We might have cited from nature and human society a hundred more such facts in proof of this law, thus the whole fourth section of Marx's "Capital" entitled "Production of Relative Surplus Value in the realm of co-operative industry, the Division of Labor, and Manufacture, Machinery and the Great Industry," goes to show innumerable instances in which qualitative change alters the quantity of the thing, and where also, to use Herr Duehring's exceedingly odious expression, quantity is converted and transformed into quality. So also the mere cooperation of large numbers, the melting of several diverse crafts into one united craft, to use Marx's expression, produces a new "industrial power" which is substantially different from the sum of the individual crafts. Marx, in the interest of the entire truth, has remarked, in complete contrast to the perverted style of Herr Duehring "The molecular theory employed in modern chemistry, first scientifically developed by Laurent and Gerhardt, rests upon no other law." But what does Herr Duehring care for that? He knows that "the eminently modern constructive elements of scientific thought make just the same mistake as was made by Marx and his rival Lassalle; half-knowledge and a touch of pseudo-philosophy furnish the tools necessary for a display of learning." While with Herr Duehring "elevated notions of exact knowledge in mechanics, physics and chemistry" are, as we have seen, the foundations. But that the public may be in a position to decide we shall examine somewhat more closely the example cited by Marx in his note. Here we have, for example, the homologous series of compounds of carbon of which many are known and each has its own algebraic formula. If we, for example, according to the practice of chemistry, represent an atom of carbon by C, an atom of hydrogen by H, an atom of oxygen by O and the number of atoms contained in each combination of carbon by n, we can express the molecular formula of each one of this series thus, C_{n}H_{2n+2}--Series of normal paraffin. C_{n}H_{2n+2}O--Series of primary alcohol. C_{n}H_{2n}O_{2}--Series of the monobasic oleic acids. Let us take, for example, the last of this series and set one after the other n = 1, n = 2, etc., we get the following results omitting the compounds. CH_{2}O_{2}--Formic Acid--boiling point 100 deg.--melting point 1 deg. C_{2}H_{4}O_{2}--Acetic Acid--boiling point 118 deg.--melting point 17 deg. C_{3}H_{6}O_{2}--Propionic Acid--boiling point 140 deg.--melting point--. C_{4}H_{8}O_{2}--Butyric Acid--boiling point 162 deg.--melting point--. C_{5}H_{10}O_{2}--Valerianic Acid--boiling point 175 deg.--melting point--. And so on to C_{30}H_{60}O_{2}, Melissic Acid, which melts first at 180 deg., and which has no boiling point, because it does not evaporate without splitting up.