So surprisingly retentive was his memory, that he never forgot what he had once learned; nor did it appear that he ever suffered even an Image to be effaced from his mind; whilst the ideas which he had so rapidly accumulated, existed in his brain, not as a huge chaos, but in clear and well-organized systems, illustrative of every subject, and subservient to every call. It was this quality which made him so superior a disputant; for as his mind had investigated the various sentiments and hypotheses of men, so had his almost intuitive discrimination stripped them of their deceptive appendages, and separated fallacies from truth, marshalling their arguments, so as to elucidate or detect each other. But in all his disputations, it was an invariable maxim with him never to interrupt the most tedious or confused opponents, though, from his pithy questions, he made it evident, that, from the first, he anticipated the train and consequences of their reasonings.
His favourite studies were, Philology, History, Astronomy, Medicine, Theology, Logic, and Metaphysics, with all the branches of Natural and Experimental Philosophy; and that his attainments were not superficial, will be readily admitted by those who knew him best.—As a Linguist, he was acquainted with the Persian, Arabic, Hebrew, Greek, and Latin languages; together with the French, Spanish, Italian, and German; and he not only knew their ruling principles and predominant distinctions, so as to read them with facility, but in the greater part conversed fluently.
About the age of twenty-two, he accidentally met with the acute and learned Dr. Tucker, Dean of Gloucester, in a stage coach, who soon discovered the superiority of his companion, and after a reasonable acquaintance, in which the opinion he had at first entertained of John Henderson's surprising genius was amply confirmed, he wrote to his father, urging him to send a young man of such distinguished talents to an UNIVERSITY, where only they could expand, or be rightly appreciated; and, in the most handsome way, he accompanied this request with a present of TWO HUNDRED POUNDS. Such an instance of generosity, will confer lasting credit on the name of DEAN TUCKER.
On John Henderson's arrival at Oxford, he excited no small degree of surprise among his tutors, who very naturally inquired his reason for appearing at that place, and, as might be supposed, were soon contented to learn, where they had been accustomed to teach.[113]
It might be stated also, the late Edmund Rack, a gentleman possessed of much general knowledge, and antiquarian research, and whose materials for the "History of Somersetshire," formed the acknowledged basis of Collinson's valuable History of that county, thus expressed himself, in writing to a friend in London.
"My friend, Henderson, has lately paid me a visit, and stayed with me three weeks. I never spent a three weeks so happily, or so profitably. He is the only person I ever knew who seems to be a complete master of every subject in literature, arts, sciences, natural philosophy, divinity; and of all the books, ancient and modern, that engage the attention of the learned; but it is still more wonderful, that at the age of twelve, he should have been master of the Latin and Greek; to which he subsequently added, the Hebrew, Italian, Spanish, German, Persian, and Syriac languages; and also, all the ancient rabbinical learning of the Jews, and the divinity of the fathers; this was, however, the case. The learned DR. KENNICOTT told me, four years since, 'That the greatest men he ever knew were mere CHILDREN, compared to HENDERSON.' In company he is ever new. You never hear a repetition of what he has said before. His memory never fails, and his fund of knowledge is inexhaustible."
Dr. Kennicott, (before whom nothing superficial could have stood for a moment,) died in the year 1783, and John Henderson, at the time Dr. K, passed on him this eulogium, could have been only twenty-three years of age! One year after he had entered at Oxford.
Though not of the higher order of attainments, it may not be improper to mention his singular talent for IMITATION. He could not only assume the dialect of every foreign country, but the particular tone of every district of England so perfectly, that he might have passed for a native of either: and of the variations of the human accent in different individuals his recollection was so acute, and the modulation of his voice so varied, that, having once conversed with a person, he could most accurately imitate his gestures and articulation for ever after.[114]
No man had more profoundly traced the workings of the human heart than himself. A long observation on the causes and effects of moral action, with their external symbols, had matured his judgment in estimating the characters of men, and from the fullest evidence, confirmed him in a belief of the Science of PHYSIOGNOMY.
Though the "Physiognomical Sensation," in a greater or less degree, may exist in all, yet the data which support it are so obscure, and at all times so difficult to be defined, that if nature does not make the Physiognomist, study never will: and to be skilled in this science requires the combination of such rare talents, that it cannot excite wonder, either that the unskilful should frequently err, or that the multitude should despise, what they know they can never attain.