ATOMIC THEORY

(In Chemistry.) When substances combine chemically, they are found to unite in certain weights; thus, water is constituted of one part by weight of hydrogen and eight of oxygen, and the gases only combine in those proportions to form it. It is a umed lhat water is a compound ol" an atom of hydrogen and an iilom of oxygen, and that the relative weight of the atom of hydrogen to the atom of oxygen is as 1: 8; hence the atomic weight of water is 1 + 8, or = 9. The same theo retical news are applicable to all other simple and compound bodies, and the numbers which represent their combining weights are hence called their atomic or equivalent numbers. See Equivalents and Affinity. (See Daubeny on the Atomic Theory.) [s. 118]