Sentence:  Those who have had the care and government of politic societies introduced coinage, as a remedy of those two inconveniences. The stamp was a <WSD>warranty</WSD> of the public, that, under such a denomination, they should receive a piece of such a weight, and such a fineness; … 
Meaning of the word marked with <WSD> tags:  A guarantee that a certain outcome or obligation will be fulfilled; security.