In regard to the proportion of Roman capital letters, it may be taken as a general rule, that the whole of the letters, with the exception of S, J, I, F, M, and N, are formed in squares. The top and bottom of the letters should project the width of the thick line. The letters I and J are formed in a vertical parallelogram, half the width of the square; the letters M and N in a horizontal parallelogram, one third larger than the square. The letters A, B, E, F, H, X, and Y, are either divided, or have projections from the middle. This rule may be varied, and the division placed nearer the top than the base of the square. Capitals in the same word should have a space equal to half a square between them; at the beginning of a word, a whole square, and between the divisions of a sentence two squares should be left. This is the general rule for the proportions of the letters; but they may be made longer or wider, as may be deemed expedient. The small letters are half the size of the capitals; the long lines of the letters b, d, f, h, k, and l, are the same height as the capitals; the tails of j, p, q, and y, descending in like proportion. The letter s is founded on the form of two circles at a tangent to each other. These rules are applicable to sloping as well as to upright letters. In _italic_ letters it is usual to make the capitals three times the height of the smaller letters, and the long strokes of the small letters nearly equal to the capitals. The letters having been duly set out, and painted on the walls, the amateur must next either himself encounter, or employ some experienced hand to overcome, the technical difficulties of successfully gilding those portions of his work he may desire to remain in gold. The following directions may assist him; but he is not likely to succeed until practice shall have given him considerable dexterity and confidence:-- _Gilding for Walls, &c._ The implements with which the gilder should provide himself are not numerous, nor are they expensive, as they consist merely of a cushion of particular form, a knife for cutting the gold-leaf, a tip for transferring it, and a cotton ball or pad for pressing it down; these and a few brushes are all the requisites, with the addition of an agate burnisher when burnish gilding is desired. The cushion is a species of palette made of wood, about 9 inches by 6 inches, having on the upper surface a covering of leather stuffed with wool, and on the under side a loose band, through which the thumb being passed, the cushion is kept firmly resting on the left hand. To prevent the gold flying off (for, being extremely light, this very readily takes place), a margin of parchment is fixed on the edge of the cushion, rising about three inches, and enclosing it on three sides. The knife very much resembles a palette-knife, the blade is about four inches long and half an inch wide, perfectly straight, and cutting on one edge only.