In diet, Percival was the most abstemious person I ever knew. His health was uniformly good,—the specimens of a geologist, when he collects them himself, being as favorable to digestion and appetite as the pebbles to a chicken; yet, I am persuaded, my companion in no case violated the golden rule of leaving the table unsated. No matter how long had been his fast, he showed no impatience of hunger, made no remark upon the excellence of any dish, found fault with nothing, or, at most, only seemed to miss drinkable coffee and good bread, articles seldom to be met with in the country. He ate slowly, selecting his food with the discrimination which ought to belong to a chemist or physiologist, and then thought no more about it. Alcoholic drinks he never tasted, except an occasional glass of wine, to which his attention perhaps had been called on account of its age or superior excellence. Even then it was not the flavor which interested him, so much as the history, geographical and other.
Peculiar as he was in his own habits of diet, he offered no strictures upon the practice of others, however different, unless it ran into hurtful excesses. The maxim of Epictetus in the "Enchiridion," "Never preach how others ought to eat, but eat you as becomes you," seemed to be his rule. Indeed, Percival was one of those rare men who withhold alike censure and praise respecting the minor matters of life. Not that he was without opinions on such subjects; but, to obtain them, one was forced to question him. On the whole, I do not think it would be going too far to apply to him the above-named moralist's description of the wise man:—"He reproves nobody, praises nobody, blames nobody, nor even speaks of himself; if any one praises him, in his own mind he contemns the flatterer; if any one reproves him, he looks with care that he be not unsettled in the state of tranquillity that he has entered into. All his desires depend on things within his power; he transfers all his aversions to those things which Nature commands us to avoid. His appetites are always moderate. He is indifferent whether he be thought foolish or ignorant. He observes himself with the nicety of an enemy or a spy, and looks on his own wishes as betrayers."
Percival's solitary habits, combined with the invariable seriousness of his manner, led many persons to believe him melancholy, and even disposed to suicide. He did, indeed, confess to me, that he sometimes felt giddy on the edge of a precipice. This was his nearest approach, I am confident, to the idea of self-destruction. While we were examining the great iron furnaces of Salisbury, he told me that he was afraid of walking near the throat of a chimney when in blast, and that more than once he had turned and run from the lurid, murky orifice, lest a sudden failure of self-control should cause him to reel into the consuming abyss. No,—Percival neither felt nor expressed disgust with life. On the contrary, he was strongly attached to it; the acquisition of knowledge clothed it with inexpressible value; the longest day was ever too short to fulfil his designs. Like the wise, laborious men of all ages, he almost repined at the swiftness of the years. "I am amazed at the flight of time," he said to me, on the arrival of his forty-second birthday; "it seems only a year since I was thirty-two;—I have lost ten years of my life."
Before entering upon the survey of Connecticut, he was not specially devoted to any one branch of physics, although his tastes inclined him most toward geology. While he could sympathize perfectly, he said, with those who threw their whole force into a single study, he felt himself attracted equally by the entire circle of Nature, and thought omniscience a nobler object of ambition than any one science. He admitted that the search after all knowledge is incompatible with eminence in any particular department; but he believed that it affords higher pleasure to the mind, and confers ability to do signal service to mankind in pointing out the grand connections, the general laws, of Nature.
It is not, perhaps, widely known, that Percival was a well-informed botanist. He studied this branch when a medical student under Professor Ives, and assisted his instructor in laying out a small botanical garden, the plants of which were arranged after the natural orders of Jussieu. Soon after finishing his medical education, he gave a course of lectures on botany in Charleston, South Carolina, before a very select audience, composed mostly of Ladies. The only drawback to the lecturer's success was his excessive timidity. As an evidence of the assiduity with which he botanized, it may be mentioned that he had seen the Geranium Robertianum (a plant which nestles in the sunny clefts of our trap mountains) in bloom, during every month of the year. One year he found its blossoms in December, another in January, and so on, until the round of the monthly calendar was completed.
Percival was an earnest advocate of popular education. He manifested much interest in the first systematic attempt (at the instance of Mr. James Brewster) to furnish the people of New Haven with popular instruction in the form of lectures. At a public dinner, given by Mr. Brewster, on the occasion of opening the building in which rooms had been fitted up for these lectures, the late Mr. Skinner gave the toast, "Our mechanics, the right arm of New Haven," and Percival followed with, "Science, the right eye which directs the right arm of New Haven." He believed most fully in the superiority of intelligent labor. He pointed out cases in which a college-training had been connected with signal eminence in mechanical invention, and said, that, according to his observations, persons engaged in industrial pursuits usually succeeded in proportion to the thoroughness of their education.
Percival himself gave a course of lectures, or rather, lessons, in New Haven,—not in the building above mentioned, for his natural timidity was too great to encounter a public audience, but in the theological lecture-room of Yale College. They were on the German language, and consisted chiefly of translations of prose and poetry into English, intermingled with philosophical commentaries on the peculiarities of the original. It was pure grammar; he did not talk German, and claimed no acquaintance with the niceties of pronunciation; but all his listeners, most of whom were graduates, were struck with his perfect mastery of the subject.
Percival held one peculiar opinion concerning a branch of college education. He objected to the modern practice of teaching the natural sciences by means of a profusion of drawings, models, showy experiments, and other expedients addressing the mind so strongly through the eye. While these might be allowable in popular lectures, before audiences lacking in early intellectual discipline, where amusement was a consideration, and where without it the public ear could not be secured, he thought that the collegian should study differently,—that 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.