In an early part of this article we have stated that different bodies combine in proportions that are fixed with regard to each other in a given compound.

We may now observe that these proportions are definite with regard to every other substance with which they are capable of entering into composition, so that there are certain determinate proportions of all bodies which are equivalent to each other in their powers of combining with all other bodies. Thus, acetate of lead is a compound of 50 parts of acetic acid and 112 parts of lead, in the state of an oxide. White vitriol, or sulphate of zinc, is composed of 40 parts of sulphuric acid and 41 parts of oxide of zinc. Now these proportions are all equivalent to one another, and if the numbers are written against the different substances as follows, we can at once perceive the proportions in which they will unite in any new combination.

The same equivalent numbers or their multiples are preserved in every possible combination with other bodies; and when any body is compounded of two simple substances, the sum of the equivalents of the two elements will give the number, denoting the proportion in which it will combine. Thus the prime equivalent of hydrogen is 1, that of oxygen 8; these combine to form water, the equivalent of which is 9. The following table contains the names of those substances which being, in the present state of chemistry, undecomposable, are considered as simple elementary bodies, classed in two divisions, and having their equivalent or combining numbers attached.

Non-Metallic.

Metallic Elements.

A particular description of the properties of these bodies, with the compounds formed by their union with each other, will be found under the initial letter of their respective names.