Andrew pooh-poohs my suggestion that Marx is talking about first
differences, but after looking back at the text I'm reinforced
in my opinion. Here is the Progress (1971) translation:
"We have shown previously that although surplus-value is
manifested in a surplus-product the converse does not hold
that a surplus-product, representing a mere increase in the
mass of product, constitutes surplus-value. It may represent
a minus quantity in value. Otherwise the cotton industry of
1860, compared with that of 1840, would show an an enormous
surplus-value, whereas on the contrary the price of the yarn
has fallen."
1860 compared with 1840, note. The physical product is larger,
yet (says Marx) its value is smaller. He goes on...
"Rent may increase enormously as a result of a succession of
crop failures, because the price of grain rises, although
this surplus-value appears as an absolutely decreasing mass
of dearer wheat. Conversely, the rent may fall in consequence
of a succession of bountiful years, beacuase the price falls,
although the reduced rent appears as a greater mass of cheaper
wheat"
The whole discussion is about first differences. Cotton there
may (or may not) be in abundance, but there is no grist here
for the "anti-simultaneist" mill. The notion that Marx is
talking about negative surplus value here is entirely fanciful.
Allin Cottrell
Department of Economics
Wake Forest University