152 



merely because they lose their warmth quicker. More 

 dew falls on a clear night than a cloudy one, because 

 objects cool quicker on the surface under a clear sky 

 than a cloudy one, more dew falls during a still night 

 than a windy one for the air must remain still long 

 enough for the various objects to lower its temperature 

 and collect its moisture, heavy winds prevent this 

 while gentle breezes favor it by bringing new air in 

 contact with the objects. In the tropics during sea- 

 sons when the sky is clear, the dew is so copious as to 

 resemble a gentle rain. In many hot countries there 

 are no rainfalls. In such cases these devv^s are uncom- 

 monly large thus making a full provision for the ab- 

 scense of this needful article. Some mountainous 

 regions, owing to the winds and other agencies ara en- 

 tirely without rain, in other localities the year has 

 two seasons, the wet and the dry. 



Along with rain and dew, the clouds should be classi- 

 fied. There are four primary forms of clouds as fol- 

 lows: Cirrus clouds or those consisting of a fleecy or 

 feathery mass of condensed vapor, which is deposited 

 in the higher regions of the air. Second, Cumulus or 

 heap clouds, which are denser and are found in the 

 lower portions of the atmosphere where the quantity 

 of vapor is greater. They generally consist of round- 

 ed masses looking like snow-banks in beautiful purity 

 and w^hiteness. They are caused by ascending cur- 

 rents of air which have their moisture condensed by 

 elevation and occur during the hottest part of the 

 day. Third, Stratus clouds or those formed in long 

 horizontal sheets, they occur mostly in the evening 

 and morning when the ascending currents are weak. 



