The partnership of Sawyer & Hobby operated in New York City from 1840 to 1854.  The two partners were Horace Sawyer and Jonathan T. Hobby.  Horace Sawyer was born in Bolton, Massachusetts in 1811 and died in 1889.  Jonathan T. Hobby was born in New Rochelle, New York in 1813 and died in 1883.

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