Another use of the rattlesnake was upon a ground of thirteen horizontal
bars alternate red and white, the snake extending diagonally across the
stripes, and the lower white stripes bearing the motto—“Don’t Tread on
Me.” The snake was always represented as having thirteen rattles, and
the number thirteen seems constantly to have been kept in mind. Thus,
thirteen vessels are ordered to be built; thirteen stripes are placed
on the flag; in one design thirteen arrows are grasped in a mailed
hand; and in a later one thirteen arrows are in the talons of an eagle.