53. Quick-lime _ib._ 54. The various kinds of sand. The combinations of sand with lime _ib._ 55. Defects in building. Plasters for walls 374 56. Columns. The several kinds of columns _ib._ 57. Five remedies derived from lime 375 58. Maltha _ib._ 59. Gypsum 376 60. Pavements. The Asarotos œcos _ib._ 61. The first pavements in use at Rome 377 62. Terrace-roof pavements _ib._ 63. Græcanic pavements 378 64. At what period mosaic pavements were first invented. At what period arched roofs were first decorated with glass _ib._ 65. The origin of glass 379 66. The various kinds of glass, and the mode of making it 380 67. Obsian glass and Obsian stone 381 68. Marvellous facts connected with fire 383 69. Three remedies derived from fire and from ashes _ib._ 70. Prodigies connected with the hearth 384 BOOK XXXVII. THE NATURAL HISTORY OF PRECIOUS STONES. 1. The first use of precious stones 386 2. The jewel of Polycrates _ib._ 3. The jewel of Pyrrhus 387 4. Who were the most skilful lapidaries. The finest specimens of engraving on precious stones 389 5. The first dactyliothecæ at Rome 390 6. Jewels displayed at Rome in the triumph of Pompeius Magnus _ib._ 7. At what period murrhine vessels were first introduced at Rome. Instances of luxury in reference to them 392 8. The nature of murrhine vessels 393 9. The nature of crystal 394 10. Luxury displayed in the use of crystal. Remedies derived from crystal 395 11. Amber: the many falsehoods that have been told about it 397 12. The several kinds of amber: the remedies derived from it 402 13. Lyncurium: two asserted remedies 404 14. The various precious stones, classified according to their principal colours 405 15. Adamas: six varieties of it. Two remedies _ib._