Magnesium Flash Powder Explosion
Photograph by Charles Martin
A blast of highly explosive magnesium flash powder allowed photographers Longley and Martin to photograph underwater life for the first time. When the men wanted to take a photograph, they clicked the camera’s shutter, which tripped a battery on a raft they dragged behind them. The battery, in turn, triggered the magnesium powder explosion, which illuminated the sea down to 15 feet (4.6 meters).