We will turn now to a sketch of a different kind. In the ‘Edinburgh,’ ‘Heysham’ and ‘Hornby’ sketches, as in most of those we have examined, we have seen Turner making a note of what we may call the chief items of the topographical data, leaving the problem of their arrangement, modification and amplification for future solution. In the two sketches of Rochester (Plates LXII. (_a_) and (_b_)) which I have had reproduced, we see the artist’s mind moving on a different track. A few pages earlier in the sketch-book from which these two leaves are taken, he has indeed made his usual record of the facts about the church, bridge, etc., at Rochester, but apparently, as time did not press, he remained in his boat watching the scene and criticising, as one who understood such things, nature’s own methods of design. His sketches now become not topographical records but swift and eloquent designs for pictures. The concrete particularity of the castle, church, bridge, etc., becomes abrogated or submerged. These objects are now taken up into a new kind of systematic unity, in which their relationship to the whole and to each other is of much more importance than their discrete individuality. Now, the important point is just how the Castle and the other topographical items drop into place with regard to the shipping on the river,--the kind of groups they all make, the way the one item affects the other, half hiding it or setting it off to advantage. In the sketch on page 18 of the sketch-book (Plate LXII. (_a_)) the exact position of the mast of the foreground vessel is the dominant factor,--the way it unites the lines described by the silhouette of the castle and the trees sloping down to the bridge, bringing the [Illustration: _PLATE LXII_ ROCHESTER PENCIL. ABOUT 1821] [Illustration: ROCHESTER PENCIL. ABOUT 1821] [Illustration: _PLATE LXIII_ ROCHESTER. ON THE RIVER MEDWAY WATER COLOUR. ABOUT 1822] curves to a focus, as it were, and providing a rigid base for them to spring from again. In the other sketch (Plate LXII. (_b_)) Turner is trying a different arrangement of the material, or, to put it more accurately, nature is trying another effect, and Turner is watching and making notes of the experiment.