CHAPTER II.

12. The Beginnings of Engineering Works of Record 19 13. The Appian Way and other Roman Roads 20 14. Natural Advantages of Rome in Structural Stones 22 15. Pozzuolana Hydraulic Cement 24 16. Roman Bricks and Masonry 25 17. Roman Building Laws 27 18. Old Roman Walls 27 19. The Servian Wall 28 20. Old Roman Sewers 29 21. Early Roman Bridges 31 22. Bridge of Alcantara 35 23. Military Bridges of the Romans 35 24. The Roman Arch 36