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

60.  Amount of transpiration 109

61.  To show that growing leaves contain starch 114

62.  To show that starch disappears from the leaf when
    the plant is placed in the dark 114

63.  To show that sunlight is necessary for starch-making
    by leaves 115