Anthropometric laboratory / arranged by Francis Galton.

  • International Health Exhibition (1884 : London, England)
Date:
1884
Catalogue details

Licence: Public Domain Mark

Credit: Anthropometric laboratory / arranged by Francis Galton. Source: Wellcome Collection.

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    runs freely between guides. The blow is delivered with the fist straight at the pad, driving the rod nearly or quite home, and its swiftness of motion is measured as follows :— Across its path a bridge is fixed and a flat steel rod projects from the bridge, lying above the bar and parallel to it. Its free end points in the same direction as that towards which the bar is driven by the fist. When the bar is set back ready for use, a stud upon its face holds the spring forcibly to one side, but as soon as the bar begins to move, the stud leaves the spring, which thereupon vibrates transversely to the moving bar. A pencil is attached to the spring, and the upper face of the bar carries a strip of the cardboard used for white flexible slates. The pencil leaves a sinuous trace on the strip, and the points where the trace crosses its own median line can be measured with precision. The spring that is used, makes twenty-five complete vibrations in a second. Hence, if the interval between any two alternate crossing points is 048 inch in length, the bar is travelling 1 foot per second. A scale is constructed of which the unit is 0*48 of an inch, and the graduations upon it are in feet per second. By applying this scale to the curve, the swiftness of the cor¬ responding blow is immediately read off. Strength (a) of pull.—The instrument is held as an archer holds his bow when in the act of drawing it, and the strength of the pull is given by the index. (b) of squeeze.—The instrument is tried first in the right hand, secondly, in the left hand. Span of Arms.—-A pair of rods, sliding over each other and with projections at either end, is held so that the tips of the fingers press against those projections ; then the arms are extended to their full stretch. The graduations show the span. Height (a) above seat of chair.—A quickly acting measuring-rod is fastened upright to the back of a solid and narrow chair.