Two Observations on Early Origins of the Western: Pressure Studies
Lit in silhouette, a bubble is suspended from a short rod, filling most of a vignetted black-and-white frame. Immediately a solid form enters from the left, headed directly for the delicate sphere. The contour of this smaller round is irregular. Excreted from an unseen ejector, its stuttered trail reveals it traveled faster, thus farther, between film frames than was captured, but not by much.
Source: brooklynrail.org