But even in this hedonistic bathing one's ridiculous mind makes tasks for itself, and it has become an affair of duty with me to swim backwards and forwards twice to a certain rock that lies some three hundred yards away. There (for Luigi is not alone in this island in the matter of caches) I have what you may really call an emporium stowed away in a small seaweed-faced nook which I believe to be undiscoverable. If you know exactly where that nook is (it lies about two feet above the surface of the water), and put your hand through the seaweed at exactly the right spot, you will find a tin box containing (_i_) a box of matches, (_ii_) a handful of cigarettes, (_iii_) a thermometer. The first time that I arrive at the rock I have no truck with my cache, but only touch the rock with a finger, and swim back to the beach again. There I touch another rock with my finger (these two rocks, in fact, are like the creases at cricket, which you must touch with your bat in order to score a run), and swim back for the second time to my wicket out at sea. Then, oh then, after a cautious survey, in order to see that no one, not even Francis, can observe my movements, I take the tin box from its place, get out of the water on to the rock, and having dried my fingers on wisps of seaweed, light a cigarette and smoke it. As I smoke it, I submerge the thermometer in the sea, and when the cigarette is finished, read the temperature. After that the thermometer has to be dried, and is put back in the box with the cigarettes and matches, and the treasure is stowed away again in its seaweed-fronted cave. Once a fortnight or so I must go through a perilous manoeuvre, for I have to bring the box back to be refilled. This entails swimming with one hand in the air holding the box like Excalibur above the sea, and it can only be done on very calm mornings, for otherwise there is danger of some ripples intruding through the hinges or edge of the lid, which does not shut very well. And all the time the risk of detection is imminent, for if Francis saw me swimming to land with a bright tin box in my hand, he would be certain to make inquires. But so far no such heartbreaking disaster has befallen, and without detection (and I humbly trust without suspicion) the cache-box has been twice taken back to be refilled and gone on its return journey again to its romantic hiding-place. Sometimes I have been within an ace of discovery, as when, to my horror, two days ago Francis swam out to my rock, instead of going to his own, while I was in the middle of my cigarette. I had time to put the box back, but somehow it never occurred to me to throw the cigarette away. By a special dispensation of Providence, however, it was not permitted that it should occur to him as odd that I should be seated on a rock in the middle of the sea, smoking. He was accustomed to the sight, I must suppose, of my smoking on land, and the question of locality did not occur to him. But it seemed a weary, weary time before he slid off into the sea again, I airily remarking that I should sit there a little longer. Sometimes, when Francis has been unusually communicative about private matters that concern himself alone, I wonder whether I ought to tell him about my cache. But I don't, for those who understand the true science of caches understand that if you have made a cache alone, you might just as well not have made it at all if you share your secret with anybody. You can have joint caches, of course....