A perpetuity is an asset or a contract that pays a fixed amount of money each time period, forever.

永续年金是一种财产或者合同,规定在每一时间段内,支付一定数量的货币,直至永远

耶鲁公开课 - 金融市场课程节选

The problem with private banks issuing notes is that there would periodically be banking crises when the banks failed to pay on their notes and they couldn't pay out the gold that was demanded--that was required.

私有银行发行纸币的问题在于,当它们没法用要求的金子-规定的金子数量,支付它们发行的纸币时,它们将周期性的,陷入银行业危机。

耶鲁公开课 - 金融市场课程节选