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
Thirty years long measurements of plumb line variations carried on with help of horizontal pendulums provided us information of non-tidal effects. Installation of the long water tube tiltmeter opens for us new possibility to answer the question, which part of non-tidal effects observed by means of pendulums was associated with geodynamic phenomena and which part was of instrumental or local origin. Two years long measurements of the long water-tube tiltmeter showed us some important similarities between non-tidal effects registered by both instruments: comparable amplitudes of non-tidal effects, time of durations of non-tidal effects as well as irregularity of occurring of non-tid al events. In spite of disjunction of time series of measurements obtained with help of horizontal pendulums and long water-tube tiltmeters we are able to conclude that the reasons of large non-tidal effects can not be simply explained by influence of temperature or pressure variations., Marek Kaczorowski., and Obsahuje bibliografické odkazy
Among the first GPS geodynamics projects in Czech Republic the MORAVA network was founded in 1994 with aim to determine the positional changes at border zone between the Bohemian Massif and the Carpathians. Initial project included three successive GPS campaigns in period 1994 - 1996, but was not continued because of lack of support. It had been possible to carry out new measurements in southern part of the MORAVA network including five stations, after gap of 15 years. In the paper comparison of previous and contemporary results of epoch GPS measurements are presented, which indicate block movement tendencies at the Bohemian Massif and the Western Carpathians border, thus confirming activity of the area up to present days., Otakar Švábenský, Michal Witiska, Jan Ratiborský, Radim Blažek, Lubomil Pospíšil and Josef Weigel., and Obsahuje bibliografii
The permanent GPS stations are particulary important for studying various phenomena because they provide uninterrupted measurements allowing to form the time series of station coordinates. Analysis of GPS solutions time series (GPSSTS) for short meridian baselines were explored in the paper (Kryński and Zanimonskiy, 2000). In our article we intend to extend the analysis of the GPSSTS for baselines of different lengths and azimuths. GPS observation data from the ASG-PL network have been used in the research. The GPSSTS in time and frequecy domain have been analyzed. The spectrums of the GPSSTS with the using coherence function were compared. Moreover, a practical approach to correct any unmodeled effects in GPS baseline solutions that cannot be computed using classical GPS adjustment was presented., Władysław Góral and Daniel Jasiurkowski., and Obsahuje bibliografii