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