"But this is mere child's play compared to the refinement of a first- rate mechanical work—much more of brush or pencil drawing by a master's hand. In order at once to furnish you with authoritative evidence on this point, I wrote to Mr. Kingsley, tutor of Sidney-Sussex College, a friend to whom I always have recourse when I want to be precisely right in any matter; for his great knowledge both of mathematics and of natural science is joined, not only with singular powers of delicate experimental manipulation, but with a keen sensitiveness to beauty in art. His answer, in its final statement respecting Turner's work, is amazing even to me, and will, I should think, be more so to your readers. Observe the successions of measured and tested refinement: here is No. 1:—
"'The finest mechanical work that I know, which is not optical, is that done by Nobert in the way of ruling lines. I have a series ruled by him on glass, giving actual scales from .000024 and .000016 of an inch, perfectly correct to these places of decimals, and he has executed others as fine as .000012, though I do not know how far he could repeat these last with accuracy.'
"This is No. 1 of precision. Mr. Kingsley proceeds to No. 2:—
"'But this is rude work compared to the accuracy necessary for the construction of the object-glass of a microscope such as Rosse turns out.'
"I am sorry to omit the explanation which follows of the ten lenses composing such a glass, 'each of which must be exact in radius and in surface, and all have their axes coincident:' but it would not be intelligible without the figure by which it is illustrated; so I pass to Mr. Kingsley's No. 3:—
"'I am tolerably familiar,' he proceeds, 'with the actual grinding and polishing of lenses and specula, and have produced by my own hand some by no means bad optical work, and I have copied no small amount of Turner's work, and I still look with awe at the combined delicacy and precision of his hand; IT BEATS OPTICAL WORK OUT OF SIGHT. In optical work, as in refined drawing, the hand goes beyond the eye, and one has to depend upon the feel; and when one has once learned what a delicate affair touch is, one gets a horror of all coarse work, and is ready to forgive any amount of feebleness, sooner than that boldness which is akin to impudence. In optics the distinction is easily seen when the work is put to trial; but here too, as in drawing, it requires an educated eye to tell the difference when the work is only moderately bad; but with "bold" work, nothing can be seen but distortion and fog: and I heartily wish the same result would follow the same kind of handling in drawing; but here, the boldness cheats the unlearned by looking like the precision of the true man. It is very strange how much better our ears are than our eyes in this country: if an ignorant man were to be "bold" with a violin, he would not get many admirers, though his boldness was far below that of ninety-nine out of a hundred drawings one sees.'
"The words which I have put in italics in the above extract are those which were surprising to me. I knew that Turner's was as refined as any optical work, but had no idea of its going beyond it. Mr. Kingsley's word 'awe' occurring just before, is, however, as I have often felt, precisely the right one. When once we begin at all to understand the handling of any truly great executor, such as that of any of the three great Venetians, of Correggio, or Turner, the awe of it is something greater than can be felt from the most stupendous natural scenery. For the creation of such a system as a high human intelligence, endowed with its ineffably perfect instruments of eye and hand, is a far more appalling manifestation of Infinite Power, than the making either of seas or mountains.
"After this testimony to the completion of Turner's work, I need not at length defend myself from the charge of hyperbole in the statement that, 'as far as I know, the galleries of Europe may be challenged to produce one sketch [footnote: A sketch, observe,—not a finished drawing. Sketches are only proper subjects of comparison with each other when they contain about the same quantity of work: the test of their merit is the quantity of truth told with a given number of touches. The assertion in the Catalogue which this letter was written to defend, was made respecting the sketch of Rome, No. 101.] that shall equal the chalk study No. 45, or the feeblest of the memoranda in the 71st and following frames;' which memoranda, however, it should have been observed, are stated at the 44th page to be in some respects 'the grandest work in grey that he did in his life.' For I believe that, as manipulators, none but the four men whom I have just named (the three Venetians and Correggio) were equal to Turner; and, as far as I know, none of those four ever put their full strength into sketches. But whether they did or not, my statement in the catalogue is limited by my own knowledge: and, as far as I can trust that knowledge, it is not an enthusiastic statement, but an entirely calm and considered one. It may be a mistake but it is not a hyperbole."