These experiments were made upon students in the University of Edinburgh, chiefly between the ages of 14 and 25, and, were intended to illustrate the general inquiry as to the law of physical development with age, but more particularly to afford data for instituting comparisons between different nations. For this purpose, throughout these experiments, natives of Scotland, England, and Ireland, were distinguished; and though the numbers belonging to the two latter countries were comparatively small, still the general coincidence of results, as to the three elements of weight, height, and strength, gives some confidence even in that part of the inquiry.