Page:Popular Science Monthly Volume 91.djvu/962

 946

��Popular Science Monthly

��be raised first and then the hand of the same side.

In gymnastic nomenclature the snap under the bar is called "short underswing for distance." It was first introduced as an athletic event by the author in 1900, and was later adopted by the A. L. N. A. Stand, grasp the vaulting bar, jump to a momentary free front rest, then drop backward as though about to start a back- ward free circle. At a point just below the bar, flex the thighs and then extend them forward ; release the grasp, project yourself horizontally forward as high as the bar. Just before the feet strike the floor swing the arms forward to bring the body to an erect position.

A regulation bar or an adj ustable (in height) horizontal bar must be used. The height of the bar must be 4 ft. 9 in., meas- ured from the top of the bar. The bar must not be raised or lowered. A line is drawn with the front edge extending from center to center of the uprights and directly beneath the horizontal bar. This is the scratch line, and all measurements must be made from the front edge of this line at right angles to the nearest mark made by any part of the person of the competitor. The start is made with both feet on the floor back of the scratch line and the hands grasping the bar. Both feet must leave the floor at the same time and may not leave the floor more than once. The hands must be grasping the bar when the feet leave the floor. No part of the person of the athlete should touch the bar.

The author objects to the limitations of these rules that have been adopted by the A. L. N. A. It is far better to allow liberty in the preparatory position and movement just as in any other athletic event. Some athletes prefer to start in the

���Climbing rope to tambourine or bell

��standing position on the bar, and others from a stand on one foot with a free swing with the other.

The snap under for height is an event

listed by the A. L. N. A., and is not popular

because of frequent injury to the forehead,

due to striking the bar in the close pull-up.

(The End.)

��Teeth of a Hack- Saw Blade Used for Spacing on Section Liner.

THE gaging device for the liner is made of a 16-in. hack-saw blade, A, having 18 teeth to the inch. This is ground on the sides to remove all set, then the points are slightly rounded to remove the sharp corners. It is preferable to select a soft hack-saw blade as it can be straightened by hammering the edge at the proper place. The straight edge B is made of sheet steel }/2 in. wide and 1/16 in. thick and is pivoted at one end in the center of a half circle C cut from No. 22-gage sheet bronze. The heel of this piece comes to the back edge of the saw-blade and a portion of each corner D is turned back and over the back edge of the saw-blade. A guide- block E is fastened to the gage piece C to keep it in place on the saw-blade.

The semi-circular edge of the spacing head has a slot, as shown, in which an ad- justing thumb-nut is used to set the angle to the blade. The edge is marked in degrees so that this setting is easily accomplished. The spacing arrangement consists of a

���The 1 teeth of the blade being accurately cut, the spacing is made perfectly uniform

knurled wheel F which has a stop-pin G to limit the motion of the pawl H. A small spring / holds the pawl in the teeth of the saw-blade. A turn of the wheel forward and back moves the straight edge up to a new position, making the spacing perfectly uniform with the spacing set by the stop- pin. — C. S. Beardsley.

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