• 1 · Religion and Magic
• 2 · Nature
• 3 · Human Being, Man in General
• 4 · Society, Civilization, Culture
• 5 · Abstract Ideas and Concepts
• 6 · History
• 7 · Bible
• 8 · Literature
• 9 · Classical Mythology and Ancient History

• Top
• 4 · Society, Civilization, Culture
• 46 · social and economic life, transport and communication
• 46E · post, telegraph and telephone; means of communication
• 46E5 · acoustic signalling
• 46E52 · acoustic signalling with instrument

46E525 · whistle ~ acoustic signalling