One x2 scale model of a Bolt patent air gun used to generate precise shock waves for seismic surveying of strata beneath sea bed (in "Perspex"). Scale model of a Bolt patent air gun
Bolt Association PAR air gun. Model 600B, serial no.720, with a 40 cubic inch capacity chamber. (As used to generate shock waves in seismic surveying at sea). Bolt Association PAR air gun. Model 600B