Milton Lockhart, the seat of - Lockhart, Esq., M.P., brother to the celebrated editor of the Quarterly Review, is a very old place, celebrated in Old Mortality as the residence of Claverhouse. A new house, by Burns, in his peculiar combination of the old Scotch, or Belgian, style and the Tudor Gothic, is just finished. It stands on a prominent point of a peninsula formed by a remarkable turn of the Clyde; which, after washing the base of the bank on which the house stands, darts away from it across the valley, and, after a course of, we should suppose, above a mile, returns to another bank near the house, enclosing, as it were in a loop, a beautiful piece of meadow scenery, fringed with trees on the banks of the river. We confess, however, that our recollections of these features are insufficient to do them justice. The approach to the house is over the Clyde, on a lofty bridge of a single arch built by Mr. Lockhart; and the steep banks between the river and the house have been begun to be laid out in terrace gardens, which, when completed, promise to have an admirable effect. At present, nothing is finished but the house; and all the ground work is at a stand-still, and likely to be so for some time, on account of electioneering expenses. We went over every part of the house, from the cellars to the garrets, and found in it everything which a villa, or rather a mansion, ought to contain, though on a small scale. When Milton Lockhart is finished, it will be a residence of great beauty and variety, from the contrast of the architectural gardens at the house, with the romantic windings and picturesque banks of the river, and the wooded hilly scenery which extends on every side. The greatest drawback to its beauty at present is the curved line of the approach, which ought to be conducted in one straight line from the bridge to the entrance court of the house. Such a straight horizontal line is wanted to balance the innumerable curved and broken lines which form the natural characteristic of the locality. In the flower-garden we found a collection of sweet-williams which surpassed in beauty every thing of the kind that we had before seen. The gardener had been collecting them for several years.