This is an Authentic Double Bellow Air Pump Fog Horn. This was a foot-operated air supply pump for either a Deep Sea Diving Helmet or a Firefighters Smoke Helmet. This originally was an air pump used to pump fresh air into the safety helmet using the double bellow system operation.

To operate the bellows, the large aluminum foot pedal was pressed down and using the tension of the large spring, air can be sent to the helmet. On the top is an early plastic label panel that explains how by using a system of pulls the wearer and attendant could communicate.

It reads:

CODE OF SIGNALS ON LIFELINE

FROM WEARER TO ATTENDANT
1 Pull – MORE AIR
2 Pulls – SLACK OFF LIFELINE
3 Pulls – HELP ME OUT IMMEDIATELY

FROM ATTENDANT TO WEARER
3 Pulls. COME OUT IMMEDIATELY

Around 1910, more advanced and efficient methods, which included oxygen tanks, etc., forced these antiquated machines out of the market. With this, companies began to add the large brass horn to the bellow pump and sold it as a portable Fog Horn for maritime sailors and fishermen to sound out to approaching ships, or to alert sailors of onboard dangers.

Also on the pump, you will see a plaque that reads: Makers Stenhouse Equipment (Safety) Limited Hull

This item would be a great addition for a nautical collector!