CONTENTS V 



EXERCISE PAGE 



66. Neutralizing a Base by an Acid 68 



67. Soap and Soap Making 69 



68. Testing of Cotton and Wool 70 



69. Dyeing 71 



70. Bleaching 73 



71. How to Remove Stains 74 



72. Plumbing 75 



73. Flames 76 



74. Gas and Electric Meters 78 



75. How Heating the Air Changes its Density 79 



76. The Dew Point 79 



77. Weather Records 80 



78. Weather Maps : 81 



79. Kinds of Rocks 81 



80. Concrete 82 



81. Ore Tests 83 



82. Kinds of Soil 86 



83. Soil Tests 86 



84> How Soils Take Up the Rain 87 



85. Contents of a Fertile Soil 89 



86. How Moisture is Taken Up by Plants 89 



87. Plants Give Off Moisture 91 



88. Seeds and Their Germination 92 



89. Materials Present in Plants 94 



90. Study of Leaves 96 



91. Stems 97 



92. Wood ; 99 



93. Roots 101 



94. The Flower. . 101 



95. The Earthworm 1Q3 



96. Mollusks 104 



97. Insects 105 



98. Birds , 107 



99. Bones and Joints 109 



100. Muscles and Tendons 110 



101. Foods and Food Tests . . Ill 



