To induce new investment 'the rate of return over cost must exceed the rate of interest'.

为了吸引新的投资， “成本回报率必须超过利率” 。

Professor Fisher explains that the extent of investment in any direction will depend on a comparison between the rate of return over cost and the rate of interest.

费舍尔教授解释说， 任何方向的投资程度都取决于成本回报率和利率之间的比较。

Thus Professor Fisher uses his 'rate of return over cost in the same sense and for precisely the same purpose as I employ 'the marginal efficiency of capital'.

因此，费舍尔教授使用他的“成本回报率” 与我使用“资本边际效率” 的意义和目的完全相同。

'The rate of return over cost', he writes, 'is that rate which, employed in computing the present worth of all the costs and the present worth of all the returns, will make these two equal'.

“成本回报率”，他写道，“是用来计算所有成本的现值和所有回报的现值，使这两者相等的比率”。

Although he does not call it the 'marginal efficiency of capital', Professor Irving Fisher has given in his Theory of Interest (1930) a definition of what he calls 'the rate of return over cost' which is identical with my definition.

尽管他没有称之为“资本的边际效率”，但欧文费雪教授在他的利率理论（1930）中给出了他所谓的“成本回报率”的定义，这与我的定义相同。