whose summit is three miles above sea level) might be sunk without showing its peak above water.”

Much of the mud at the bottom of the sea is found to be chalk, in which live countless insects so small that the naked eye cannot distinguish them.

There are beings—shall we call them 2genii ?— that daily go down into the ocean's depths, breathing and eating and drinking and walking under the sea in search of its riches. These strange creatures resemble huge monsters, larger than the largest men. Their heads are of hard, stiff material strangely shaped, with great glass eyes; and from the back of their heads grow long tails, through which they breathe. Usually they have no houses in the ocean, though sometimes they are found living and labouring in iron houses of curious form, without floors, yet into which the water cannot penetrate. Of course you have already guessed that these genii are divers, and that their houses are diving-bells.

But long before any one had built the divingbell there were men whom its riches tempted to dive naked into the sea. The pearl and sponge fishers are known to have practised diving in the waters of Europe and Asia four hundred years before the birth of our Saviour. The sponge-divers who live on the islands and coasts of the Mediterranean Sea have among their curious customs one which prohibits a young man from marrying until he can dive to a great depth, and bring to the surface a certain number of sponges each day.

The pearl-divers of Ceylon and South America do not descend to such depths as the sponge-divers. When diving they take with them a framework in which they stand, a basket in which the oysters they gather are deposited, and a huge knife, with which to fight the sharks they sometimes encounter. This weapon they carry, singularly enough, between their teeth.

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The natural divers whom I have described are 3 barbarians. Civilized nations, from an early period, have possessed artificial means of descending into the water. Something similar to the diving-bell and diving-armour was seen over three hundred years ago. In 1538 the Emperor Charles V. of Germany, and ten thousand spectators, saw with wonder and amazement two Greek divers descend in a large kettle into the water, carrying a lighted candle, and return without wetting their clothing or extinguishing the light. The first person to improve and scientifically construct a diving-bell was Dr. Edmund Halley, and to him the honour of its invention is usually paid. He was the famous astronomer who discovered the comet now called by his name, and who explained the mysteries of the magnetic needle, the 10 ocean currents, and the "trade-winds. Dr. Halley's divingbell was made of wood and was covered with lead. He supplied it with fresh oxygen when submerged, by sending down barrels of air to be emptied into it. After Dr. Halley came another inventor, who used the air-pump for forcing fresh air into the

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bell. With this improved bell the divers went to the bottom of the sea and built stone 12 piers for

The secret of the diving-bell is a very simple one. The principle of its construction is, that air and water will not mix, and that a volume of air can be forced through water as readily as a stream of water can be thrown into the air. To test this, take a deep bowl filled with clear water, a goblet, and a small lighted wax-taper set in a piece of cork large enough to float it. Then reverse the goblet over the cork in the bowl, and press it downward to the bottom. The water will rise a little way in the goblet, but the light will still burn, though below the surface of the water outside. But if the goblet is held at the bottom for two or three minutes the light will be extinguished before the taper has burned away. The reason is that the air within the goblet becomes impure, and a flame requires fresh air as well as fuel. When a man goes down in a divingbell he is in the same need of oxygen as the candle. Life, as well as flame, must be fed. The bell itself holds enough to keep an occupant alive for a short time, but not long. Hence it is necessary to force fresh air in and the bad air out, and for this purpose the air-pump is used.

1 mysterious, full of mysteries, or profound secrets; a mystery is that which is beyond human comprehension till explained. 2 genii (plural of genius), spirits good or evil; supernatural beings. 3 barbarians, people living in a rude or uncivilized state; the term applies not only to savages, but to all people whose manners and life have not been trained or cultivated. artificial, made or contrived by art; not natural. 5 scientifically, according to the principles of science. By science is meant knowledge arranged on a regular and systematic plan, and founded on correct 6 invenprinciples, established by observation and experiment.

V-Moffatt's Ex. Reader.

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tion, the discovery of how to make anything; contrivance of that which did not exist before; original contrivance. "astronomer, one well versed in the science that teaches the knowledge of the heavenly bodies. comet, a celestial body with a long tail. (See App.) magnetic needle, a slender bar of steel, having the property of always pointing to the north. 1o ocean currents, streams of water running in certain directions through the oceans. 11 trade-wind, a wind in or near the torrid zone, which blows from the same quarter throughout the year-so called from its great advantage to navigators, and hence to trade. 12 pier, a mass of solid stonework, for supporting an arch, or the timbers of a bridge, etc.

sig-ni-fi-ca'-tion ap-pa-ra'-tus gen'-er-al-ly dis-tinct'-ly DIVERS have a system of signals by which they "talk" with those above who work the air-pumps and lower and raise the bell. The water, which is a good conductor of sounds, is the telegraph which they employ. The diver cannot hear any sound made by those at the pump, but those in the open air can distinctly hear any sound made by him in the bell below. When he wants "more air" he strikes one blow with a hammer on the side of the bell; those above hear the sound borne by the water, and obey by pumping faster. If the diver wishes to be "drawn up" he strikes three blows; if to go" lower down," four; while the signal to "stop" is two blows. Divers also use small buoys of various colours, each having a different signification, and which, set free from the bell,