"Jonas H. Phelps was born in Watervliet, New York on February 6, 1809.  He first appears in the Troy city Directory of 1833-34.  (The first Troy city directory was issued in 1829).  Phelps, James H. bell founder boards 45 Fifth.  In 1834-35 directory he is:  Phelps, Jonas H., bell founder, boards 56 State.  He is also listed as a bell founder through 1837.  During this period (1833-37) he was associated with Oscar Hanks at 28 Fifth Street.  It is quite possible that during the latter part of this time he was engaged in making mathematical instruments.  From 1838 through 1844, he had a small shop in the alley on the north side of Fulton Street, between River and Fourth Streets, which he continued to occupy until 1845.  In the spring of 1844, Lewis E. Gurley became an apprentice of Mr. Phelps, serving under him until February 25, 1845, when William Gurley, who had been a foreman with Oscar Hanks, was admitted as a partner.  The firm became Phelps & Gurley.  The need for more space and conveniences caused them to rent, on March 1, 1845, the three-story brick building, No. 319, on the west side of River Street, between Grand Division and Fulton Streets, where they continued manufacturing surveyor's compasses, theodolites, transits, leveling instruments, goniometers, air pumps, electrical machines and apparatus to illustrate principles of natural philosophy.  The foundry was in the basement of the building, the office and sales rooms were on the first floor, the work rooms were on the second and third floors.  Four workmen were employed, one of whom was Lewis E. Gurley.  The surveying instruments made by the firm the first year of partnership did not aggregate in value more than $1,000.00.  During the second year there was a greater demand for them, as well as the other mathematical and philosophical instruments made by the establishment.  In 1849, the business had increased so much, that to facilitate the manufacture of engineering and other instruments, the firm rented a part of the building occupied by Philo P. Stewart, on the west side of Mechanic Street, in the rear of the establishment, and there placed a small engine to move its improved machinery.  Lewis E. Gurley continued as a workman until the fall of 1847, when he entered Union College from which he graduated in June, 1851.  That same year he was admitted to partnership with Phelps and his brother William, and the firm name became Phelps & Gurleys.  On February 1, 1852, Mr. Phelps sold his interest in the partnership, and the firm became W. & L. E. Gurley.  Mr. Phelps moved to Westport, Connecticut, and there engaged in making surveying instruments.  He also designed and partially built a circular dividing engine, which is now in storage at the Gurley plant.  He died in Westport, August 20, 1865." 

"The following information was found in the 1850 U. S. Census 4th Ward:  Phelps & Gurley 319 River Street Capital invested $14,000.00.  Raw material value $3,000.00.  Employed 26 males.  Average monthly cost of male labor $676.  Value of math instruments produced $18,000.00. Employed in 1850, Gordon Hays; Lewis Heck; Augustus Kathrinus; Edward Pierson; Edward P. Searle (19) from Mass.; H. Emmons Thayer; Austin F. Park (25); Sydney W. Park (23); Jonas H. Phelps; Lewis E. Gurley; William Gurley.  1850 Troy Directory:  William, Lewis and Clarissa Gurley 31 Fifth b. 28 Fifth, Charles C. Hart, R. B. Freeman, Henry Phillips, John Traffer, Henry Wyatt.  28 Fifth Street was a boarding house in 1850."

"Extract from the W. & L. E. Gurley Order Book January 1860 to December 31, 1866:  Memo of offer made to John W. Taylor for the Dividing Engine of the late J. H. Phelps.  We will give "t as H s" payable in our notes equal amounts payable in 4, 6, and 9 months, without interest.  (On January 12, 1866 a draft for $250.00 was sent to J. W. Taylor Exc.  The other drafts were paid as they came due).  We are taking it at our risk after it leaves the building - We to pack and transport it at our expense, except such aid as we may receive from Mr. Henry Taylor which shall be furnished at your charge.  We will further agree to purchase all the Surveyors and Engineers Instruments, partially finished and in progress and pay the sum of two hundred and fifty dollars on our note at 6 months without interest.  We will send our Mr. Searle about the 12th of September to pack, and the work should be insured from now to the 18th of September if it is not already so insured.   (About August 25, 1865 in William Gurley's handwriting)."

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