At that period of our future Philosopher’s life, early as it was, his uncultivated mind, naturally teeming with the most prolific germs of yet unexpanded science, began to unfold those buds of genius, which soon after attained that wonderful luxuriance of growth by which the usefulness and splendour of his talents became eminently conspicuous. His brother Benjamin relates,[72] that, while David was thus employed at the plough, from the age of fourteen years and for some time after, he (this informant,) then a young boy, was frequently sent to call him to his meals; at which times he repeatedly observed, that not only the fences at the head of many of the furrows, but even his plough and its handles, were covered over with chalked numerical figures, &c.[73]—Hence it is evident, that the exuberance of a sublime native genius and of almost unbounded intellectual powers, unaided by any artificial means of excitement, were enabled, by dint of their own energy, to burst through those restraints which the corporeal employments of his youth necessarily imposed upon them. ----- Footnote 72: This gentleman was commissioned by Governor Mifflin, in the year 1791, to be one of the associate judges of the court of common pleas, in and for the county of Montgomery: but his tenure of this office was afterwards vacated, by his removal to Philadelphia. Footnote 73: “Astronomy,” says Mr. B. Rittenhouse, in the letter before referred to, “appeared at a very early day to be his favourite study; but he also applied himself industriously to the study of opticks, the mechanical powers,” &c. ----- During that portion of his life in which this youthful philosopher pursued the ordinary occupations of a husbandman, which continued until about the eighteenth year of his age, as well as in his earlier youth, he appeared to have inherited from healthful parents a sound constitution, and to have enjoyed good health. It was at this period, or rather about the seventeenth year of his age, that he made a wooden clock, of very ingenious workmanship: and soon after, he constructed one of the same materials that compose the common four-and-twenty hour clock, and upon the same principles. But he had exhibited much earlier proofs of his mechanical genius, by making, when only seven or eight years old, a complete water-mill in miniature.