Rubber components comprising flat pads of vulcanized rubber secured between rigid flat surfaces are widely used as mountings and couplings. They are subjected to compression or shear, or a combination of both deformations, often of relatively large magnitude. The shear deformation is produced by the displacement of one rigid bounding surface in its own plane with respect to the other. It differs from a homogeneous shear deformation if the pad thickness is comparable with the dimensions of the cross-section, when an appreciable bending component enters into the total deflection. The corresponding load-deflection relations have been examined by Rivlin and Saunders. The compression deformation differs from a state of pure homogeneous compression in that the rubber adheres or is bonded to the rigid compressing faces and sliding at the interface is precluded. The rubber therefore bulges laterally as the deflection is imposed. The loaded surfaces are subjected to a uniform displacement, while the free surface of the pad is subjected to known stresses (zero). The resulting mixed boundary value problem has not proved tractable even for classically small displacements—its solution for large elastic displacements does not appear imminent. This problem has therefore been treated experimentally. Since the preparation of the paper, an approximate theoretical treatment has been developed. It is described in the APPENDIX. for any rubber component the presence in use of excessive local surface strains is undesirable and a longer service life may be anticipated if the geometrical design of the surface is such that high concentrations of strain do not arise. In principle it should be possible to derive the state of strain at the surface by mathematical analysis, but in practice the problem is difficult and conclusions can only be drawn in some restricted cases. Simple measuring techniques are described whereby the distribution of strain over the surface of a rubber component may be examined experimentally. These methods have been used to determine the regime of strain over the free surfaces of some bonded rubber cylinders subjected to overall compression and extension.