Antique Wigzell's Patent Sea Sounding Instrument. A remarkable depth sounding instrument based on water pressure. The instrument is contained in the original pine box and is complete with fathom scale. The original instructions are also present on the inside of the box lid.

The instrument is comprised of a clear tube mounted inside a brass housing. The housing is secured onto a lanyard which is attached to a long line for lowering to the seabed, a sounding lead is attached to the bottom lanyard. It can then be lowered over the side of the vessel, the increase in pressure forces water up into the tube and once hauled back on deck the water column can be measured against the fathom scale. Length of box 68cm / 26.75 inches.