WW1 British Military Issued Angle of Sight Instrument H.A. Mk1 – Compass Clinometer dated 1915 with Leather Case

Here on offer is a fine example of a WW1 British Military Issued, Angle of Sight Instrument H.A. Mk1 – Compass Clinometer, dated 1915 with its original leather case.

This instrument was patented jointly by J. C. Asten and Francis Barker & Son Ltd in 1909 as the 'Patent Combined Altitude Instrument and Prismatic Compass'.

Dating from 1915, this example is in excellent condition, featuring a blackened or oxidised finish brass case with green compass card and white clinometer scale card. The glass windows, prism, sights, and both compass and clinometer cards are in excellent condition.

It seems to be in full working order and finds North very well.

It is engraved on the top with:

ANGLE OF SIGHT INSTRUMENT

H.A. MK 1

Military “Broad Arrow”

No.58

J.H. STEWARD

406 STRAND

LONDON

1915



It comes with a felt lined, brown leather compass case and strap, that is stamped on the front with:

ANGLE OF SIGHT INSTRUMENT

H.A. MK 1

J.H. STEWARD Ltd

1916

Military “Broad Arrow”

214

As it bears the British War Office “broad arrow” stamp, it was military issued, rather than an officer's private purchase item.

During WW1 and WW2 this type of compass was used for artillery work. It is hard to find a genuine WW1 example, especially in this condition.

This instrument actually combines the functions of a prismatic aiming compass with that of a clinometer/Abney level.

When stood upright the clinometer can be disengaged allowing vertical angles to be measured on the white scale.
When the sights are also released a vertical angle can be sighted as with the service pattern clinometer. The clinometer scale can be locked for convenient reading. If the large visor is raised the compass card is also unlocked.

To read the compass, the clinometer card must be rotated out of the way by holding the device upside down. This will show the green compass card which can be read using the prism.


A brief history of J.H. Steward

J. H. Steward Ltd: James Henry Steward (1817-1896) established his business in London in 1852 as a maker and retailer of optical, scientific, military and surveying instruments. J.H. Steward was the head optician of the company and had businesses at 406 Strand, 457 West Strand and 54 Cornhill in London. In the mid 1800s he became the optician to Her Majesty's Government and the National Rifle, and National Artillery Associations. James Henry Steward died in 1896. J. H. Steward Ltd was incorporated in 1912 and continued in business in London until 1973. The main London office was sold in 1971, and from 1971-1973 the company rented premises in Catherine Street. All the remaining stock and long serving staff member George Goble (c.1916-1975) were moved to Catherine Street. The business finally moved to 154a Church Road, Hove, Sussex in 1973, before finally ceasing trading in 1975.


The instrument itself measures 2.9” (7.5cm) diameter (excluding the prism) and in the case, weighs 420g.


Please see my pictures for the details of the condition, which complement this description.

Please see my TERMS OF BUSINESS regarding Delivery Charges and Insurance regarding additional insurance cover, should you require it, BEFORE the item is dispatched.

The responsibility lies with the customer to check with your Customs restrictions that this item can be imported into your country.

Code: 51099