Association at the Cambridge Meeting in the year 1862. A still briefer abstract of that paper was inserted in the Report of the Meet ing a, and the paper itself was not printed until June 1866 b. Since writing that paper, I have, over and over again, questioned the truth of my own notions, but without ever finding any reason to doubt their substantial correctness. I have therefore thought it needless to delay any longer submitting the theory to the oriti cism of those who are interested in the progress of Political Economy.
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