the re-elaboration that takes place in the brain supplies an image with the perception of reliefs and depths and with a three-dimensional effect that is such that one has the sensation of observing the real object, landscape or scene.
The exemplar presented here consists of a black-lacquered brass binocular with the characteristic focusing knob in the centre fixed on the smaller end (height cm, width 14 cm) of a polished mohogany box in the form of a truncated pyramid 8 cm in height.
The larger end (height 10 cm, width 17 cm) is closed with a plate of opaque glass against which the frame, usually pasteboard, with the two side-by-side images of the object to be observed is placed.
A trapezoidal mirror (8.5 cm and 10 cm) hinged to the top of the wooden box illuminates the object to be observed by reflection when it is opaque.
The overall length of the instrument is 15 cm. ...continues