When Do Gold And Silver Become Money? - Hugo Salinas Price

``Gold will once again be used as money (it actually is money) when nobody will take anything else in payment or when there isn't anything but gold (or silver) available with which to make payments. That was the situation back in the 19th Century and before. Gold was used because there was no alternative but silver, and that situation would have continued except for the fact that the ratio of silver to gold was a fixed ratio, and was not allowed to fluctuate with the market.''