But as no such definition is contained in _the books_,[66] there are ten chances to one, that, simple as the matter is, the readiest master you shall find, will give an erroneous answer.

Suppose the teacher should say, "That is a question which I have not thought of; turn to your dictionary." The boy reads from Dr.
Webster: "NUMBER--the designation of a unit in reference to other units, or in reckoning, counting, enumerating."-- "Yes," replies the master, "that is it; Dr.Webster is unrivalled in giving definitions." Now, has the boy been instructed, or only puzzled?
Can he conceive how the number _five_ can be a _unit_?
or how the word _five_, the figure 5, or the numeral letter V, is "the designation of a _unit_ ?" He knows that each of these is a number, and that the oral monosyllable _five_ is the same number, in an other form; but is still as much at a loss for a proper answer to his question, as if he had never seen either schoolmaster or dictionary.

So is it with a vast number of the simplest things in grammar.
7.

Since what we denominate scientific terms, are seldom, if ever, such as stand for ideas simple and undefinable; and since many of those which represent general ideas, or classes of objects, may be made to stand for more or fewer things, according to the author's notion of classification; it is sufficiently manifest that the only process by which instruction can effectually reach the understanding of the pupil and remove the difficulties spoken of, is that of delivering accurate definitions.

These are requisite for the information and direction of the learner; and these must be thoroughly impressed upon his mind, as the only means by which he can know exactly how much and what he is to understand by our words.