Oops, there's a typo here:
How often this cycle repeats depends on the string tension and length. If the string is tuned to g', which is 293 cycles per second, the cycle will repeat 293 times per second.
g' is 392 Hz, not 293.
From this we conclude that the chien will tap at the same frequency as the trompette string. For a trompette tuned in d', this will be 293 Hz (cycles per second).
d' is actually 293.66 Hz, so this should round to 294 Hz. This is close to the 297 Hz referred to in the article.
A term I didn't explain: Hz is short for Hertz, which is the International unit for cycles or repetitions or vibrations per second. In old books you'll sometimes find the unit "cps", which is the same thing.
Alden
