Thus in 1797 the volcano of Pasto, east of the Guaytara River, emitted uninterruptedly for three months a lofty column of smoke, which column disappeared at the instant when, at a distance of 240 geographical miles, the great earthquake of Riobamba and the immense eruption of mud called "Moya" took place, causing the death of between thirty and forty thousand persons.
The sudden appearance of the Island of Sabrina near the Azores, on the 80th of January, 1811, was the precursor of the terrible earthquake movements which, much farther to the west, shook almost incessantly, from the month of May 1811 to June 1813, first the West Indian Islands, then the plain of the Ohio and Mississipi, and lastly, the opposite coast of Venezuela or Caraccas. Thirty days after the destruction of the principal city of that province, the long tranquil volcano of the Island of St. Vincent burst forth in an eruption. A remarkable phenomenon accom-
