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a fury that sends desolation to the country for miles from the point where the discharge takes place. But Vesuvius, which in its early years was given to furious storms, such as that which overwhelmed Herculaneum and Pompeii eighteen centuries ago has now become so mild-mannered that men till their vineyards in a fearless way on the slopes which lead up to the crater.

It was my good fortune, about fifteen years ago, on one of several visits to Vesuvius, to find it in an excellent state for inquiry, which showed me more of what goes on in an eruption, and led to a better insight into the nature of the work than has often been seen by the geologist. There was a slight eruption in progress during the night; from the windows of my lodging in Naples I could see the successive puffs of fire from the crater coming regularly, several each minute. On the following morning there was a strong northerly wind blowing, which made me hope it would be possible to approach the edge of the opening without danger from falling stones.

Climbing the long way which leads from the railway station on the shores of the bay, through the gardens, villages, and vineyards, I came at length to the observatory which has been established on the border of the area which is reasonably safe in times of trouble. Here I learned that the instruments which show the tremblings of the earth, the small earthquakes which are not perceived by our bodies, indicated that the cone was in a state of constant trembling. The observers who watch this apparatus thought it likely that some time during the day the cone would be blown away in a violent eruption, such as now and then sends the upper part of this and many other volcanoes flying into

bits before the fierce blast of the escaping vapours.

My way lay across a wide field of lava and cinders to the place. where the steep slope of the upper cone rose to the level where the crater was bombarding the sky with the rapidity of a well-served cannon. The climb up this cone, composed of the bits of lava which had been blown into the air and had fallen down again to the earth, was very laborious. The slope was as steep as a house roof. It took three steps to gain each foot in height. Now and then a stronger blast from the crater would shake the heap, so that it was hard to keep the ground that had been gained. It took a long hour to win the height of four or five hundred feet.

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Creeping to the sharp edge of the crater, and peering cautiously into the cavity, I saw into the very mouth of the volcano. The cupshaped depression was about three hundred feet in diameter, and perhaps half that depth; it passed downward into a well-like pipe, perhaps sixty feet across. lower part of the pit was, even in the bright sunlight, evidently redhot. The sides of the pipe were white-hot. On this lower part of the pit, which shone like the eye of a furnace, a mass of very fluid lava was lashing up and down, now rising until it filled the bottom of the basin with its fiery tide, again sinking until it was out of sight.

Each time the lava rose up into the basin it swelled quickly in its middle part, and in the twinkling of an eye it was broken by an explosion of such violence that a quantity of the fluid rock was tossed in fragments high into the air. As this sped upward and downward, it had a chance partly to cool, so that as it fell on the edge of the cone opposite to where I was the roar of its striking was

very suggestive of what would happen if the wind should die away. Although the circumstances were such as made it hard to observe closely, I had no difficulty in seeing that the vapour which blew out at each explosion was steam. As it came forth, it was of the steelblue colour which we see just where the steam comes from the safety-valve of a very hot boiler. As it rose in the crater it soon became white, and as it whirled around me it had the well-known odour of steam, mingled with that of sulphur.

In a word, it was evident that it was the vapour of water which was the cause of the explosions.

After I had watched this fascinating scene for about half an hour, with much inconvenience from the heat of the earth and from the shaking of the ground on which I lay, the explosions, which were at first at the rate of three or four each minute, became more and more frequent and violent, and the strong wind began to die away, so that a speedy retreat was necessary to escape the bits of lava, which were now falling heavily. Looking back from the base of the cone, I noted that the explosions came faster and faster, so that it sounded as a continuous roar. It was just as when a locomotive starts on its journey. At the outset we can count the puffs; as the cylinders move faster and faster the escape sounds perfectly continuous.

From the base of the cinder cone there flowed out a small lava stream. This lava was evidently full of steam, which poured forth from all parts of the surface. This is seen in all eruptions. Clouds of steam hung over the streams of lava. They are often visible ten miles or more away from the current of molten rock. In a great eruption the steam given forth from the crater often forms, as it condenses, into rains, that fall in

fearful torrents about the cone. It is evident, in a word, that the explosions of volcanoes are formed by the escape of the vapour of water. They are, indeed, like the explosions of boilers.

The question now arises as to the way in which this steam gets into the lava. This we can decide by a simple bit of study of the facts. Taking a map which shows the positions of several hundred active volcanoes, we find at once that they are all situated on the sea floor, from which they rise to form islands on its surface; or, when they are on the continents, they are never more than two hundred and fifty miles from the ocean. This shows that the activity of a volcano is, in some way, related to the sea-water. The only way in which we have been able to reasonably conceive of the sea bringing about volcanic explosions will now be described.

On the sea floor there is a constant laying down of sediments— limestones, sandstones, etc. We know by the parts of the old sea floor that have been uplifted into dry lands that such beds have been formed, to the thickness in all of one to two hundred thousand feet. These beds are made of small bits of rocky matter and fragments of dead animals and plants. These bits do not fit closely together, and the interspaces are filled with sea-water, so that as much as onetwelfth of the rock is usually made up of the fluid in which it was formed. As the ages go on, these beds, with the water which they hold, are buried deeper and deeper by the newer rocks which are laid down upon them, until it may be that they are thus brought to lie twenty miles or more below the surface of the solid earth.

Next let us see as to the heat to which these rocks, with their imprisoned water, are exposed. know from a great number of

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studies which have been made in mines that for each mile we go downward in the earth there is an increase in heat, differing a good deal in different places, but on the average amounting to about one hundred degrees. Therefore, at the depth of twenty miles the imprisoned water would have a temperature of about two thousand degrees. In other words, it would be about as hot as the melted iron that comes from the blast-furnace. Thus heated, the water of the tiny cells of the rock would tend to explode with something like the intensity of gunpowder when it was fired; but as it is sealed in by the great thickness of the rock above, it cannot burst into vapour-just as in the steam-boiler the water stays as a fluid even when it is heated twice as hot as it needs be to become steam when it is not confined.

Let us now suppose that a rift, or, as geologists call it, a fault, is formed in the rocks leading from the surface downward to the level where this very explosive water lies. We can readily fancy that at once the fluid would flash into steam; and as this occurred in the myriads of little cavities in the rocks, which were so heated that they tended to become melted, great quantities of the beds would forced along with the escaping steam in the form of lava. We see also that this would account for the fact that when the lava comes to the surface of the earth it is commonly filled with steam. When it rises quickly to the air, it is blown to fine dust by the expanding vapour; or if it does not fly to pieces, the little bits of water expand into bubbles, forming

pumice or lava, so full of little cavities that it will float on the water like cork.

This view as to the origin of volcanoes, although it would not be accepted by all the students of

these strange features of the earth, seems most probable, for the reason that it accounts for the fact that all the seats of present volcanic activity are on the floor of the seas or near their borders, and that the extinct volcanoes which we have had a chance to study lost their activity at a time when, by the changes in the shape of the land, the sea was moved away from the region where they were found. We easily perceive that it is only where, as in the sea, beds are being laid down, one on top of another, that the heat is rising in the rocks, and the water in their crevices becoming hotter; beneath the land the rocks are always becoming less heated, so that the water which they contain is constantly cooling down.

I have spoken of the water contained in the very heated rocks as if it remained in the state of fluid. It is likely that, when in its very hot state, it may be changed into its gases, oxygen and hydrogen, of which it is composed, and that these gases would again become the vapour of water as they rose toward the surface and were somewhat cooled. This and other matters of chemical detail which go on in the wonderful laboratory of the under-earth do not hinder our believing that volcanoes are due to the escape of the water which is constantly being buried in the rocks as they are built. So large

is the amount of this water which lies thus buried that probably it amounts to somewhere near as much as is held in all the seas. Were it not for the return of the buried fluid through the volcanoes, the oceans would doubtless be much smaller than they are. They might, indeed, have long since disappeared in the crevices of the earth.

Our own experience of climbing Vesuvius differs somewhat from that of Professor Shaler, as above

recorded, in Harper's Round Table. Night after night, like the red eye of Cyclops, burned the dull fire of the mountain. But all day long the mysterious column of white smoke ascends-" solemn and slow as erst from Ararat" the smoke of the patriarch's sacrifice.

After an hour's drive we reached Resina, a village at the foot of the mountain. Making a bargain with the chief of the guides, we were soon mounted, with the aid of much officious assistance, on good stout horses. Through the stonepaved streets of the little town we clattered, and soon began to climb the mountain, between luxuriant vineyards and fig and almond orchards growing upon the fertile volcanic soil. Our train was soon increased by four hangers-on, besides the guide. They well deserved this name, in its most literal sense, for they would catch hold of our horses' tails, and so for part of the way we helped them instead of their helping us. At length the road became so steep that horses could no longer climb, and we were forced to dismount.

Now the use of the guides whom our horses had dragged up became apparent. It was their turn to

drag us up. One stout fellow tied a leather strap to a stick and gave me the stick, which I held with both hands while he took the other end of the strap over his shoulder, and another guide pushed me up from behind. Between the two, by scrambling in zig-zags up the mountain's side-the most fatiguing climb I ever had in my life,-I at last reached the top and stood on the edge of the crater. The weird grandeur of the sight well repaid the toil of the ascent. crumbling ledge of rock ran round the summit, sloping suddenly down. to a large irregular depression which was covered, and floored as it were, with black lava, which had cooled and hardened, retaining the

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form in which it had boiled up and flowed forth. This floor was studded with a number of smaller cones from which gas and steam were escaping with a violent hissing noise. Among them was one very much larger than the others -the active crater-from which issued the most frightful bellowings. About every two minutes came a violent explosion, and a large quantity of stones and scoria were thrown high in the air, and fell back into the fiery throat of this tremendous furnace. The general appearance of the scene is shown in the accompanying small engraving.

"Do you wish to go down into the crater?" asked our guides.

[graphic]

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CRATER OF MOUNT VESUVIUS.

"Of course we do, that is what came for," was the answer. Then they haggled for an extra three francs apiece. At length we scrambled down the steep and crumbling wall amid almost suffocating sulphurous fumes, and clambered over the tortured and uneven lava floor. Through numerous cracks and crevices steam and gas were escaping; the rocks were stained yellow, red, and purple with the sulphur incrustations, and I could feel the heat through the thick soles of my boots. In many of the crevices the rock was seen to be red-hot, and when I thrust in my staff it suddenly caught fire. Soon one of the guides gave a loud cry, and

called us to see the molten lava which we found boiling up through the black floor, and flowing along in a thick, viscid stream, like tar, only of a fiery colour. The heat

was great, but I could approach so as to take some of it on the end of my staff, and press into it some copper coins which I had in my pocket, having first been shown how by the guides. When the lava cooled these were firmly imbedded, and I brought them away as souvenirs of the occasion.

My guide climbed a small cone and broke off the top with his staff. Instantly, with a violent noise, a jet of steam escaped, throwing fragments of rock into the air. As may be imagined, I hurried down as fast as possible.

I should have liked very much to have looked down into the active crater; but it was quite unsafe, so frequent were the showers of falling stones; yet the guides offered to take us up for 300 francs. I suspect, however, it was mere bravado on their part. From the summit we had a magnificent view of the distant city and beautiful bay with the wide sweep of its sickleshaped shore. After luncheon on the mountain top, part of which consisted of eggs cooked by the natural heat of this great furnace, we descended much more rapidly than we went up. All we had to do was to lift our feet well out of the cinders and down we went with tremendous strides.

MISSIONS.

BY BISHOP C. C. M'CABE.*

We have before us the most stupendous enterprise that ever was presented to human minds, the conversion of the world to God. The proposition we make is no less. than this, to put our holy Christianity into the place of every false religion in this world; to put the Bible into the place of its Vedas, its Shastas, its Confucian books, its Koran; to supplant the teachings of these false religions by the Lord's Prayer, the Sermon on the Mount, the Doxology of the Church of God. That is a great enterprise, and it is well for us to sit down, once in a while, and consider it, think about it, look at the difficulties in the way, and ponder the best means to arouse the Church to the requisite enthusiasm to accomplish it. That it will be

* An address delivered at the Chautauqua Assembly, August 2nd, 1897.

done is not to be questioned by the Christian that believes the Bible, by the Christian that utters the Lord's Prayer, by the Christian that says the Creed from his heart, sings the Doxology from his heart. If I could have my way, I would change the very Creed of Christendom. I would put a sentence in it that is not there now, though there by implication. After we

have stated our faith in the doctrines of the Gospel, I would like to have the children utter this sentence, "I believe in the conversion of the world to God." I think that would add to the Creed and make it perfect.

Says Dr. Richard Storrs, " Keep before the minds of the children a kingdom of heaven coextensive with all the earth." It would be a grand thing if the Church would learn that to-day, to teach the children that there is no doubt what

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