I recently finished reading Capital Vol. II in a non-English translation; I was also checking the text against the English edition available at marxists.org for passages that I found ambiguous. That mostly cleared everything up, but I still have two lingering questions about some of the numbers Marx used in his examples.
(1) In Chapter 4, Marx explains that capitalists (both individual capitalist producers and the capitalist class as a whole) throw a greater sum of values in the form of commodities into circulation than they withdraw from it; i.e., their supply of commodity value always necessarily exceeds their demand for commodity value. He then gives a numerical example (p. 198 in the Ben Fowkes translation / Penguin edition): c = £800, v = £200, rate of surplus value = 100%. I.e., with a capital of £1,000, the capitalist produces £1,200 worth of commodities. The idea is that both the capitalist and his workers buy from other capitalists, who (taken together) work "with the same capital and under otherwise similar conditions". Marx says: "his demand [covering strictly speaking only his constant capital, i.e. his demand for means of production] covers two thirds of their [other capitalists'] supply" – okay, his demand for £800 worth of means of production covers two thirds of their £1200 worth of supply, I can see that. But then he goes on to say: "his own total demand [i.e. including v, the articles of consumption bought by his workers] is only four fifths of his own supply, considered in value terms". But his own supply is £1,200; and (4/5)*£1,200 = £960, a number that I don't know where it could have possibly come from. Shouldn't that be £1,000, i.e., five sixths rather than four fifths?
(2) In the very last chapter ("Accumulation and Reproduction on an Expanded Scale"), my edition diverges from the English ones right at the end of the first example (p. 589 in Fowkes/Penguin). My edition gives 535 as the surplus value originally consumed by dept. II (original total = 1,035) and 958 as the surplus value consumed by it in the final year (final total = 1,690), yielding a ratio of 100:163. Both of the English editions (the Progress Publishers one at marxists.org and the Penguin one) give 600 originally (total = 1,100) and 745 in the final year (total = 1,477), arriving at a ratio of 100:134. The numbers given for the surplus value consumed by dept. I are the same everywhere (500 originally, 732 in the final year).
Now, if you follow all the calculations, it's not hard to find out that it's the "English" numbers which are correct. In particular, I have no idea how you can get 535 as the surplus value consumed by II at the start. Which leads me to a question: what's happening in my edition of the book? Are these Marx's original numbers, which were quietly replaced in the English editions to make the results numerically correct? Or is it the other way around, and my book had an overzealous editor who for some reason decided to "correct" the right numbers to the wrong ones?
I'm not pretending these are questions of great importance – I'm just curious, that's all.
. I've looked at the original manuscript as reprinted in MEGA II/11. Instead of 4/5ths, it says 5/6ths, in the case you quoted as well as in the one quoted by zugzwang (it's on pp. 681-682 if anyone wants to have a look). I then looked at the "Redaktionsmanuskript" (MEGA II/12), i.e. Engels' editorial manuscript that was the basis for the first edition (MEGA II/13). It says 4/5ths.
I'm also wondering about (1), if anyone can shed some light there. If total demand were 800 and supply 1000 then 4/5 of 1000 (supply) would be 800 (total demand), but that doesn't make any sense... He repeats the same four fifths thing later on:
4/5 of 120 doesn't give 100...