This Rev.War surveyor's semi-circumfentor was part of the Wm. Guthman's collection(Antique Road show). The original auction tag will be included. It was carried by Pvt. Henry Oliver during the Revolution. He originally joined the 1st Mass. Regt. in 1776 but switched to Capt Jordan Parker's Artillery Co. under Col. Samuel McCobb's Mass.Regt. in 1777 where he served out the War until 1783. I imagine this instument would have come in handy for a Artilleryman. The face of the instrument has an old paper attached stating "Henry Oliver 1775 loaned by M.C. Percival" . I would assume that this was on loan to a museum at one time. Also , it's signed on the back in old ink" Henry Oliver 1775 ". A really neat piece of history from a well respected collection.