It appears to me, that the difficulty may be very simply solved, by referring this different state of the value of the guinea at the two periods mentioned, to the different _quantities_ of debased silver currency in circulation. In King William's reign gold was not a legal tender, it passed only at a conventional value. All the large payments were probably made in silver, particularly as paper currency, and the operations of banking, were then little understood. The quantity of this debased silver money exceeded the quantity of silver money, which would have been maintained in circulation, if nothing but undebased money had been in use; and consequently it was depreciated as well as debased. But in the succeeding period when gold was a legal tender, when bank-notes also were used in effecting payments, the quantity of debased silver money did not exceed the quantity of silver coin fresh from the mint, which would have circulated if there had been no debased silver money; hence though the money was debased, it was not depreciated. Mr. Buchanan's explanation is somewhat different, he thinks that a subsidiary currency is not liable to depreciation, but that the main currency is. In King William's reign silver was the main currency, and hence was liable to depreciation. In 1774 it was a subsidiary currency, and therefore maintained its value. Depreciation, however, does not depend on a currency being the subsidiary or the main currency, it depends wholly on its being in excess of quantity.