Part 6 (2/2)

In the Middle Ages there were many legends of evil spirits dwelling in caves, who beguiled human beings to their rocky homes, whence the visitors never returned. Probably the truth of this particular fable lay in the growing spirit of exploration into the recesses of Nature, the dangers of which--ill provided with light, ropes, and modern means of security as they were--must have been extreme.

About this era, too, the forests of Northern Europe were largely thinned, and fairies, dwarfs, and such folk, it was thought, were obliged to take refuge in caverns and grottoes. Within the last hundred years a legend was common in the Hartz Mountains, that if a wedding feast lacked copper or bra.s.s kettles, cooking-pans, or plates, the needs would be supplied on invoking the dwarfs at the entry of their rocky homes. No payment was asked for or expected, but a little meat left in the pans on their return was appreciated and might lead to future civilities.

Moorish children are still brought up to believe that Boabdil, the last King of Granada, with his mighty host, is still sleeping in a huge cavern, whence he will some day issue to a last great victory over the Christians.

So far we have seen only the imaginative ideas of these great hollows of the earth, for 'hollow' is the true meaning of the Latin word _cavea_, from which cave or cavern is derived: now we will glance at the more practical purposes to which the smaller and more superficial caves have been adapted.

With the dawn of Christianity, many men and women, shocked at the excesses of Greek and Roman civilisation, retired from the world and led simple lives as hermits in remote caves. To this day, 'The Hermit's Cave' is a common name in England, and, though it is not always a genuine one, it usually denotes that in olden times some hermit or 'anchorite' pa.s.sed his lonely existence in the spot in question.

Long before this era, in Hindoostan, advantage had been taken of natural caverns to hew into shape the marvellous rock temples of Elephanta, Ellora, and Ajunta, still accounted as amongst the wonders of the world.

In New Mexico and Arizona in remote ages whole tribes lived in caves, some natural, but more often made habitable by the aid of masonry. Most of these are high up on shelves edging precipitous cliffs, and were clearly chosen as places of refuge from enemies of the plain.

All over Europe caves are found containing bones of human beings, most of which are recognised by scientists to belong to an earlier race, who made use of these homes provided by Nature, both for abiding-places during life and resting-places for the dead. In many of these caves, sketches on bone, horn, and ivory have been found, remarkable for their clear and vigorous drawing at a time when art was an unknown quant.i.ty.

It is noticeable that drawings found amongst the Esquimaux relics depict seals, whales, and walruses, whilst those of more southern races show mammoths, wild horses, and bisons; the only animals drawn by both being the reindeer.

Numerous caves in Britain, and indeed all over the world, contain bones of animals, and from cla.s.sifying these, learned folk have found out a great deal respecting the geological and geographical changes which have taken place on the crust of the earth since the Creation.

Now that we have thought of the terrors with which caverns inspired our remote forefathers, as well as of the practical uses to which they have been put by less imaginative men and animals, let us try to see how and why these mighty hollows came to exist at all.

Earthquakes are often accountable for rocks heaped in wild confusion, leaving great chasms below. Volcanic agency also deposits huge roofs of lava over tracts of ice and snow, and the melting of the latter leaves empty s.p.a.ces of vast extent. The neighbourhood of Mount Etna, in Sicily, has various wonderful caverns of this formation. Landslips and rock-falls on the surface account for many small grottoes, but water is the main origin of all the most celebrated caverns of the world.

Underground streams and rivers gradually eat their way along the surface of their rocky flooring, the carbonic acid in the water acting chemically on the stone in addition to the wearing force of the element.

Once a shallow channel is worn, new forces set to work to deepen it: sand, pebbles and grit of all kinds, washed down by the current, grind and wear away the rock. In course of time great depths are hollowed out, and if it happens that some obstacle turns the course of the water, and the river finds a new outlet, a long deep gallery is left dry, and here and there an apparently bottomless pit where the water has acted on specially soft stone. From above, also, a steady action of moisture has been eating away the cliff, adding height to the cavern, as well as coating its roof and sides with a sparkling substance derived from the union of water and particles of the limestone, in which caves usually abound.

Nothing can be more beautiful, when illuminated, than a roof of stalact.i.tes, with ascending pillars of stalagmite often meeting and forming pillars, like those which will be later on described in the Mammoth Cave and others. The building of these fairy grottoes is really a simple matter, but one only possible to the Great Architect to whom a thousand years are as one day; for a very little bit of one of those stony icicles would take hundreds of years in formation. Water flowing above a cave is certain to contain carbonic acid, some given to it by the atmosphere, and some imparted from decaying vegetation. This water oozes slowly through the rock, and the carbonic acid in pa.s.sing dissolves a mite of lime, carrying it through the roof, to which the lime adheres whilst the water evaporates. Drop follows drop, each tiny particle sliding down its fellow, until, as weeks and years and centuries roll by, a lovely long pendant is formed, known as a stalact.i.te. Sometimes the drops of acidulated watery lime fall through the roof by an easier pa.s.sage, and fall right on to the floor of the cavern, when an upward process takes place, each drop exactly striking the one before, until one of the stately columns arises known as a stalagmite.

HELENA HEATH.

AN OCEAN POLICEMAN.

Amid a flutter of flags and the cheers of onlookers, the 'ocean policeman,' H.M.S. _Speedy_, first took to the water on May 18th, 1893.

Its birthplace was the banks of the Thames at Chiswick, but hardly had it settled itself on the smooth surface of the river when orders came from official quarters that it should proceed at once to school. They were no easy lessons that it had to learn, and the subsequent examinations were extremely difficult and trying, for they were conducted by a large crowd of the most learned gentlemen in England and the Continent connected with naval matters. The school was at Sheerness, and here the _Speedy_ spent four months in preparation. On September 28th the first run was made, and three weeks later the examiners were delighted to find that this splendid new boat was able to steam at a speed of twenty knots an hour. Everything the inventor and designer had claimed for her was proving true. The new style of tubing in the boilers made it possible to get up steam very quickly after the fires were lighted, so that when the order came to start there was no 'Oh, wait a minute, please; I am not quite ready!'

The engines, four thousand five hundred horse-power in strength, did their work far more nimbly than those in any previous gunboat of the same size. The vessel is two hundred and thirty feet long, and can steam triumphantly through water no more than ten feet deep. That in itself is enough to terrify evil-doers who would otherwise hope to escape by getting into shallow water beyond her reach. But in addition, she carries two large guns and a search-light.

Having thoroughly satisfied the examiners, this huge scholar soon had the honour of receiving a commission, and is now on duty in the North Sea among the brown-sailed fis.h.i.+ng-smacks, like a gigantic duck watching over her ducklings. There are several gunboats of the British navy employed in the same way, but few of them quite so modern as the _Speedy_, or so capable of guarding the interests of the fishermen. Any foreign smack or lugger that comes within three miles of the English coast is 'trespa.s.sing,' and is immediately called upon by the _Speedy_ to give an explanation. If the trespa.s.ser hesitates, a boat is lowered from the steamer with an officer on board to make inquiries, and should the answers to his questions be unsatisfactory, the stranger and his boat are sent prisoners to the nearest English port.

Thus, up and down among the great fleet of peaceful fishers, the _Speedy_ plies all day, and even in the darkest night her watching is as keen and sure, for then her search-light, a dazzling beam, sweeps over the sea in all directions, and not the tiniest rowboat could escape unseen. Many a time it has revealed some stealthy marauder who hoped, under the cover of darkness, to pull in a net of fish from these forbidden waters and then sail into some French or Dutch port undetected. All chance of escape, however, is over when once that dazzling light falls upon the dishonest craft.

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