Thirdly:--If you adopt any historical style or particular period as a basis on which your text, miniatures, or ornamentation are to be constructed, maintain its leading features consistently, so as to avoid letting your work appear as though it had been begun in the 10th century, and only completed in the 16th; or, as I have once or twice seen, _vice versâ_. For however erratic changes of style may appear to be in Art, as they run one another down along the course of time, it will be invariably found that there exists a harmony between all contemporary features, which cannot be successfully disregarded; and this it is which has ever rendered eclecticism in art a problem,--not impossible, perhaps, to solve, but one which, as yet at least, has never met with a satisfactory practical solution. Fourthly:--Sustain your energies evenly throughout your volume; for, remember, your critics will estimate your powers, not by your best page, but by a mean struck between your best and your worst. Book illumination is generally looked upon as microscopic work, demanding the greatest exactitude; and whatever merits any page may display, they will go for little, if that page is disfigured by a crooked line, or a single leaf insufficiently or incorrectly shadowed; and the greater the merit, the more notable the drawback. Fifthly:--Rigidly avoid contrasting natural with conventional foliage. Adopt which you like, for by either beautiful effects may be produced; but mix them, and the charm of both is gone. Natural foliage may be successfully combined with any other varieties of conventional ornament, excepting those based upon natural foliage. Sixthly:--Take care that some at least of your dominant lines and borders are kept parallel to the rectangular sides of your pages; for unless your flowing and wayward ornaments are corrected by this soberer contrast, they will, however beautiful in themselves, have a straggling and untidy appearance in the volume. Where the lines of text are strongly marked, as in black ink on a white ground, and the page is so far filled with text as to leave but little space for ornament, this rule may be, to a great extent, disregarded, for the lines of the text will themselves supply the requisite contrast to the flowing forms; but where the page is nearly filled with ornament, or when the text is faint only, as in gold lettering on a white ground, it becomes imperative.