One sum of money is distinguishable from another only by its amount. The character and tendency of the process M—C—M, is therefore not due to any qualitative difference between its extremes, both being money, but solely to their quantitative difference. More money is withdrawn from circulation at the finish than was thrown into it at the start. The cotton that was bought for £100 is perhaps resold for £100 + £10 or £110. The exact form of this process is therefore M—C—M', where M' = M + ΔM = the original sum advanced, plus an increment. This increment or excess over the original value I call "surplus-value." The value originally advanced, therefore, not only remains intact while in circulation, but adds to itself a surplus-value or expands itself. It is this movement that converts it into capital.
Of course it is also possible, that in C—M—C, the two extremes C—C, say corn and clothes, may represent different quantities of value. The farmer may sell his corn above its value, or may buy the clothes at less than their value. He may, on the other hand, "be done" by the clothes merchant. Yet, in the form of circulation now under consideration, such differences in value are purely accidental. The fact that the corn and the clothes are equivalents, does not deprive the process of all meaning, as it does in M—C—M. The equivalence of their values is rather a necessary condition to its normal course.
The repetition or renewal of the act of selling in order to buy, is kept within bounds by the very object it aims at, namely, consumption or the satisfaction of definite wants, an
or the principles of Trade and Speculation explained." London, 1841, p. 5.) Although Corbet does not see that M—M, the exchange of money for money, is the characteristic form of circulation, not only of merchants' capital but of all capital, yet at least he acknowledges that this form is common to gambling and to one species of trade, viz., speculation: but then comes MacCulloch and makes out, that to buy in order to sell, is to speculate, and thus the difference between Speculation and Trade vanishes. "Every transaction in which an individual buys produce in order to sell it again, is, in fact, a speculation." (MacCulloch: "A Dictionary Practical, &c., of Commerce." Lond., 1847, p. 1058.) With much more naïveté, Pinto, the Pindar of the Amsterdam Stock Exchange, remarks, "Le commerce est un jeu: (taken from Locke) et ce n'est pas avec des gueux qu'on peut gagner. Si l'on gagnait long-temps en tout avec tous, il faudrait rendre de bon accord les plus grandes parties du profit pour recommencer le jeu." (Pinto: "Traité de la Circulation et du Crédit" Amsterdam, 1771, p. 231.)
