One of the phantasmagoric conceptions of my friend, partaking not so rigidly of the spirit of abstraction, may be shadowed forth, although feebly, in words. A small picture presented the interior of an immensely long and rectangular vault or tunnel, with low walls, smooth, white, and without interruption or device. Certain accessory points of the design served well to convey the idea that this excavation lay at an exceeding depth below the surface of the earth. No outlet was observed in any portion of its vast extent,