This textbook is the third in a series of science readers adapted to Secondary Grades comprising pupils who are in their third and fourth years of school work. The lessons are progressive, each one of the series being built on the facts taught in the previous lesson. Moreover, the subject matter--the properties of bodies; the nature, growth, and structure of plants; the common types of animals; minerals and metals; the phenomena relating to weather; in short, all the conditions which surround us--is exactly the science which should he taught in the elementary schools. [For Book II, see ED623471.]