[454] Allen and Anderson’s _Early Christian Monuments of Scotland_. [Illustration: Evolution of Knot No.7 from an eight-cord plait] The most common kinds of circular knotwork appear to have been evolved in the following manner. It has already been shown how knot No. 3 can be derived from a four-cord plait by making a series of horizontal breaks at regular intervals, leaving two crossing-points of the cords between each break; and how knot No. 4 can again be derived from knot No. 3 by making a horizontal break at the point A. [Illustration: Knot No. 3] [Illustration: Knot No. 4] Now if a pair of knots like No. 4 be placed opposite each other thus— [Illustration] [Illustration] and repeated in a vertical row, we get the pattern shown below. [Illustration] [Illustration: Sections of pattern shown on p. 273] [Illustration: Knotwork from Ramsbury, Wilts, and Nigg, Ross-shire] By making pointed ends to the loops forming the knots and “sweetening” the curves of the bands between each knot the appearance of the whole is changed, and its development from the plait disguised. Almost all geometrical ornament is capable of conveying several different impressions to the mind according to the way it is observed by the eye for the time being, and the intellectual pleasure which a pattern gives is most probably dependent on the infinite variety of these kaleidoscopic changes. Taking this pattern for example, if the attention is concentrated upon the portions of the pattern between each of the points where the bands cross in the centre, it will seem as if the whole was formed of repetitions of knot No. 4; but if the attention be now directed towards the portions lying between the middle points of each of the knots, the pattern will appear to consist entirely of circular curves with two diameters crossing each other diagonally. [Illustration: ERECT CROSS-SLAB FROM COLLIEBURN, SUTHERLAND, NOW IN THE DUNROBIN MUSEUM _Photograph supplied by the Rev. J. M. Joass, LL.D., Honorary Curator_] When the circular knot thus obtained is repeated in a double row we get a comparatively simple pattern, in which the circular curves assume much greater prominence. More complicated forms of circular knots can be derived from the elementary circular knot by combining it with a circular ring, either a larger one enclosing the four loops in the middle entirely, or a smaller one interlaced through the loops thus:— [Illustration] Further variations can again be produced from these by severing the bands in places, and joining parts of the loops to the rings on the same principle that breaks can be made in a plait. [Illustration] The connection between the different knots will at once become clear if they are drawn on separate pieces of tracing paper and placed one over the other.