Whistle

This was made by J Hudson & Co sometime between 1888-1909. In 1884, Hudson's was awarded the contract to make whistles for the Metropolitan police when he demonstrated how it could be heard up to a mile away. He also showed how using a whistle meant a policeman could have his hands free - this was not possible when they were using their rattles, the precursor to the whistle.

J Hudson is still going, making all manner of noisy things. They have had a change of name, though and are now Acme Whistles.

I quite like the fact that as well as making police whistles (and developing the pea in the whistle for increased decibels), they also invented the silent dog whistle.