J.T. Hobby surveying transit
The compass face is decorated with a 2" diameter floral ring in the center and is engraved in script "J.T. Hobby, Hempstead, L.I.". The compass needle is 5" long and the compass is 6" in diameter, the upper plate is 7 3/4" in diameter. The two vernier scales are marked "A" and "B".
The 10" telescope has a rack focusing knob on the side of the tube for focusing the object and a draw tube focus of the eyepiece. The cross hairs are present and in good condition. A 5 1/2" bubble vial is mounted under the telescope. A 3 1/2" bubble vial is mounted on the plate and a 3 1/4" vial is mounted on the standard, just under the tangent screw. There is a spring opposed axis tangent and a decorative heart shaped locking screw. The spindle tangent mount has an old repair. The circle is engraved from 0-360 and also from 0-90 degrees in either direction. The 4 screw leveling base is decorated with 4 knurled bands and fitted with a screw eye for attaching a plumb bob (this screw is removed in the photos so the base would rest flat on the table). The instrument is uncleaned, with a dark patina. However, it likely originally had a blackened brass finish, long since gone. The original box with hand dovetailed joints is lacking its door and the slide out wood base is broken.
Jonathan T. Hobby began work in 1840, in partnership with Horace Sawyer. His earlier instruments are marked "New York", while those marked "Hempstead, L.I." were made from 1869 to 1873, when he worked on Long Island. He apparently closed his business in 1873 and died in 1883. Instruments by J.T. Hobby are uncommon.
the transit - side view
the vernier scale
the spindle tangent
another view, including the needle arrester knob
the leveling base and decorative locking screw
bottom view (note the old repair to the tangent screw mount)
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