for ten hundred thousand, we introduce the new word _million_.
With this name we begin again as before, and proceed till we have used it a
million of times, each combination denoting a number clearly distinguished
from every other; and then, in like manner, we begin and proceed, with
_billions, trillions, quadrillions, quintillions, etc._, to any extent we
please.

20. Now can any one suppose that words are not here, in some true sense,
the instruments of thought, or of the intellectual process thus carried on?
Were all these different numbers to be distinguished directly by the mind
itself, and denominated by terms destitute of this artificial connexion, it
may well be doubted whether the greatest genius in the world would ever be
able to do what any child may now effect by this orderly arrangement of
words; that is, to distinguish exactly the several stages of this long
progression, and see at a glance how far it is from the beginning of the
series. "The great art of knowledge," says Duncan, "lies in managing with
skill the capacity of the intellect, and contriving such helps, as, if they
strengthen not its natural powers, may yet expose them to no unnecessary
fatigue. When ideas become very complex, and by the multiplicity of their
parts grow too unwieldy to be dealt with in the lump, we must ease the view
of the mind by taking them to pieces, and setting before it the several
portions separately, one after an other. By this leisurely survey we are
enabled to take in the whole; and if we can draw it into such an orderly
combination as will naturally lead the attention, step by step, in any
succeeding consideration of the same idea, we shall have it ever at
command, and with a single glance of thought be able to run over all its
parts."--_Duncan's Logic_, p. 37, Hence we may infer the great importance
of method in grammar; the particulars of which, as Quintilian says, are
infinite.[44]

21. Words are in themselves but audible or visible signs, mere arbitrary
symbols, used, according to common practice and consent, as significant of
our ideas or thoughts.[45] But so well are they fitted to be made at will
the medium of mental conference, that nothing else can be conceived to
equal them for this purpose. Yet it does not follow that they who have the
greatest knowledge and command of words, have all they could desire in this
respect. For language is in its own nature but an imperfect instrument, and
even when tuned with