This section is from the book "Complete Self-Instructing Library Of Practical Photography", by J. B. Schriever. Also available from Amazon: Complete Self-Instructing Library Of Practical Photography.
For Lime. Drop two drops of strong oxalic acid solution in a glass of water. If it turns the water milky, lime is present.
For Alkalies. If red litmus paper is immersed in the water and allowed to remain one-half hour and does not change color, alkali is not present.
For Carbonic Acid. Add an equal part of lime water. If carbonic acid is present, a precipitate is seen. Add muriatic acid and it will effervesce.
For Iron. Boil nutgalls and add to the water. If iron is present it turns slate gray. Add a pinch of prus-siate of potash; if it blues, iron is there.
For Hard Water. Dissolve good soap in alcohol; drop a few drops in a glass of water. If the water becomes milky, the water is hard. If it remains clear, the water is soft.
 
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