All such phenomena indicate to the political economist places where the labour is unbalanced. In the first case, the just balance is to be effected by taking labourers from the spot where the pressure exists, and sending them to that where food is redundant. In the second, the cheapness is a local accident, advantageous to the local purchaser, disadvantageous to the local producer. It is one of the first duties of commerce to extend the market and thus give the local producer his full advantage. Cheapness caused by natural accidents of harvest, weather, etc., is always counterbalanced, in due time, by natural scarcity similarly caused. It is the part of wise Government, and healthy commerce, so to provide in times and places of plenty for times and places of dearth, as that there shall never be waste, nor famine. Cheapness caused by gluts of the market is merely a disease of clumsy and wanton commerce. But their price is dependent on the human will. Such and such a thing is demonstrably good for so much. And it may demonstrably be bad for so much. But it remains questionable, and in all manner of ways questionable, whether I choose to give so much.[84] [84] Price has already been defined (pp. 214, 215) to be the quantity of labour which the possessor of a thing is willing to take for it. It is best to consider the price to be that fixed by the possessor, because the possessor has absolute power of refusing sale, while the purchaser has no absolute power of compelling it; but the effectual or market price is that at which their estimates coincide. This choice is always a relative one. It is a choice to give a price for this, rather than for that;--a resolution to have the thing, if getting it does not involve the loss of a better thing. Price depends, therefore, not only on the cost of the commodity itself, but on its relation to the cost of every other attainable thing. Farther. The power of choice is also a relative one. It depends not merely on our own estimate of the thing, but on everybody else's estimate; therefore on the number and force of the will of the concurrent buyers, and on the existing quantity of the thing in proportion to that number and force. Hence the price of anything depends on four variables.[85] 1. Its cost. 2. Its attainable quantity at that cost. 3. The number and power of the persons who want it. 4. The estimate they have formed of its desirableness. (Its value only affects its price so far as it is contemplated in this estimate; perhaps, therefore, not at all.)