Age:  c1845
Made by: C.A. & H. Spencer Co
Made in: Canastota, NY, USA
This microscope is a Spencer Trunnion Microscope made c1845 by Charles Achilles Spencer (1813-1881). The Spencer optical company has a celebrated history. Charles had his first optics workshop in New York starting in 1838, and soon after was joined by his cousin Hamilton to make microscopes and other optical devices under the name "C. A. & H. Spencer". Spencer microscopes from this era are the earliest microscopes made in the US, and also the first microscopes equipped with achromatic objectives made in the US. This instrument in the Golub Collection is a fine example of of one of Spencer's very early Trunnion microscopes.

In 1854 EK Eaton joined Charles and the new firm continued making optical instruments, but now under the name of "Spencer & Eaton". This partnership lasted until c1865 when Eaton left the firm and Charles' son, Herbert joined his father to form "CA Spencer & Sons". This firm moved to Geneva NY in 1875 and began making microscopes for the Geneva Optical Company. Between 1875 and 1877 the firm made microscopes under the name "CA Spencer & Sons for Geneva Optical Company". This association lasted only three years, at which time the firm changed names again, this time to "CA Spencer & Sons, Geneva". Herbert continued to make instruments well after Charles died (1881). He moved the firm to Buffalo in 1890, and in 1895 he changed the name of this firm to the Spencer Lens Co. That firm lasted until 1935 when it was purchased by the American Optical Company ("AO").

This microscope is all brass monocular compound microscope with a claw-foot. It has one bayonette-mounted objective and a camera lucida mirror attached to the body tube. Focus is via rack & pinion (coarse) and long-arm (fine). The microscope body is supported by two large trunnions (thus the name) with a compass joint connecting the main support pillar, allowing it to tilt fully horizontal. The sample stage is mounted to a large block that contains the triangular upper support and circular mirror support below. Coarse focus is via rack & pinion with two control knobs. Bolted to the top of the triangular pillar is the "long arm" fine focus consisting of a control knob at one end and the moveable objective mount at the other. The body tube screws onto the end of the arm. The optics consist of an achromatic objective labeled "Uncov'd", a field lens mounted inside the tube, and an eye lens. The illuminating mirror has two reflective surfaces, both parabolic. There is a focusing condenser mount below the stage, but the condenser is missing. A camera lucida is the only accessory remaining with this instrument. The body tube is engraved "C. A. & H. Spencer, Canastota, NY". Height c45cm.

Thanks go to Ms. AG Riley Maxon for her help with the photography.

Microscope featured 01/2017

C.A. & H. Spencer Trunnion Microscope, No. 304