But it happens that this standard is not an accurate standard. It does not _stand_, while other things alone move, but moves itself; its value is changeable,--fluctuating from time to time according to the relation of supply and demand, and from place to place according to the perturbations of the trade of the world. Moreover, its very preeminence of function--the universality and the durability of its worth--renders it peculiarly sensitive to accidental influences, or to influences outside of the usual workings of trade. A great war or revolution occurring anywhere, the loss by tempests or frosts of an important staple, such as wheat or cotton, the fall and reaction consequent upon some great speculative excitement, are all likely to produce enormous drains or sequestrations of this valuable material. When the revolt of 1848 broke out in Italy, every particle of specie disappeared as effectually as if it had been thrown into the Adriatic or the mouth of Vesuvius; when the corn crop failed in England in 1846, the Bank of England lost ten millions of dollars in gold in less than nine days, and the country five times that in about a month; and in our own late experiences, with three hundred millions of gold among the people, we have seen it so put away, that no charm or bait could allure it from its hiding-places. Need we go any farther, then, than these simple truths, to lay our finger on the primal fact which underlies all financial embarrassments and panics? The mass of the transactions in commerce rests upon credit; the solvent of that credit is gold; and gold has not only a sliding scale of value, but is apt to disappear when most wanted. While business is moving on in the ordinary way, it is more than ample for every purpose; but the moment any event arises, such as a rapidly falling market, inducing hurried sales, or a drain of specie, disturbing the general confidence, everybody gets apprehensive, everybody calls upon everybody for payment, and everybody puts everybody off,--till a feeling of _sauve qui peut_ becomes universal.