Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: CHAPTER II WATER IX GEXERAL What is Watkr? What do we know about it and how do we obtain the facts? Every one knows what water is—for every life depends upon it, yet as in the case of other well-known substances in common use, the wider it is known the greater the difficulty of giving complete answers to such simple questions. The word itself probably originated in northern Kurope. The Greek equivalent is in frequent use as our prefix hydro- and the Latin is aqua; the use of these terms affording opportunity for a wide range of expressions permitting nice shades of meaning. The substance as we ordinarily know it and as it forms the basis of life is a fluid, but we may properly consider it as a mineral, a portion of the rocky crust of the earth, but one which melts at a temperature below that necessary for the support of life. It is hardly necessary to more than refer to the fact that from the chemical standpoint pure water consists of two parts of hydrogen and one of oxygen, but as oxygen is about sixteen times as heavy as hydrogen, bv weight water consists of one part of hydrogen to eight of oxygen. The combination of these two gases is so stable that to separate them is usually required a somewhat powerful electric current or chemical reaction involving the absorption of considerable heat. It is the most important of all chemical agents, for it takes into solution most of the substances with which it is in contact, and is the universal life fluid. Because of this eagerness in taking to itself portions of other substances it is practically never pure unless artificially prepared. From the physical standpoint water is also of the highest interest and importance. It is continually in motion, even as a solid; as ice it is moving slowly under the influence of gravity, settl...