  Let \(U\) be the unit of account. Consider a consumption stream \(\{C(t)\}\). It follows that \(U_{C(t)}\) is the social worth of a marginal unit of consumption. Write \(P(t)\) for \(U_{C(t)}. P(t)\) is called the (spot) accounting price of consumption. Because \(e^{-\delta t}P(t)\) is the discounted value of \(P(t)\), it is called the present-value accounting price of consumption. If \(\{C(t)\}\) satisfies the Ramsey Rule in Mark III, \(e^{-\delta t}P(t)\) is also the present-value accounting price of a unit of capital stock.  von Weizsacker (1965) showed that a sufficient condition for the optimality of \(\{C(t)\}\) is \(e^{-\delta t}P(t)K(t) \rightarrow A\) as t \(\rightarrow \infty\), where \(A\) is a (finite) non-negative number. In words, a necessary and sufficient condition for \(\{C(t)\}\) to be the optimum is (i) that it satisfies the Ramsey Rule, and (ii) that the present-value of the economy’s stock of capital is finite. Condition (ii), which is widely known as the “transversality condition,” eliminates those feasible consumption streams that satisfy the Ramsey Rule but along which there is excessive saving. A simple calculation confirms that in Example 2 the transversality condition is satisfied if the saving rate is \(s^*\) (eq. 18).