The oranges selected by John were such beauties that neither Mark nor his mother regretted the extra quarter paid for them.  After that, during the rest of their stay in Key West, whenever Mark went near a fruit auction he was addressed politely by the auctioneer as “Mr. Elder,” and invited to examine the goods offered for sale that day.

One day Mark and Ruth rowed out among the vessels of the sponging fleet that had just come in from up the coast.  Here they scraped acquaintance with a weather-beaten old sponger, who sat in the stern of one of the smallest of the boats, smoking a short pipe and overhauling some rigging; and from him they gained much new information concerning sponges.

“We gets them all along the reef as far as Key Biscayne,” said the old sponger; “but the best comes from Rock Island, up the coast nigh to St. Mark’s.”

“Why, that’s where we’re going!” interrupted Ruth.

“Be you, sissy?  Wal, you’ll see a plenty raked up there, I reckon.  Did you ever hear tell of a water-glass?”

“No,” said Ruth, “I never did.”

“Wal,” said the old man, “here’s one; maybe you’d like to look through it.”  And he showed them what looked like a wooden bucket with a glass bottom.  “Jest take an’ hold it a leetle ways down into the water and see what you can see.”

Taking the bucket which was held out to her, Ruth did as the old man directed, and uttered an exclamation of delight.  “Why, I can see the bottom just as plain as looking through a window.”

“To be sure,” said the old sponger; “an’ that’s the way we sees the sponges lying on the bottom.  An’ when we sees ’em we takes those long-handled rakes there an’ hauls ’em up to the top.  When they fust comes up they’s plumb black, and about the nastiest things you ever did see, I reckon.  We throws ’em into crawls built in shallow water, an’ lets ’em rot till all the animal matter is dead, an’ we stirs ’em up an beats ’em with sticks to get it out.  Then they has to be washed an’ dried an’ trimmed, an’ handled consider’ble, afore they’s ready for market.  Then they’s sold at auction.”

The sponge crawls of which the old man spoke are square pens make of stakes driven into the sand side by side, and as close as possible together.  In some of them at Key West Mark and Ruth saw little negro boys diving to bring up stray sponges that the rakes had missed.  They did not seem to enjoy this half as much as Mark and his boy friends used to enjoy diving in the river at Norton, and they shivered as though they were cold, in spite of the heat of the day.

When the children told Mr. Elmer about these little, unhappy-looking divers that night, he said,

“That shows how what some persons regard as play, may become hard and unpleasant work to those who are compelled to do it.”

Several days after this Mr. Elmer engaged a carriage, and took his wife and the children on a long drive over the island.  During this drive the most interesting things they saw were old Fort Taylor, which stands just outside the city, and commands the harbor, the abandoned salt-works, about five miles from the city, and the Martello towers, built along the southern coast of the island.  These are small but very strong forts, built by the government, but as yet never occupied by soldiers.