Yet a slight acquaintance with the history of grammar will suffice to show us, that it is much easier to acknowledge this principle, and to commend it in words, than to ascertain what it is, and abide by it in practice.

Good use is that which is neither ancient nor recent, neither local nor foreign, neither vulgar nor pedantic; and it will be found that no few have in some way or other departed from it, even while they were pretending to record its dictates.

But it is not to be concealed, that in every living language, it is a matter of much inherent difficulty, to reach the standard of propriety, where usage is various; and to ascertain with clearness the decisions of custom, when we descend to minute details.

Here is a field in which whatsoever is achieved by the pioneers of literature, can be appreciated only by thorough scholars; for the progress of improvement in any art or science, can be known only to those who can clearly compare its ruder with its more refined stages; and it often happens that what is effected with much labour, may be presented in a very small compass.
5.

But the knowledge of grammar may _retrograde_; for whatever loses the vital principle of renovation and growth, tends to decay.