Diagram for reading time from latitude?

ID:	ZBA1710
Collection:	Astronomical and navigational instruments
Type:	Diagram for reading time from latitude?
Display location:	Not on display
Creator:	Unknown
Date made:	Unknown
Credit:	P&D. National Maritime Museum, Greenwich, London, RGO Collection
Parts:	Diagram for reading time from latitude? Diagram for reading time from latitude? (ZBA1710.1) Diagram for reading time from latitude? (ZBA1710.2) Diagram for reading time from latitude? (ZBA1710.3)