CONTACT OF ELASTIC SOLIDS 155 the cube root of the total pressure and as the cube root of the quantity 9, +9. By the preceding the distance through which the bodies approach each other under the action of the given pressure is 3p D1 + D2 α= 8π a dz ´(1+h² z²) (1+z²) · 1 If we perform the multiplication by 9, +92 a splits up into two portions which have a special meaning. They denote the distances through which the origin approaches the infinitely distant portions of the respective bodies; we may call them the indentations which the respective bodies have undergone. With a given form of the touching surfaces the distance of approach varies as the pressure raised to the power and also as the same power of the quantity 9, +92 When A and B alter in magnitude while their ratio remains unchanged, the dimensions of the surface of pressure vary inversely as the cube roots of the absolute values of A and B, and the distance of approach varies directly as these roots. When A and B become infinite, the distance of approach becomes infinite; bodies which touch each other at sharp points penetrate into each other. In connection with this we shall determine what happens to the element at the origin of our system of coordinates by de an ar In the first dx' dy' dz finding the three displacements place we have at the origin 2 Әр 3p 1 σ= = K(1+20) Əz 2K(1+20)π аb " ay Əz = 1 ap 3p 1 4K(1+20)π ab K(1+20) Əz Further, at the plane z = 0 II = 1 દુઃ = K(1+20) әп მე: ∞ " n= Pdz= әп dy " 1 2K(1+20)) -8 ∞ Pdz.