We have shewn how population must go on, in proportion to subsistence, and in proportion to industry: now the machine eats nothing, so does not diminish subsistence, and industry (in our age at least) is in no danger of being overstocked in any well governed state; for let all the world copy your improvements, they still will be the scholars. And if, on the contrary, in the introduction of machines you are found to be the scholars of other nations, in that case you are brought to the dilemma of accepting the invention with all its inconveniencies, or of renouncing every foreign communication. In speculations of this kind, one ought not, I think, to conclude, that experience _must_ of necessity prove what we imagine our reasoning has pointed out. The consequences of innovations in political oeconomy, admit of an infinite variety, because of the infinite variety of circumstances which attend them: no reasoning, therefore, however refined, can point out a priori, what upon such occasions must indispensably follow. The experiment must be made, circumstances must be allowed to operate; inconveniencies must be prevented or rectified as far as possible; and when these prove too many, or too great to be removed, the most rational, the best concerted scheme in theory must be laid aside, until preparatory steps be taken for rendring it practicable. Upon the whole, daily experience shews the advantage and improvement acquired by the introduction of machines. Let the inconveniencies complained of be ever so sensibly felt, let a statesman be ever so careless in relieving those who are forced to be idle, all these inconveniencies are only temporary; the advantage is permanent, and the necessity of introducing every method of abridging labour and expence, in order to supply the wants of luxurious mankind, is absolutely indispensable, according to modern policy, according to experience, and according to reason. ------------------------------------------------------------------------ CHAP. XX. _Miscellaneous Observations upon Agriculture and Population._ I have hitherto considered the object of agriculture, as no more than the raising of grain; the food of mankind has been estimated by the quantity they consume of that production; and husbandmen have been supposed to have their residence in the country. As my subject has but an indirect connection with the science of agriculture, I have simplified many things complex in themselves, the better to adapt them to the principal object of my inquiry, and the better to keep my attention fixed upon one idea at a time. I am now going to return to some parts of my subject, which I think I have treated too superficially; and to examine, as I go along, some miscellaneous questions which will naturally arise from what is to be said. [Sidenote: QUEST. I.]