The M'Kay Compass is a Very Nice Example of a Fourth Design GC Compass

Fourth Design - Counters (Poles/Miles), the later W” for WEST designations, Added L-T Tables
Early 1800s to 1821 (When GC Died)

To date GC Compasses with Counters, I look for 3 things:

1. What the W's look like.
2. Whether the Compass has a L - T table (L is for Links, T for Tenths).
3. Whether the Compass features an Eagle.

ALL of the compasses that GC made after 1804 include L - T tables and the later style "W".

The Key Compass from a dating perspective is the McKay Compass (GC 21). The McKay Compass is a Fourth Design compass - it has the later W design AND a L - T table. GC and McKay were close friends, and McKay died in 1804. Thus, we know for sure that the Second and Third Design compasses were done by 1804.

A collector who visited my website sent me a pic of his GC compass - Grayson (7a). This compass is unique - it features the early“W” for WEST designations AND has an L-T Table. I suspect that the late 1790s and early 1800s was a transitional time for GC in terms of his compass-making. And the Grayson compass might have a story - the compass mainplate might be engraved at a different time, for example.