In discussing the question of variability in the purchasing power of gold, he says:
"The reason of the liability to fluctuation in the purchasing power of the sovereign is plain: When gold rises in value a larger quantity of any other commodity, say of corn, of meat, of butter, or of cloth, will have to be given in exchange for any given quantity of gold, such, for example, as the quantity contained in a sovereign. On the other hand, when gold falls in value a smaller quantity of any other commodity, say of corn, of meat, of butter, or of cloth, will suffice to obtain in exchange any given quantity of gold, such as that which is contained in the sovereign. It is an obvious inference that our gold coinage, however useful as a medium of exchange, does not furnish us with a standard of value fixed and unalterable. It does not furnish us, for example, with such a standard as the yard is of length or as the pound troy is of weight. The popular notion that the pound sterling constitutes a fixed standard of value is merely a popular delusion. The sole foundation for that delusion manifestly is that in these countries the values of all commodities are commonly stated in terms of a pound sterling; in other words, in pounds, shillings, and pence; a shilling being a twentieth part of the pound, and a penny the twelfth part of that again.
"The natural result of this method of enhancing the value of commodities other than gold is that when prices rise or fall the impression is conveyed to a superficial observer that it is the value of other things that changes, the value of the sovereign remaining fixed."
"The price of things estimated in gold--their gold price--may change, whilst their price estimated in silver--their silver price--remains unaltered. This will occur if the value or purchasing power of gold goes up or down, while the value or purchasing power of silver remains unaltered. Suppose, for instance, that gold is in any way scarce in relation to the demands upon it. Then, in any country where gold is the standard metal of the currency, those who wish to obtain, a certain quantity of gold, whether in coin or in bullion, will have to give a larger quantity of other commodities in exchange for it; or, to put the matter in another light, those who have only a definite commodity to part with will receive less gold in return for that; in other words, there is a fall in gold prices. Suppose, on the contrary, that gold is abundant in relation to the demands upon it, then those who wish to obtain a certain quantity of gold, whether in currency or in bullion, will not have to give so large a quantity of other commodities to obtain the quantity of gold they require; or, to put the matter as before in another light, those who have a definite quantity of other commodities to dispose of will obtain more gold in return for them; in other words, there is a rise in gold prices. If in either case there is no change in the value of silver, then the price of commodities stated in silver, that is, their silver price, will remain unchanged."