He was rarely visible abroad except in his walks to and from the country, whither he often resorted to pass not hours only, but frequently entire days, in solitary wanderings,—­partly for physical exercise,—­still more, perhaps, to study the botany, the geology, and the minutest geographical features of the environs; for his restless mind was perpetually observant, and could not be withheld from external Nature, even by his poetic and philosophic meditation.  In these excursions, he often passed his fellow-mortals without noticing them.  A friend, if observed, he greeted with a slight nod, and possibly stopped him for conversation.  Once started on a subject, Percival rarely quitted it until it was exhausted; and consequently these interviews sometimes outlasted the leisure of his listener.  You excused yourself, perhaps; or you were called away by some one else; but you had only put off the conclusion of the discourse, not escaped it.  The next time Percival encountered you, his first words were, “As I was saying,”—­and taking up the thread of his observations where it had been broken, he went straight to the end.

The excellent bookstore of the late Hezekiah Howe, one of the best in New England, and particularly rich in those rare and costly works which form a bookworm’s delight, was one of Percival’s best-loved lounging-places.  He bought freely, and, when he could not buy, he was welcome to peruse:  He read with marvellous rapidity, skipping as if by instinct everything that was unimportant; avoiding the rhetoric, the commonplaces, the falsities; glancing only at what was new, what was true, what was suggestive, he had a distinct object in view; but it was not to amuse himself, nor to compare author with author; it was simply to increase the sum of his own knowledge.  Perhaps it was in these rapid forays through unbought, uncut volumes, that he acquired his singular habit of reading books, even his own, without subjecting them to the paper-knife.  People who wanted to see Percival and obtain his views on special topics were accustomed to look for him at Mr. Howe’s, and always found him willing to pour forth his voluminous information.

His income at this time was derived solely from literary jobs, and was understood to be very limited.  What he earned he spent chiefly for books, particularly for such as would assist him in perfecting that striking monument of his varied and profound research, his new translation and edition of Malte-Brun.  For this labor the time had been estimated, and the publishers had made him an allowance, which, if he had worked like other men, would have amounted to eight dollars a day.  But Percival would let nothing go out of his hands imperfect; a typographical error, even, I have heard him say, sometimes depressed him like actual illness.  He translated and revised so carefully, he corrected so many errors and added so many footnotes, that his industry actually devoured its own wages; and his eight dollars gradually diminished to a diurnal fifty cents.