=Rain=, _n._ A.-S. _regn_, rain; the water falling in drops through
the atmosphere. Water rises as vapor from the moist earth and the
sea; it is then condensed by coming in contact with the cold upper
air, and falls to the earth as rain.
=Reproduced=, _pp._ L. _re_, again, _producere_, to produce, to bring
forth; produced again, having formed new plants or animals from
those already existing.
=Retrogressed=, _pp._ Went backward.
=Retrogression=, _n._ L. _retro_, backward, _gradi_, to go; the act of
going backward.
=Rhea=, _n._ In classical mythology, the wife of Saturn and mother of
Jupiter.
=Ribs=, _n._ The bones that form the framework of the chest in the
higher animals; the timbers that form the framework of a ship; the
stiff fibres that form the framework of a leaf.
=Robinson Crusoe=, _n._ A story written by Daniel Defoe and published
in 1719. The adventures of Robinson are said to have been suggested
by the life of Alexander Selkirk, who was shipwrecked and lived for
four years on the desert island of Juan Fernandez.
=Root=, _n._ The part of a plant that usually grows down into the
soil, fixing the plant and absorbing nutriment.
=Root cap=, _n._ The hard cap which covers and protects the growing
tip of a root.
=Root hairs=, _n._ The fine filaments growing from the skin of young
roots that absorb the nutriment for plants.
=Rubythroat=, _n._ The name of the North American humming bird, so
called because of the bright red feathers on its throat.