All this difficulty, however, attaches to the rendering merely the dark form of the sprays as they come against the sky. Within those sprays, and in the heart of the tree, there is a complexity of a much more embarrassing kind; for nearly all leaves have some lustre, and all are more or less translucent (letting light through them); therefore, in any given leaf, besides the intricacies of its own proper shadows and foreshortenings, there are three series of circumstances which alter or hide its forms. First, shadows cast on it by other leaves, - often very forcibly. Secondly, light reflected from its lustrous surface, sometimes the blue of the sky, sometimes the white of clouds, or the sun itself flashing like a star. Thirdly, forms and shadows of other leaves, seen as darknesses through the translucent parts of the leaf; a most important element of foliage effect, but wholly neglected by landscape artists in general.

The consequence of all this is, that except now and then by chance, the form of a complete leaf is never seen; but a marvellous and quaint confusion, very definite, indeed, in its evidence of direction of growth, and unity of action, but wholly indefinable and inextricable, part by part, by any amount of patience. You cannot possibly work it out in facsimile, though you took a twelvemonth's time to a tree; and you must therefore try to discover some mode of execution which will more or less imitate, by its own variety and mystery, the variety and mystery of Nature, without absolute delineation of detail.

Now I have led you to this conclusion by observation of tree form only, because in that the thing to be proved is clearest. But no natural object exists which does not involve in some part or parts of it this inimitableness, this mystery of quantity, which needs peculiarity of handling and trick of touch to express it completely. If leaves are intricate, so is moss, so is foam, so is rock cleavage, so are fur and hair, and texture of drapery, and of clouds. And although methods and dexterities of handling are wholly useless if you have not gained first the thorough knowledge of the form of the thing; so that if you cannot draw a branch perfectly, then much less a tree; and if not a wreath of mist perfectly, much less a flock of clouds; and if not a single grass blade.Perfectly, much less a grass bank; yet having once got this power over decisive form, you may safely - and must, in order to perfection of work - carry out your knowledge by every aid of method and dexterity of hand.

But, in order to find out what method can do, you must now look at Art as well as at Nature, and see what means painters and engravers have actually employed for the expression of these subtleties. Whereupon arises the question, what opportunity you have to obtain engravings ? You ought, if it is at all in your power, to possess yourself of a certain number of good examples of Turner's engraved works: if this be not in your power, you must just make the best use you can of the shop windows, or of any plates of which you can obtain a loan. Very possibly, the difficulty of getting sight of them may stimulate you to put them to better use. But, supposing your means admit of your doing so, possess yourself, first, of the illustrated edition either of Rogers's Italy or Rogers's Poems, and then of about a dozen of the plates named in the annexed lists. The prefixed letters indicate the particular points deserving your study in each engraving.1 If you can, get first the plates marked with a star.The letters mean as follows:a stands for architecture, including distant grouping of towns,cottages, c. c clouds, including mist and aerial effects. f foliage.

g ground, including low hills, when not rocky. l effects of light.

m mountains, or bold rocky ground. p power of general arrangement and effect. q quiet water.

r running or rough water; or rivers, even if calm, when their line of flow is beautifully marked.

From the England Series.

a cfr. Arundel.

i. Ashby de la Zouche. alqr.Barnard Castle.

fmr. Bolton Abbey. fgr. Buckfasileigh.* a If. Caernarvon.Sure, therefore, that your selection includes, at all events, one plate marked with each letter - of course the plates marked with two or three letters are, for the most part, the best.

Do not get more than twelve of these plates, nor even all the twelve at first. For the more engravings you have, the less attention you will pay to them. It is a general truth, that the enjoyment derivable from art cannot be increased in quantity, beyond a certain point, by quantity of possession; it is only spread, as it were, over a clq. Castle Upnor. afl. Colchester.

Iq. Cowes. cfp. Dartmouth Cove. clq. Flint Castle.* afgl. Knaresborough.* afp. Lancaster. clmr. Lancaster Sands.

agf. Launceston. cflr. Leicester Abbey. fr. Ludlow.

afl. Margate. a I q. Orford. cp. Plymouth. f. Powis Castle. Imq. Prudhoe Castle. fIm r. Chain bridge over Tees.* m r. High Force of Tees.* afq. Trematon. mq. Ulles water. fm. Valle Crucis.

From the Keepsake.

mpq. Arona. / m. Drachenfells. //. Marly.* p. St. Germain en Laye. Ipq. Florence. Im. Ballyburgh Ness.*

From the Bible Series.

fm. Mount Lebanon. m. Rock of Moses at Sinai. a l m. Jericho.

a c g. Joppa.

c l p q. Solomon's Pools.* a l. Santa Saba. a l. Pool of Bethesda.

From Scott's Works.

p r. Melrose. f r. Dryburgh.* c m. Glencoe.