These advantages, however, great and unbounded as they are, have been, till very recently, counterbalanced, and perhaps more than counterbalanced, by the _serious decrease_ which, for the greater part of the period that has elapsed since the peace of 1815, has been going on, from the effect of human violence or folly, in the _circulating medium of the globe_. The South American revolution at once almost destroyed the working of the mines of Mexico and Peru: the annual produce of those mines sank from £10,000,000, to which, according to Humboldt, it had risen prior to 1810, to less than £3,000,000. The diminution in the supply of the precious metals for the use of the globe, from the effects of this most calamitous revolution, which Great Britain did so much to promote, was, during the thirty years which elapsed from 1810 to 1840, certainly not less than £150,000,000 sterling. Contemporaneous with this immense reduction, took place the great contraction of the paper currency of Great Britain, the commercial heart of the globe, which was reduced by the bill of 1819 from £60,000,000, which it had reached in 1814, to little more than £30,000,000, its average since that time. These two great causes of decrease, operating simultaneously during a period of general peace, unbroken industry, great increase in population both in Europe and America, and a vast addition to the transactions and mercantile dealings of men in every part of the world, produced that universal and unlooked-for decline of prices which has been everywhere felt as so discouraging to industry, and nowhere so much so as in the highly taxed and deeply indebted realm of Great Britain. It was the exact converse of the general and long-continued prosperity which the progressive rise of prices consequent on the discovery of the South American mines produced during the sixteenth and seventeenth centuries. It was apparently the commencement of a long and disastrous period of rise in the value of money, and fall in the price of every species of produce, similar to that which, in the first four centuries of the Christian era, crushed the industry and paralysed the strength of the Roman Empire, and at length prostrated the dominion of the legions before the arms of an untutored and barbarous enemy.