or Dark Chamber, in Optics, a machine, or apparatus, representing an artificial eye; whereon the images of external objects, received through a double convex glass, are exhibited distinctly, and in their native colours, on a white matter placed within the machine, in the focus of the glass.

The first invention of this instrument is ascribed to Baptista Porta. See his Magia Naturalis, lib. xvii. cap. 6. first published at Frankfort about the year 1580 or 1591; the first four books of this work were published at Antwerp in 1560.

The camera obscura affords very diverting spectacles; both by exhibiting images perfectly like their objects, and each clothed in their native colours; and by expressing, at the same time, all their motions; which latter no other can imitate. By means of this instrument, a person unacquainted with designing will be able to delineate objects with the greatest accuracy and justness, and another well versed in painting will find many things herein to perfect his art. See the construction under Dioptrics.

CAMERARIA.