"Why, professor, what, in the name of all that is comical, is the meaning of this? Are we to walk forth among the fishes equipped like the knights of old?" asked the baronet, pointing to the armour. "I will explain," said the professor. "In an ordinary diving-dress a man can only descend to a depth of something like fifteen fathoms. Instances have certainly occurred where this depth has been exceeded, a Liverpool diver named Hooper having descended as far as thirty-four fathoms, if my information is correct; but this was quite an exceptional circumstance; and, as I have said, fifteen fathoms may be taken as the average depth at which a man can move about and work in comfort. The reason for this limit is that beyond it the pressure of the water on the exposed hands is so great as to drive the blood to the head and bring on a fainting fit, if nothing worse; besides which, the volume of air inside the dress necessary to counteract the outside pressure of the water would be so great as to speedily result in suffocation. Now, if our explorations were limited to a depth of fifteen fathoms only they would hardly be worth the undertaking; so I have devised these suits of armour, in which we may safely explore the profoundest depths of the ocean to which the _Flying Fish_ can penetrate. The armour is, as you see, composed of a number of small scales or plates of aethereum, and is so constructed that, whilst it is perfectly flexible, permitting the utmost freedom of movement to the wearer, it is also absolutely water- tight and incompressible, no matter how great the exterior pressure to which it is subjected. The wearer of it will consequently be perfectly protected at all points from the enormous water pressure; and he will be able to breathe in comfort, his air being supplied to him at the normal atmospheric pressure. In equipping himself the diver will first don the india-rubber diving-dress in the usual way. Then he will assume this double-haversack, the larger chamber of which, worn on the back, will contain a supply of air, whilst the smaller of the two, worn on the chest, is charged with a supply of chemicals for the purification of the air after it has been breathed. The two are connected together by a pair of flexible tubes, as you may perceive, and the mere expansion and contraction of the chest, in the act of breathing, sets in motion the simple apparatus which produces the necessary circulation of air between the two chambers. Having secured this haversack in position the diver next dons his body armour, and straps about his waist this belt, with its electric lamp and its dagger. The dagger, as you see, is double- bladed; it has a haft of insulating material, and the blades have connected to them this insulated wire at the point where the blades and the handle unite. You thus have a weapon which, on being plunged into the body of a foe, not only inflicts a severe wound, but also