19.6

ON MEASURES
certain in what degree either of these causes
operated. If salmon continued to sell for £1,
whilst deer rose to £3, we might conclude that
more labour was required to obtain the deer. If
deer continued at the same price of £2, and
salmon sold for 13s. 4d. we might then be sure
that less labour was required to obtain the salmon ;
and if deer rose to £2. 10s. and salmon fell to
16s. 8d. we should be convinced that both causes
had operated in producing the alteration of the
relative value of these commodities.”

Here we have a very accurate description,
by Mr. Ricardo, of what a commodity pro-
duced by an invariable quantity of labour
(not a commodity of invariable value, as he
erroneously terms it) would enable us to ascer-
tain, under the supposition that all things were
determined in value by quantity of labour.
He does not tell us that such a commodity
would enable us to ascertain the value of fish
or game, or their variation in value, but this
variation being given, that it would enable us
to infer how much of it was to be attributed to a