86 flature'0 /ilMraclea, 



1000 miles an hour at the equator to the east- 

 ward, and the projectile was fired from the 

 pole, where there is practically no motion, in 

 the same direction along the longitudinal lines 

 as before, the observer would have to be in a 

 position on the equator 1000 miles west of 

 this longitudinal line in order to see the 

 projectile when it arrived; therefore the ap- 

 parent movement of the projectile would not 

 be along the line at the instant that it was 

 fired, but along a line that would cross the 

 equator at a point 1000 miles west. When a 

 southward impulse is given to the air it fol- 

 lows, to some extent, the same law, so that to 

 one standing on the equator the northern 

 trade wind will blow from the northeast and 

 the southern trade wind from the southeast. 



Owing to the fact that the air rises in the 

 heated zone there is always a region of calms 

 at this point where there is no wind and no 

 rain. There are two other regions of calms in 

 the ocean, one at the north at the tropic of 

 Cancer and another at the south near the 

 tropic of Capricorn. As has been stated, there 

 are currents flowing back in the upper regions 

 at the equator north and south, and these are 

 called the upper trades the lower currents 

 being called the lower trades. These upper 

 trades gradually fall till they reach the tropic 

 of Cancer on the north, where the lower part 

 of the current stops and bends back toward the 



