────────────┬────────┬─────────┬─────────┬────────┬────────┬───────────┐ │Spring, │Artesian,│Ripley's,│ Well, │River │Beamhouse │ │Watford,│Well │Well │ Council│Witham, │ well, │ │Herts. │Trafalgar│Holbeck, │ Acad., │Lincoln.│ Lowlights.│ │ │Square. │Yorks. │ Vienna.│ │ │ ────────────┼────────┼─────────┼─────────┼────────┼────────┼───────────┤ Total solids│ 33·8 │ 84·9 │ 150·4 │ 212·2 │ 33·0 │ .. │ Ca │ 11·0 │ 1·56 │ 1·22 │ 19·6 │ 6·08 │ .. │ Mg │ .. │ ·84 │ ·42 │ 10·4 │ .. │ .. │ Na │ 1·1 │ 29·4 │ 58·1 │ 41·1 │ .. │ .. │ K │ .. │ ·85 │ ·83 │ 10·5 │ .. │ .. │ CO_{3} │ 15·6 │ 11·3 │ 39·8 │ 97·6 │ .. │ .. │ SO_{4} │ ·68 │ 20·6 │ 1·03 │ 26·7 │ 7·59 │ .. │ Cl │ 1·21 │ 16·5 │ 45·2 │ 3·5 │ 2·60 │ 21·8 │ SiO_{2} │ 1·16 │ ·57 │ 2·63 │ ·3 │ .. │ .. │ Temporary │ │ │ │ │ │ │ hardness │ .. │ .. │ .. │ .. │{ 8·0 │ 39·7 │ Permanent │ │ │ │ │ │ │ hardness │ .. │ .. │ .. │ .. │{ 8·4 │ 48·0 │ ────────────┴────────┴─────────┴─────────┴────────┴────────┴───────────┘ CHAPTER VI. METHODS OF CHEMICAL ANALYSIS FOR THE TANNERY. It is assumed that the reader has an elementary knowledge of chemistry, and of the common manipulations of the laboratory; but at the risk of giving information which to many is already familiar, the principles that underlie those methods of testing which are most applicable to technical purposes must be briefly explained.