Karl Marx à Nikolaï Danielson, le 19 février 1881

p. 62As soon as I shall sail in more quiet waters I shall enter more fully upon your Esquisse. For the present I cannot omit one observation. The soil being exhausted and getting not the elements — by artificial and vegetable and animal manure, etc. — to supply its wants, will with the changing favour of the seasons, of circumstances independent of human influence — still continue to yield harvests of very different amounts, though, summing up a period of years, as f. i. from 1870-80, the stagnant character of the production presents itself in the most striking character. Under such circumstances the favourable climatic conditions pave the way to a famine year by quickly consuming and setting free the mineral fertilizers still latent in the soil, while vice versa a famine year, and still more a series of bad years following it, allow the soil-inherent minerals to accumulate anew, and to work efficiently with returning favour of the climatic conditions. Such a process goes of course everywhere on but elsewhere it is checked by the modifying intervention of the agriculturist himself. It becomes the only regulating factor where man has ceased to be a ‘power’ — for want of means.

So we have 1870 an excellent harvest in your country, but that year is a climax year, and as such immediately followed by a very bad one; the year 1871, the very bad harvest, must be considered as the starting point for a new little cycle, till we come to the new climax year 1874, which is immediately followed by the famine year 1875; then the upwards movement begins again, ending in the still worse famine year 1880. The summing up of the years during the whole period proves that the average annual production remained the same and that the mere natural factors have alone produced the changes comparing the single years and the smaller cycles of years.