Rain. Rain falls in drops, because the vapoury particles attract each other in their descent, and those which are sufficiently near unite and form into drops. These drops are sometimes larger than at other times, because the rain-cloud is floating nearer the earth; when this is the case the drops are large, because such a cloud is more dense than one more elevated. The size of the drop is also increased according to the rapidity with which the vapours are condensed. "Wind may sometimes increase the size of the drops by blowing two into one.