his understanding should be taxed severely, and that he should be inured, from the first, to rigid attention, in order to a lasting remembrance of the truths offered to him.  It would be a useful exercise for the instructor, he thought, to elucidate obscure phenomena and complicated structures by words only, assisting himself, perhaps, occasionally, by extemporaneous drawings.  Such a course would inspire the scholar with deference for his teacher, and confidence in his own ability to acquire a similar grasp of the subject.  While there is certainly some truth in this opinion, it would not be difficult, perhaps, to invalidate its general force.  Why should the ear be the only admitted means of acquiring knowledge?  Nature, the greatest of teachers, does not judge thus:  she conveys half her wisdom to us by sight, instead of by faith; she gives her first lessons to the infant through the eye.  Would Percival, in looking for his attentive audiences, have preferred a congregation of blind men?

Speaking of literary composition, he said that he often took great pains with his productions, shifting words and phrases in many ways, before satisfying himself that he had attained the best form of expression; and he assured me that these slowly elaborated passages were the very ones in which he afterwards recognized the most ease and nature, and which others supposed him to have thrown off carelessly.  I asked him how it was that children, in their unpremeditated way, expressed themselves with so much directness and beauty.  They have but a single idea to present at a time, he said; they seize without hesitation on the first words that offer for its expression, unperplexed by any such choice of terms as would surely occur to maturer minds; and most important of all, perhaps, they are wholly unembarrassed by limiting qualifications arising from a fuller knowledge of the subject.

His prose style is a rare exemplification of classic severity and perspicuousness.  In each paragraph the ideas arrange themselves in faultless connection, like the molecules of a crystal around its centre.  The sentences are not long, the construction is simple, the words are English in its purity, without admixture of foreign phrase or idiom.  But the most striking peculiarity of his diction is the utter absence of ornament; for Percival evidently held that the chief merits of composition are clearness and directness.  Poetic imagery, brilliant climaxes and antitheses, fanciful or grotesque turns of expression, he rejected as unfavorable to that simple truth for which he studied and wrote.  This dry, almost mathematical style, was no necessity with him; few men, surely, have had at command a richer vocabulary, English and foreign, than Percival; few could have adorned thought with more or choicer garlands from the fields of knowledge and imagination.