6 70. What are plains covered with sand called? A. They are denominated deserts; some are also covered with stones and gravel. Deserts are generally destitute of water. 71. Which are the largest deserts in the world? A. The great African desert, and the desert of Cobi, in Asia. 72. With what is the African desert interspersed ? A. Various fertile spots that are scattered here and there over the surface, like islands in the ocean. 73. What are these called? A. They are called Oases: they are generally inhabited, and serve as resting places for travellers. The Great Desert is frequently crossed by parties of travellers, with camels; these are called caravans; both men and beasts often suffer greatly from want of water, and sometimes perish from thirst. The picture represents a small caravan crossing the desert, one of the people of which appears to have just expired. 74. What are Caves or Caverns? A. They are openings in the earth, often wonderful on account of their great size and extent. Fingal's Cave.. One of the most remarkable is Fingal's Cave, in Staffa, an island on the west coast of Scotland. Its sides are formed with the regularity of walls of hewn stone. It is 227 feet in length, and 42 feet wide, and presents a most striking example of the sublime and beautiful creations with which God has adorned the world. 75. Are there any remarkable caves in the United States? A. The Mammoth Cave in Kentucky is said to extend 10 miles under ground. 76. What are public roads? A. Pathways used for travelling from place to place. 77. What is a rail road? A. An improved kind of road, now much used in the United States; also in Great Britain and other European countries. The cars or carriages used on them are drawn by steam locomotive engines, at the rate of 20 or 30 miles an hour, and sometimes even Vast numbers of people, and great quantities of merchandise, are conveyed by them from place to place, much more rapidly than by other methods. more. 7 PRODUCTIONS OF THE EARTH. 78. What are the productions of the earth? A. They are either vegetable, animal, or mineral. 79. What are vegetable productions? A. Things that grow out of the ground, as trees, plants, grains, fruits, and flowers. 80. What are the vegetable productions most useful to mankind? A. Wheat, corn, rye, rice, potatoes, bread-fruit, &c. 81. What are the chief classes of the animal kingdom? A. Beasts, birds, fishes, reptiles, and insects. 82. What are minerals? A. They consist of substances of various kinds, that are dug out of the earth. 83. What are the principal classes of minerals? A. Four: the metallic, the inflammable, precious stones, and building-stones. 84. What are the most important metallic minerals? A. They are gold, silver, iron, copper, and lead. Diamonds are highly valuable, and are often found amongst the earth, at the bottoms of rivers. The engraving represents a river in South America, from which the water has been nearly all pumped out by the machine on the right hand of the picture, and negro slaves are examining the earth for diamonds. 87. What are some of the principal building-stones? A. Granite, limestone, marble, and sandstone. Mineral springs, both hot and cold, occur in many parts of the earth. The most remarkable are the Geysers, or Spouting springs of Iceland, which throw up volumes of hot water, with a noise like cannon, to the height of 90 or 100 feet. 8 ON THE FORM AND MOTIONS OF THE EARTH. 88. What is the earth? A. It is the planet we inhabit. 89. What are the planets? A. Immense bodies, which revolve round the sun and receive their light from it. 90. What is the shape or form of the earth? A. It is nearly round, being slightly flattened at the poles. 91. By what other names is the earth known? A. It is also called the World, the Globe, and the Sphere. 92. How many motions has the earth, and what are they? A. Two: the daily and the yearly. 93. What is the daily motion of the earth? A. That in which it turns round once every twenty-four hours. 94. What is the yearly motion of the earth? A. That in which it goes round the sun once every year. 95. What takes place during the earth's yearly motion? A. A change of seasons. 96. What is a change of seasons? A. The change from winter to spring, from spring to summer, from summer to autumn, and from autumn to winter again. 97. What is the length of the path travelled over by the earth every year, in its passage round the sun? A. Upwards of 567 millions of miles, or more than a thousand miles every minute. 98. What is the effect of the earth's daily motion? A. It produces a change from day to night. 99. If the earth did not turn round on its axis, what effect would be produced? A. The day and night would then each be six months long, and, consequently, there would be but one day and one night in the year. In that case, our earth would be scarcely habitable. 100. What do these things teach us? H A. That the works of the Almighty are directed by infinite wisdom and goodness. 101. What is the axis of the earth? A. It is an imaginary line passing through its centre North and South. 102. What are the poles of the earth? A. The ends of the axis. 103. How many poles are there? A. Two; the North, and the South Pole. 104. Where are the poles situated? A. The North Pole is the north point of the earth's axis, and the South Pole is the south point. Point out on Map of the World, No. 1, of the Atlas, the North Pole and the South Pole. You will perceive that this map consists of the Eastern and Western Hemispheres, that is, a map of both sides of the earth presented to view at once; and, although the words North Pole and South Pole are engraved twice, yet there is but one North Pole and one South Pole. 105. How far distant are the poles situated from each other? A. One hundred and eighty degrees. 106. How many miles is that? About 12,500 miles, which is half round the world. 107. What is the size or bulk of the earth? |