Nautical instruments

This part of the collection includes mainly navigational instruments from the early sailing period, the time when ships were made of wood and men were made of steel.

An early and interesting three mirror octant with Vernier nonius, made by or for S. Williams at Hull in 1767.

The first octant was created by Hadley in 1731. In Great-Britain and North-America the instrument was called the Hadley’s quadrant to distinguish it from the Davis quadrant. Hadley got in 1734 a patent for eleven years. Immediately after it came to an end other instrumentmakers started with making octants.
This octant is an early ebony one. The graduated scale is made of ivory with a Vernier nonius. The engraving is made by hand. At the graduation every degree is divided in parts of 20 minutes. The Vernier nonius is divided in twenty equal parts. The accuracy of reading with this nonius is one minute.
The lower horizon mirror and peepsight were used for backward observation. As the horizon just below the sun was invisible, in this way it was possible to use the opposite horizon. The instrument was used back to front. The observer had the sun in his back. The sunshades moved to the lower position.

This beautiful instrument with nice patin, is complete and in a fine condition, with three mirrors, two peep sights and three sunshades. On the backside three brass legs and the adjusting-screws.
The mirror table of this octant is also made of ebony. Octants of a later date have brass ones. The nonius does not have a double scale anymore but still has the width of a double scale.

Catalog: NM.2-44
Date: 1767
HW: 45,5×38,5 cm (18×15 in)
Radius (rotation axis till nonius): 39,5 cm (15.5 in)
Signed: * S. Williams Hull 1767 *
Origin: England
Condition: very well

On the log, behind a rotary slide there are three dials, the first registers the miles up to 100, the second registers the units up to 10 mile, the third registers quarters of a mile.
On the enamel scale: NEW YACHT LOG – ORIGINAL LLL TRADEMARK – EDWd. MASSEY, LONDON – PATENTEE
In the four rotator blades is stamped a star shaped motif with the letter M.

The log is a scaled down version of the fritionless log which was introduced in 1865. A start date of manufacturing of this yacht log is unknown, but a similar sized and shaped log, called the Conical End Log was being advertised in the Wilson 1877 catalogue. (Distance Run p120).
In Yachtsman Manual of 1874 this log was adverised for a price three pounds.

From the 17th century onwards people had made many attempts to devise a mechanical log which would automatically record the ships distance done. Edward Massey invented a mechanical log in 1802 with four blades which was used by the Admiralty from 1807-1815. As the rotator was dragged behind the ship then the log rotated and the revolutions were transformed in miles on the dials, to be read after the rotator was brought on deck.
The design of Massey was further refined by Thomas Walker and Son, including the stabilizer. Walker took out a patent for the A1 Harpoon Log in 1861.

Catalog: NM.2-33
Date: 1870-1900
L: 40 cm (15,7”)
Signed: EDWd MASSEY and insciption of the trader, F.M. Moore Ltd, Belfast
Origin: England
Condition: excellent