C—3

11

PAGE Pumping Machinery .. .. .. .. 40-43 Knowles's Patent Compound Condensing Min-ing-pump .. .. .. .. 42 Useful Information in connection with Steampump*-.. .. .. .. .. 43 Wrought-iron Welded Pipe .. .. 44 Friction of Water in Pipes .. .. 44 Rotary Pump .. .. .. .. 45 Mineral Railways .. .. .. .. 45 Cost of Railway .. .. .. .. 46 Cost of Steel Sleepers .. .. .. 40 Wagon-wheels and Axlea .. .. .. 46 New Explosives .. .. .. .. 47 Rackarock .. .. .. .. .. 47 Tasmania—Mount Bischoff Tin-mine .. .. 48 Reduction and Dressing Works .. .. 49 Pyramidal Boxes .. .. .. .. 49 Jiggers .. .. .. .. .. 50 Concave Buddies .. .. .. .. 50 Convex Table .. .. .. .. 51 Tossing-tub .. .. .. .. 52 Broken Hill Mine and Works .. .. .. 52-55 Zinc Desilverisation Process .. .. .. 55-68 Dry Creek Smelting-works, Adelaide.. .. 55 Softening Process .. .. .. 56 Load-ores .. .. .. .. 56 Dry Ores .. .. .. .. 57 Silver-and-gold ore .. .. .. 67 1. Softening the Lead .. .. 58 2. Incorporation of Zinc and Separation of Zinc Scums .. .. .. 60 3. Refining the Desilverised Lead .. 63 4. Treatment of Zinc Scums .. .. 64 Distillation of Zinc rich in Silver .. .. 67 Description of Process used in Extracting Metals from Ore at the Boston and Colorado Works, in America .. .. .. .. 68-72 Separation of Gold and Silver from Copper, Boston and Colorado Smelting-works .. 69 Gold-ores .. .. .. .. 69

PAGB Process used in Extracting Metals — continued. Silver-ores .. .. .. .. 09 1. Sampling the Ores' .. .. .. 70 2. Roasting the Ores .. .. .. 70 (a.) Eoasting the Ores in Heaps .. 70 (6.) Roasting the Ores in Reverberatory Furnace .. .. 71 3. Fusion for Matte .. .. .. 71 4. Ziervogel Process .. .. .. 72 (a.) Crushing and Roasting the Matte for Sulphate of Silver.. 72 Roasting Sulphate of Silver .. 73 Leaching Sulphate of Silver .. 74/ (b.) Precipitating the Silver .. li (c.) Washing and Fusing the Ce-ment-silver .. .. .. 74 (d.) Precipitation of Copper .. 75 (c.) Refining the Copper .. .. 75 5. Treatment of the Ziervogel Tub-residues 75 (a.) Fusion for White-metal .. 75 (6.) Roasting the White-metal .. 75 6. Treatment of Residues of Ziervogel Process .. .. .. 76 (b.) By the Augustine Process .. 76 Solution .. .. .. 76 7. Treatment of Bottoms .. .. 76 8. Treatment of the Oxidized Copper-alloy 76 Brick-making Machinery .. .. .. 77-79 Pulverising-and-sifting Mill .. .. .. 77 Patent Mixing-and-kneading Machine .. 78 Moulding-and-pressing Machine .. .. 78 Brick-pressing or Caleindering Machine .. 78 General Remarks .. .. .. .. 79-80 Improved Planing, Matching, and Moulding Machine, No. 3 Size .. .. .. 79 Plajiing-and-matching Machine, No. 5 Size .. 79 Appendix .. .. .. .. .. 80 Professor Roberts-Austen's Report on Smeltingworks, Freiberg, Germany .. .. 80