“What, river water! That won’t do at all,” he cried. “You’ll all have the typhoid fever. We must build a filter.
Fig. 68. The Small 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.
Immediately after breakfast the next day we started out in two parties to search the island. The only discovery of any
Fig. 69. The Barrel Filter. moment was that made by Dutchy’s party, which found a small island separated from ours by a narrow channel, through which the water ran like a mill-race. No spring was discovered, so Uncle Ed had to construct his large filter. Bill and I went over to Lumberville in search of a couple of cider barrels and a pailful of charcoal. The barrels were placed one on top of the other after cutting a large hole in the top of the lower barrel, and a smaller one in the bottom of the upper one. The latter opening was covered by an inverted saucer. Over this we spread a 3-inch layer of coarse sand, then a 2-inch layer of charcoal, a 4-inch layer of clear, sharp sand, and a 2-inch top layer of gravel. The lower barrel was provided with a faucet, through which we could draw off the filtered water as desired. In order to keep the water cool we placed the filters in a shady place near the river, and piled up earth around the lower barrel.
“Now, boys,” said Uncle Ed, “form in line there, and we will go through a fire drill.”