We find this class of trade monopolies most powerful and effective on the frontier. Wherever railroad communication is easy and cheap the tradesmen of different towns--between whom combinations are seldom formed--compete with each other. The extension of postal, express, and railway-freight facilities to all parts of the country, too, have made it possible for country buyers to purchase in the cities, if necessary. Thus the railways have been a chief instrument in _lessening_ the power of this species of monopoly in country retail trade, which was of great power and importance a half century ago. Of retail trade in the cities, it is not necessary to speak at length. Combination here has seldom been found practicable because of the great number of competing units. There is, however, a noticeable tendency of late to the concentration of the trade in large establishments, which by their prestige and capital are able to take away business from their smaller competitors. It does not seem likely, however, that this movement will result in any very injurious monopoly among city retailers. The wholesale trade is on quite a different basis from the retail. The number of competitors being so much less, combination is vastly easier. The tendency toward it has been greatly fostered and strengthened by the formation of trusts among the producers. These combinations made the manufacturer more independent in his treatment of jobbers, and disposed him to cut their profits to the lowest point. Naturally these men combined to resist this encroachment on their income. They refused to handle any goods for less than a certain minimum commission. It might be possible in many cases for manufacturers to sell directly to the retail traders, but in general the difficulty of changing old commercial channels is such that the friction and expense is less if the goods are permitted to pass through the wholesaler's hands. It is to be noted that one cause for ill-feeling between manufacturer and wholesaler is the fact that before the days of trusts the latter often reaped much greater proportionate profits than the producer himself. But in time this cause of dissension will be forgotten, and the trust and the wholesalers' association will work in harmony.