1.0 milliseconds -- cycle time for frequency 1 kHz
1 ms -- duration of light for typical photo flash strobe
2.27 ms -- cycle time for the A above middle C in music (440 Hz). If an electric tuning device for musical instruments generates just one tone, this is probably that tone.
... and the Congo River
William Stairs, (1863-1892), Victorian explorer, discovered one source of the Nile River, first non-African to ever climb
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Abel Tasman, ...