Page:Popular Science Monthly Volume 21.djvu/65

Rh of not causing injurious straining to weakly persons. Trials of lifting heavy weights are positively dangerous. If a multitude of persons were tested in that way, some instances of broken blood-vessels and of abdominal ruptures would be almost sure to occur.

Agility may be defined in terms say of the number of seconds required to run a hundred yards, of the greatest horizontal distance that can be covered by a leap, of the distance to which a cricket-ball can be thrown, and by means of various gymnastic feats. The several merits of the latter, however, require to be carefully considered, and those that can be performed indoors and in a confined space should be selected as standards.

The coordination of muscles and eye is another faculty that varies widely in different persons, while it is also greatly increased by education. Some persons are gifted with a high power of accurate movement, while others are as notoriously clumsy. In all cases, however, this faculty may be largely developed in special directions, as is shown by the superior dexterity of artisans to that of amateurs. It seems a most simple faculty to be tested, nevertheless I know of no recognized methods of doing so; and, in default of one, the best plan of defining its amount might be, in the case of youths, by their measured skill in well-known games, as racquets, cricket, rifle-shooting, billiards, and wherever else a good eye and steady hand are required.

The faculty of sense-discrimination has in many respects been the subject of most elaborate experiments, chiefly in regard to the relation between the amounts of stimuli, as measured by objective standards (such as weight in pounds, as brightness in units of intensity, etc.), and the corresponding amount of evoked sensations, measured by subjective standards, namely, by the feelings of the several persons operated on. Out of all the contrivances that have been devised for these experiments, some of which are extremely delicate, we want a battery of the most simple ones that are sufficiently effective for ordinary anthropometric purposes. I find it difficult, in obedience to the programme already laid down, to enter as much as I should like to do into particulars concerning this wide and important part of the subject before us. The sources of error to be guarded against, the principles that have to be attended to, and the instruments already in use, can not be properly explained in a few paragraphs. The reader must take it for granted that all this is a familiar subject to many writers and experimenters, such as Fechner and Delbœuf, and that the work remaining to be done is to select out of extant instruments those that are sufficiently inexpensive and quick in manipulation to be appropriately placed in an anthropometric laboratory. Under these circumstances I will refrain from doing more than specifying the more important measurements among the many that admit of being made:

—Its keenness; the appreciation of different shades; that of different colors.