The oscillograph described has been developed primarily as a laboratory instrument to evaluate rubber and Neoprene compounds for mechanical applications. It is complete in itself as a means of measuring all of the quantities inherently involved in such service in units which are understandable to rubber technologists and mechanical engineers alike. It is hoped that it may serve its purpose by bringing into closer cooperation those who make and those who use rubber springs. The details of the test have been carefully developed, and it is expected that the machine and standard test-specimen described will not need essential modification for routine use. However, enough background has been given so that the machine may be modified in accordance with definite principles in order to gain greater load capacity if required. The test has been restricted thus far to compression. The author expects to adapt the machine to tests in shear, and by correlation between shear data and compression data to obtain figures capable of substitution in relationships already offered by other investigators for calculations in the applications and design of rubber springs. This field of calculation is complicated and in an early state of development, but by the use of the oscillograph it should be easier to obtain the quantities of information required to clarify our understanding of the mechanical characteristics of rubber-like materials within the range of deformation encountered in structural use.