Pieces of amber torn from the sea-floor are cast up by the waves, and collected at ebb-tide.
The instrument generally employed is a bag-shaped net attached to a semicircular hoop, provided with a long handle and pushed over the surface of the sand by a fisherman wading in the water at ebb-tide.
There was a strong ebb tide with 15 feet of water.
Essentially the water would be drawn from the ebb tide of the Thames, which is about two thirds less salty than the sea.
The crossing of the bar requires considerable care, and at ebb tide the outward current runs 51knots per hour.