Tom Tennent was born 1822 in Pennsylvania (probably Philadelphia) and at the age of 13 was apprenticed to William J. Young.  He completed his apprenticeship in October 1843.  He lived in Newburyport, Massachusetts from 1845-1848, then in 1849 he headed out west where he briefly prospected for gold.  By 1856 he had established Surveying and Navigation Warehouse which continued to his death in the early 1900s.  Known instruments bearing his name are a William J. Young compass with the signature "Tom Tennent" on the underside of the circular level housing, one or two other compasses, and a protractor marked "Thos. Tennent Newburyport"