“Common paintings and prints may be considered as parts of a panoramic representation, showing as much of that general field of view which always surrounds a spectator, as can be seen by the eye turned in one direction, and looking through a window or other opening.  The pleasure from contemplating these is much increased by using a lens.  There is such a lens fitted up in the shops, with the title of optical pillar machine, or diagonal mirror, and the print to be viewed is laid upon a table beyond the stand of the lens, and its reflection in a mirror supported diagonally over it, is viewed through the lens.  The illusion is rendered more complete in such a case by having a box to receive the painting on its bottom, and where the lens and mirror, fixed in a smaller box above, are made to slide up and down in their place to allow of readily adjusting the focal distance.  This box used in a reverse way becomes a perfect camera obscura.  The common show-stalls seen in the streets are boxes made somewhat on this principle, but without the mirror; and although the drawings or prints in them are generally very coarse, they are not uninteresting.  To children whose eyes are not yet very critical, some of these show boxes afford an exceeding great treat.”

Cosmoramas and Dioramas.

“A still more perfect contrivance of the same kind has been exhibited for some time in London and Paris under the title of Cosmorama (from Greek words signifying views of the world, because of the great variety of views.) Pictures of moderate size are placed beyond what have the appearance of common windows, but of which the panes are really large convex lenses fitted to correct the errors of appearance which the nearness of the pictures would else produce.  Then by farther using various subordinate contrivances, calculated to aid and heighten the effects, even shrewd judges have been led to suppose the small pictures behind the glasses to be very large pictures, while all others have let their eyes dwell upon them with admiration, as magical realizations of the natural scenes and objects.  Because this contrivance is cheap and simple, many persons affect to despise it; but they do not thereby show their wisdom; for to have made so perfect a representation of objects, is one of the most sublime triumphs of art, whether we regard the pictures drawn in such true perspective and colouring, or the lenses which assist the eye in examining them.

“It has already been stated, that the effect of such glasses in looking at near pictures, is obtainable in a considerable degree without a glass, by making the pictures very large and placing them at a corresponding distance.  The rule of proportion in such a case is, that a picture of one foot square at one foot distance from the eye, appears as large as a picture of sixty feet square at sixty feet distance.  The exhibition called the Diorama is merely a large painting prepared in accordance with the principle now explained.  In principle it has no advantage over the cosmorama or the show box, to compensate for the great expense incurred, but that many persons may stand before it at a time, all very near the true point of sight, and deriving the pleasure of sympathy in their admiration of it, while no slight motion of the spectator can make the eye lose its point of view.”