DescriptionGaltonwhistle.jpg English: A Galtonwhistle, the first ultrasonic whistle or "dog whistle".. It was invented in 1876 by Francis Galton and used
DescriptionGalton'swhistle.jpg Русский: Свисток Гальтона English: Galton'swhistle Date before 1930 date QS:P,+1930-00-00T00:00:00Z/7,P1326,+1930-00-00T00:00:00Z/9