22. Percolation experiment. To show the relative powers of soils to take in water falling on the surface 41 23. Bottles used in place of the lamp chimneys in Figs. 22 and 24 44 24. Capillarity of soils. To show the relative powers of soils to take water from below 44 25. Water-absorbing and water-holding powers of soils 45 26. Capillary tubes. To show how water rises in small tubes or is drawn into small spaces 48 27. Capillary plates 48 28. A cone of soil to show capillarity 49 29. To show the relative amounts of film-moisture held by coarse and fine soils 49 30. To show the effect of a soil mulch 56 31. Soil temperature experiment 57 32. Charts showing average temperature of a set of dry and wet soils during a period of five days 60 33. To show the value of organic matter 61 34. Soy-bean roots, showing nodules or tubercles 64 35. Garden-pea roots, showing tubercles or nodules 65 36. To show that seeds need water for germination 72 37. To show that seeds need air for germination 72 38. To show that seeds need air for germination 73 39. A seed-tester: two plates and a moist cloth 80 40. A seed-tester: a plaster cast with cavities in the surface for small seeds 80 41. Germinating corn-kernel and bean 81 42. To show how the bean-plant gets up 82 43. To show how the corn-plant gets out of the soil 82 44. To show the use of cotyledons 83 45. To show the use of the kernel to the young corn-plant 86 46. To show how deeply seeds should be planted 87 47. Operations of seed-planting 88 48. A collection of planting machines 89 49. Spading-fork and spade 92 50. A wood beam-plow 93 51. A slip-nose share and a slip-nose 96 52. A straight knife coulter 96 53. An iron beam-plow with rolling coulter and double clevis 96 54. A rolling cutter-harrow 97 55. Spring-toothed harrows 97 56. Spike-toothed harrows 104 57. A coulter-toothed harrow 104 58. A plank harrow 105 59. To show transpiration 108