28 sec Brass Log-glass

Brass Log glass 28 sec used in Royal Navy

Type of object:

Timekeeper & Sundial & Compass & Barograpf

Time period:

Britain rules the waves + France

Place:

possibly Porthmouth

Date:

1800

Maker / Author:

Not Known

Publisher / Printer:

idem

Dimensions:

8.3 cm high, 3.1 cm diameter

Material:

Brass and Glass . san

Graduation:

28 seconds

Inscription:

28 sec

Provenance:

England: F. Clemens bought it from a friend who bought it from an English marine officer whose family was serving at the Royal Navy since 18 th century at Porthmouth

References:

See full item list

Description

Hourglass, Glass and Brass, used as Log-glass with 28 sec duration. Opening Orange collared Silicate. 3 pieces of brass and glass bulbs with opening. This opening was close with paper tape with the inscriptions of 28 sec.
This type of hourglasses was used with the classic shiplog, to measure the speed of a ship 'in knots'.