"Educational Concave Mirror, Good Signature"
By Ducretet and Roger, late 19th century, early 20th century Physical device for the study of light rays. Telescopic and adjustable. Height with the print as in the photos: 50 cm. Diameter of the mirror with its wooden setting: approximately 18.5 cm. (other devices by Ducretet are currently available, contact me) 
Le Magazine de PROANTIC
TRÉSORS Magazine
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