Page:On the economy of machinery and manufactures - Babbage - 1846.djvu/279

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(301.) In many instances it is exceedingly difficult to estimate beforehand the sale of an article, or the effects of a machine; a case, however, occurred during a recent inquiry, which although not quite appropriate as an illustration of probable demand, is highly instructive as to the mode of conducting investigations of this nature. A committee of the House of Commons was appointed to inquire into the tolls proper to be placed on steam-carriages; a question, apparently, of difficult solution, and upon which widely different opinions had been formed, if we may judge by the very different rate of tolls imposed upon such carriages by different "turnpike trusts." The principles on which the committee conducted the inquiry were, that "The only ground on which a fair claim to toll can be made on any public road, is to raise