POTASSIUM 59 LITHIUM 60 BROMINE, IODINE, ARSENIC, AND BORIC ACID 61 BROMINE AND IODINE 61 ARSENIC 63 BORIC ACID 63 HYDROGEN SULFIDE 63 CHLORINE 64 DISSOLVED OXYGEN 65 ETHER-SOLUBLE MATTER 69 RELATIVE STABILITY OF EFFLUENTS 69 BIOCHEMICAL OXYGEN DEMAND OF SEWAGES AND EFFLUENTS 71 RELATIVE STABILITY METHOD 71 SODIUM NITRATE METHOD 72 ANALYSIS OF SEWAGE SLUDGE AND MUD DEPOSITS 73 COLLECTION OF SAMPLE 73 REACTION 73 SPECIFIC GRAVITY 74 MOISTURE 74 VOLATILE AND FIXED MATTER 74 TOTAL ORGANIC NITROGEN 74 ETHER-SOLUBLE MATTER 75 FERROUS SULFIDE 76 BIOCHEMICAL OXYGEN DEMAND 76 ANALYSIS OF CHEMICALS 77 REAGENTS 77 SULFATE OF ALUMINIUM 78 INSOLUBLE MATTER 78 OXIDES OF ALUMINIUM AND IRON 78 TOTAL IRON 79 FERRIC IRON 79 FERROUS IRON 80 BASICITY RATIO 80 LIME 80 SULFATE OF IRON 81 INSOLUBLE MATTER 81 IRON AS FERROUS SULFATE 81 ACIDITY 81 SODA ASH 82 INSOLUBLE MATTER 82 AVAILABLE ALKALI 82