And this is the reason why the rock-pools are always so neat and clean; because the water babies come inshore after every storm to sweep them out, and comb them down, and put them all to rights again. Only where men are wasteful and dirty, and let sewers run into the sea instead of putting the stuff upon the fields like thrifty, reasonable souls; or throw herrings' heads and dead dog-fish, or any other refuse, into the water; or in any way make a mess upon the clean shore--there the water babies will not come, sometimes not for hundreds of years (for they cannot abide anything smelly or foul), but leave the sea anemones and the crabs to clear away everything till the good, tidy sea has covered up all the dirt in soft mud and clean sand, where the water babies can plant live cockles and whelks and razor shells and sea cucumbers and golden combs, and make a pretty live garden again, after man's dirt is cleared away. And that, I suppose, is the reason why there are no water babies at any watering place which I have ever seen. Now when Tom got to the home of the water babies, in Saint Brandan's fairy isle, he found that the isle stood all on pillars, and that its roots were full of caves. There were pillars of black basalt and pillars of green and crimson serpentine; and pillars ribboned with red and white and yellow sandstone; and there were blue grottoes and white grottoes, all curtained and draped with seaweeds, purple and crimson, green and brown; and strewn with soft white sand, on which the water babies sleep every night. But, to keep the place clean and sweet, the crabs picked up all the scraps off the floor and ate them like so many monkeys; while the rocks were covered with ten thousand sea anemones, and corals and madrepores, who scavenged the water all day long, and kept it nice and pure. But, to make up to them for having to do such nasty work, they were not left black and dirty, as poor chimney-sweeps and dustmen are. No; the fairies are more considerate and just than that, and have dressed them all in the most beautiful colours and patterns, till they look like vast flower beds of gay blossoms. And, instead of watchmen and policemen to keep out nasty things at night, there were thousands and thousands of water snakes, and most wonderful creatures they were.