He would still be co-operating with the users of every steam-engine in the world to-day, and adding to their products something which they could not have produced alone.
Here, then, we see that in one respect at all events the two kinds of capital, which George attempts to contrast, yield interest for a precisely similar reason.

Both consist of a productive power or agency which is external to the borrower himself; and it makes no difference to him whether the auxiliary power borrowed inheres in living tissue, or in a mechanism of brass or iron.
But the resemblance between these two forms of capital, and the identity of the reasons why both of them bear interest, do not end here.

I quoted in a former chapter an observation of Mr.Sidney Webb's, which he himself applies in a very foolish way, but which is obviously true in itself, and in the present connection is pertinent.

Some men he admits are incomparably more productive than others, because they happen to be born with a special kind of ability.

But what is this ability itself?
It is simply the result, he says, of a process which lies behind them--namely, the natural process of animal and human evolution; and its special products are like those of exceptionally fertile land.