With no less interest will the schoolboy gaze on the forms of insect life, which will almost flutter before him, and on the tenants of the air and of the ocean, defective only in the colours which adorn them. The structures of the inorganic world will equally command his admiration. The minerals which have grown in the earth beneath his feet, and the crystals which chemistry has conjured into being, will display to him their geometric forms, infinite in variety, and interesting from their rarity and value. Painted by the very light which streamed from them, he will see, in their retiring and advancing facets, the Kohinoor and other diamonds, and the huge rubies, and sapphires, and emeralds, which have adorned the chaplet of beauty, or sparkled in the diadem of kings. The gigantic productions of the earth will appeal to him with equal power,—the colossal granites, which have travelled in chariots of ice, and the rounded boulders, which have been transported in torrents of mud; and while he admires, in their strong relief, the precipices of ancient lava—the Doric colonnades of basalt—the upheaved and contorted strata beside them, and the undisturbed beds which no internal convulsions have shaken, he will stand appalled before the fossil giants of the primeval world that trod the earth during its preparation for man, and have been embalmed in stone to instruct and to humble him. In acquiring a knowledge of physical geography, in which the grander aspects of nature arrest our attention, their stereoscopic representations will be particularly instructive. The mountain range, whether abrupt in its elevation, or retiring from our view,—whether scarred with peaks or undulating in outline,—the insulated mountain tipped with snow or glowing with fire,—the volcano ejecting its burning missiles,[67]—the iceberg fixed in the shore, or floating on the deep,—the deafening cataract,—the glacier and its moraines, sinking gently to the plains,—and even the colossal wave with its foaming crest, will be portrayed in the binocular camera, and exhibited in all the grandeur and life of nature. [67] An accomplished traveller, the Rev. Mr. Bridges, who ascended Mount Etna for the purpose of taking Talbotype drawings of its scenery, placed his camera on the edge of the crater to obtain a representation of it. No sooner was the camera fixed and the sensitive paper introduced, than an eruption took place, which forced Mr. Bridges to quit his camera in order to save his life. When the eruption closed, he returned to collect the fragments of his instrument, when, to his great surprise and delight, he found that his camera was not only uninjured, but contained a picture of the crater and its eruption.