191. The principle that price, at any moment, is dependent on the relation of the supply to the demand, is true to the full extent only when the whole supply is in the hands of a very large number of small holders, and the demand is caused by the wants of another set of persons, each of whom requires only a very small quantity. And the reason appears to be, that it is only in such circumstances that a uniform average can be struck between the feelings, the passions, the prejudices, the opinions, and the knowledge, of both parties. If the supply, or present stock in hand, be entirely in the possession of one person, he will naturally endeavour to put such a price upon it as shall produce by its sale the greatest quantity of money; but he will be guided in this estimate of the price at which he will sell, both by the knowledge that increased price will cause a diminished consumption, and by the desire to realize his profit before a new supply shall reach the market from some other quarter. If, however, the same stock is in the hands of several dealers, there will be an immediate competition between them, arising partly from their different views of the duration of the present state of supply, and partly from their own peculiar circumstances with respect to the employment of their capital. 192. The expense of ascertaining that the price charged is that which is legally due is sometimes considerable. The inconvenience which this verification produces in the case of parcels sent by coaches is very great. The time lost in recovering an overcharge generally amounts to so many times the value of the sum recovered, that it is but rarely resorted to. It seems worthy of consideration whether it would not be a convenience to the public if government were to undertake the general conveyance of parcels somewhat on the same system with that on which the post is now conducted. The certainty of their delivery, and the absence of all attempt at overcharge, would render the prohibition of rival carriers unnecessary. Perhaps an experiment might be made on this subject by enlarging the weight allowed to be sent by the two-penny post, and by conveying works in sheets by the general post. This latter suggestion would be of great importance to literature, and consequently to the circulation of knowledge. As the post-office regulations stand at present, it constantly happens that persons who have an extensive reputation for science, receive by post, from foreign countries, works, or parts of works, for which they are obliged to pay a most extravagant rate of postage, or else refuse to take in some interesting communication. In France and Germany, printed sheets of paper are forwarded by post at a very moderate expense, and it is fit that the science and literature of England should be equally favoured.