The ultrasonic training instruments are easy to use. But there’s a dark history behind their inventor—and their initial ...

His invention, a shrill whistle called "pousse relou", has met with unprecedented popularity, extending beyond France's borders and attracting the interest of women in neighbouring countries.

Old poets have sung, and old chronicles tell, What champions ventur'd, what champions fell; The son of great Loda was conqueror still, And blew on the Whistle their requiem shrill. Till Robert ...