Of course, you will understand that we have given only a few of the most notable of the eruptions of Mt. Vesuvius. Since the yea a. d. 1500 there have been no less than fifty-six recorded eruptions, that of the year 1857 being especially violent.

Omitting these eruptions we at last come to the great recent eruption of 1872.

Fortunately, the eruption of 1872, as well as still more recent eruptions that have occurred, have been more accurately described than have most volcanic eruptions, for the Italian Government, recognizing the value to the natives of Italy of a knowledge of what was going on at the crater of Vesuvius, has maintained for the past thirty years an observatory on the western part of the mountain. This observatory has been placed in charge of Prof. Luigi Palmieri, a well-known student of volcanoes and earthquakes. At this place records are kept of the behavior of the volcano, of all earthquake disturbances, as well as other phenomena. At the same time, by the use of photography, excellent pictures have been obtained showing the appearance of the sky during an eruption.

Vesuvius had been in a quiet state from November, 1848, to the year 1871, when small quantities of lava flowed continuously for several months. Again, early in 1872, other quiet eruptions of lava continued for weeks at a time. Finally, on April 26th, of that year, a violent explosive eruption occurred. The following account has been taken from Palmieri's report, entitled, "The Eruption of Vesuvius in 1872."

On April 23d the recording earthquake instruments, the seismographs, were greatly affected. On the evening of the 24th lava streams flowed down the cone in various directions. These streams were continued on the 25th and the 26th, so that on the night of the 26th the observatory lay between two streams of molten lava that threw out so much heat that the glass windows in the observatory were cracked, and a scorching smell was quite perceptible in the rooms. The cone of the mountain was deeply fissured, lava escaping freely from all the fissures, so that the molten rock appeared to ooze from over its entire surface, or as Palmieri expressed it, "Vesuvius sweated fire."

This great cracking or fissuring of the cone was accompanied by the opening of two large craters at the summit, that discharged, with a great noise, immense clouds of steam, dust, lapilli, and volcanic bombs. These latter are very curious and consist of masses of soft lava that are thrown high into the air by the outrushing columns of steam. Being rotated or spun, as they rise in the air, they assume a spherical shape. Some of these volcanic bombs were thrown to a height estimated by Palmieri to have been nearly 4,000 feet above the top of the mountain. When the height of a projectile is known, the velocity with which it left the opening from which it was projected or thrown can be estimated, so that the volcanic bombs must have left the crater at a velocity of about 600 feet per second.

On the 27th, in the evening, the lava streams ceased flowing, but the dust and lapilli continued to fall during the 28th and the 29th. On the 30th the detonations decreased and by the 1st of May the eruption was entirely over.

Palmieri calculated that the quantity of molten rock thrown out during this eruption was sufficient to cover an area of about 1.8 square miles to an average depth of about thirteen feet.

As we can see from the above descriptions, the volcanic activity of Vesuvius is characterized by long periods of rest followed by periods of activity. The periods of rest are measured by years, and often by centuries; the periods of activity by days or hours.

But Vesuvius was not to have a long period of rest after its eruption of 1872. On the contrary, shortly after the great disaster of Martinique in 1906, it again became active, and on the 5th of April, 1906, began throwing large blocks of lava out of its central cone, and on the next day began to throw out large streams of lava, which, on April 7th, destroyed a village in the neighborhood. At the same time rumbling sounds were heard, and violent earthquake shocks shattered the windows of the houses.

Professor Matteucci, the present director of the Vesuvius Observatory, made the following report on April the 8th.

On April 9th Matteucci made the following report:

On April 10th Matteucci sent the following report:

The eruption of Vesuvius of 1906 was especially noted for the great quantities of sand and ashes thrown out of the crater. The amount of sand that fell on the roof of the market house at Monti Olivetto was so great that the roof fell in. In this eruption there were some six lava streams that poured down the mountain. The most formidable of these was that which descended towards Torre Annunziata. Here it stopped just short of the wall of the cemetery outside of the town.

During this eruption of Vesuvius, as in previous eruptions, clouds of volcanic dust collected in the air, shutting off the light of the sun. Naples was in a state of semi-darkness. The roofs of the houses were covered to a depth of several inches with an exceedingly fine reddish dust. In some places this dust had drifted into heaps fully a yard in depth.

CHAPTER VI

OTHER VOLCANOES OF THE MEDITERRANEAN

The relative positions of the other volcanic mountains of the Mediterranean Sea; i. e., Etna, Stromboli, and the volcanoes of the Santorin group of the Grecian Archipelago, are shown in the map, Fig. 12.

We will begin with the volcanic mountain of Etna, under which, according to mythology, the angry gods had buried the rebellious Typhoon.

Etna is situated on the island of Sicily, immediately southwest of Italy. It is a much larger mountain than Vesuvius, rising, as it does, from a circular base about eighty-seven miles around, to a height of 10,840 feet above the level of the Mediterranean. It forms a conspicuous object when seen either from the Mediterranean, or from distant parts of Italy.

The height of Etna is so great that its slopes can be divided into three distinct climatic zones or belts. The lowest of these lies between the sea and a height of 2,500 feet. In this zone the mountain slopes are covered with cultivated fields, olive groves, orchards, and vineyards. The middle zone lies between 2,500 feet and 6,270 feet. This zone is covered with forests of chestnuts, oaks, beeches, and cork trees. The third and highest zone includes the rest of the mountain, and may be called the desert zone, since it is a sterile region, covered with huge blocks of lava and scoriæ, and terminating, in the higher portions, in a snow-covered plain, from which the central cone rises.

Etna is continually sending up columns of steam and sulphur vapor. Every now and then it starts in eruption, throwing out large quantities of lava either from the crater on its summit, or from some of the 200 smaller cones or craters that occupy portions of its slopes. On account, probably, of its height the eruptions are most frequently on the sides. Etna affords a magnificent example of a huge volcanic pile of the Vesuvian type, which has been slowly built up by the gradual accumulation of materials that have escaped from its craters.

One of the most interesting features of the higher regions of Etna is an immense chasm rent in a side of the cone near the summit, and known as the Val del Bove. This chasm forms a vast amphitheater.

The great force that removed such an immense mass of matter from the cone could not have been the eroding power of water, since the materials of the cone are too porous to permit streams of any size to rush down the slopes. The force is most probably to be found in some explosive eruption of the mountain, when a portion of the crater was suddenly blown off, just as was done in Vesuvius when a large part of the old crater of Somma was blown away. What is especially interesting about the Val del Bove is the opportunity it affords for studying the interior structure of the mountain, for it practically enables one to enter to almost the heart of this great volcano.

The Val del Bove has the shape of a great pit five miles in diameter. It has almost vertical walls, the height of which varies with their position. Those which reach highest up the mountain vary from 3,000 to 4,000 feet in height.

Like Vesuvius, Etna has been split or fissured into great crevices that have been filled with lava during the many eruptions of its central crater. On hardening, these lava streams form what are known as dikes. As the sides of the mountain are worn away by erosion, the dikes, being harder than the rest of the cone, project from its sides like huge walls. An excellent opportunity for seeing them is afforded in the walls of the Val del Bove.

Sir Charles Lyell, the English geologist, who has carefully studied Mt. Etna, asserts that this mountain began to be formed during a geological period known as the Tertiary Age, through a crater that opened on the floor of the Mediterranean Sea. The material thus thrown out, collected around the crater and produced a mountainous pile that gradually emerged above the level of the sea, and on fresh materials continuing to be thrown out, at length reached its present height. It would appear that at some former time in its history, there were two vents near the top of the mountain, the second crater being formed immediately under the Val del Bove. Soon, however, the second and lower crater was closed, the upper one alone remaining active. The mountain, therefore, continued to be slowly raised in the air by the materials brought out through this opening. Then came the great explosive eruption during which the side of the mountain was blown off to form the great chasm of the Val del Bove.

Because of its almost constant activity, Mt. Etna must have been well known to the ancients, who described some of its most violent eruptions. The following brief notes concerning these eruptions have been taken from Lyell.

According to Diodorus Siculus, an eruption that occurred before the Trojan war, caused the people living in districts near the mountain to seek new homes. Thucididies, the Greek historian, states that in the sixth year of the Peloponnesian war, which would be about the spring of 425 b. c., a lava stream caused great destruction in the neighborhood of Campania, this being the third eruption that had occurred in Sicily since it had been settled by the Greeks.

Seneca, during the first century of the Christian Era, calls the attention of Lucullus to the fact that during his time Mt. Etna had lost so much of its height that it could no longer be seen by boatmen from points at which it had before been readily visible.

But passing by these very early eruptions of Etna we come to the great eruption of 1669. This eruption was preceded by an earthquake that destroyed many houses in a town situated in the lower part of the forest zone, about twenty-five miles below the summit of the mountain, and ten miles from the sea at Catania. During this eruption two deep fissures were opened near Catania. From these such quantities of sand and scoriæ were thrown out, that, in the course of three or four months, a double cone was formed 450 feet high, which is now known as Monte Rosso. But what was most curious was the sudden opening, with a loud crash, of a fissure six feet broad reaching down to unknown depths that extended in a somewhat crooked course to within a mile of the summit of Etna. This great fissure was twelve miles in length and emitted a most vivid light. Five other parallel fissures of considerable length opened, one after another, throwing out vapor, and emitting bellowing sounds which were heard at a distance of forty miles. These fissures were afterwards filled with molten rock, and in this manner were formed the long dikes of porphyry and other rocks that are seen to be passing through some of the older lavas of Mt. Etna.

The great lava streams which flowed down the side of the mountain during this eruption, destroyed fourteen towns and villages, and at length reached Catania. A great wall had been raised around this city to prevent the lava from entering it. The molten rock, however, accumulated, until it rose to the top of the wall, which was sixty feet high, and then pouring over it in a fiery cascade, overwhelmed part of the city. It is said that during the first part of its journey, the lava streams moved over thirteen miles in twenty days, or at the rate of 162 feet an hour. Beyond this, after the lava had thickened by cooling, it had a velocity of only twenty-two feet per hour.

Fig. 14 represents a plan of Mt. Etna reduced from a map by the Italian Government. During the eruption of 1865, a rent was made in the mountain extending from Mount Frumento (B in the preceding map) for one and one-half miles, and six cones from 300 to 350 feet in height were formed along the fissure.

During the eruption of 1874, great fissures three miles in length were formed in the mountain.

There exists on the slopes of Mt. Etna vast subterranean grottoes formed by the sudden conversion into steam of great quantities of water that were overwhelmed by the molten mass. These immense volumes of steam produced enormous bubbles in the molten lava. When the lava hardened irregular grottoes were left. Lyell describes one of these as follows:

Besides the eruptions mentioned there have been many others, such as those of 1811, 1819, and 1852. The last of these was greater than any eruption except that of 1669. It began in August, 1852, and continued until May, 1853, and was remarkable for the immense quantity of lava thrown out.

We come now to the volcano of Stromboli. Stromboli, one of the Lipari islands, is situated about sixteen miles west of the Straits of Messina. Its general appearance is shown in Fig. 15. The form of the mountain is that of an irregular four-sided pyramid, which rises about 3,090 feet above the level of the Mediterranean, and stands on the bottom of the sea in water about 3,000 feet deep.

If you carefully examine the appearance of Stromboli, as shown in the preceding figure, you will notice that the flat cloud which hangs over the island is made up of a number of globular masses of vapor, formed during the peculiar action of the volcano.

When examined by night Stromboli presents a still more curious appearance. Since the mountain stands alone, its height permits it to be seen readily at sea for distances of at least a hundred miles. At night a curious glow of red light may be seen on the lower surfaces of the cloud. This light is not continuous, but increases in intensity from a faint glow to a fairly bright red light, then gradually decreases, and finally dies away completely. After awhile the light again appears, again gradually decreases, and disappears, and this continues until the rising sun prevents the red glow from being any longer visible. Stromboli, therefore, acts not unlike the flashing lighthouses so common on the sea coasts of all parts of the world. Indeed, it is actually used by sailors in the Mediterranean for the purpose of showing them their direction. For this reason Stromboli is commonly called "The Lighthouse of the Mediterranean."

As Judd remarks, from whom much of the information concerning some of the volcanic districts of the Mediterranean has been obtained, the flashing light of Stromboli differs from that of the ordinary flashing light in two important respects; viz., in the intervals that elapse between the successive flashes, and in the intensity of the light emitted. As you know, it is necessary that the different lighthouses placed near one another on a coast must have their lights of such a nature that they can be readily distinguished. In order to do this, the flashing light has been devised. In flashing lighthouses, the lights only appear at intervals, one lighthouse being distinguished from another in its neighborhood by the intervals between successive flashes, or, sometimes, indeed, by the color of some of the flashes. Now, in the case of Stromboli, the intervals between the successive glowings of the red lights are very irregular, varying between one and twenty flashes per second. Moreover, the intensity of the light also varies greatly from time to time.

You naturally inquire as to the cause of these flashes of light that are emitted by Stromboli. If, as Judd suggests, you should climb to the summit of the mountain, during the daytime, and look down the inside of the crater, you could see its black slag bottom crossed by many cracks and fissures. From most of the smaller fissures the vapor of water is quietly escaping. This vapor rises in the air in which it soon disappears. There are, however, larger cracks on the bottom of the crater from which, at more or less regular intervals, masses of steam are emitted with loud snorting puffs not unlike those produced by a locomotive. From some of the openings molten matter is seen slowly oozing out, collecting in parts of the crater and moving up and down in a heaving motion. Every now and then a bubble is formed on the surface of this liquid. The bubble swells to a gigantic size, and suddenly bursts. The steam it contained escapes, carrying fragments of scum which are thrown high into the air. The masses of steam, formed below the surface of the sticky, boiling, lava, in endeavoring to escape, force their way through the mass, blow huge bubbles, which, on bursting, produce the roaring sounds that are heard, and throwing great columns of vapor in the air, produce the rounded masses of clouds you can see floating high up in the air over the mountain. At the same time the scum is partially removed from the red hot surface, its light illumines the lower surface of the overhanging cloud, which flings it back again to the earth. With the bursting of each bubble, and the clearing of the scum from the surface of the red hot mass, the light begins, increases in intensity, and then as the scum again begins to collect on the surface, decreases, and finally disappears, and not until the bursting of the next bubble is it again visible.

But let us make a study of some of the peculiarities of Vulcano, another of the Lipari islands, which lies north of Sicily.

Vulcano affords a curious example of a volcano that has been harnessed by man, or made to do work for him. All volcanoes bring from inside of the earth different kinds of chemical substances, in the form of vapors, gases, or molten materials. Now, these materials acting on one another, produce chemical substances some of which, such as sal ammoniac, sulphur, and boracic acid, possess commercial value. This is especially true in the case of Vulcano, and since the eruptions are not generally violent, a chemical works has actually been erected by a Scotch firm on the side of the mountain, where the materials are collected from the crevices.

This effort to harness a volcano was for a time so successful that the same people contemplated the building of great leaden chambers over the principal fissure at the bottom of the crater, so that the large volumes of ejected vapors might be condensed and collected. But Vulcano, like all other volcanoes, could not be relied on continually to keep the peace. One day it suddenly burst forth more fiercely than usual, so that the workmen were compelled to abandon the factory and fly down the mountain for their lives, but not, however, before some of them were severely injured by the explosions.

Vulcano is an instance of a volcano in an almost exhausted or dormant condition. It has had, however, many eruptions during the past few centuries, some of which have been very violent, for example, that of 1783, and that of 1786.

There still remains to be considered the volcanic region of the Santorin group of the Grecian Archipelago. The island of Santorin or Thera, is the southernmost of the Cyclades. It is an exceedingly curious island, being a submerged volcano, with most of the top of the crater remaining above the waters, so that the entire island has the shape of an irregular circle or crescent broken at several points. Its formation is, probably, due to the gradual sinking of a volcanic mountain until its crater has been almost completely submerged, only the higher parts of the edges of the crater being left above the surface of the waters. Suppose, for example, a mountain like Vesuvius at the time the crater Somma existed, was sunk below the level of the Mediterranean until only the highest parts of the crater remained above the waters. If, now, one or more volcanic eruptions occurred, producing craters or volcanic islands inside the submerged rim, you would have a condition of affairs seen in the island of Santorin.

CHAPTER VII

ORIZABA, POPOCATEPETL, IXTACCIHUATL, AND OTHER VOLCANOES OF MEXICO

While some of the volcanoes of Mexico are still in an active condition, most of them are either only slightly active or are dormant or extinct. Humboldt, the celebrated traveller and geographer, states that there are only four active volcanic mountains in Mexico; namely, Popocatepetl, Tuxtula, Colima, and Jorullo. But there are many others, among which may be mentioned Orizaba, Ixtaccihuatl, Xinantecatl, Tuxtula, Cofre de Perote, and Colima.

Of course, you can understand that, since extinct volcanoes may at any time become active, in parts of the world where communication with the interior is not good, many volcanic mountains that have been regarded as extinct may have broken out temporarily, during historical times, without their eruptions having been recorded.

It was at one time thought that Popocatepetl was the highest mountain in North America. More recent measurements, however, have shown that there are at least three other mountains in this part of the world, that are much higher. One of these is the active volcano of Orizaba that we will now briefly describe.

Orizaba is situated in the north central part of Mexico, about seventy-five miles west of Vera Cruz. Its ancient Aztec name was Cittaltepetl, or Star Mountain. The height of the mountain is 18,200 feet. Like all high tropical mountains whose summits are snow-clad, one would pass through the same changes in climate, in going from its base to its summit, as in going along the earth's surface from the equator to the poles. Near the base of the mountain will be found a tropical climate, above that a temperate climate, while in still higher regions, the climate of the Arctic region.

According to Russell, from whose work on the volcanoes of North America much of the information concerning the volcanoes of Mexico and Central America has been condensed, Orizaba has three craters on its summit. The last recorded eruption took place about the middle of the Eighteenth Century. The mountain is now in a dormant or extinct condition, as may be seen from the fact that its three craters are for the greater part filled with snow.

Orizaba, like Etna, and many other volcanoes, has deep fissures extending through its sides. Through these, lava streams have flowed during times when it was active. There are also found on the slopes of this mountain many cones of a type known as parasitic cones. These cones are not caused by materials that have been brought to the surface during an eruption, but have been formed by the steam passing through lava streams that have come out of the crater during other eruptions.

Popocatepetl, or, as the word means, The Smoking Mountain, is the second highest mountain in Mexico. According to recent measurements made by the Mexican Government, its height is 17,876 feet. Popocatepetl is situated on the edge of the great plateau of Mexico, forty miles southeast of the City of Mexico. It is a conical mountain, and is a magnificent object when seen from the City of Mexico, rising, as it does, fully 10,000 feet from the elevation of the city, while on the east it towers for nearly 18,000 feet above the level of the sea. This splendid mountain is poetically described by Russell:

Popocatepetl takes its name, The Smoking Mountain from the fact that gases and vapor are continually being emitted from its summit crater. It has a conical peak with a depression or crater on its summit. The bottom of the crater is crossed by fissures from which small quantities of steam escape, not, however, sufficient to melt all the snow which covers the slopes of the mountain to a depth of from eight to ten feet. A small lake of hot water has collected in the crater from the water derived from the melting snow. This water, sinking through the porous materials in the cone, is the source of a great number of large hot springs that occur around the base of the mountain.

Reclus states that the first to climb to the top of Popocatepetl was one of Cortez' officers, 1519.

Another snow-capped volcano, which rising from the plain of Mexico is in clear view of the city, is Ixtaccihuatl (Ets-tak'-se-wat-el), or as the word means in the ancient Aztec, The White Woman. This mountain, as measured by Heilprin, is 16,960 feet in height. Ixtaccihuatl is now in so dormant a condition that many who have climbed to the top assert that it is not a volcano at all, since they find no crater on its summit. Nor are there any signs of volcanic heat, the summit being snow clad during summer. The conical form of the mountain, however, and the fact that the entire mountain is formed of volcanic rocks, show beyond doubt that it is an extinct volcano, whose crater has most probably been completely filled in by the washing away of its sides.

Xinantecatl is another extinct volcanic mountain situated about forty miles southwest of the City of Mexico. It is about 16,500 feet high. Its name means in the ancient Aztec language, The Naked Lord. It is also sometimes known as the Nevado de Toluca, or The Snow of Toluca. On the top of the peak are two craters filled with lakes of fresh water. Russell states that the larger of these lakes is about thirty feet in depth and contain a peculiar species of fish.

Tuxtula is another volcano of Mexico, situated on the western coast of the Gulf of Mexico, about eighty miles southeast of Vera Cruz. It was an active volcano in 1664, when it threw out molten lava. It then became dormant until March, 1793, when its long rest was broken by one of the grandest explosive eruptions of modern times. This eruption rivalled in energy the great explosive eruption which blew off the summit of Coseguina, in Central America, in 1835. As is common in the case of explosive eruptions, volcanic dust and scoriæ were blown high into the air, and, being carried by the winds, fell on the roofs of houses and on the land at a distance of 150 miles.

There have been a number of less violent eruptions of Tuxtula since 1835. Tuxtula is a comparatively low mountain, being only 4,960 feet high, because much of the mountain was blown away by the eruption of 1793.

As Russell points out, it is not safe to infer that because an eroded mountain is not lofty it cannot be young or energetic, since the very energy of some of its eruptions may, as in the case of Tuxtula, blow away a large part of the mountain. A low mountain, with an unusually large crater, generally means a mountain that has been visited by a great explosive eruption.

Another extinct volcano known as the Cofre de Perote is situated on the eastern coast of Mexico, east of Ixtaccihuatl, about thirty miles north of Orizaba. It takes its name Cofre de Perote which means the Coffin of Perote, from its peculiar box-like shape. It was called in the Aztec language "Nauhcampatepetl," or the Four-Ridged Mountain. Cofre de Perote is in a dormant or extinct condition.

We will conclude this brief description of the volcanoes of Mexico with the volcano of Colima, a mountain about 5,500 feet high situated on the western coast of Mexico.

Colima has been active of recent years, eruptions having occurred in 1869, 1872, 1873, and 1885. During these eruptions lava escaped from lateral openings in the sides of the mountain, these openings being termed by the natives the Sons of Colima.

CHAPTER VIII

COSEGUINA AND OTHER VOLCANOES OF CENTRAL AMERICA

Central America has a great number of volcanoes extending along nearly all its western coast, or on the Pacific side of the country.

Central America consists of a high plain or table-land sloping gently towards the northeast, but terminating abruptly on the southwest. In the opinion of geologists this table-land consists of the surface of a huge tilted block of the earth's crust, or, perhaps, more probably, of a series of such blocks, that are limited on the southwest by a narrow belt of intersecting fractures. It is in these fractures that scores of volcanoes are situated, together with active craters, solfataras, and hot springs. The volcanoes are mainly of the Vesuvian type. There are so many volcanoes in this part of the world that it will be possible to describe but a few of them.

We will begin with the volcano of Coseguina, situated on the Pacific coast of Nicaragua. Its appearance is that of a conical mountain with the top cut off, and suggests that it is most probably an explosive volcano which has had the top blown away during some of its great eruptions.

Coseguina is celebrated by reason of its tremendous eruption of 1835. Before the still more tremendous explosive eruption of Krakatoa in 1883, described in the first two chapters of this book, Coseguina shared with Sombawa, on the island of Sumatra, as being the foremost of explosive volcanoes.

It had been estimated that before its eruption of 1835, Coseguina had a height of perhaps 10,000 feet, but so much of it was blown away by this eruption that it now is a little less than 4,000 feet.

The following description of the great eruption of Coseguina in 1835 has been condensed from an account prepared by Squier, published in 1850.

You will note in reading this brief account how closely many of the phenomena resemble those that occurred during the eruption of Krakatoa in 1833.

The eruption of Coseguina was heralded on the morning of January 20th, 1835, by several loud explosions that were heard for a distance of some 300 miles around the crater of the volcano. Then followed an ink black cloud formed directly over the mountain, which gradually spread on all sides shutting off the light of the sun, except for a sickly yellowish light. Fine sand was thrown from this cloud, which made it both difficult and painful to breathe. For two whole days the cloud continued to grow denser, the explosions louder and more frequent, and the rain of sand thicker. On the third day the explosions were strongest and the darkness greatest.

The amount of sand that fell from the cloud was so great that people left their houses, fearing the roofs would be crushed in by the great weight. This sand fell in large quantities over an area more than 1,500 miles in diameter, or, quoting the language of Squier:

It appears that the eruption of Coseguina was followed by violent earthquake shocks and other evidences of volcanic energy over extended regions. For example, there were fearful earthquakes along the Andes, the worst of which occurred on February 20th, and continued at the rate of three or four a day up to March 6th, and, less frequently, to March 17th. It was during one of these earthquakes that the city of Concepcion, Chile, was so completely destroyed, that but a single house remained.

The same brilliant sunsets and sunrises occurred in different parts of the world after the eruption of Coseguina, due to the presence of large quantities of volcanic dust that followed the great eruption of Krakatoa.

The cause of this great explosive eruption of Coseguina was most probably the same as that which is believed to have caused the eruption of Krakatoa, namely, a large volume of water suddenly gaining access to a mass of liquid lava.

Volcán del Fuego is another of the many volcanoes of Central America. It is situated as one of a group of volcanoes on the highest summit of the Isthmus. This volcanic mountain has a regular cone with regular slopes on all sides, except on the north, where a table-like projection, about 1,000 feet below the summit, is all that remains of a vast cone, the summit of which was blown away, according to Russell, in prehistoric times, just as was the crater of Somma on Vesuvius.

There have been in Central America, since the time of the Spanish conquest, some fifty volcanic eruptions sufficiently great to have been recorded. Some idea of the activity of Fuego during this time may be had from the fact that of all these eruptions some twenty were those of Fuego. At the present time, however, the volcano is dormant and apparently almost extinct.

The recorded eruptions of Fuego are nearly all of the explosive type. Among the most violent were those that occurred during 1526, 1541, and 1581. During 1582, 1585, and 1586, there were eruptions nearly every month, the most terrible being near Christmas day in 1586. Other memorable eruptions occurred in 1614, 1623, 1686, and 1705, and at other dates down to August 17th, 1860, from which date to the present time the volcano has been quiet.

We will conclude this brief description of the volcanoes of Central America with that of Volcán de Agua, or, as the word means, The Water Volcano. It is situated in Guatemala near the coast, and is one of the mountains that occupies the plateau on which Fuego is situated.

The Volcán de Agua is one of the most remarkable volcanoes in Central America, standing, as it does, nearly alone, and rising to an elevation of 3,350 metres (10,988 ft.), above the level of the sea. It has been extinct for a long time.

It has been supposed by some, from its name, that this is a volcano that throws out water. Others believe that the name comes from the water produced by the melting of the snow that is collected on the sides of the mountain. Now there almost always escapes from the craters of volcanoes during violent eruptions immense quantities of water vapor, which, condensing, fall as vast showers of rain that often deluge the surrounding country. In snow-clad mountains, the escape of lava is often attended by floods caused by the rapid melting of the snow. The water volcano did not, however, take its name from either of these facts, but rather because at the time of the Spanish invasion, the crater of the mountain was occupied by a large lake, and that during an earthquake in 1541 the wall of the crater was broken, when the lake was poured as an immense stream of water down the side of the mountain, overwhelming a village which was situated on this slope. That this was the correct origin of the same may be seen from the fact that the crater at the present time still shows the remains of its former lake basin, and that on the sides of the broken rim an immense ravine can be seen through which the water poured down on the village below.

Daubeny describes this volcano as follows:

Another volcano in this part of the country is described by Daubeny as follows:

CHAPTER IX

THE VOLCANIC MOUNTAINS OF SOUTH AMERICA

The volcanoes of South America are limited to the Andes Mountain System that stretches like a huge wall along the entire western side of the continent. The names of the more important of these volcanoes are marked on the map of South America, shown in Fig. 17. As will be seen, this huge mountain wall reaches from Patagonia on the south to the Isthmus of Panama on the north. The arrangement of the volcanoes in South America is of the linear type. The craters follow one another in more or less straight lines, or are situated along the lines of great fissures that lie near the ocean. You must not, however, suppose that there is a continuous chain of active volcanic mountains from the Isthmus of Panama to the southern part of the continent. According to Lyell, from lat. 2° N., or from the north of Quito, to lat. 43° S. or south of Chile, a total distance including 45° of latitude, there is a succession of districts with active and extinct volcanoes, or at least with volcanoes that have been quiet during the last three centuries.