Since expenses of production always enter into the determination of competition-prices, which are fixed by the interaction of expenses and money estimates of utility--_i.e._, by supply and demand, it is evident that the curve of monopoly prices has no assignable relation whatever to the curve of competition prices, and that the most profitable output and prices of Trust-made goods are in no way identified with the most profitable output and prices in a competitive trade. In competition the curve of selling prices tends to follow closely the curve of expenses, and consequently the areas of profits and expenses tend to bear the same proportion to each other at different points of increment in the trade. For if at any point great increases in economy of production are achieved, while the large elasticity of demand maintains a price nearly the same as before, the wide margin of profit which might fix the actual price at that point for a monopolist only serves to stimulate such increased output on the part of trade competitors as will continue until the flexibility of demand weakens, and prices are lowered to such a point as will yield the normal margin or market rate of profit. There is, therefore, nothing in common between competition prices and monopoly prices for different quantities of supply, nor anything to secure that the actual quantity of supply and the price shall be the same in the two cases. § 6. It is, however, conceivable that in a certain commodity where a genuine monopoly holds the market, the price should be as low as under free competition. This may be illustrated by the following curves of expense and price:-- [Illustration] where the economies of increased production continue to be very great, while the flexibility of demand is also high. In other words, it may pay the Trust better to make very large sales at a low price when the expenses of production are low, than to sell a smaller quantity at a higher price and with a higher expense of production. In this case the consumer may get a part of the advantage of large-scale production along with the saving of expense of competition. There is, however, no guarantee to society that low prices will be fixed. In the vast majority of cases it will probably pay the Trust better to limit production and sell at higher prices.