But there are other causes to which we must ascribe the extension of British manufactures and commerce; of these we shall only enumerate what we regard as the principal and the most powerful:  the stimulus which any particular improvement in manufactures gives to future and additional improvements, or rather, perhaps, the necessity which it creates for such additional improvements; the natural operation of enlarged capital; the equally natural operation of encreased wealth among the various classes of the community; the peculiar circumstances in which Britain has been placed since the termination of the war which deprived her of her American colonies; and, lastly, her national debt.  A short view of each of these particulars will, we believe, sufficiently account for the present unparalleled state of British manufactures and commerce.

The direct effect of improvement in the mode of manufacturing any article, by the introduction of a more powerful machinery, is to encrease the quantity, and to lower the price of that article.  Hence it follows, that those who manufacture it on the old plan must be undersold, unless they also adopt such machinery; and as knowledge, both speculative and practical, has greater chance to improve in proportion as it is spread, from this cause, as well as from the more powerful cause of rival interests, wherever improvements in manufactures have begun and been extended, they are sure to advance.

That this is not theoretical doctrine requires only an appeal to what has been effected, and is yet effecting in Britain, to prove.  A very curious, interesting, and instructive work might be written on the improvements in the cotton machinery alone, which have been made in this country during the last forty years:  we mean interesting and instructive, not merely on account of the tacts relative to mechanical ingenuity which it would unfold, but on account of the much higher history which it would give of the mechanism of the human mind, and of the connections and ramifications of the various branches of human knowledge.  In what state would the commerce of Great Britain have been at this time, if the vast improvements in the machinery for spinning cotton had not been made and universally adopted?—­and how slowly and imperfectly would these improvements have taken place, had the sciences been unconnected, or greater improvements, which at first were unseen or deemed impracticable, not been gradually developed, as lesser improvements were made.  The stimulus of interest, the mutual connection of various branches of science, and above all the unceasing onward movement of the human mind in knowledge, speculative as well as practical, must be regarded as the most powerful causes of the present wonderful state of our manufactures, and, consequently, of our commerce.