Filter, Drinking Water, Gravel and CharcoalEdit
Take an oak cask or barrel that is sound, sweet and clean; bore an inch hole near the bottom of one side, in which insert the end of a piece of three-quarter inch lead pipe (from inside), ten or twelve inches long, the other end projecting inward and bent upward toward the middle of the cask. In the lower end place a common beer faucet or stop cock, from which to draw water as desired.
Have ready say one bushel of good hard wood charcoal, and the same quantity of clean, fine gravel—not limestone—from the fineness of coarse sand, up to the size of peas, and if not clean, wash it till no dirt will appear in the water.
Break the charcoal to the size of walnuts and smaller, then mix it evenly with the gravel. Cover the bottom of the cask three or four inches thick with this mixture, pounding it down firmly. Next take a clean tin vessel, the shape of a garden flower-pot, of large size (say two gallons), and place it bottom upward in the center of the barrel, on top of the layer of gravel and coal, and over the end of the lead pipe. Then take a piece of small sized one-quarter or threeeighth inch lead or wood pipe, and place one end firmly into a hole in the bottom of the vessel, and bring the other end through a hole bored near the top of the barrel, for the purpose of admitting air into the space under the pail. Now fill in the space around and above the tin vessel with the mixture of coal and gravel, pounding it firmly down as you proceed, till the cask is about threefourths full; then place some thin flat stones (not limestones) on top, and the filter is complete.
The water being poured in on top, passes through the gravel and charcoal, by which it is purified, and enters the chamber from which it is drawn by the faucet, as required, the small pipe admitting air into the chamber to supply the place of the water while it is being drawn out.
This filter is only designed for rain or soft water, and will serve for constant use a year or more without renewal; but if used for hard water, the charcoal soon loses its virtue. When first put up, the water drawn from the filter will have an alkaline taste, but that disappears after the filter has been in operation a day or two.