CHAPTER III. 25. The Roman Water-supply 37 26. The Roman Aqueducts 38 27. Anio Vetus 39 28. Tepula 40 29. Virgo 40 30. Alsietina 40 31. Claudia 41 32. Anio Novus 42 33. Lengths and Dates of Aqueducts 42 34. Intakes and Settling-basins 43 35. Delivery-tanks 44 36. Leakage and Lining of Aqueducts 44 37. Grade of Aqueduct Channels 45 38. Qualities of Roman Waters 46 39. Combined Aqueducts 46 40. Property Rights in Roman Waters 46 41. Ajutages and Unit of Measurement 47 42. The Stealing of Water 49 43. Aqueduct Alignment and Design of Siphons 49 CHAPTER IV. 44. Antiquity of Masonry Aqueducts 52 45. Pont du Gard 52 46. Aqueducts at Segovia, Metz, and other Places 53 47. Tunnels 54 48. Ostia, the Harbor of Rome 56 49. Harbors of Claudius and Trajan 58