serve as effectively to induce the individual to produce it as though he desired the thing itself.
THE LAW OF VARIABLE PROPORTIONS
The process of production, in turn, calls for a new exercise of economy, because the means of production are scarce in some cases and abundant in others. In the last analysis, all industry consists in moving materials from one place to another. That is all that the moving-picture machine, or the human eye as a mechanical device, would reveal. But the mind sees plans, purposes, and laws back of this process of moving materials. One of the great generalizations of the scientific observer is that all this moving of materials is for the purpose of getting things together in the right proportions. Of course there are purposes back of all this, but the observed fact is that every industrial purpose is carried out by getting materials together in the right proportion. All this moving of materials which the eye sees is dominated by the law of proportionality, and the skill of the producer consists first in knowing the right proportions in which to combine materials, and, second, in his ability to bring them together.
This applies everywhere from a chemical experiment to the irrigation of a desert, from the work of the artist in his studio to that of the farmer in his field. The chemist, however, works under a law of definite proportions, under which chemical elements have to be combined in exact mathematical ratios, whereas the greater part of the work of production is under the law of variable proportions. In the irrigation of a piece of land, for example, there are variable quantities of water which may be used in the growing of a crop. One cannot say that an exact quantity of water must be applied, otherwise there will be no crop at all, or that the slightest variation either way would utterly ruin the crop. Within fairly wide limits of moisture a crop can be grown, though within these limits the crop will vary somewhat—but not exactly—according to the quantity of moisture provided.
Wherever the law of variable proportions holds, that is, wherever the law of definite proportions does not hold, the product may vary whenever any of the factors which are necessary to its production
