“So much the better if you understood the matter. I will add that we have another vessel to officer, and that the examination will be general; that is, the offices will be assigned throughout the squadron, instead of confining the result to a single vessel. The one who stands highest will have his choice of all the places in the squadron; and so on till all the positions are given out. I wish you all to consider the subject during the next week, so that you can choose your places without any delay. I have adopted this method, after consulting the faculty, rather because it affords a little variety than because it is a superior plan to the one we have been using.” The principal retired, and Professor Mapps took his place before the chart he had made of the Bermudas. “These islands are different in many respects from any you have yet visited,” the professor began. “They are coralline,--the most northerly of this type in the world. The rock formed is a gray limestone, which is very soft. They are in latitude thirty-two, twenty; and in longitude sixty-four, fifty. The group consists of five principal islands, and about five hundred small ones, varying in size from a few square feet up to a square mile in extent. The largest island is Bermuda, which is fifteen miles long, and occupies the most southern position in the group. On it is Hamilton, the capital. The land on our starboard side, where you see the town, is St. George, three miles and a half in length; on the other side of us is St. David’s, about two and a half miles long. The other two are in the south-west, Somerset and Ireland, each two or three miles in length. None of the islands are more than two miles wide, and in some places you can hardly choose on which side you would fall overboard. The group is twenty miles long; and they contain only twenty-four square miles of land, with a population of about twelve thousand. More than half of the people are negroes. “There are few wells, or at least few that produce good water. You observe that the houses in the town of St. George are all white or nearly so, including the roofs. They have not been whitewashed, as you may suppose; but they are plastered. This is done to keep them clean; for all the water used is gathered on them, and kept in cisterns or tanks. Where large quantities are required, and the roofs do not afford a sufficient supply, portions of the hillside are plastered in the same manner, and the water that is collected on them is saved. The water from the clouds is the purest that can be had, if it can be kept free from impurities after it falls.