John Stuart Mill, in his "Principles of Political Economy," says:—
"There is such a thing as a general rise of prices. All commodities may rise in their money price. But there cannot be a general rise of values. It is a contradiction in terms." "That the money prices of all things should rise or fall, provided all rise or fall equally, is in itself, and apart from existing contracts, of no consequence. It affects nobody's wages, profits, or rent. Every one gets more money in the one case and less in the other; but of all that is to be bought with money they get neither more nor less than before. It makes no other difference than that of using more or fewer counters to reckon by. The only thing which in this case is really altered in value is money; and the only persons who either gain or lose are the holders of money, or those who have to receive or pay fixed sums of it.... There is a disturbance, in short, of fixed money contracts, and this is an evil whether it takes place in the debtor's favour or in the creditor's.... Let it therefore be remembered (and occasions will often rise for calling it to mind) that a general rise or a general fall of values is a contradiction; and that a general rise of prices is merely tantamount to an alteration in the value of money, and is a matter of complete indifference save in so far as it affects existing contracts for receiving and paying fixed pecuniary amounts."
"The value of a thing is what it will exchange for: the value of money is what money will exchange for; the purchasing power of money. If prices are low, money will buy much of other things, and is of high value; if prices are high, it will buy little of other things, and is of low value. The value of money is inversely as general prices: falling as they rise and rising as they fall."
"The value of money, other things being the same, varies inversely as its quantity; every increase of quantity lowering the value, and every diminution raising it in a ratio exactly equivalent."
"That an increase of the quantity of money raises prices, and a diminution lowers them, is the most elementary proposition in the theory of currency."
The expression, "other things being the same," in one of these quotations, evidently means "demand remaining the same," and the terms increase and decrease of money unquestionably refer to the increase and decrease relative to demand, since the writer further says:—
"If there be at any time an increase in the number of money transactions, a thing continually liable to happen from differences in the activity of speculation, and even in the time of year (since certain kinds of business are transacted only at particular seasons); an increase of the currency which is only proportional to this increase of transactions, and is of no longer duration, has no tendency to raise prices."
Per contra, therefore, unless the currency be increased to meet such increased demand, there will be a tendency to decreased prices and consequent change in the value of money.
Stronger statements than these of Mill's, or by an abler authority, could not be asked for.
Prof. R. T. Ely, in his "Political Economy," remarks, p. 179:—