A simple body; at least one that is supposed to be so, as it has never been decomposed. It is always found united with the negative electricity. It will be one of the first of the elementary bodies whose properties I shall explain to you, and, as you will soon perceive, it is one of the most important in nature; but it would be irrelevant to enter upon this subject at present. We must now confine our attention to the enumeration and classification of the simple bodies in general. They may be arranged as follows: CLASS I. _Comprehending the imponderable agents, viz._ HEAT or CALORIC, LIGHT, ELECTRICITY. CLASS II. _Comprehending agents capable of uniting with inflammable bodies, and in most instances of effecting their combustion._ OXYGEN, CHLORINE, IODINE.* [Footnote *: It has been questioned by some eminent chemists, whether these two last agents should not be classed among the inflammable bodies, as they are capable of combining with oxygen, as well as with inflammable bodies. But they seem to be more distinctly characterised by their property of supporting combustion than by any other quality.] CLASS III. _Comprehending bodies capable of uniting with oxygen, and, forming with it various compounds. This class may be divided as follows:_ DIVISION 1. HYDROGEN, _forming_ water. DIVISION 2. _Bodies forming acids._ NITROGEN, _forming_ nitric acid. SULPHUR, _forming_ sulphuric acid. PHOSPHORUS, _forming_ phosphoric acid. CARBON, _forming_ carbonic acid. BORACIUM, _forming_ boracic acid. FLUORIUM, _forming_ fluoric acid. MURIATIUM, _forming_ muriatic acid. DIVISION 3. _Metallic bodies forming alkalies._ POTASSIUM, _forming_ potash. SODIUM, _forming_ soda. AMMONIUM, _forming_ ammonia. DIVISION 4. _Metallic bodies forming earths._ CALCIUM, _or metal forming_ lime. MAGNIUM, _forming_ magnesia. BARIUM, _forming_ barytes. STRONTIUM, _forming_ strontites. SILICIUM, _forming_ silex. ALUMIUM, _forming_ alumine. YTTRIUM, _forming_ yttria. GLUCIUM, _forming_ glucina. ZIRCONIUM, _forming_ zirconi.* [Footnote *: Of all these earths, three or four only have as yet been distinctly decomposed.] DIVISION 5. _Metals, either naturally metallic, or yielding their oxygen to carbon or to heat alone._ _Subdivision 1._ _Malleable Metals._ GOLD, PLATINA, PALLADIUM, SILVER* MERCURY† TIN, COPPER, IRON, LEAD, NICKEL, ZINC. [Footnote *: These first four metals have commonly been distinguished by the appellation of perfect or noble metals, on account of their possessing the characteristic properties of ductility, malleability, inalterability, and great specific gravity, in an eminent degree.] [Footnote †: Mercury, in its liquid state, cannot, of course, be called a malleable metal. But when frozen, it possesses a considerable degree of malleability.] _Subdiv. 2._