17. Blast Furnace 41 18. Section and Plan of Blast Furnace (obsolete type) 42 19. Section of a Reverberatory Furnace 45 20. Fibrous Fracture of Wrought Iron 47 21. Cup and Cone 49 22. Section of Blast Furnace 51 23. Experiments at Baxter House 58 24. Bessemer Converter 63 25. Model of Bessemer Steel Apparatus 65 26. Section of Regenerative Stoves and Open Hearth 68 26_a_. Rolling Mill 71 26_b_. The Eiffel Tower in course of construction 73 26_c_. The Eiffel Tower 75 26_d_. St. Paul Building, N. Y. 77 26_e_. Manhattan Insurance Co.’s Building in course of 79 erection 26_f_. Manhattan Insurance Co.’s Building nearly completed 80 26_g_. Original Design for the Great Wheel 82 27. Portrait of Sir Joseph Whitworth 85 28. Whitworth’s Screw Dies and Tap 86 29. Screw-cutting Lathe 87 30. Whitworth’s Measuring Machine 89 31. Whitworth’s Drilling Machine 91 32. Whitworth’s Planing Machine 93 33. Pair of Whitworth’s Planes or Surface Plates 94 34. Interior of Engineer’s Workshop 95 35. Blanchard Lathe 96 36. Vertical Saw 98 37. Circular Saw 99 38. Pit-Saw 100 39. Box Tunnel 101 40. Coal-pit, Salop 102 41. Sankey Viaduct 103 42. Rails and Cramp-gauge 104 43. Fish-plate 105 44. Section of Rails and Fish-plates 106 45. Conical Wheels 107 46. Centrifugal Force 107 47. Points 108 48. Signal Box on North London Railway 109 49. Post Office Railway Van 111