Experiments with rubber and gelatine under lubricated conditions confirmed that with rubber-like materials the load dependence of friction is consistent with elastic deformation of surface asperities and partial adhesion over the true area of contact. However, the F ∝ W^2/3 relation found by previous investigators obtains only over a limited load range. At very low loads the friction is very nearly proportional to load, whilst at very high loads contact between specimen and track is complete, and the friction remains sensibly constant.When rubber slides on rough tracks there is a large additional friction force unrelated to true contact area.