us is hardly to be wondered at. An additional reason for the adoption of this language is that it is a much more convenient vehicle for thought than the ancient language of the island could ever have been, and that our literature is chiefly derived from the libraries that came into our possession from the shipwrecked British and American vessels.
"French and German are by no means unknown among us, and we have at various times received the crews and passengers of vessels from other countries than England. But, for the reasons I have given, English has come to be the only language spoken by us; and our knowledge of all the changes that from time to time take place in the English language is derived from the continued accessions of men and books the wrecks on our reef bring us.
"It is probable that the aboriginal inhabitants were a thick-skinned race who could stand the heat and could bear with impunity the assaults of the insects, for we find throughout the islands many traces of their dwellings and monuments, which; show that at one time the land was occupied by human beings.
"It is not known at what precise period the habits of the people underwent such a change as to lead them to forsake entirely the land, except for certain necessary operations which you will learn hereafter and to betake themselves to an aquatic life.
"It is probable that this change took place gradually. It is supposed that, as the Anglo-Saxon infusion increased, the race became less and less able to withstand the heat and other annoyances of a land-life; that they found immersion in the sea-water spared them many of the discomforts they experienced in the air; and that gradually, by little and little, the genius of our engineers and chemists succeeded in rendering a permanent or quasi-permanent abode under the water not only possible but absolutely preferable to a residence on the land.
"This faculty we found ourselves to possess of adapting ourselves to a subaqueous life, early drew the attention of our philosophers to the probable evolution of the human race from some aquatic ancestor; and although all the missing links have not been discovered, it is considered highly probable that an animal allied to the seal-tribe was our not very remote progenitor. Some of our philosophers pretend, from the presence in man of certain rudimentary parts, to trace our origin to a fish; and a few go still farther, and affect to believe his parentage can be traced back I to a mollusc."
"Ah," I interrupted, "our own philosophers go quite as far as yours. From noticing the monthly phases of some of our normal and morbid actions, they pretend to deduce the origin of man from a littoral ascidian mollusc that must have been powerfully affected by spring-tides to account for these phenomena of monthly periodicity in its descendants."
"But," he replied, rather testily—as he evidently did not like to be interrupted, or perhaps he was unwilling to admit that the speculations of our philosophers were worthy to be ranked with those of his countrymen,—"as spring-tides happen fortnightly, I don't see what they could have to do with phases of a monthly character."
"But you are aware," I rejoined, "that fortnightly periodicity has a tendency to become monthly; thus, our Fortnightly Review now only appears once a month."
"Bosh!" he exclaimed, raising his left elbow as high as his shoulder, which I afterwards learned was the gesture employed in this part of the world to denote contempt.
I begged pardon for interrupting him, and he went on:—
"There can be no doubt that we have solved the problem of life below the water, and whether this be a return to the habits of a remote ancestor, or a totally new faculty we have acquired, is of much less importance than the fact itself.
"It is believed that the first great requisite for our subaqueous life was the invention of a corrective of that defect of vision produced by the contact of the eye with the water. The cause of this defective vision is the optical structure of the eye itself, the refractive power of whose humours differs but slightly from that of water; consequently, when it is immersed in water, the rays of light are not deflected sufficiently to allow the images of external objects, to be accurately focussed on the retina; hence only a very imperfect vision is possible for the unaided eye below the water.
"Our opticians discovered that perfect vision could be restored under water by means of a lens of considerable power. Spectacles were constructed with such lenses, and the first step was made towards rendering life below water practicable.
"At first, we, like yourselves, constructed our lenses of solid glass; but as the refractive power of glass is not very much greater than that of water, there was an enormous difference between the power of a lens used in air and in water. Hence our opticians early adopted the plan of making lenses of all descriptions for use below water, of air. Air being the less refractive medium, our air lenses are of precisely the opposite shape to that of your glass lenses. Our ordinary method of making these air lenses is to have sections of thin glass globes of certain diameters fixed in a ring of metal or bone, with their concavities looking outwards. They thus enclose a concave lens-shaped portion of air, which effects the required refraction. In the better kind of lenses the two surfaces of the glass are ground so that both shall be of exactly the same radius of curvature.
"All the lenses of our optical instruments for subaqueous use, microscopes, telescopes, &c., are made in this way. For spectacles these lenses are especially convenient, for while they are lenses of the required power under water, they have no refractive power in air, and consequently may be worn both in and out of the water; in the former case causing, in the latter not preventing, perfect vision.
"The next question that seems to have occupied the attention of the pioneers of our submarine life was that of obtaining the needful supply of air below the water; for it was extremely awkward, and indeed quite fatal to anything like residence under the water, to be obliged to come to the surface every minute or so, to get a chestful of air.
"This difficulty was overcome by the distribution of air-pipes throughout the area occupied.
"At first, as you may imagine, this was done on a very small scale. It was originally not expected that it would ever be possible to remain permanently below the water, but only for a few hours during the extreme heat of the day.
"But as time went on, the ingenuity of our engineers and mechanicians who kept themselves well posted in all the improvements in their arts that were made in Europe—for works on mechanical science formed a considerable proportion of the books rescued from the wrecks that were more frequent formerly than now,—overcame all difficulties; and as the area of inhabited space yearly extended, the net-work of air-pipes gradually spread over every portion of the vast inland sea enclosed by our coral reefs, which includes many hundreds of square miles.
"At the same time the air-supply through these pipes was so improved that the air in the pipes, by mechanical contrivances, was kept at a considerable pressure; and by means of valves and stopcocks, the act of breathing below water is performed as easily as in the atmosphere; and there is no need to come to the surface at all for purposes of respiration. The breathing apparatus is so constructed that every mouthpiece is connected with two sets of tubes, one of which receives and carries off the expired air, whilst the other supplies the fresh air to be breathed. In this way the awkward and unsightly gurgling of the expired air is prevented.
"The quality of the air for breathing has also been much improved by the admixture of a considerable proportion of oxygen with the air supplied, so that one respiration of this oxygenated air is only required where many respirations of non-oxygenated air would be needed.
"Thus you will find that it is not necessary to breathe oftener than once in four or five minutes when you are used to this mode of breathing.
"When we make excursions beyond the reef into the ocean we carry with us metal bottles of condensed oxygenated air, whereby
