Page:Paper and Its Uses.djvu/100

88 Tearing paper as a method of comparing strength is one of the simplest as well as one of the surest methods. Paper has to withstand tearing stresses, and the paper which ruptures with most difficulty is usually the most resistant to wear. Tearing will reveal whether the paper is composed of long or short fibres, and whether it is tough or brittle, and is a method of testing which requires no apparatus.