Abraham Abraham was born about 1799 in Exetor, Devonshire and moved with his family the following year to Bath, Somersetshire.
Abraham's father was Jacob Abraham ( 1770 - 1845) who was also a manufacturer of optical and scientific instruments.
Abraham moved to Liverpool and opened an optician/ scientific business in 1817. In 1838 Abraham went into partnership with Simon Phineas Cohen which lasted until 1843.
There are several other records for partnerships and name changes that included A. Abraham and Co but I believe that this compass was made between 1817 to 1838.
This compass is in excellent condition, has a four and a half inch compass needle, and is hand engraved. The engraving has various differences in both the numbering and line etches.
I have never seen a compass as old as this with the ability to measure vertical angles. It may have been used as a mining compass and may have been used in field surveying, as all title distances shown on plans relate to the horizontal plane.
The base plate on this compass is very thick at 7.5 mm.
In comparison the base plates for other mounted compasses in my collection measure as follows:
The large Gurley Compass at 5.3 mm
The Shaw Compass at 4.5 mm
The Gurley Compass with Sighter 5.8 mm
This compass is a great find !!