General Science (1912)

GENERAL SCIENCE BY BERTHA M. CLARK, PH.D. HEAD OF THE SCIENCE DEPARTMENT WILLIAM PENN HIGH SCHOOL FOR GIRLS, PHILADELPHIA NEW YORK - CINCINNATI - CHICAGO AMERICAN BOOK COMPANY 1912 Ebd E-BooksDirectory.com PREFACE This book is not intended to prepare for college entrance examinations; it will not, in fact, prepare for any of the present-day stock examinations in physics, chemistry, or hygiene, but it should prepare the thoughtful reader to meet wisely and actively some of life's important problems, and should enable him to pass muster on the principles and theories underlying scientific, and therefore economic, management, whether in the shop or in the home. We hear a great deal about the conservation of our natural resources, such as forests and waterways; it is hoped that this book will show the vital importance of the conservation of human strength and health, and the irreparable loss to society of energy uselessly dissipated, either in idle worry or in aimless activity. Most of us would reproach ourselves for lack of shrewdness if we spent for any article more than it was worth, yet few of us consider that we daily expend on domestic and business tasks an amount of energy far in excess of that actually required. The farmer who flails his grain instead of threshing it wastes time and energy; the housewife who washes with her hands alone and does not aid herself by the use of washing machine and proper bleaching agents dissipates energy sadly needed for other duties. The Chapter on machines is intended not only as a stimulus to the invention of further laborsaving devices, but also as an eye opener to those who, in the future struggle for existence, must perforce go to the wall unless they understand how to make use of contrivances whereby man's limited physical strength is made effective for larger tasks. The Chapter on musical instruments is more detailed than seems warranted at first sight; but interest in orchestral instruments is real and general, and there is a persistent desire for intelligent information relative to musical instruments. The child of the laborer as well as the child of the merchant finds it possible to attend some of the weekly orchestral concerts, with their tiers of cheap seats, and nothing adds more to the enjoyment and instruction of such hours than an intimate acquaintance with the leading instruments. Unless this is given in the public schools, a large percentage of mankind is deprived of it, and it is for this reason that so large a share of the treatment of sound has been devoted to musical instruments. The treatment of electricity is more theoretical than that used in preceding Chapters, but the subject does not lend itself readily to popular presentation; and, moreover, it is assumed that the information and training acquired in the previous work will give the pupil power to understand the more advanced thought and method. The real value of a book depends not so much upon the information given as upon the permanent interest stimulated and the initiative aroused. The youthful mind, and indeed the average adult mind as well, is singularly non-logical and incapable of continued concentration, and loses interest under too consecutive thought and sustained style. For this reason the author has sacrificed at times detail to general effect, logical development to present-day interest and facts, and has made use of a popular, light style of writing as well as of the more formal and logical style common to books of science. No claim is made to originality in subject matter. The actual facts, theories, and principles used are such as have been presented in previous textbooks of science, but the manner and sequence of presentation