"Thomas Whitney advertised in the Federal Gazette of April 12, 1798, as from London, and 'moved from 72 (late Mr. Gould's) to No. 74 South Front Street where he makes various instruments in the most approved manner.'   Whitney did not depend solely on the sale of instruments for his income.  Bunting by the piece was sold, writing slates and razors, silversmith's anvils and files; pen-knives and sailor's pocket knives, scissors and bone moulds - whatever they many be - could all be purchased at the shop of Thomas Whitney from London."

"Thomas Whitney is listed in the Philadelphia, Pennsylvania directories from 1802 to 1824 as a mathematical instrument maker, although the Gurley company has repaired a compass marked, "Thos. Whitney, Phila 1828."

William James Young at the age of 15 or 16 was indentured as an apprentice to Thomas Whitney for a period of seven years.

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