232
Outline of a class-room lesson on the white pine;
correlations; references 235

Apples--Comparative Lesson on Winter Varieties 239
King, Baldwin, Northern Spy 239
Codling moth; references 240

Some Common Animal Forms; references 242
Centipeds and millipeds 243
Salamanders or newts 243
Spiders 244

Bird Studies 245

CHAPTER XIII. FORM IV: WINTER

Forest Trees 246
Evergreens; Wood Specimens 246

Fruits 247

Weeds and Weed Seeds 248

Physical Science Phase of Nature Study 248
Water Pressure--exercises 248
Study of Air 249
The barometer; the common pump; expansive
force of air; composition of air;
oxygen; carbon dioxide; impurities of air 250
Solutions of Solids 255
Solutions of Liquids 256
Solutions of Gases 256
Limestone 256
Carbon 257
Hydrogen 258
Magnets 258
Electricity 259
Steam 260
Farm tools--machines; problems 260

CHAPTER XIV. FORM IV: SPRING

Method of Improving Home and School Grounds 263
Making and Care of a Lawn; References 264

Soil Studies 265
Weight 265
Subsoils