“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 difficult.”
“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 thing’s complete.”
“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!”