The Colosseum.

“A round building of prodigious magnitude has lately been erected in the Regent’s Park, in London, on the walls of which is painted a representation of London and the country around, as seen from the cross on the top of St. Paul’s Cathedral.  The scene taken altogether is unquestionably one of the most extraordinary which the whole world affords, and this representation combines the advantages of the circular view of the panorama, the size and distance of the great diorama, and of the details being so minutely painted, that distant objects may be examined by a telescope or opera-glass.

“From what has now been said, it may be understood, that for the purpose of representing still-nature, or mere momentary states of objects in motion, a picture truly drawn, truly coloured, and which is either very large to correct the divergence of light and convergence of visual axes, or if small, as viewed through a glass, would affect the retina exactly as the realities.  But the desideratum still remained of being able to paint motion.  Now this too has been recently accomplished, and in many cases with singular felicity, by making the picture transparent, and throwing lights and shadows upon it from behind.  In the exhibitions of the diorama and cosmorama there have been represented with admirable truth and beauty such phenomena as—­the sun-beams occasionally interrupted by passing clouds, and occasionally darting through the windows of a cathedral and illuminating the objects in its venerable interior—­the rising and disappearing of mist over a beautiful landscape, runningwater, as for instance the cascades among the sublime precipices of Mount St. Gothard in Switzerland;—­and most surprising of all, a fire or conflagration.  In the cosmorama of Regent-street, the great fire of Edinburgh was admirably represented:—­first that fine city was seen sleeping in darkness while the fire began, then the conflagration grew and lighted up the sky, and soon at short intervals, as the wind increased, or as roofs fell in, there were bursts of flame towering to heaven, and vividly reflected from every wall or spire which caught the direct light—­then the clouds of smoke were seen rising in rapid succession and sailing northward upon the wind, until they disappeared in the womb of distant darkness.  No one can have viewed that appalling scene with indifference, and the impression left by the representation, on those who knew the city, can scarcely have been weaker than that left on those who saw the reality.  The mechanism for producing such effects is very simple; but spectators, that they may fully enjoy them, need not particularly inquire about it.”

Even for the present we cannot omit mention of the delight with which we have read several of the more playful portions of the present work; we allude to such passages as the Influence of Heat on Animated Beings, in which Dr. Arnott has really blended the pencil of the artist with the pen of the philosopher, and thus produced many sketches of extreme picturesque beauty.