GEOGRAPHY
What causes winter and summer? 574.
When are days and nights equal? 574.
What is the meaning of equinox? 622.
What is the cause of ocean-currents? 1369.
What is the temperature of the Gulf Stream? 813.
What are the great ocean-routes? 1370.
What is a Sargasso sea? 1369.
What causes the Newfoundland fogs? 1017.
What causes spring tides and neap tides? 1911.
How are waves caused? 2058.
Does steam cause volcanic eruptions? 2027.
What volcano's dust was carried around the earth? 2028.
What scientific instrument looks like an ordinary gate halfway open?
574.
What do we know ahout the causes of earthquakes? 574. What recent earthquake destroyed $200,000,000 worth of property?
2000:
What is the shape of the inside of a geyser? 762. Who first explained how a geyser works? 762, 289. In what city do 1,000,0000 gallons of hot water flow every day from the
ground? 888.
Where does the water of hot springs and geysers come from? 1805. What are artesian wells? 1806. Where is the most famous artesian well? 113. How does a mountain resemble a plateau? 1484. How are they caused? 1486, 574.
What is the up-and-down movement of the earth's crust called? 1483. Why is the atmosphere purer in the country than in the city? 33. What changes take place in the composition of the air? 33. Why does physiography study the air? 1482. What substance in the air is needed by the soil? 657. What causes the wind to blow? 2094. How fast does a hurricane travel? 2094. How long does a simoon last? 1759. What is the sirocco? 1762. What is a cold wind called in Mexico? 421. What is the belt of calms? 199. How did the trade-winds get their name? 1932. Where do storms come from? 1833. When is a cyclone a tornado? 492. Does a barometer tell when it is about to rain? 174. What causes the rain? 1582. Who first explained the rainbow? 1583. What is a rain-gauge? 1583. Why do fogs need dust-particles? 688. Why don't the clouds fall to the earth? 413. Why doesn't dew form on a cloudy night? 526. How did we find out what lightning is? 1069. What are the Northern Lights? 140.
How are sandbars and deltas and flood-plains formed? 2051, 683. How much earth does the Mississippi river carry yearly to the gulf?
1240.
How is alluvial land formed? 53. How does running water degrade the land? 1482. What is the bottom of a glacier called? 770. How did Lake Superior copper get down into Indiana? 553. What is drift-soil? 553. What are plant societies? 580. What is geographical botany? 580.
What two races comprise two thirds of the world's population? 1578. How was the Caucasian race misnamed? 353. How is the Malay language written? 1152.
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