100 EXPERIMENTS. 



sudden changes of temperature than the sea. Thus, 

 the land in warm regions is much heated by the 

 sun's rays during the day; the atmosphere over it 

 becomes also heated, in virtue of which it rises : the 

 cool atmosphere over the sea rushes in to supply its 

 place, and forms the sea breeze : which occurs only 

 during the day. 



At night the converse of this takes place. Land 

 heats and cools rapidly ; water heats and cools 

 slowly. After the sun sets, the cooling of the 

 land goes on faster than that of the sea. In a 

 short time the atmosphere over the land becomes 

 cooler than that over the sea; it descends and flows 

 off out to sea; thus forming the land breeze. It 

 occurs only at night, and when the change from one 

 to the other is taking place there is always a short 

 period of calm. Land and sea breezes are of the 

 greatest use in refreshing those regions which, with- 

 out them, would be almost, if not altogether, unin- 

 habitable. 



In " The Tempest," an interesting work on the 

 origin and phenomena of wind, published by the 

 Society for Promoting Christian Knowledge, a curi- 

 ous and simple experiment is described, whereby 

 the existence of upper and under currents of air and 

 the action of land and sea breezes may be clearly 

 seen and understood. We quote the passage : 



" The existence of the upper and under currents 

 of air which mark the phenomena of the trade- 

 winds, and of land and sea breezes, may be beauti- 



