Ve vlnách pluje Tritón (v pravé ruce drží kormidlo), na jeho zádech leží Nymfa, pravou rukou jej objímá na hrudi, levá spočívá na jeho levém rameni., Zlatohlávek 1997#, 62, č. 30., and Pochází ze zámku Libochovice, v NG od roku 1945. Libochovická sbírka grafických listů byla vznikla pravděpodobně z iniciativy Alexandriny Andrejevny Šuvalovové (Zlatohlávek 1997, 8-9).
The prehistory of clay mineralogy is highlighted from the beginnings in ancient Greece to the mineralogical works of Agricola, in particular his famous handbook of mineralogy, entitled De natura fossilium (1546). Starting with a few scattered hints in the works of Archaic and Classic Greek authors, including Aristotle, the first treatment of clays as a part of mineralogy is by Theophrastus. This basic tradition was further supplemented by Roman agricultural writers (Cato, Columella), Hellenistic authors (the ge ographer Strabo and the physicians Diosco rides and Galen), the Roman engineer-architect Vitruvius, and finally summarized in Pliny’s encyclopedia Naturalis historia, which has become the main source for later authors, including Agricola. It is shown to what extent Agricola’s work is just a great summary of this traditional knowledge and to what extent Agricola’s work must be considered as original. In pa rticular, Agricola’s attempt to a rational, combinatorical classification of "earths" is recalled, and aplausible explanation is given for his effort to include additional information on Central European clay depos its and argillaceous raw material occurre nces. However, it is shown that - in contrast to common belief - Agricola was not the first to include "earths" in a mineralogical system. This had been done almost one thousand years earlier by Isidore of Seville., Willi Pabst and Renata Kořánová., and Obsahuje bibliografické odkazy