nt "halloa" from the
mainland. There was Uncle Ed sitting on a pile of goods on the railroad
bank looking for all the world like an Italian immigrant. We answered
with a shout and scrambled back to the clearing. Then we ran splashing
through the water, pushing the boat before us. It didn't take us long to
load up and carry him back to the island.

A RUSTIC TABLE.

[Illustration: Fig. 67. The Rustic Table.]

Uncle Ed entered into our fun at once. He was as enthusiastic as a boy
over the surroundings, and when we told him of the old bridge he started
right off to investigate, taking the ax with him. Soon he had pried off
a number of the planks, which we used for a flooring to our tent. Then
he built us a table out of four forked sticks, driven into the ground,
and supporting two cross sticks, on which a pair of planks were laid.

THE SMALL FILTER.

"Well, now, boys," said Uncle Ed, wiping the perspiration from his
forehead, "I am as thirsty as a whale. Where do you get your drinking
water? Is there a spring on the island?"

We told him that we used the river water.

[Illustration: Fig. 68. The Small Filter.]

"What, river water! That won't do at all," he cried. "You'll all have
the typhoid fever. We must build a filter. I brought some charcoal with
me for this very purpose."

Taking one of our pails he broke a hole in the bottom of it and stuffed
a sponge in the hole. A layer of small stones was then placed in the
pail, over this a layer of broken charcoal with the dust carefully blown
out, then a layer of clean sand, and finally a layer of gravel. Each
layer was about two inches thick. The pail was suspended from a branch
in a cool place and proved an excellent filter, the water trickling out
through the sponge being perfectly pure and sweet, no matter how dirty
it had been when poured in; but the capacity of the filter was too
small, and Uncle Ed said he would make us a larger one on the morrow if
no spring was discovered in the meantime.

The sun was getting low in the west, and we therefore postponed the
exploration of our island until the following day. We had been up since
four o'clock that morning and had done some pretty hard work; so,
immediately after supper, we turned in and, lulled by the murmuring of
the river, were soon fast asleep.

THE BARREL FILTER.

[Illustration: Fig. 69. The Barrel Filter.]

Immediately after breakfast the next day we started out in two parties
to search the isla