The remaining blades in the illustration are grooved in as many different ways. The function of the _cannelure_ is to obviate over-flexibility; it also takes from the weight and adds to the strength. By channelling either side of a thin or ‘whippy’ blade it becomes stiffer, because any force applied to bend such a blade sideways meets with the greatest amount of resistance that form can supply. Mechanically speaking, it is to crush an arch inwards upon its crown, and the deeper the arch the greater the resistance. Hence the narrow groove is preferable to a broader channel of the same depth. No. 9, hollowed on each side near the base, is a good old form, superior to the ‘regulation’ (No. 8): its weak point, the space between the grooves where the metal is thinnest, lies in the best place—near the back, where strength and thickness are least required. No. 10, though somewhat lighter, doubles its weak points. No. 11 is better in this respect: it has three grooves which are far shallower, and consequently the metal between them is thicker. The same remark applies to Nos. 12 and 13, which are sections of claymores, single- and treble-grooved. No. 14 shows an ingenious method of obviating the weakness caused by deep _cannelures_: it is the section of a blade made at Klingenthal (not ‘Klegenthal’), the Sword manufactory established by Napoleon Buonaparte in Elsass-Lothringen. Two very marked grooves are cut in the metal, but not directly opposite each other, and thus the channels can touch and even overlap the axial line. This disposition gives great stiffness, but, as testing shows, the edge is deficient in cutting power, probably from loss of force by vibration. Nos. 15 and 16 are experimental blades. The former has the groove placed in the base, preserving the wedge-sides intact; but there is great difficulty about grinding this shape, and, the resistance of the arch-crown being wanting, there is a small increase of stiffening—the Sword, in fact, ‘springs’ almost as readily as the straight form. No. 16 has some good points, but, on the whole, the combination is a failure. Lastly, No. 17, the old ‘ramrod-back’ regulation blade, is perhaps the worst of all: the sudden change from the thick round base to the thin sharp edge makes an equal tempering very difficult, and the weapon cleverly undoes its own work, the base acting as check or stop to the cut. [Illustration: FIG. 119.—FOIL WITH FRENCH GUARD.] [Illustration: FIG. 120.—REGULATION SWORD FOR INFANTRY.] [Illustration: FIG. 121.—SCYMITAR-SHAPE.]