XXXVII Grafting 184 XXXVIII Grafting (Continued) 190 XXXIX Grafting (Concluded) 197 XL Rotation of Crops 202 XLI Rotation of Crops (Continued) 208 XLII Land-Drainage 214 XLIII Paring and Burning 219 XLIV Wine-Making 223 XLV The Stag-Beetle 228 XLVI Sheath-Winged Insects 235 XLVII The June-Bug 242 XLVIII Caterpillars and Butterflies 249 XLIX Ants 256 L The Ant-Lion 264 LI Venomous Animals 271 LII The Phylloxera 279 LIII The Phylloxera (Continued) 288 LIV Nocturnal Birds of Prey 295 LV The Smaller Birds 300 LVI Birds’ Nests 305 LVII Migration of Birds 317 LVIII Carrier-Pigeons 322 LIX Some Prehistoric Animals 328 LX The Origin of Coal 336 LXI The Farmer’s Helpers 342 LXII The Farmer’s Helpers (Continued) 348 FIELD, FOREST AND FARM CHAPTER I THE STAFF OF LIFE With his nephews as willing companions and eager listeners, Uncle Paul continued his walks and talks in the pleasant summer afternoons. “Bread is made of flour,” he began, “and flour is wheat reduced to powder under the millstone. What an interesting mechanism that is, the flour-mill, driven by water, by the wind, sometimes by steam! What wearisome effort, what waste of time, if we had not this invention and were forced to do its work of grinding by sheer strength of arm! “I must tell you that in ancient times, for want of knowing how to grind wheat, people had to content themselves with crushing it between two stones after parching it a little over the fire. The coarse meal thus obtained was cooked in water to a sort of porridge and eaten with no further preparation. Bread was unknown.