A remarkable sea-sounding instrument, invented by the Norwegian Captain Sigurdsons, based on atmosheric pressure as the sea-sounding instrument of Wigzell. The instrument is put away in a pine box with a deep lead. On the lid an instruction sheet pasted to the inside.
The instrument exists of a clear tube mounted inside a brass housing. The housing is fixed on a lanyard. The top end of the lanyard will be fixed to a sling and with the lead on the other side it will be dropped into the water.
Pressure forces water into the tube depending on the the depth. Back on deck the water column indicatest he depth to be read in meters and fathoms at the scale.

Catalog: NM.4-32
Date: 1900-1940
HWL case: 6,5×57,5×11,5 cm (2.5×22.5×4.5 in)
Signed: Sigurdsons Depth Recorder
Origin: Denmark
Condition: very good