Crossing Battersea Bridge, in the neighborhood of Chelsea, I remember seeing a distant gleam of the Crystal Palace, glimmering afar in the afternoon sunshine like an imaginary structure,--an air-castle by chance descended upon earth, and resting there one instant before it vanished, as we sometimes see a soap-bubble touch unharmed on the carpet,--a thing of only momentary visibility and no substance, destined to be overburdened and crushed down by the first cloud-shadow that might fall upon that spot. Even as I looked, it disappeared. Shall I attempt 'a picture of this exhalation of modern ingenuity, or what else shall I try to paint? Everything in London and its vicinity has been depleted innumerable times, but never once translated into intelligible images; it is an "old, old story," never yet told, nor to be told. While writing these reminiscences, I am continually impressed with the futility of the effort to give any creative truth to my sketch, so that it might produce such pictures in the reader's mind as would cause the original scenes to appear familiar when afterwards beheld. Nor have other writers often been more successful in representing definite objects prophetically to my own mind. In truth, I believe that the chief delight and advantage of this kind of literature is not for any real information that it supplies to untravelled people, but for reviving the recollections and reawakening the emotions of persons already acquainted with the scenes described. Thus I found an exquisite pleasure, the other day, in reading Mr. Tuckerman's "Month in England,"--a fine example of the way in which a refined and cultivated American looks at the Old Country, the things that he naturally seeks there, and the modes of feeling and reflection which they excite. Correct outlines avail little or nothing, though truth of coloring may be somewhat more efficacious. Impressions, however, states of mind produced by interesting and remarkable objects, these, if truthfully and vividly recorded, may work a genuine effect, and, though but the result of what we see, go farther towards representing the actual scene than any direct effort to paint it. Give the emotions that cluster about it, and, without being able to analyze the spell by which it is summoned up, you get something like a simulachre of the object in the midst of them. From some of the above reflections I draw the comfortable inference, that, the longer and better known a thing may be, so much the more eligible is it as the subject of a descriptive sketch.