To protect two rings from rubbing against each other, an exceedingly narrow gold circlet is worn between them. Where there is risk that a hard stone in one ring will come in contact with a pearl in the other, or a diamond with any other stone, necessarily softer, one or more very small beads are welded on that part of the hoop nearest to the setting. In cases where a treasured ring has worn almost to the thinness of paper, it is possible to strengthen it by adding gold at either side of the hoop. [Illustration: THE “ALLEN RING GAUGE” Generally used in the United States for measuring accurately the size of the ring required to fit a given finger] [Illustration: 1, Engelmann’s ring, finger and millimeter locking gauge. 2, “Display rings,” in which a succession of precious stones can be set and tried on the fingers] The size of the finger is often recorded by what is known as the Allen gauge, a tapering stick numbered from 1 to size 13 in half sizes. To this stick is attached a chain, and pendant to the chain is a series of rings of graduated sizes. When it is decided which ring of the series best fits the finger, it is slipped on the gauge and its size ascertained. If size 6 is a little tight and 6½ a trifle loose, this indicates that 6¼ is the correct size. In measuring the finger for a ring, by Engelmann’s Ring, Finger and Millimeter Locking Gauge, the ring is set _over_ the _outside_ perpendicular ends of the gauge (see plate). These are then separated to their fullest extent, so that they touch the ring on both sides. The exact size of the ring is thus indicated on the scale over the mark on the movable upper part of the right-hand end. To measure the size of a finger, the ends should be separated sufficiently to permit the finger to pass through the aperture between them. They are then to be closed so as to touch lightly--not pinch or squeeze--the flesh of the finger. When this has been done the ends are locked, and if the knuckle passes easily through the aperture, the right size has been found. This is recorded on the scale in the same way as in the ring measurement. In measuring the finger of either a child, boy, girl, or woman, who has not a large or high knuckle, a safe rule is to add a ½ _ring-size_ to that which has been indicated by the measurement. The width of the metal ring-shank is ascertained by placing its lower, centre part between the two inside perpendicular ends, and the exact dimensions will be made apparent on the millimeter scale. Where the shank is tapered, the maximum and minimum widths must be taken, and these must both be stated in ordering a ring. An unset stone is to be measured in the way just described, maximum and minimum widths being taken; for this purpose also, only the extreme pointed ends are to be used; these dimensions should be correctly stated when the ring is ordered.