On Monday we left Edale, and a beautiful drive we had along the banks of the Derwent, woody and rocky, and wild enough in some places to be thought a river of our own country. Of our visit to Chatsworth, the seat of the Duke of Devonshire, one of the proudest of the modern English nobility, and to Haddon Hall, the finest specimen remaining of the residences of their ancestors, I will say nothing, for these have already been described till people are tired of reading them. We passed the night at Matlock in sight of the rock called the High Tor. In the hot season it swarms with cockneys, and to gratify their taste, the place, beautiful as it is with precipices and woods, has been spoiled by mock ruins and fantastic names. There is a piece of scene-painting, for example, placed conspicuously among the trees on the hill-side, representing an ancient tower, and another representing an old church. One place of retreat is called the Romantic Rocks, and another the Lover's Walk. To-day we arrived at Derby, and hastened to see its Arboretum. This is an inclosure of eleven acres, given by the late Mr. Josiah Strutt to the town, and beautifully laid out by London, author of the work on Rural Architecture. It is planted with every kind of tree and shrub which will grow in the open air of this climate, and opened to the public for a perpetual place of resort. Shall we never see an example of the like munificence in New York? Letter XX. Works of Art. London, _June_ 18, 1845. I have now been in London a fortnight. Of course you will not expect me to give you what you will find in the guide-books and the "Pictures of London." The town is yet talking of a statue of a Greek slave, by our countryman Powers, which was to be seen a few days since at a print-shop in Pall Mall. I went to look at it. The statue represents a Greek girl exposed naked for sale in the slave-market. Her hands are fettered, the drapery of her nation lies at her feet, and she is shrinking from the public gaze. I looked at it with surprise and delight; I was dazzled with the soft fullness of the outlines, the grace of the attitude, the noble, yet sad expression of the countenance, and the exquisite perfection of the workmanship. I could not help acknowledging a certain literal truth in the expression of Byron, concerning a beautiful statue, that it "——fills The air around with beauty."