I have sent these facts to you, Sir, because I think that they bear out the psychological distinction which is drawn in your leading article of the 17th inst. Briefly put, this distinction amounts to that between sensuous estimation and intellectual notation. Any child, a year after emerging from infancy, and not yet knowing its numerals, could immediately see the difference between five pigs and six pigs, and therefore, as your writer indicates, it would be an extraordinary fact if a savage were unable to do so. The case, of course, is different where any process of calculation is concerned: _e.g._ 'each sheep must be paid for separately; thus, suppose two sticks of tobacco to be the rate of exchange for one sheep, it would sorely puzzle a Damara to take two sheep and give him four sticks.' (F. Galton, 'Tropical South Africa,' p. 213.) But if the savage had to deal with a larger number of pigs the insufficiency of his sensuous estimation would increase with the increase of numbers, until a point would be reached at which, if he were to keep count at all, he would be obliged to resort to some system of notation, _i.e._ to mark off each separate unit with a separate _nota_, whether by fingers, notches, or words. Similarly with the sense of hearing and the so-called muscular sense. We can tell whether a clock strikes 1, 2, 3, 4, or 5 without naming each stroke, and whether we have walked 1, 2, 3, 4, or 5 paces without naming each pace, but we cannot in this way be sure whether a clock has struck 11 or 12, or we ourselves have, walked as many yards.