Observe, now, how all the phraseology employed in speaking of these successive generalizations of science is borrowed from the action of mind. The word _action_ itself has no real significance, except when applied to the _doings_ of an intelligent agent; we cannot speak of the doings of matter, as we could if the word _action_ were applicable to it in any other than a figurative sense. Again, in speaking of the similarity of facts and the regularity of sequences, we refer them to a _law_ of nature, just as if they were sentient beings acting under the will of a sovereign. Parts of pure matter--the chemical elements, for instance--do not _act_ at all; being brute and inert, it is only by a strong metaphor that they are said to be subject to law. Again, we attribute _force_, _power_, &c., to the primitive particles of matter, and speak of their natural _agencies_. Just so, we talk of _tone_ in coloring, and of a _heavy_ or _light_ sound; though, of course, in their proper significance, tone belongs only to sound, and heaviness to gravitating bodies. These modes of speech are proper enough, if their figurative character be kept in view; but it is a little too bad, when a whole scientific theory is made to rest upon a metaphor as its sole support. _Agency_ is the employment of one intelligent being to act for another; _force_ and _power_ are applicable only to will; they are characteristic of volition. It is a violent trope to apply either of these words to senseless matter. Chemical _affinities_ are spoken of, as if material elements were united by family ties, and manifested choice, and affection or aversion.