London, 7 January 1851 

Dear Engels, 

I am writing to you today, to lay before you a questiuncula 
theoretica? naturally naturae politico-economicae? 

You know, to begin ab ovo, that according to Ricardo’s theory, 
rent is nothing else but the difference between the production 
costs and the price of agricultural produce, or, as he also 
expressed it, the difference in the price at which the produce of 
the poorest Jand must be sold in order to cover costs (the 
tenant-farmer’s profit and interest being always included in the 
costs), and that at which the produce of the best land can be sold. 

The increase in rent proves, according to his own exposition of 
his theory, that: 

1. Recourse is had to ever poorer types of soil, or that the same 
amount of capital, successively employed on the same land, does 
not give the same yield. In a word: the soil deteriorates in like 
proportion to the increasing demands the population must make 
upon it. It becomes relatively less fertile. Wherein Malthus 
discovered the real basis for his theory of population, and wherein 
his disciples now seek their last sheet-anchor. 

2. Rent can only rise when the price of corn rises (at least 
according to economic laws); it must fall when the latter falls. 

3. When a country’s overall rental rises, this can only be explained 
by the fact that a very large mass of relatively poorer land has 
been brought under cultivation. 

Now these 3 propositions are everywhere refuted by history. 

1. There is no doubt that, with the advance of civilisation, ever 
poorer types of soil are brought under cultivation. But equally, 
there is no doubt that, as a result of the progress of science and 
industry, these poorer types of soil are relatively good as against 
those previously regarded as good. 

2. Since 1815 the price of corn has fallen, irregularly but 
steadily, from 90 to 50 shillings and, before the repeal of the Corn 

A page from Marx’s letter to Engels of 7 January 1851 

Laws,’”? even lower. Rent has steadily risen. Thus in England. 

Mutatis mutandis everywhere on the Continent. 

3. In all countries, as Petty has already observed, we find that, 
when the price of corn fell, the country’s overall rental rose. 

The main point of all this is to adjust the law of rent to progress 
in fertility in agriculture generally, this being the only way, firstly, 
to explain the historical facts and, secondly, to eliminate the 
Malthusian theory of the deterioration, not only of the ‘hands’, but 
also of the soil. 

1 believe that the matter can be explained simply, as follows: 

Let us assume that, at a given state of agriculture, the price of 
wheat is 7 shillings a quarter* and one acre of the best quality 
land, subject to a rent of 10 shillings, produces 20 bushels. 
The return per acre thus=20X7 or=140 shillings. In this case 
the production costs amount to 130 shillings. Hence 130. shil- 
lings is the price of the product of the poorest land under cul- 
tivation. 

Let us assume that there is a general improvement in 
agriculture. If this be presupposed, we at the same time assume 
that science, industry and population are in a state of growth. A 
general increase in the fertility of the land resulting from 
improvements presupposes these conditions, as against the fertility 
fortuitously induced by a favourable season. 

Say the price of wheat falls from 7 to 5 shillings a quarter.* The 
best land, No. 1, which formerly yielded 20 bushels now yields 30 
bushels. This now returns, instead of 20X7, or 140 shillings, 
305, or 150 shillings. I. e. a rent of 20 shillings instead of 10 as 
formerly. The poorest land, which bears no rent, must produce 26 
bushels, for, in accordance with our foregoing assumption, the 
requisite price of these is 130 shillings and 26x5=130. If the 
improvement, i. e. the general progress of science, which goes 
hand in hand with the overall progress of society, growth of 
population, etc., is not so general as to enable the poorest land 
that must be brought under cultivation to produce 26 bushels, the 
price of corn cannot fall to 5 shillings a quarter.’ 

As before, the 20 shillings rent is an expression of the 
difference between production costs and the price of corn on the 
best land, or between the production costs on the poorest and 
those on the best land. Relatively speaking, one piece of land is no 
less infertile by comparison with the other than before. But fertility 
in general has improved. 

All that is presupposed is that, if the price of corn falls from 7 
to 5 shillings, consumption or demand increases correspondingly, 
or that productivity does not exceed the demand that may be 
expected when the price is 5 shillings. False though this hypothesis 
might be if the price had fallen from 7 to 5 as the result of an 
exceptionally abundant harvest, it is a necessary one where fertility 
has increased gradually and as a result of measures taken by the 
producers themselves. In any case, all we are concerned with here 
is the economic feasibility of this hypothesis. 

From this it follows that: 

1. Rent may rise although the price of agricultural produce 
falls, and yet Ricardo’s law still holds good. 

2. The law of rent, as laid down by Ricardo in its simplest form 
and leaving aside its exposition, does not presuppose the 
diminishing fertility of the land, but only—and this despite the 
general increase in fertility that accompanies the development of 
soctety—the varying fertility of fields or the varying results 
obtained by the capital successively employed on the same land. 

3. The more genera] the improvement in the land, the greater 
the variety of the fields it will embrace, and the country’s overall 
rental may rise, although there is a general fall in the price of 
corn. E. g., given the above example, it is simply a question of 
the number of fields producing over 26 bushels at 5. shillings 
without actually having to go as high as 30, i.e. of the extent to 
which the quality of the land varies as between the best and the 
poorest. This has nothing to do with the ratio of rent of the best 
land. In fact it has nothing to do directly with the ratio of rent 
at all. 

As you know, the real joke where rent is concerned is that it is 
generated by evening out the price for the resultants of varying 
production costs, but that this law of market price is nothing other 
than the law of bourgeois competition. Even after the elimination 
of bourgeois production, however, there remains the snag that the 
soil would become relatively more infertile, that, with the same 
amount of labour, successively less would be achieved, although 
the best land would no longer, as under bourgeois rule, yield as 
dear a product as the poorest. The foregoing would do away with 
this objection. 

I should like to have your views on the matter. 

Having bored you with this muck, I am sending you by way of 
comic relief the enclosed bundle of letters from Dr Magnus Gross 
(doubly great Great! Greatest of the Great!) of Cincinnati.*** You 
will see that if Monsieur Gross is not grand, he is nevertheless 

gros Tellering II in nuce” These Coblenzers are all alike!‘ Send 
the things back to me with, if you have the time and the 
inclination, a Jine or two for Dronke. 

Your 
K. M.