Let us now see what we would effect by the enforcement of this principle of non-discrimination. We have explained in the chapter on combinations in trade how one monopoly gains strength by alliance with another; as when the firms belonging to the car-spring combination made a contract with the steel combination by which that monopoly agreed to sell to them at a reduced price and to make an extra rate to their competitors. Under this law it would be impossible to found one monopoly upon the favors of another in this manner. The obnoxious trade boycott, too, which is now becoming so common, would be effectually checked. And the scheme for crushing out a rival by giving all his customers specially favorable rates would no longer be practicable. The fact is that if we can stop the discriminations which the monopolies have practised, we shall cure a large share of the evils they have caused. It may be said that the courts will already punish many conspiracies of this sort; but a monopoly which is already breaking the law by its contracts of combination, finds in its methods of doing business plenty of chances to evade the laws against conspiracy. Certainly with a properly drawn law with reference to the publicity and stability of prices, it should be possible to practically wipe out the evil of discrimination by monopolies. It is also to be noted that the requirement of non-discrimination and of public and stable prices would bring profit in doing away with the waste of competition. We have now to inquire what means it is possible to take to ensure that the prices charged by the monopoly shall not only be the same to all, but that they shall not in themselves be so exorbitant that the monopoly will reap large profits at the public expense. How can we keep the prices charged by the monopoly from rising far above the point where they would stand if free competition were in force? Two methods are open to us. We may keep down the monopoly's rates by what we will call _potential_ competition, or we may reduce them directly by legislative enactment.