PROPORTION _ 



S e* "^fss P Z fl ofLanA&Water e <t coTVection or ^ 



VIII. LAND AND WATER. 



THE SURFACE OF THE EARTH, 



OR FIRST NOTIONS OF GEOGRAPHY. 



CHAPTER III. 



141. Source of Mississippi. 142. Missouri and its tributaries. 143. 

 The Amazons. 144. Its tributaries. 145. The Orinoco. 146. 

 The Rio de la Plata. 147. The river system of Europe. 148. 

 General plan of the rivers of the world. CLIMATE. 149. Deter- 

 mines the animal and vegetable kingdoms. 150. Its dependence 

 on latitude. 151. Explained by the varying positions of the 

 earth. 152. Spring equinox. 153. Sun vertical at equator. 

 154. Oblique at all other points. 155. Its thermal influence in 

 different latitudes. 156. Position of the earth on 21st June. 

 157. Days longer than nights in northern hemisphere. 158. Tem- 

 perature depends on sun's altitude and length of day. 159. 

 Thermal influence greatest on 21st June in northern hemisphere. 

 160. Position of the earth at autumnal equinox. 161. Why the 

 longest day is not the hottest. 162. Why the summer is warmer 

 than the spring. 163. The Dog-days. 164. Like phenomena in the 

 southern hemisphere. 165. Position of the earth on 21st December. 

 166. Winter season explained. 167. Why the shortest day is not 

 the coldest. 168. The Tropics. 169. The sun can only be vertical 

 within them. 170. Illustration of the varying position of the earth 

 in the successive months. 171. The ai'ctic polar circles and the 

 frigid zones. 172. Diurnal and nocturnal phenomena which cha- 

 racterise them. 173. The torrid zone. 174. Sun vertical twice a 

 year in the torrid zone. 175. Temperate zone. 



LAHDNER'S MUSEUM OF SCIENCE. M 161 



No. 115. 



