就业、利息和货币通论 (17)

就业、利息和货币通论CHAPTER 17THE ESSENTIAL PROPERTIES OF INTEREST AND MONEY第十七章利息和货币的主要性质IIT seems, then, that the rate of interest on money plays a peculiar part in setting a limit to the level of employment, since it sets a standard to which the marginal efficiency of a capital-asset must attain if it is to be newly produced. That this should be so, is, at first sight, most perplexing. It is natural to enquire wherein the peculiarity of money lies as distinct from other assets, whether it is only money which has a rate of interest, and what would happen in a non-monetary economy. Until we have answered these questions, the full significance of our theory will not be clear.从以上的论述来看，货币的利息率对就业量水平的限制似乎起着一种特殊的作用，因为如果资本资产是新生产出来的，利息率会为该资本资产必须得到的边际效率建立一个标准。

这个说法，乍一看来，很令人感到困惑。

于是，人们很自然地会问：（1）货币和其他资产相区别的特殊性在哪里；（2）是否只有货币才有利息率；（3）在一个非货币经济中，将会发生什么情况。

直至这些问题得到回答以前，我们的理论的全部意义是不会被了解到的。

The money-rate of interest--we may remind the reader--is nothing more than the percentage excess of a sum of money contracted for forward delivery, e.g. a year hence, over what we may call the "spot" or cash price of the sum thus contracted for forward delivery. It would seem, therefore, that for every kind of capital-asset there must be an analogue of the rate of interest on money. For there is a definite quantity of (e.g.) wheat to be delivered a year hence which has the same exchange value to-day as 100 quarters of wheat for "spot" delivery. If the former quantity is 105 quarters, we may say that the wheat-rate of interest is 5 per cent. per annum; and if it is 95 quarters, that it is minus 5 per cent. per annum. Thus for every durable commodity we have a rate of interest in terms of itself,—a wheat-rate of interest, a copper-rate of interest, a house-rate of interest, even a steel-plant-rate of interest.我愿提醒读者，利息率不过是一定数量的货币，与根据契约，例如未来一年之后，所得到的超过我们称之为“现货”的差额，或者根据契约未来支付的一定数额现金的价格之间的百分比。

所以，似乎可以说，对每种资本资产而言，都存在一个类似利息率的东西。

以小麦为例，一年后的交货量是一个确定的数量，它今天的交货价值也即“现货”交割为100夸特小麦。

如果一年以后交货的数量为105夸特，则可以说，小麦的利息率为每年5％。

如果一年以后交货的数量为95夸特，则小麦的利息率为每年－5％。

这样，对于每种耐久性的消费品来说，都有一个用它本身计量的利息率——如同有小麦利息率，有铜利息率，房屋利息率，甚至钢厂利息率等等。

The difference between the "future" and "spot" contracts for a commodity, such as wheat, which are quoted in the market, bears a definite relation to the wheat-rate of interest, but, since the future contract is quoted in terms of money for forward delivery and not in terms of wheat for spot delivery, it also brings in the money-rate of interest. The exact relationship is as follows:对于像小麦这样的商品，其“期货”和“现货”市场价格的差额，同小麦利息率维系着一定的关系。

但是，由于期货合同是以货币计量未来交割的市场价格，“现货”的市场价格也不是以小麦来计量的，所以，此处牵涉到货币利息率的问题，其中的确切关系可以表述如下：Let us suppose that the spot price of wheat is £100 per 100 quarters, that the price of the "future" contract for wheat for delivery a year hence is £107 per 100 quarters, and that the money-rate of interest is 5 per cent. ; what is the wheat-rate of interest γ £100 spot will buy £105 for forward delivery, and £105 for forward delivery will buy 105/107 . 100 (=98) quarters for forward delivery. Alternatively £100 spot will buy 100 quarters of wheat for spot delivery. Thus 100 quarters of wheat for spot delivery will buy 98 quarters for forward delivery. It follows that the wheat-rate of interest is minus 2 per cent. per annum1.我们假设，小麦的现货价格是每100夸特为100英镑，一年后交割的“期货”价格是每100夸特为107英镑。

同时，假设货币的利息率为每年5％，那么，小麦的利息率是多少呢？既然100英镑的现货能买到105英镑的期货，而105英镑1This relationship was first pointed out by Mr. Sraffa, Economic Journal, March 1932, p. 50.的期货将买到98夸特小麦的期货。

这就是说，100英镑的现货能买到100夸特小麦的现货，而100夸特小麦的现货只能买到98夸特小麦的期货，这样，小麦的利息率就是每年－2％1。

It follows from this that there is no reason why their rates of interest should be the same for different commodities,--why the wheat-rate of interest should be equal to the copper-rate of interest. For the relation between the "spot" and "future" contracts, as quoted in the market, is notoriously different for different commodities. This, we shall find, will lead us to the clue we are seeking. For it may be that it is the greatest of the own-rates of interest (as we may call them) which rules the roost (because it is the greatest of these rates that the marginal efficiency of a capital-asset must attain if it is to be newly produced); and that there are reasons why it is the money-rate of interest which is often the greatest (because, as we shall find, certain forces, which operate to reduce the own-rates of interest of other assets, do not operate in the case of money).由此可知，没有理由认为，不同的商品会有相同的利息率——或者，为什么小麦利息率会等同于铜利息率。