Page:Popular Science Monthly Volume 33.djvu/185

Rh the dog's-head whistle (10) for hunters, and many-ended whistles, like the army whistle with compass (11), the match-box whistle

 1. Roulette whistle. 2. Swiss railroad-station agent's whistle. 3. Scholar whistle. 4. Another type of the same. 5. Fireman's whistle. 6. Marine regulation whistle. 7. Square whistle with two holes. 8. Round whistle. 9. Army regulation whistle. 10. Dog's-head whistle. 11. Army compass whistle. 12. Whistle and horn of three notes. 13. Railroad whistle. 14. Match-box and compass whistle. 15. Belgian whistle.

(14), cigarette-case whistles, whistling canes, whistling hunting-whips, whistling sleeve-buttons, etc.

Among the matters to be taken into account in the making of whistles are the effect of the length and the diameter of the