CORRELATIVE ELEMENTS.

Any pair of the general elements, the interstices of one of which are the only interstices for receiving and retaining the atoms of the other, or that can be occupied by the atoms of any other of the general elements, such elements are correlatives.

Elementary co-relation is conspicuous in the opposite polarities of the loadstone, magnet, and crystals, and all bodies subject to polarization, which includes the animal frame. Similar co-relation is evinced between the galvanic fluids, those of the pile, and those named electricity; likewise between oxygen and hydrogen, the oxygenating element and nitrogen, acids and alkalies and all mutually neutralizing substances. Still it is not meant that all the general elements are so paired; doubtless, there are several ratios of size between the atoms of the different elements, for the purpose of multiplying variety among formations, the substance of which is of the same species throughout. Possibly the correlative principle gave rise to the ideal scale of chymical affinities, subsequently refined to affections of matter. Naturally, correlative elements will be found together, as are nitrogen and the imponderable element; also the magnetic fluids common to iron.