Raising the alarm in the Roman camp

[M. Caecilius]

Bear in mind that the modern pea whistle (as used by policemen, sports referees etc) was only invented in the 1880s. Whistles have been found in Roman forts, but they're pea-less flute-like things. They could still be fairly loud, but not louder than a human shout...

Thanks for the information. I'll have to check at one of the Roman festivals in the future whether anyone has reconstructed such a whistle. As far as volume goes, is this a matter simply of decibels, but also of scale - are ancient whistles less shrill than the modern ones? I believe I have red somewhere that Sparta used flutes to communicate rather than drums or trumpets because their piercing sound can be heard through the din of the battle, but can't find the reference, and indeed have found that much of the evidence seems to rest on a vase painting... I don't assume that hand-bells, such as used by the city watch (and still used in the 19th century, iirc), are much louder than a human voice at full capacity?

De Bello Gallico. I don't have the book at hand at the moment. One instance has already been mentioned below (the surprise attack) and another was just something like, "the trumpets were sounded", said in an offhand manner as if we would all know what he was talking about.

Thanks. I'll have to check again. That's the problem with ancient sources, they just don't imagine they are writing for people 2000 years ahead. I do wonder what people will think of our society, when they try to puzzle out aspects that we would consider so perfectly obvious that we don't even manage to question them!