拍品专文
Used for experiments in stereoscopic television.
细节
A disc with two spirals of square holes,
fifteen in each spiral, tinplate, painted black -- 12 in. (30.4 cm.) diam., centre hole 1/4 in. (6 mm.)
fifteen in each spiral, tinplate, painted black -- 12 in. (30.4 cm.) diam., centre hole 1/4 in. (6 mm.)