Originally published in 1913. PREFACE: This text is offered to teachers of elementary physics with the hope that it will not only prove to be teachable in method, but also that it may possess that "human touch" which will make it interesting to read as well as profitable to study. This early works is a comprehensive and informative look at the subject with much of the information still useful and practical today. Many of the earliest books, particularly those dating back to the 1900's and before, are now extremely scarce and increasingly expensive. We are republishing these classic works in affordable, high quality, modern editions, using the original text and artwork.