The Tools You Will Use : Page 87

foration of a stamp or to measure in millimeters the sizeof the stamp. There are many types available, all ofwhich are satisfactory. The most common type is thekind that provides a series of dots or points within agiven space; below each such line of dots or points thegauge of the perforation is indicated. Use the perforation-gauge part of this instrument by sliding the stamp fromone row of dots or points to the other until all of theteeth, or holes of the perforations, on the stamp coincideexactly with the dots or points on the gauge (see illus-tration ). Use the millimeter part of the instrument as anordinary ruler; only measure in millimeters instead ofinches.