2. “Sociale Briefe an Von Kirchmann”—“Social Letters to Von Kirchmann” (1850-51). Out of print. 3. “Zur Beleuchtung der Socialen Frage”—“Elucidation of the Social Question” (Berlin, 1875). This contains a second edition of the second and third letters to Von Kirchmann, and, with the two following essays, gives a very good idea of his economic theories. 4. “Der Normal Arbeitstag”—“The Normal Labor Day” (Berlin, 1871). Reprinted in _Tübinger Zeitschrift für die gesammte Staatswissenschaft für 1878_. Cf. also, in the same volume of the _Zeitschrift_, an essay on Rodbertus by Adolf Wagner, entitled “Einiges von und über Rodbertus-Jagetzow.” 5. “Offener Brief an das Comité des Deutschen Arbeiter-Vereins”—“Open Letter to the Committee of the German Laborers Union” (Leipzig, 1863). Reprinted in Volume I. of Lassalle’s collected writings—F. Lassalle’s “Reden und Schriften” (New York, 1882). 6. “Zur Erklärung und Abhülfe der heutigen Creditnoth des Grundbesitzes”—“An Explanation of the Necessity of Credit for Land-owners and Proposal of Measures to Assist Them” (2 vols. 1868-69). Out of print. The aim of Rodbertus is naturally to solve the social problem, to abolish the sharp contradiction between the real life of society and the desired and striven-for ideal. But there are two chief evils in the existing economic life of man, which are the cause of most of the others. These evils are PAUPERISM and COMMERCIAL AND FINANCIAL CRISES, the latter leading to over-production and a glut in the market. Rodbertus directs his attention principally to the means of abolishing these evils. The starting-point of Rodbertus’s political economy is his conception of labor expressed in the following sentence: “All economic goods are to be regarded only as the products of labor, and they cost nothing but labor.”[162] This proposition he claims was first introduced into economic science by Adam Smith, and was more firmly established by the school of Ricardo. His whole theory consists of a logical extension of this theory, according to which pauperism and crises result from one and the same circumstance—viz., “that when economic processes are left to themselves in respect to the distribution of goods, certain relations (_Verhältnisse_) connected with the development of society bring it about that as the productivity of social labor[163] increases, the wages of the laboring classes constitute an ever-decreasing portion of the national product.”[164] This does not mean necessarily that what the laborer receives becomes absolutely smaller; only that it decreases relatively. If ten laborers produce now twenty bushels of wheat in a given time, and receive ten bushels as wages, and at a later period the productivity of labor has increased to such an extent that they produce thirty bushels in the same time, but receive only thirteen, their portion, their quota has decreased.[165]