William J. Young (1800-1870) was raised in Philadelphia. In 1830, William J. Young applied for a patent on an "Improved Surveying Compass" designed to measure horizontal angles either with or without reference to magnetic north. Young’s design proved to be especially useful for railroad surveys, and most examples were sold for that purpose.  
This c1840 compass is about 14 ¼” long with a 6” diameter center and an 8 ¾” height when assembled. It is marked, “W. J. Young Maker Philadelphia Patent.” It was found in a, probably original, wooden fitted case with a period plumb bob. It is in good used condition overall. The compass works but I cannot guarantee accuracy. The brass shows a good patina of tarnish, marks, stains and small dents. There is a tiny chip on the glass edge. The veins or sites have old “make do” repairs (see photos).  
The case is sturdy and shows an old patina on the surface with a worn leather strap. 
Please look at the photographs as they are considered part of the description.
I guarantee it to be old and as described. 
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