A line to the sky

That dictum ''No lines in nature'' is contradicted outright by trees - though not every artist has done so with the vital linearity exercised by Ben Nicholson in his ''Concourse of Trees, Tuscany.'' The distinctness of his line contrives to be both consciously artful and admiringly natural, obedient to alert direction from hand and eye. It is as if a concurrence has been found between the independent enjoyment of drawn lines springing, curving and stretching themselves on a paper surface, and the lines of the trees themselves, narrowly carrying the sap through trunk to branch to twig to sky.

Drawing, in Nicholson's hands, was an event at the same time sensitive and forcefully direct: responsive to the finest relationships (in this case, of branch to branch), observing, with precision and delight, the actual process of branching, the way a tree articulates itself, while also being unfussed and cutting through complication with the positive certainty, the elegance, of practice. In reducing volume and form largely (though not totally) to a matter of contour, he was being highly selective. This quality of choice, of a decisiveness applied to a confusion of phenomena so that it is made to serve the ends of a designed clarity without losing unpredictable liveliness, is evident in every part of a drawing like ''Concourse of Trees.''

Nicholson himself used the playing of games, of tennis, table tennis, billiards, as an instructive analogy for drawing: accuracy, speed, flight, ricochet, bounce, return, even the unexpectedness of the spin - such niceties of play translate into his unmistakable agility of line, its adroitness, and its paradoxical mixture of the flexible and the inflexible. His way of moving a pencil point over a surface (unlike, for example, Cezanne's) is as calculated as a good tennis stroke and as necessarily unhesitant. The shortest route between two points is a line, no doubt, but like a ball slammed across a court it may well describe, not so much straightness, as a tense, piercing curve.

Nicholson not only drew and painted, he also made reliefs, and the incisive cutting edge, involved in delineating the shapes of the differing levels or spaces in his reliefs, is apparent also in this drawing. So determined has he made the contour of the tree trunks that the separation between the solid wood and the empty space between is strongly accentuated. The ancient Egyptians, in stone reliefs, differentiated between figures and their environment with a similar lucidity. Nicholson has also neatly made his receding row of trees act like perspective, so deepening the space of the picture. But such analysis still fails to explain the excitement of something which was pointed out to me about twenty years ago when I first saw this drawing, in a private collection. I haven't forgotten: ''Concourse of Trees'' is, more than anything, a drawing of that invisible, ungraspable - and essentially undrawable - commodity, thin air.

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