AO Delineascope auditorium slide projector
Date: circa 1945
Inventory Number: WJ1129
Classification: Slide Projector
Dimensions:slide projector: 24 x 73 x 20 cm (9 7/16 x 28 3/4 x 7 7/8 in.)
case: 20 x 24 x 73 cm (7 7/8 x 9 7/16 x 28 3/4 in.)
Accessories: slide holders (3); alternate lenses (2); lantern slides (2)
Bibliography:Spencer Scientific Instruments
DescriptionThis glass slide projector is stored in maroon rectangular steel box, which is held shut with a thick strap and buckle. The slide projector is of the same color. The paint is a crackle finish. It is from the Delineascope family of projectors. Non-sagging bellows (to adjust image focus) is supported by double extension rods, moved by a rack and pinion system. There is also a cooling system against the heat of the light to protect the slides. The cooling fan has a rheostat to control the speed of the when operating on other than 60 cycle A.C. There is a handle on the top front of the projector. Elevating legs are located on the front. Handle support on the rear allows for inclining the projector when operating from a balcony position.
It has two glass lantern slides in one of the slide carriers. One shows music; the other is an illustration of the German composer and musicographer Michael Praetorius (1571-1621).
The price range for this instrument in 1946 was between $175 to $229.50, depending on the objective dimension. This one here was $175 with 2½" x 12" and 2½" x 16" objectives.
Signedon plate, back: American Optical Company
on plate, side: AO / SPENCER
on objective: AO 12
on objective: AO 16
Inscribedhand-etched on case: MUSIC / Dept / HARVARD / University
label on top of instrument: MUSIC DEPT
on lamp: DGH / BASE DOWN / GE / 750 W 120V
FunctionThe 1946 trade catalogue mentions: "New brilliance, vividness, and realism have been brought to the projection screen by Model GK Auditorium Colorslide Delineascope. It is a 750 watt instrument and projects 2" x 2" or 3¼" x 4" slides."
"Clear, sharp definition and a flat field is secured with objectives 2½" in diameter." [...]
"Different condensing systems are used to direct the light efficiently through the small and large slides. Each condensing system is mounted in a container which may be lifted out as a unit and replaced by the other." [...]
"For large auditorium audiences the full brilliance of Model GK is appreciated. For smaller, intimate gatherings, illumination for slides of different density can be controlled with an iris diaphragm."
Primary SourcesAmerican Optical Company, Spencer. Scientific Instruments (Buffalo: American Optical Company, Scientific Instrument Division, [1946]), 186-188.
ProvenanceMusic Department, Harvard University.