For line drawings, the border should be a geometrical design, in lines, with curved or angular corners, or with combinations of straight or curved lines, forming geometrical corner-pieces. These borders may vary in complexity from a rectangular border in single lines to borders which, though geometrical, may be elaborate and elegant. Thus: a plate of varieties of straight horizontal lines may have a plain rectangular border; one including oblique lines may include oblique lines in the border, either as a little tuft in each corner, a truncated corner, or a square set diagonally, etc. Plates em-bracing curve lines may have quarter-circle borders, either convex or concave inwards - of which the former have most decision. Such plates may also have little circles for corner-pieces. Borders may sometimes conform in a pleasing manner to the general outline of a drawing. Thus, an arched bridge may have a semi-oval upper border and a square-cornered border at the base of the drawing; and an ornamental device may crown the summit of the border.

When the drawing is a shaded one, containing, therefore, some free-hand work, the border may be partly freehand also; but should still be largely geometrical in its design, and should represent a real border of substantial materials, corresponding to the subject of the drawing. Thus, the mouldings and ornaments should represent ornamental metallic castings, carvings in wood, mouldings in plaster, or scrolls and leaves of rolled metal; but garlands, tassels, and tendrils, etc., should not be introduced.

The border to a geometrical drawing should be like the drawing itself in being executed with the drawing pen and brush, as well as with the mapping pen. Free-hand pen borders, representing the products of the soil, with cornucopias, little pen sketches of scenery, or similar agricultural or landscape devices, worked in as corner-pieces, are more appropriate on topographical drawings.

As to colour, primary colours should not be largely introduced into the border; first, since they, when obtrusive, are adapted to ruder or less impressible tastes than the secondary hues, shades, and tints, which arc more gratifying to delicate tastes; and secondly, from the impertinent conspicuousness which they may give to the border.

Drawings which are shaded only in sepia or ink, or any dark neutral tint, may have the border done in the same, or in a dark complementary colour. Tinted ink drawings are best finished with a plain ink border.

Indian Ink is used for producing the finished lines of all kinds of geometrical drawing. Being free from acid, it does not injure or corrode the steel points of the instruments. The genuine ink, as it is imported from China, varies considerably in quality; that which answers best for line drawing will wash up the least when other colours are passed over it. This quality is ascertained in the trade, but not with perfect certainty, by breaking off a small portion. If it be of the right quality it will show, when broken, a very bright and almost prismatic-coloured fracture. Indian ink should be used immediately after it is mixed; if re-dissolved it becomes cloudy and irregular in tone, but with every care, it will still wash up more or less. (See also ii. 335.)