Wednesday, September 30, 2009

Galton's Dog Whistle



Francis Galton, Charles Darwin's cousin, invented the inadudible dog whistle.

The original whistle was made of a brass tube with an internal diameter of approximately 2 millimetres. By moving a small plunger, the size of the resonanting cavity in the whistle could be changed, enabling the pitch of the whistle to be altered from audible up into the ultrasonic range, which humans cannot hear but which dogs can. Galton was able to determine that the normal upper limit of human hearing was about 18kHz.

Galton, of course, also invented the field of eugenics, fingerprint indentification, and mathematical correlation and regression.

1 comment:

  1. Anonymous8:27 AM

    I know all about Galton's regression.

    I use a variant of it in nearly every paper I write.

    ReplyDelete

All comments are moderated, and all zombies, trolls, time wasters, and anonymous cowards will be shot.

If you do not know what that means, click here and read the whole thing.

If you are commenting on a post, be sure to actually read the post.

New information, corrections, and well-researched arguments are always appreciated.

- The Management