(a)A sufficient quantity of the solid potassium permanganate is to be added to give the water of the well a faint pink colour which lasts for at least 12 hours. Two ounces of the substance will be sufficient for an ordinary-sized clean well. This quantity should be dissolved in a bucket or two of water and poured into the well. Half an hour afterwards a specimen of the water should be drawn up and inspected. If pink colour is still present, enough has been employed, but if the pink colour has vanished, as may be the case if the well is dirty, a further quantity of permanganate should be added. The well should then be allowed to remain undisturbed as long as possible, but may be again opened for use of the following day.
