Chemistry is the science of phenomena which are attended by a change of the objects which produce them. We know that when a candle burns, or when wood is burned, or even a piece of metal becomes what we term “rusty,” that certain chemical changes take place. There is a change by what is termed chemical action. Rust on iron is not iron; it is oxide of iron. The oxygen of the air causes it. So we endeavour, by Chemistry, to find out the nature of various bodies, their changes, and the results. [Illustration: Fig. 301.—The Laboratory.] In nature we have simple and compound bodies. The former are called ELEMENTS. We must not confuse these elements with the so-called elements—earth, air, fire, and water. These are really compound bodies. An element is a substance or a gas which is not composed of more than one constituent; _it is itself_—a compound of perfectly identical particles. Every “compound” body, therefore, must be made up of some of the elements, of which there are sixty-five. These bodies are divided into non-metallic and metallic elements, and all bodies are composed of them, or are these bodies themselves. The list is as follows. The non-metallic elements are “metalloids.” We have omitted fractions from the weights, on which chemists differ. TABLE OF ELEMENTS WITH THEIR CHEMICAL SYMBOLS AND COMBINING WEIGHTS. Non-Metallic Atomic or Elements. Symbols. Combining Derivation of Name. Weights. Oxygen O 16 Gr. Oxus, acid; gennaō, to make. Hydrogen } { H 1 Gr. Udor, water; gennaō, to make. Nitrogen } Gaseous { N 14 Gr. Natron, nitre; gennaō, to make. Chlorine } {Cl 35 Gr. Chloros, green. Iodine } { I 127 Gr. Ioeides, violet. Fluorine } { F 19 Fluor spar, the mineral. Carbon } { C 12 Lat. Carbo, coal. Sulphur } { S 32 Lat. Sulphurium. Phosphorus } { P 31 Gr. Phos, light; pherein, to carry. Arsenic* } Solid{ As 75 Gr. Arsenicon, potent. Silicon } { Si 28 Gr. Silex, flint. Boron } { B 11 Gr. Borax, Arab., baraga, to shine. Selenium } { Se 79 Gr. Selene, the moon. Tellurium } { Te 129 Lat. Tellus, the earth. Bromine Fluid 80 Gr. Bromos, offensive smell. METALS. Name. Symbols. Atomic or Derivation. Combining Weights.