"Thomas Greenough, Sr. was born in Boston, Massachusetts in 1710 and died there in 1785.  Thomas Greenough, Jr. was born in Boston in 1738 and died there in 1775."

Note:  We are unsure whether Thomas Greenough, Sr. or his son, Thomas Jr., was the craftsman of the pictured compass.

Reference:  Smart, Charles E.  The Makers Of Surveying Instruments In America Since 1700  Troy, New York:  Regal Art Press.  1962