Our newest and most wonderful fuel, natural gas, has already come under the control of a few great corporations, who own the wells and the pipes for conveying and distributing it to the consumers. A striking instance of the arbitrary nature of prices when under a monopoly's control was shown at Pittsburgh a few months ago. As is well known, upon the introduction of natural gas to that city a great number of the manufactories, as well as the private houses, discarded coal, and at considerable expense fitted up boilers, furnaces, etc., to use the new fuel. After the use of the gas had become general and its value had come to be thoroughly understood, the company furnishing the supply advanced the rates 100 per cent., without previous notice; and despite the remonstrance of indignant consumers, the advanced rate had to be paid or the use of the gas discontinued, the latter alternative involving the loss of the money invested in piping, burners, etc. Of the minor products of mines and quarries, marble, sandstone, borax, salt, and asphalt are all known to be more or less thoroughly under the control of monopolies, which, though less important and powerful, show the same tendency toward the destruction of competition. Great as is the extent to which the monopoly of the mineral wealth of the world has gone, we can scarcely doubt that if the movement is unchecked it will go much farther. In one sense the only absolute necessaries of life are food and clothing. But to the civilization of to-day the metals and minerals are no less indispensable; and these cannot be made anywhere, like manufactured goods; or grown on wide areas, like the products of the soil. We are absolutely at the mercy of the men who own our deposits of coal and copper and lead, and it is only to be expected that they will take greater advantage of their legal industrial advantage. The combinations that exist will be made stronger and more binding, and new ones will be formed. The French copper "corner" has taught men that under the broad protection of International law their schemes of industrial conquest may embrace the world; and it is not to be doubted that the temporary "corner" will yet result in a strong permanent combination; and that the precedent set by this successful monopoly will be eagerly followed by those who wish to secure like profits by the control of some other form of mineral wealth. IV. MONOPOLIES OF TRANSPORTATION AND COMMUNICATION. We have already alluded to the fact that the concentration of manufacturing in large mills at great commercial centres has been made possible by the development of railway transportation, and that the rapid settlement of our Western prairies is due to the same agency; but it is worth while to note more fully the difference between ancient and modern conditions in the business of transportation.