1 The Birth of Science - MSRI

5.7 Chemistry 143
We shall see that in Hellenistic times there developed also other industries
involving the transformation of matter, from metal extraction and
refining to the manufacture of cosmetics, fragrances and medicines. 83
Already the Stoics, and particularly Chrysippus, in the third century page 186
B.C., had clearly in mind the distinction between heterogeneous materials,
homogeneous mixtures and single compounds. We know this from
various sources. Stobaeus, for instance, writes:
Stoics like to distinguish between juxtaposition (©), mixture
(), blend (©) and composition (©) . . . A mixture is
the complete interpenetration of two or more bodies, preserving the
properties of each . . . A blend, according to them, is the complete
interpenetration of two or more liquids, preserving the properties
of each. A blend displays simultaneously the properties of each of
the blended liquids, such as wine, honey, water, vinegar and so on.
That in such blends the properties of the constituents are preserved
is clearly shown by the fact that one can generally separate them
again with the right trick. If a sponge dipped in oil is introduced in
a blend of water and wine, the water will be attracted to the sponge
and separated from the wine. The composition (©) of two or
more qualities is instead a transformation () of the bodies
that gives rise to qualities diverse from the original ones, as happens
in the synthesis (©) of perfumes or medicines. 84
It is worth remarking that the noun we have translated as composition
(©) never appears in Aristotle’s works, 85 and that the concept
it designates is illustrated here with examples from the new mattertransformation
industries. The noun derives from the same root (of the
verb ) that probably also gave rise to the word chymeia ( or
), attested at a later date and from which we ultimately got chemistry.
86
The modern concept of a molecule has an interesting forerunner in the page 187
83 See pages 223–224.
84 Stobaeus, Eclogae I, xvii, 154, 8 –155, 14 (ed. Wachsmuth) = [SVF], II, 471. Other passages on the
same point are Philo of Alexandria, De confusione linguarum, II, 264 (ed. Wendland) = [SVF], II, 472,
and Alexander of Aphrodisias, De mixtione, 216, 14 – 218, 6; 221 = [SVF], II, 473, 474.
85 The most intimate combination of substances considered by Aristotle is the homogeneous mixture,
which he calls by the terms and © (De generatione et corruptione, 328a).
86 In Arabic the adjunction of the article transformed the Greek word into alchimia, which coexisted
in Latin for centuries with chimia. In the modern age, chemistry ennobled itself by appropriating
the Greek name, but usually when the Greek science is referred to, the Arabic word
is scornfully used. This strange situation illustrates the complex and contradictory way in which
modern scientists have regarded the relationship between themselves and the classical tradition.
Revision: 1.9 Date: 2002/09/14 19:12:01