Page:Popular Science Monthly Volume 51.djvu/775

Rh {|align=center
 * width=20 | A.
 * width=380 |Figure painters of national repute
 * width=30 |·08
 * width=20 |2°
 * B.
 * Landscape painters, telegraph operators, coasting and yacht |mates and masters, village blacksmiths, expert baseball players
 * ·17
 * 4°
 * C.
 * Mechanical engineers
 * ·30
 * 7°
 * D.
 * Mechanical draughtsmen
 * ·40
 * 9·
 * 5°
 * E.
 * Teachers, journeymen house carpenters, farmers thirty years old or more
 * ·50
 * 12°
 * O.
 * Children eight years of age
 * 2.00
 * 50°
 * }
 * Teachers, journeymen house carpenters, farmers thirty years old or more
 * ·50
 * 12°
 * O.
 * Children eight years of age
 * 2.00
 * 50°
 * }
 * 50°
 * }
 * }
 * }

To remove opinion the test must be equally new to all tested. It must be easy enough for the child of eight to draw quickly; difficult enough, so that the most expert of any age will be unable to reproduce it perfectly. To be novel to all it must be abstract. The above table is the result of measures obtained in the following way:

Tests No. 1 and No. 2, mechanically enlarged to three feet by two feet, are placed vertically before groups of from twenty to fifty or more individuals. The copies are drawn on paper nine by six inches, and must not be raised from the horizontal position.

The usual mechanical aids to accuracy, such as measuring by the hand or pencil held between the eye and the object, are not allowed in any way.

For test No. 1 the operator calls attention to the chart that is to be proportionally reproduced by words that in no way hint at the position or proportion, and by motion, pointing out and holding for a few seconds, until recorded, each point on the chart. The time consumed will be about two minutes, and the result tabulated for age and error may be read in line No. 1 on large chart, showing no variation for age. The least error is nothing; greatest, six tenths of an inch; average, three tenths of an inch. Between this line and the top of the chart lies all the error of eye and hand. The eye of the child sees as accurately as the adult's.

Test No. 2 is to be drawn under exactly the same conditions as the above, except that no word or motion must aid the attention of those drawing, either to the chart or their copy of it. The attention given it must be voluntary. The result, measured and charted by age, position, and angle error, may be read for any age—eight to twenty—on line No. 2. This curve is the center of