IN

NATURAL PHILOSOPHY.

BY

EDWIN J. HOUSTON, A.M.,

PROFESSOR OF PHYSICAL GEOGRAPHY AND NATURAL PHILOSOPHY IN
THE CENTRAL HIGH SCHOOL OF PHILADELPHIA; AUTHOR OF
ELEMENTS OF PHYSICAL GEOGRAPHY. ETC., ETC.

KD 325 54.

A SERIES OF TEXT-BOOKS

ON

THE NATURAL SCIENCES.

By Prof. E. J. HOUSTON.

1. Easy Lessons in Natural Philosophy.
2. Intermediate Lessons in Natural Philosophy.
3. Elements of Natural Philosophy.
4. Elements of Physical Geography.

Entered, according to Act of Congress, in the year 1881, by
ELDREDGE & BROTHER,

In the Office of the Librarian of Congress, at Washington.

THIS

HIS book has been prepared at the request of numerous teachers. As its name indicates, it is an intermediate work, and is intended to fill the gap between the author's "Easy Lessons in Natural Philosophy" and his "Elements of Natural Philosophy." In extent and scope it has been so graded as to enable it, in connection with the two other works, to form a comprehensive series, suited to the wants of high schools and academies. Each of the lower books of the series, though complete in itself, leads naturally to the next higher.

The text, as far as practicable, is based on experiments. These experiments are of an exceedingly simple character, and can readily be performed without the aid of an expensive cabinet of apparatus. Plain and simple instructions are given as to the