London, 19 December 1882 

Dear Moor, 

Your letter arrived at 5 o’clock yesterday afternoon and this morn- 
ing I got back the ms.* Your opinion is most flattering though it is one 
I cannot share, at any rate so far as form is concerned. As it was fine 
and warm at midday you will doubtless be released at last for an hour 
or two from your confinement indoors. Here, though, the fog has 
grown worse again since 1 o’clock and at times it is like night. 

This is how I see the Podolinski business.*’’ His real discovery is 
that human labour is capable of retaining solar energy on the earth’s 
surface and harnessing it for a longer period than would otherwise 
have been the case. All the economic conclusions he draws from this 
are wrong. I have not got the thing to hand but read it in Italian not 
long ago in the Plebe. The point in question, namely how the 
amount of energy contained in a specific amount of foodstuffs can, 
through labour, yield a greater amount of energy than itself, I resolve 
as follows: Let us assume that the amount of food a person needs each 
day represents an amount of energy expressed as 10,000 cal (units of 
heat). These 10,000 cal will, ad infinitum, = 10,000 cal and are known 
in practice to lose on conversion into other forms of energy as a result 
of friction, etc., a portion that cannot be put to use. Significantly so in 
the case of the human body. Hence the physical labour performed in 
economic labour can never = 10,000 cal; it is invariably less. 

But this is by no means to imply that physical labour is economic la- 
bour. The economic labour performed by 10,000 cal in no way con- 
sists in the reproduction, complete or partial, of these same 10,000 cal in 
any form whatever. On the contrary, they are for the most part lost in 
the increased heat given off by the body, etc., and such useful residue 
as remains lies in the fertilising property of excretions. The economic 
labour performed by an individual through the expenditure of these 
10,000 cal consists rather in the stabilisation over a longer or shorter 

* F. Engels, “The Mark’. 

period of the fresh cal he absorbs from the radiation of the sun, and 
this is the only connection the latter have, so far as labour is con- 
cerned, with the first 10,000 cal. Now whether the fresh cal stabilised 
by the expenditure of 10,000 cal of daily nourishment amount to 
5,000, 10,000, 20,000 or a million is dependent solely upon the level 
of development of the means of production. 

To demonstrate this in the form of calculations is possible only in 
the case of the most primitive branches of production: hunting, fish- 
ing, stock farming, agriculture. In hunting and fishing fresh solar 
energy is not even stabilised; rather, use is simply made of what has 
been stabilised already. At the same time it is clear that, assuming the 
individual concerned takes normal nourishment, the amount of pro- 
tein and fat he obtains by hunting or fishing is independent of the 
amount of these substances he consumes. 

In stock farming energy is stabilised in as much as the vegetation, 
that would otherwise rapidly wither, die and decompose, is systemati- 
cally converted into animal protein, fat, skin, bone, etc., hence 
stabilised over a longer period. Here calculations already become 
complicated. 

Even more so in agriculture where the energy value of auxiliary 
materials, fertilisers, etc., must also be taken into consideration. 

In industry all calculations come to a full stop; for the most part the 
labour added to a product simply does not permit of being expressed 
in terms of ca]. This might be done at a pinch in the case of a pound of 
yarn by laboriously reproducing its durability and tensile strength in 
yet another mechanical formula, but even then it would smack of 
quite useless pedantry and, in the case of a piece of grey cloth, let 
alone one that has been bleached, dyed or printed, would actually 
become absurd. The energy value conforming to the production costs 
of a hammer, a screw, a sewing needle, is an impossible quantity. 

To express economic conditions in terms of physical measures is, in 
my view, a sheer impossibility. 

What Podolinski has completely forgotten is that the working indi- 
vidual is not only a stabiliser of present but also, and to a far greater 
extent, a squanderer of past, solar heat. As to what we have done in 
the way of squandering our reserves of energy, our coal, ore, forests, 
etc., you are better informed than I am. From this point of view, 
hunting and fishing may also be seen not as stabilisers of fresh solar 
heat but as exhausters and even incipient squanderers of the solar 
energy that has accumulated from the past. 

Further: Man, by his labour, does deliberately what plants do 
unconsciously. Plants — and there is nothing new in this of course — 
are the great absorbers and repositories of solar heat in modified 
form. Thus man, by his labour, in so far as it stabilises solar energy 
(which in industry and elsewhere is by no means always the case), 
succeeds in combining the natural functions of the energy-consuming 
animal with those of the energy-gathering plant. 

Podolinski went astray after his very valuable discovery, because 
he sought to find in the field of natural science fresh evidence of the 
rightness of socialism and hence has confused the physical with the 
economic. 

Encl. cheque for £40 so that you can cash it when you want and 
will have something to fall back on. 

As regards Tussy’s coming, I shall speak to her this evening. So 
far as we ourselves are concerned Jollymeier at once agreed, of 
course; the details can only be arranged if he does come.* More 
tomorrow. 

Your 
F. E.