quantities of evaporated moistiire, and tlie electrical condition of the air botli 

 aids its motion and its capacity to retain this moisture. 



Two opinions are advanced as to the course taken by the ascending atmos- 

 phere. CJne maintains that the air passing over the northern hemisphere returns 

 directly back to the north, the other that the meeting columns from the north 

 and south pass through each other in strata, best represented by passing the 

 fingers of one hand through the other. The latter opinion we regard as correct; 

 and if so, then the vast evaporations of the southern hemisphere, which is 

 chiefly water, supply the northern hemisphere, which is principally land, with 

 the rain that foils upon it. 



This upper ascending current is called the Upper or Counter trade-winds. In 

 passing through each other these strata produce a calm, which also may be repre- 

 sented by passing the lingers of one hand through the other, the space between 

 the palms of the hand representing this calm, which is the rainy belt first de- 

 scribed. The calm produces condensation, and hence the great amount of rain 

 which falls from this belt. 



This counter or upper trade in passing to the north goes into a cooler atmos- 

 phere, and having lost a portion of its heat, it becomes heavier and its moisture 

 more condensed. At the fifteenth degree of latitude, beyond the rainy belt, it 

 begins to descend to the earth, producing the showers of the extra-tropical belt. 

 The cause of no rain falling in the trade- wind belts is here seen. These winds 

 cannot part with what moisture they have, because they are continually expand- 

 ing from their increasing heat as they near the equator, and the moisture of the 

 counter trade-M'ind is not condensed until it arrives at the northern limit of the 

 trade-wind. 



To change water into vapor or steam requires nine hundred and seventy 

 degrees of latent heat. This is an enormous quantity, and we see the wonderful 

 provision nature has created for the purpose of absorbing the great heat of the 

 equator. When it has become latent in changing Avater into vapor, it is insensi- 

 ble to the touch or to any test by the thermometer. When the vapor is carried 

 into higher and more northern places, it parts with this latent heat by being 

 condensed into water. The heat thus liberated warms the surrounding atmos- 

 phere, and thus other portions of the vapor are kept from condensing until it passes 

 further north into colder air. Here a portion of it is condensed into rain. 

 Again latent heat is given out to warm this part of the atmosphere. Thus por- 

 tions of the vapor absorbed at the equator are carried to the poles, and the enor- 

 mous heat of the equator taken up and distributed to the very poles. No law of 

 nature is more beneficent or more wonderful than that of latent heat when 

 thus performing its office as the chief agent in the distribution of moisture. Thus 

 are the showers of the extra-tropical belt formed. It is these showers that sus- 

 tain the rivers, and "all the rivers run into the sea, yet the sea is not full," for 

 its evaporations equal the water poured into it by the rivers. "Note the place 

 whence the rivers come ; hither they return again." 



When the upper or counter trade has thus passed from the equator to the 

 poles, it has lost all of the moisture and heat it acquired at the equator. It de- 

 scends at every place OA'er the extra-tropical region, and passing along the sur- 

 fjTcc of the earth, forms the northwest wind — that cool, dry, and absorbing wind 

 that constitutes the dry winds of the trade-wind belt. 



If the earth did not revolve upon its axis, the upper or counter trade would 

 pass from the equator directly north, and when it had descended to the earth, it 

 would return to the equator by a direct south course. But the diurnal revolu- 

 tion of the earth turns the upper or counter trade in an eastern direction, causing 

 it to become the southwest wind in the extra tropical regions, and the returning 

 or trade wind to blow from the northeast. 



If we follow this machinery in its passage from the tropic of Capricorn to 

 that of Gander and back, it will be seen that the central or rainy belt furnishes 



