Discoveries and inventions of the nineteenth century (1905)
Routledge, Robert · London : G. Routledge and Sons · leaf 529
seen onclocks. The illusion is best when the slits areso narrow that only one of the several imagesis visible by reflection, namely, that which isadjacent to the slit. Thus, as the disc rotates,each little circle is visible for an instant as the slit passes in front of thespectators eye; and if the… … FiG. 250.
Inventions
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