Mr. Miller, however, said that a great quantity of salt was washed into the sea by rivers, and that though the water was drawn up by the sun, in the form of vapour, the salt was not. Besides this, it is supposed that there are, in the bottom of the sea, large rocks of salt, which are constantly being dissolved by the water, and give it its bitter taste. Not many days after, when Henry wanted to know how salt was made, Mr. Miller reminded him of sea-water, and told him that, in some parts of England, during summer, salt-water was allowed to flow into shallow pits, from which the heat of the sun drew up the water in vapour, leaving the salt behind. This, he said, was scraped up and purified. In some inland countries, such as Poland, salt is dug out of mines. A great deal of the salt which we use is got from salt springs, a long way from the sea, which, it is supposed, flow through or over rocks of salt under ground. A man now passed by, having something in his hand, which he showed to Mr. Miller, and asked him if it was coral. “No,” said Mr. Miller, “it is not coral, but a kind of sponge, which has been torn by the late storm from the rock on which it grew.” Henry looked about very carefully, in the hope of finding a piece which he might wash himself with, when he went home; but though he was told that it was not likely that he would find the right sort, which is brought from the Mediterranean Sea, he did not give over his search. He did not succeed, but presently came to his papa bringing something, which, he had made up his mind, must be a sea-beetle. It was about as large as his hand, nearly square; black, shining, and leathery, and from each corner stuck out a long, black horn. Two of these horns were hooked at the end, and two were straight. When he pressed it, he found that it was hollow; but as soon as he took off his fingers it recovered its shape again, being as elastic as an india-rubber ball. “This,” said Mr. Miller, “is not a beetle, but an egg.” Henry had seen thrushes’ eggs, and eaten hens’ eggs, but they were so unlike this black leather bag that he thought his papa must be joking. [Illustration: PURSE OF SKATE.] “Not the egg of a bird, but of a fish. As we came through the market to-day, I showed you some flat and very ugly fishes, with eyes and mouth something like those of a human being, and with a long tail like that of a quadruped.” Henry remembered to have seen them, and that they were called skates. “And is this the egg of a skate?” Not exactly the egg, but the egg-shell. There was once a yelk in it, something like that in a hen’s egg. Out of this yelk a young skate grew, and when it was large enough it forced its way out through this end. Mr. Miller pinched one end of the egg-shell, or purse, as it is called, between his finger and thumb, holding it as one would a letter which one wanted to read without breaking the seal, and the end of the purse opened.