One circumstance will form a great element in his calculation—the number of commodities in the production of which this instrument will assist while it lasts. He has a primary standard of comparison—the present labours to which he is subjected every time he wishes to procure the satisfaction directly and without assistance. He estimates how much labour the tool or instrument will save him on each occasion; but labour is required to make the tool, and this labour he will in his own mind spread over all the occasions on which such an instrument can be made available. The greater the number of these occasions, the stronger will be his motive for seeking the co-operation of natural agents. It is here—in this spreading of an ‹advance› over an aggregate of products—that we discover the principle and foundation of Interest. When Robin Crusoe has once made up his mind to construct the instrument, he perceives that his willingness to make it, and the advantage it is to bring him, are not enough. Tools are necessary to the manufacture of tools—iron must be hammered with iron—and so you go on, mounting from difficulty to difficulty, till you reach the first difficulty of all, which appears to be insuperable. This shows us the extreme slowness with which Capital must have been formed at the beginning, and what an enormous amount of human labour each satisfaction must originally have cost. Again, in order to construct the instruments of labour, not only tools, but ‹materials› are wanted. If these materials, as for instance stones, are furnished gratuitously by nature, we must still combine them, which costs labour. But the possession of these materials supposes, in almost every case, anterior labour both long and complicated, as in the manufacture of wool, flax, iron, lead, etc. Nor is this all. Whilst a man is thus working for the exclusive [p198] purpose of facilitating his ulterior labour, he can do nothing to supply his present wants. Now, here we encounter an order of phenomena in which there can be no interruption. Each day the labourer must be fed, clothed, and sheltered. Robinson will perceive, then, that he can undertake nothing for the purpose of procuring the co-operation of natural forces until he has previously accumulated a stock of ‹provisions›. He must every day redouble his activity in the chase, and store up a portion of the game he kills, and subject himself to present privations, in order that he may have at his disposal the time requisite for the construction of the instrument he has projected. In such circumstances, it is most probable that all he will accomplish will be the construction of an instrument which is rude and imperfect, and not very well fitted for the purpose he has in view. Afterwards, he will obtain greater facilities. Reflection and experience will teach him to work better; and the first tool he makes will furnish him with the means of fabricating others, and of accumulating provisions with greater promptitude.