A. As one portion is heated _it rolls away_, and is succeeded by _another_; and this constant motion prevents _one_ part of the sea from being heated _more than another_. Q. _How is the WIND affected by the SEA?_ A. When air from the hot earth _reaches the sea_, it is often _condensed_, and either rushes _back again_, or else its violence is very greatly _abated_. Q. _Do CLOUDS affect the WIND?_ A. Yes. As passing clouds screen the direct heat of the sun from the earth, they diminish the _rarefication of the air also_: and this is _another_ cause why neither the strength nor direction of the wind is _uniform_. Q. _Would the winds blow regularly from east to west, if these OBSTRUCTIONS were REMOVED?_ A. Without doubt they would. If the whole earth were covered with _water_, the winds would always _follow the sun_, and blow from east to west. Their irregularity is owing to the interspersion of _sea and land_, and the irregularities of the earth's surface. Q. _Do winds NEVER blow REGULARLY?_ A. Yes; in those parts of the world, where these obstructions do not exist; as on the Atlantic and Pacific Ocean, the winds are pretty uniform. Q. _What are the winds, which blow over the ATLANTIC and PACIFIC Ocean, called?_ A. They are called "Trade Winds." Q. _Why are they called TRADE WINDS?_ A. Because (as they blow uniformly in one direction) they are very convenient to those who _carry on trade_ by means of these oceans. Q. _In what DIRECTION do the TRADE WINDS blow?_ A. That in the _northern_ hemisphere blows from the _north-east_: that in the _southern_ hemisphere from the _south-east_. Q. _Why do they not blow from the FULL NORTH and SOUTH?_ A. Because the _polar current_, combining with the _equatorial current_, give the wind a _new direction_. Q. _What is the CAUSE of the EQUATORIAL current?_ A. The rotation of the earth upon its axis. Q. _What is the cause of the POLAR CURRENT?_ A. As the heat in the _torrid zone_ is always _greatest_, and at the _poles_ the _least_, therefore a constant current of air rushes _from the poles_ towards the _equator_. Q. _How does the COMBINATION of these two currents give a new direction to them both?_ A. When these currents of air meet at the equator, they _clash together_, and fly off in a new direction. Q. _Do trade winds blow from the north-east and south-east ALL the YEAR ROUND?_ A. Yes, _in the open sea_; that is, in the Atlantic and Pacific Oceans for about 30 degs. each side of the equator. Q. _Do the TRADE WINDS blow uniformly from north-east and south-east in the INDIAN OCEAN?_ A. No; nor yet in those parts of the _Atlantic_ and _Pacific_ which _verge on the land_. Q. _Why do not the trade winds blow uniformly from north-east and south-east in the INDIAN OCEAN?_