The internal strength of an adhesive is its cohesiveness. To prevent a label from splitting when removed from a surface, the cohesive strength has to be greater than the specific adhesion. One method of measuring the cohesive strength of a label adhesive is by vertically bonding a label sample to a test bar. A weight is then attached to the sample. The amount of time that elapses before the sample pulls free of the bar is a measure of shear strength.