Something wrong with the tank—Jack's wisdom and Peterkin's impertinence—Wonderful
behaviour of a crab—Good wishes for those who dwell far from the sea—Jack commences to
build a little boat.
 REST is sweet as well for the body as for the mind. During my long experience, amid the vicissitudes
of a chequered life, I have found that periods of profound rest at certain intervals, in addition to
the ordinary hours of repose, are necessary to the well-being of man. And the nature as well as the
period of this rest varies, according to the different temperaments of individuals, and the peculiar
circumstances in which they may chance to be placed. To those who work with their minds, bodily
labour is rest. To those who labour with the body, deep sleep is rest. To the downcast, the weary,
and the sorrowful, joy and peace are rest. Nay, further, I think that to the gay, the frivolous, the
reckless, when sated with pleasures that cannot last, even sorrow proves to be rest of a kind,
although, perchance, it were better that I should call it relief than rest. There is, indeed, but
one class of men to whom rest is denied—there is no rest to the wicked. At this I do but hint,
however, as I treat not of that rest which is spiritual, but more particularly of that which applies
to the mind and to the body.
Of this rest we stood much in need on our return
 home, and we found it exceedingly sweet when we indulged in it after completing the journey just
related. It had not, indeed, been a very long journey, nevertheless we had pursued it so diligently
that our frames were not a little prostrated. Our minds were also very much exhausted in consequence
of the many surprises, frequent alarms, and much profound thought to which they had been subjected;
so that when we lay down on the night of our return under the shelter of the bower, we fell
immediately into very deep repose. I can state this with much certainty, for Jack afterwards
admitted the fact, and Peterkin, although he stoutly denied it, I heard snoring loudly at least two
minutes after lying down. In this condition we remained all night and the whole of the following day
without awaking once, or so much as moving our positions. When we did awake it was near sunset, and
we were all in such a state of lassitude that we merely rose to swallow a mouthful of food. As
Peterkin remarked, in the midst of a yawn, we took breakfast at tea-time, and then went to bed
again, where we lay to the following forenoon.
After this we arose very greatly refreshed, but much alarmed lest we had lost count of a day. I say
we were much alarmed on this head, for we had carefully kept count of the days since we were cast
upon our island, in order that we might remember the Sabbath-day, which day we had hitherto with one
accord kept as a day of rest, and refrained from all work whatsoever. However, on considering the
subject, we all three entertained the same opinion as to how long we had slept, and so our minds
were put at ease.
We now hastened to our Water Garden to enjoy a bathe, and to see how did the animals which I had
 placed in the tank. We found the garden more charming, pellucid, and inviting than ever, and Jack
and I plunged into its depth and gambolled among its radiant coral groves, while Peterkin wallowed
at the surface, and tried occasionally to kick us as we passed below. Having dressed, I then
hastened to the tank; but what was my surprise and grief to find nearly all the animals dead, and
the water in a putrid condition! I was greatly distressed at this, and wondered what could be the
cause of it.
"Why, you precious humbug," said Peterkin, coming up to me, "how could you expect it to be
otherwise? When fishes are accustomed to live in the Pacific Ocean, how can you expect them to exist
in a hole like that?"
"Indeed, Peterkin," I replied, "there seems to be truth in what you say. Nevertheless, now I think
of it, there must be some error in your reasoning; for if I put in but a few very small animals,
they will bear the same proportion to this pond that the millions of fish bear to the ocean."
"I say, Jack," cried Peterkin, waving his hand, "come here, like a good fellow. Ralph is actually
talking philosophy. Do come to our assistance, for he's out o' sight beyond me already!"
"What's the matter?" inquired Jack, coming up, while he endeavoured to scrub his long hair dry with
a towel of cocoa-nut cloth.
I repeated my thoughts to Jack, who, I was happy to find, quite agreed with me. "The best plan," he
said, "will be to put very few animals at first into your tank, and add more as you find it will
bear them. And look here," he added, pointing to the sides of the tank, which, for the space of two
inches above the water-level, were
 encrusted with salt, "you must carry your philosophy a little further, Ralph. That water has
evaporated so much that it is too salt for anything to live in. You will require to add fresh
water now and then, in order to keep it at the same degree of saltness as the sea."
"Very true, Jack; that never struck me before," said I.
"And, now I think of it," continued Jack, "it seems to me that the surest way of arranging your tank
so as to get it to keep pure and in good condition, will be to imitate the ocean in it. In
fact, make it a miniature Pacific. I don't see how you can hope to succeed unless you do that."
"Most true," said I, pondering what my companion said. "But I fear that that will be very
"Not at all," cried Jack, rolling his towel up into a ball and throwing it into the face of
Peterkin, who had been grinning and winking at him during the last five minutes—"not at all.
Look here. There is water of a certain saltness in the sea; well, fill your tank with sea-water, and
keep it at that saltness by marking the height at which the water stands on the sides. When it
evaporates a little, pour in fresh water from the brook till it comes up to the mark, and
then it will be right, for the salt does not evaporate with the water. Then there's lots of seaweed
in the sea; well, go and get one or two bits of seaweed and put them into your tank. Of course the
weed must be alive, and growing to little stones; or you can chip a bit off the rocks with the weed
sticking to it. Then, if you like, you can throw a little sand and gravel into your tank and the
"Nay, not quite," said Peterkin, who had been gravely attentive to this off-hand advice—"not
quite; you must
 first make three little men to dive in it before it can be said to be perfect; and that would be
rather difficult, I fear, for two of them would require to be philosophers. But hallo! what's this?
I say, Ralph, look here. There's one o' your crabs up to something uncommon. It's performing the
most remarkable operation for a crab I ever saw—taking off its coat, I do believe, before
going to bed!"
We hastily stooped over the tank, and certainly were not a little amused at the conduct of one of
the crabs which still survived its companions. It was one of the common small crabs, like to those
that are found running about everywhere on the coasts of England. While we gazed at it, we observed
its back to split away from the lower part of its body, and out of the gap thus formed came a soft
lump which moved and writhed unceasingly. This lump continued to increase in size until it appeared
like a bunch of crab's legs; and, indeed, such it proved in a very few minutes to be, for the points
of the toes were at length extricated from the hole in its back, the legs spread out, the body
followed, and the crab walked away quite entire, even to the points of its nipper-claws, leaving a
perfectly entire shell behind it, so that, when we looked, it seemed as though there were two
complete crabs instead of one.
"Well!" exclaimed Peterkin, drawing a long breath, "I've heard of a man jumping out of his
skin and sitting down in his skeleton in order to cool himself, but I never expected to see a
crab do it!"
We were, in truth, much amazed at this spectacle, and the more so when we observed that the new crab
was larger than the crab that it came out of. It was also quite soft, but by next morning its skin
had hardened into a good shell. We came thus to know that crabs
 grow in this way, and not by the growing of their shells, as we had always thought before we saw
this wonderful operation.
Now I considered well the advice which Jack had given me about preparing my tank, and the more I
thought of it the more I came to regard it as very sound and worthy of being acted on. So I
forthwith put his plan in execution, and found it to answer excellently well, indeed, much beyond my
expectation; for I found that, after a little experience had taught me the proper proportion of
seaweed and animals to put into a certain amount of water, the tank needed no further attendance;
and, moreover, I did not require ever afterwards to renew or change the sea-water, but only to add a
very little fresh water from the brook, now and then, as the other evaporated. I therefore concluded
that if I had been suddenly conveyed, along with my tank, into some region where there was no salt
sea at all, my little sea and my sea-fish would have continued to thrive and to prosper
notwithstanding. This made me greatly to desire that those people in the world who live far inland
might know of my wonderful tank, and, by having materials like to those of which it was made
conveyed to them, thus be enabled to watch the habits of those most mysterious animals that reside
in the sea, and examine with their own eyes the wonders of the great deep.
WE WERE STRUCK DUMB WITH THE WONDERFUL OBJECTS THAT WERE
REVEALED TO OUR GAZE.
For many days after this, while Peterkin and Jack were busily employed in building a little boat out
of the curious natural planks of the chestnut tree, I spent much of my time in examining with the
burning- glass the marvellous operations that were constantly going on in my tank. Here I saw those
anemones which cling, like little red, yellow, and green blobs of jelly, to the
 rocks, put forth, as it were, a multitude of arms and wait till little fish or other small
animalcules unwarily touched them, when they would instantly seize them, fold arm after arm around
their victims, and so engulf them in their stomachs. Here I saw the ceaseless working of those
little coral insects whose efforts have encrusted the islands of the Pacific with vast rocks and
surrounded them with enormous reefs. And I observed that many of these insects, though extremely
minute, were very beautiful, coming out of their holes in a circle of fine threads, and having the
form of a shuttlecock. Here I saw curious little barnacles opening a hole in their backs and
constantly putting out a thin, feathery hand, with which, I doubt not, they dragged their food into
their mouths. Here, also, I saw those crabs which have shells only on the front of their bodies, but
no shell whatever on their remarkably tender tails, so that, in order to find a protection to them,
they thrust them into the empty shells of whelks, or some such fish, and when they grow too big for
one, change into another. But, most curious of all, I saw an animal which had the wonderful power,
when it became ill, of casting its stomach and its teeth away from it, and getting an entirely new
set in the course of a few months! All this I saw, and a great deal more, by means of my tank and my
burning-glass; but I refrain from setting down more particulars here, as I have still much to tell
of the adventures that befell us while we remained on this island.