540 MR CLERK MAXWELL ON THE THEORY OF ROLLING CURVES. 



Ex. 3. When it is the involute of the circle, the traced curve is the spiral of 

 Archimedes. 



Ex. 4. Wlien it is a parabola, the focus traces the directrix, and the vertex 

 traces the cissoid. 



Ex. 5. When it is the hyperbolic spiral, the traced curve is the tractory of the 

 circle. 



Ex. b'. When it is the polar catenary, the equation of the traced curve is 



. /2 a T ■ I ^ 



S = . 1 — versin"' — 



'^' /■ a 



Ex. 7. When it is the curve whose equation is 

 the equation of the traced curve is, r = a C6-e-'). 



