"Jonathan T. Hobby was born in New Rochelle, New York on July 6, 1813.  He died in Hempstead Long Island, New York on August 1, 1883.  New York City Directories:  1840-41 Hobby, Jonathan T., math ins. 156 Water  h. 258 Delancy; 1853-54 Hobby, Jonathan T., surv. inst. 156 Water  h. 105 Schermerhorn, Brooklyn.  From 1840 to 1854 he is a partner of Sawyer & Hobby 156 Water.  1855 Hobby, Jonathan T., mth inst. 156 Water  h. 114 State, Brooklyn.  1862 the same but house Hempstead, Long Island.  Hobby is listed until 1869 at 146 Water Street as a supplier of instruments under one of the above descriptions.  There is no record of him in 1870 in the New York City Directories.  Curtains Directory of Long Island, Hempstead, N. Y.; 1867-68 Hobby, Jonathan, spyglasses, h. Joraleman n. Henry.  Long Island Directory, 1872-73 Hobby. Jonathan T. math. inst. mkr. Hempstead, h. Greenwich.  From 1865 to 1921 Gurley serviced 11 Transits, 2 Levels and 4 Compasses made by Hobby."

 

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