The general scope of the paper was to show how by graphic methods we might find the relation between effort exerted at one part of a machine and the resistance overcome at another part. It was shown that for a given machine at any instant a linear frame might be substituted, such that the stresses in the links corresponded to the pressures at the joints between the elements of the machine, including the pressures due to driving effort and resistance. Numerous examples were given of the application of this frame, called the dynamic frame, to the solution of the above problem, the friction, inertia, and weight of all the parts being taken rigidly into account.