Accession No

2663

Brief Description

artificial horizon, by L. Casella, English, 1870 (c)

Origin

England; London

Maker

L. Casella

Class

navigation

Earliest Date

1870

Latest Date

1870

Inscription Date

Material

glass; metal (oxidised brass); wood

Dimensions

box length 180mm; breadth 139mm; height 53mm

Special Collection

Provenance

Inscription

‘L. CASELLA, Maker to the Admiralty & Ordnance, LONDON’
‘No. 87’

Description Notes

Artificial horizon consisting of rectangular polished black glass plate (one corner broken) held by 3 clips in cast oxidised brass mount with 3 levelling screws. Separated bubble level in oxidised brass mount. Fitted wooden box.

References

Events

Description
Artificial horizon
An artificial horizon can be used in darkness, fog, or when the real horizon is obscured for any other reason. They were often used in conjunction with other instruments that need a horizontal level, such as a sextant or reflecting circle. There are records of use from the mid 16th century onwards.

The 2 basic types of artificial horizon were mercury with a glass cover – the top layer of the mercury always staying level (this type is not very practical for use on a ship) and bubble levels, where the position of bubbles in a liquid shows which way the axis is tilting.

18/10/2002
Created by: Saffron Clackson on 18/10/2002

FM:44457