1535, March till 1537.

1500.

1538, 29th September, Formation of the Monte Nuovo,

near Puzzuoli.

1689, March 14.

1681, December 16.

1660, July.

1682, August 12.

1694, March to December. (Eruption 1694, March 12, with feeble recur

1702, March 8.

only of ashes.)

1701, July 2 till 15.

1723, November, beginning of the month.

1735, October, beginning of the

rences of action till 1698.

month.

1737, May 14,

It appears from this Table that the nearest coincidence between the eruptions of the two Volcanos was in 1694 and in 1811, when they occurred within a month of each other; and that on eight several occasions an interval of less than half a year elapsed between them, viz. that of Vesuvius Dec. 2, 1754, was followed by one of Etna on March 2, 1755; Vesuvius August 3, 1779, by Etna May 18, 1780; Vesuvius October 31, by Etna July 28, 1787; Etna June, 1788, by Vesuvius February, 1799; again followed by one of Etna in June, same year; Etna March 27, 1809, by Vesuvius 10 December, 1809; Vesuvius October 12, 1811, by Etna October 25, 1811; again followed by Vesuvius December 31, same year; Vesuvius May 27, 1819, by Etna, November 25, same year.

LECTURE III.

ON VOLCANOS EXISTING IN COUNTRIES NOT
VISITED BY THE AUTHOR.

EUROPE.

ICELAND-Distinction of its Lavas into terrestrial and submarine-Dykes that occur in the latter-Cavernous Lavas-Sulphur Mountains-Geysers-Siliceous Sinter-Formation of Rocks by Geysers considered— Surturbrand of Iceland-General remarks. ISLAND OF JAN MAYEN.

Volcanic rocks in the GRECIAN ARCHIPELAGO-Santorino and the adjoining Islands-Milo-Argentiere-Lemnos -Cerigo-Delos.

CONTINENT OF GREECE-Acroceraunian MountainsChalcis in Eubœa-Mount Parnassus-Megalopolis in Arcadia-Trazene in Argolis-Methone-ThessalyBosphorus.

Volcanic appearances in SARDINIA.

SPAIN-near Barcelona-Murcia-Cape di Gaieta-Cape St. Vincent.

PORTUGAL-near Lisbon-Province of Beira.

AFRICA.

AFRICAN ISLANDS-Teneriffe-antient Lavas-Trachyle -modern Lavas-modern eruptions of the Volcano of Teneriffe.

Palma-Von Buch's remarks on that Island-on Great Canary-on Fortaventura.

Lanzerote-volcanic phænomena that occurred in 1730-36 -in 1825.

Madeira-Bowdich's account of the physical structure of that Island—and of Porto Santo. Cape de Verde Islands.

Azores-Dr. Webster's account of St. Michael- El Pico, &c.-Island of Sabrina.

Question as to the former existence of the Island or Continent of Atlantis, in this situation.

Island of Ascension-of Saint Helena.

ISLANDS ON THE EASTERN COAST OF AFRICA-Madagascar, Isle of France-Isle of Bourbon.

Volcanic appearances on the CONTINENT OF AFRICAnear Mount Atlas-Tripoli-Egypt.

ASIA.

Coasts of the RED SEA and PERSIAN GULPH-ARABIAPALESTINE-Dead Sea, the effect of a volcanic eruption-Asia MINOR-near Scandaroon-near Smyrna.In the Caucasus-near the CASPIAN SEA-in PERSIA-in MESOPOTAMIA-INDIA-THIBET-SIBeria -KAMSCATKA-JAPAN-LOO CHOO.

Islands in the Indian ArcHIPELAGO.-PhilippinesJava-Sumatra, &c.

ISLANDS IN THE SOUTH SEA.

AMERICA.

Islands of the ANTILLES, divisible into four Classes, according to their physical constitution.-Volcanic appearances considered-Island of Trinidad.

NORTH AMERICA - California-Mexico-GuatemalaNicaragua.

SOUTH AMERICA - Columbia- Quito-Peru-ChiliHumboldt's remarks on the Volcanos of the New World generally.

LECTURE III.

HAVING in my preceding Lectures confined myself, in great measure, to the consideration of those volcanic districts which I had been able personally to visit, it is my purpose in the present to lay before you such facts as I could collect respecting the existence of similar formations in other parts of the globe.

By so doing I shall the better enable you to judge of the soundness of the conclusions which I shall afterwards attempt to deduce, and be less likely to incur a censure similar to that which has been passed by Humboldt on the geologists of the last century, who, ignorant of the variety of aspects which these appearances assume in different parts of the world, considered Etna and Vesuvius the type of all existing volcanos, a proceeding no less absurd than that of the shepherd in Virgil, who expected his own little hamlet to contain within itself the type and image of imperial Rome.

In my first Lecture I alluded to the travels in Iceland, which seem to have been in some measure suggested by the discussions that were carried on with so much warmth at Edinburgh respecting the origin of basalt; in my present it is my intention to lay before you such of its contents as appear to illustrate the subjects more immediately under our consideration.

Sir G. Mackenzie, in the work to which I refer, notices two varieties of volcanic products in this island, one of which appeared to him of submarine, the other of terrestrial origin.

Among the rocks referred to the former period, the prevailing substance was a tuff containing fragments of cel