NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Bill Morris
Date: 2019 Apr 9, 21:48 -0700
Hello, Richard, and welcome.
George Lee and Son were active between 1850 and 1900, and appear in a trade directory of Hampshire for 1878, so your guess for the sextant's age is probably not too far off mark. At least in later sextants, Troughton and Simms numbered their sextants at the top of the middle of the limb in a rather tiny font, so have a look there with a hand lens in a good light. You should then try the left hand end of the arc. To clean the arc dip your finger in a 50% solution of houehold ammonia and rub it on the silver tosafely remove the tarnish. It will clean your finger too! If you have a steady hand you can use fine abrasive paper (800 grit) on the brass of the limb, but keep it away from the silver arc.
Bill Morris
Pukenui
New Zealand (www.sextantbook.com and www.chronometerboook.com)