62 THE ELEMENTS OF CHEMISTRY CHAP. the flask with water at the ordinary temperature, so that the water extends several inches into the tube. Now cool the vessel by placing it in ice or in a freezing mixture, and notice the contraction of the water indicated by the fall of the column of water in the tube. By means of this experiment, it can be shown also that the water expands as it is cooled below 4° C. (39.2° F.) Just as water contracts when cooled, so it expands when heated, and when it reaches the temperature of 100° C. (212° F.), it is converted into an invisible vapour. When a given volume of water is converted into vapour, the vapour at 100° C. occupies about 1600 times the volume that the water did. When partly condensed, water-vapour is visible, and then it is called steam. EXPERIMENT 58.-Fill a vessel with water at a low tem perature and weigh it. Fill the same vessel with water at a comparatively high temperature. What difference do you notice? How do you account for the difference? Fill with Heat, and notice Arrange an apparatus, as for Experiment 57. water to the lower part of the glass tube. change in position of the column of water. What does this prove? Compare the result with that reached in Experiment 57. Water is a bad conductor of heat. When a mass of water is heated by a flame applied beneath it, the particles of water which are lowest first become heated. They expand and rise. The same changes take place in the next following particles, and so on until the whole mass becomes heated to the boiling temperature. The heat is thus distributed through the mass by means of currents caused by the heat. These are called convection-currents, and the process is called convection. EXPERIMENT 59. Heat a mass of water contained in a good-sized flask, and note the formation of currents from below. Some light powder, as powdered charcoal, put in the water will show the currents strikingly. Boiling Point.-The boiling point of a liquid is that New Edition. Globe 8vo. Price 2s. 6d. Inorganic Chemistry FOR BEGINNERS BY SIR HENRY ROSCOE, F.R.S., D.C.L., LL.D., M.P. ASSISTED BY JOSEPH LUNT, B.Sc. (Vic.), F.C.S. With One hundred and eight Illustrations in the Text ADAPTED TO THE ELEMENTARY STAGE OF THE SOUTH KENSINGTON SYLLABUS London MACMILLAN AND CO., LIMITED NEW YORK: THE MACMILLAN COMPANY ELEMENTARY PRINCIPLES Solids, Liquids, and Gases. The Air-Introductory. Water, Introductory-Mechanical Mixture and Chemical Combination-Indestructibility of Matter. Elements and Compounds-Symbols and Formula-Distribution of the Elements. Combination in Definite and Multiple Proportions-Dalton's Atomic Theory-Atomic and Molecular Weights-Calculations. Physical Measurements. Physical Properties of Gases. SYSTEMATIC STUDY OF CERTAIN NON-METALLIC Hydrogen. Oxygen and the Oxides, Hydroxides, Acids, Bases, and Salts. Ozone. Compounds of Hydrogen and Oxygen. Heat Relations of Water. Water as a Solvent-Water of Crystallisation, Efflorescence, Deliquescence-Solubility of Gases-Natural Waters-Temporary and Permanent Hardness and the Softening of Water-Distillation and Purification. Nitrogen and Air. Compounds of Nitrogen and Oxygen, Nitrous Acid, Nitric Acid, The Nitrites and Nitrates. Compounds of Nitrogen and Hydrogen, Ammonia and the Ammonium Compounds. Chlorine, Hydrochloric Acid, and the Chlorides. Sulphur, Sulphuretted Hydrogen, and the Sulphides. Oxides and the Oxy-Acids of Sulphur. Carbon and its Allotropic Modifications-Carbon Monoxide-Carbon Dioxide-Methane Acetylene-Ethylene-Coal Gas and Flame. PRESS NOTICES Nature-" In every respect the book is a good one, and contains the kind of knowledge that should be imparted to all beginners in science." Chemical Trade Journal-"This work is admirably adapted to the requirements of science teachers, each lesson being supplemented with a summary of 'What We have Learnt,' and a list of about ten questions relevant to the lesson.. The book is well printed and got up, and constitutes an excellent and modernised text-book for beginners, which will be found highly useful to both student and teacher, and should gain equal favour with both.” Glasgow Herald-" An important feature of this book is a summary of the contents of each chapter placed at the end, together with a few searching questions well adapted to test the student's understanding of what has gone before. It is admirably got up in every way, and the illustrations are very numerous and invariably excellent." Manchester Courier-"The different methods of chemical combination are clearly set forth, and the heat relations of water, as well as the properties of gases and the modifications of carbon, are explained with a lucidity which cannot but be profitable to the student. The manual is very profusely illustrated, and contains directions for a great number of instructive experiments." Now Ready. Globe 8vo. Price 4s. 6d. Inorganic Chemistry FOR ADVANCED STUDENTS BY SIR HENRY ROSCOE, F.R.S., D.C.L., LL.D. AND ARTHUR HARDEN, PH.D., M.Sc. (Vict.) WITH FIFTY-ONE ILLUSTRATIONS IN THE TEXT ADAPTED TO THE ADVANCED STAGE OF THE London MACMILLAN AND CO., LIMITED NEW YORK: THE MACMILLAN COMPANY LESSON I. Molecular and Atomic Weights-2. Experimental Deter- mination of the Molecular Weights of Gases and Volatile Liquids and Solids-3. Solution and Crystallisation-4. The Halogen Elements : Fluorine. Chlorine. Bromine. Iodine-5. The Halogen Elements (continued)—6. The Halogen Elements (continued)-7. The Action of Alkalis on the Halogens; Oxides and Oxy-Acids of the Halogens— 8. The General Properties of the Halogen Elements-9. Equivalents; Direct Determination of the Equivalents of the Halogen Elements and Silver; The Foundation of Quantitative Analysis; Indirect Determin- ation of Equivalents-10. Metals and Non-Metals-11. The Nitrogen Group: Nitrogen. Phosphorus. Arsenic. Antimony. Bismuth- 12. The Elements of the Nitrogen Group (continued)—13. The Elements of the Nitrogen Group (continued)-14. Bismuth; The General Pro- perties of the Elements of the Nitrogen Group-15. Determination of the Atomic Weight from the Specific Heat of the Solid Element- 16. Crystals; Isomorphism-17. The Alkali Metals--18. The Alkali Manufacture: Sulphuric Acid. Salt Cake. Soda Ash. Caustic Soda. Chlorine. Bleaching Powder. Potassium Chlorate-19. The Alkali Metals (continued)-20. Constitutional Formulæ ; Valency; Constitution of Hydroxides and Oxyacids-21. The Ammonium Compound; Dissociation-22. The Metals of the Alkaline Earths-23. The Metals of the Zinc Group: Magnesium. Zinc. Cadmium. Mercury-24. The Metals of the Zinc Group (continued)-25. The Metals of the Copper Group: Copper. Silver. Gold-26. Metals of the Copper Group (continued)-27. Thermochemistry-28. Electro-chemistry-29. The Elements of the Aluminium Group: Boron. Aluminium-30. The Elements of the Carbon Group: Carbon. Silicon. Tin. Lead- 31. The Elements of the Carbon Group (continued)—32. The Metals of the Iron Group: Iron. Nickel. Cobalt-33. The Metals of the Iron Group (continued)-34. Chromium-35. Manganese-36. Platinum, Argon, and Helium-37. Classification: The Periodic System-38. Determination of the Molecular Weights of Dissolved Substances. |