447.  It may also be urged, that in each kind of machinery a maximum of perfection may be imagined, beyond which it is impossible to advance; and certainly the last advances are usually the smallest when compared with those which precede them:  but it should be observed, that these advances are generally made when the number of machines in employment is already large; and when, consequently, their effects on the power of producing are very considerable.  But though it should be admitted that any one species of machinery may, after a long period, arrive at a degree of perfection which would render further improvement nearly hopeless, yet it is impossible to suppose that this can be the case with respect to all kinds of mechanism.  In fact the limit of improvement is rarely approached, except in extensive branches of national manufactures; and the number of such branches is, even at present, very small.

448.  Another argument in favour of the exportation of machinery, is, that it would facilitate the transfer of capital to any more advantageous mode of employment which might present itself.  If the exportation of machinery were permitted, there would doubtless arise a new and increased demand; and, supposing any particular branch of our manufactures to cease to produce the average rate of profit, the loss to the capitalist would be much less, if a market were open for the sale of his machinery to customers more favourably circumstanced for its employment.  If, on the other hand, new improvements in machinery should be imagined, the manufacturer would be more readily enabled to carry them into effect, by having the foreign market opened where he could sell his old machines.  The fact, that England can, notwithstanding her taxation and her high rate of wages, actually undersell other nations, seems to be well established:  and it appears to depend on the superior goodness and cheapness of those raw materials of machinery the metals—­on the excellence of the tools—­and on the admirable arrangements of the domestic economy of our factories.

449.  The different degrees of facility with which capital can be transferred from one mode of employment to another, has an important effect on the rate of profits in different trades and in different countries.  Supposing all the other causes which influence the rate of profit at any period, to act equally on capital employed in different occupations, yet the real rates of profit would soon alter, on account of the different degrees of loss incurred by removing the capital from one mode of investment to another, or of any variation in the action of those causes.