(a) It is easy enough to see why the solution of this general problem is so extremely difficult. The new is mixed in with the old. The result of the old labor and capital is a productive piece of land; the current labor and capital is expended upon the same piece to make it more productive; the same sort of thing is done now that was done then, and the results of the two are now thoroughly intermixed; there were original free utilities in soil and growths and deposits, but these had and have no value and can never yield rent; the old labor and capital improved the soil by clearing and drainage and fertilizers, and made the growths and deposits more valuable and accessible, so that even the old onerous was more or less transformed into the original gratuitous; and now the new onerous, the fresh cultivation and fertilization and betterments generally, in soils and roads and buildings, are inextricably commingled with former betterments of the same general kind and with the original free gifts of Nature. No wonder the Commission of 1881 found difficulty in determining what was what and which was which! No wonder that Irish tenants on long leases quarrel with their landlords about the betterments, how much is new, how much is old! It is clear, that when the lease is ended, the landlord ought to compensate the tenant for all that portion of the latter's betterments, which is not already worn out; it is equally clear, that the tenant ought to be willing to pay a fair rent for the use of the unexpended betterments of the landlord and his predecessors; while there is room and verge enough for endless disputes between them as to the respective amounts of these, and consequently as to the amounts of rent and of its remissions. These difficulties and intricacies do not belong to the _principles_ of the Science of buying and selling, which are in the main clear and certain in their action, but are incidents of determining in certain cases _what that is_, which is bought and sold. Parties in interest in all kinds of buying and selling are sometimes compelled to go to the courts in order to have the Law decide what their respective rights are as buyers and sellers; but this is no fault of Political Economy as a science, or of trading as an art; two men in all cases make their own bargain, according to their own estimate of the respective rendering and receiving of each; if the uncertainties of language, the misconception on the part of one or both of the terms agreed upon, and the misapprehension of some of the circumstances of the case, breed confusion and litigation, all this cannot be justly charged to the science of Political Economy.