The bicentenary of Georg Hartung, a German pioneer geologist, explorer, and illustrator

We present a tribute to Georg Friedrich Karl Hartung (1821–1891), a less-known, non-academic German geologist, on his 200th birthday anniversary. Influenced by eminent 19th century scientific personalities, such as Oswald Heer, Charles Lyell, and Alexander von Humboldt, he performed pioneer geological observations and sampling in the Azores, Madeira, and Canary Islands volcanic archipelagos. Later in his life, he travelled to the USA and explored the Scandinavian countries. His scientific endeavours were published in several books and papers, many of them co-authored by academic German geologists and palaeontologists. His works on Macaronesia are deemed as classics, and many have been enriched by his detailed geological illustrations.

On the high scientific quality of early research on strain and deformation fabrics (1835–1908)

High-quality research developed during the 19th century established the foundations of rock strain investigations. Careful observation and description of rock fabrics and deformed objects in rocks allowed early researchers to obtain mathematical expressions that are still used today to quantify strain. Thus, in a span of a few decades, and applying basic scientific methodology, these researchers developed the concept of the strain ellipsoid, defined mathematically the difference between constant-volume and volume-loss deformation, constructed the basic equations that define pure and simple shear deformation, and discovered the mechanism of pressure–solution deformation. These advances were fundamental to seminal works on strain analysis and deformation fabrics in the mid-20th century. However, they are rarely addressed in modern studies, which suggests a lack of awareness among current researchers. In order to bring attention to these landmarks of strain research, I provide a historical review of the high standards of analysis that led to the definition of the fundamental equations and concepts on strain during the 19th century.

Scientific journeys to one of the oldest copper cementation sites in Central Europe (Smolník, Slovakia)

The process of copper cementation has already been known since the period of antiquity in Europe. Nevertheless, the first historically relevant reports come from the 14th century from the mining town of Smolník in Upper Hungary (present-day Slovakia), which makes this site the oldest place of the commercial production of copper using cementation in Europe. It is one of the oldest known sites in the world after China, where this process has been used since the 11th century. The cementation copper from Smolník was considered to be a high-quality copper in the period between the 14th and 19th century and was an important export product of Hungary. The study processes the history of cementation and discusses the production process of the artificial cementation water, as well as its subsequent mining and sedimentation. A detailed description of the technological progress of cementation from the earliest times up to the first half of the 19th century is given. The study is based upon the historical works of medieval alchemists and the first miners and naturalists, which were published as early scientific books in Europe from the 16th to the 18th century. These findings are complemented by original archival research.

Tradition of geodetic instruments production in the Czech Republic

The article describes the development of geodetic surveying and production of geodetic instruments in what is now Czech Republic. The beginnings of development can be found in the 12th–13th centuries during the colonization of the territory and the consolidation of state administration. Significant development peaks occurred in the 14th century during the reign of the Holy Roman Emperor and King of Bohemia Charles IV and then at the turn of the 16th and 17th centuries during the reign of the Holy Roman Emperor Rudolf II. The new direction is related to the development of industry at the end of the 19th century. At that time, several dozen companies in fine mechanics and optics were operating in Prague. The company J. & J. Frič was a world leader in the use of a glass divided circle in 1864. The production of astronomical and geodetic instruments in Czechoslovakia was successful until the end of the 1960s.

Eduard Heis, an early pioneer in meteor research

At the beginning of the 19th century, meteor observations were not well established. One of its pioneers, who observed meteors on a regular basis, was Eduard Heis in Münster, Germany. We summarise the life of this scientist. Besides his main task of teaching mathematics in Aachen and Münster, he observed atmospheric phenomena and variable stars with exceptional perseverance. He was an editor of Wochenschrift für Astronomie and contributed to the circulation of astronomical reports and knowledge. We focus on his contributions to meteor astronomy, in which he predated the work of Schiaparelli by 30 years.

Early history of sudden commencement investigation and some newly discovered historical facts

The history of the research on the SC (sudden commencement) of magnetic storms before World War II is studied in this paper. Since geomagnetic research activities before World War II are still not yet fully known, this paper aims to reveal some historical facts related to SC investigation at that time. The first conclusion of this paper is the possible first discoverer of the simultaneity of SC at distant locations. We show that a Portuguese scientist had already pointed it out 16 years earlier than believed. The second conclusion is the role and activities of Aikitu Tanakadate as the reporter of the SC investigation committee of STME (Section of Terrestrial Magnetism and Electricity) and IATME (International Association of Terrestrial Magnetism and Electricity) in the IGGU (International Geodetic and Geophysical Union) or IUGG (International Union of Geodesy and Geophysics). Very little was known about his activities as the reporter of this committee. Our investigation at the Tanakadate Aikitu Memorial Science Museum disclosed how he acted and what he thought of SC, based on his frequent letters to and from other scientists. The third conclusion concerns SC research carried out by Japanese scientists during the period of the Second International Polar Year (1932–1933). Not only Tanakadate but also many other Japanese scientists participated in SC research during this international project. This formed a traditional basis of SC investigation in Japan, prompting a number of Japanese scientists to study SC after World War II.

The Geophysical Observatory in Sodankylä, Finland – past and present

After a preface, we will first try to depict the history of the Geophysical Observatory in Sodankylä (SGO) by referring to the personalities who have run and have shaped the observatory. Thereafter, we describe the history from a technical point of view, i.e., what the measurements were, and which instruments were primarily used at the observatory. We will also refer to present operational forms and techniques. We start with the very first systematic meteorological and geophysical observations made in Finland and end by referring to the involvement in ongoing international scientific programs.

The Great Comet of 1577: a Palestinian observation

C/1577 V1 was one of the brightest comets and one of the few early observed twin-tail comets. This paper presents the historical and cultural background for the observation of the comet from Safed, Palestine (1577).

The temperature–CO₂ climate connection: an epistemological reappraisal of ice-core messages

As simply based on fundamental logic and on the concepts of cause and effect, an epistemological examination of the geochemical analyses performed on the Vostok ice cores invalidates the marked greenhouse effect on past climate usually assigned to CO2 and CH4. In agreement with the determining role assigned to Milankovitch cycles, temperature has, instead, constantly remained the long-term controlling parameter during the past 423 kyr, which, in turn, determined both CO2 and CH4 concentrations, whose variations exerted, at most, a minor feedback on temperature itself. If not refuted, the demonstration indicates that the greenhouse effect of CO2 on 20th century and today's climate remains to be documented, as already concluded from other evidence. The epistemological weakness of current simulations originates from the fact that they do not rely on any independent evidence for the influence of greenhouse gases on climate over long enough periods of time. The validity of models will, in particular, not be demonstrated as long as at least the most important features of climate changes, namely the glacial–interglacial transitions and the differing durations of interglacial periods, remain unaccounted for. Similarly, the constant 7 kyr time lag between temperature and CO2 decreases following deglaciation is another important feature that needs to be understood. Considered in this light, the current climate debate should be considered as being the latest of the great controversies that have punctuated the march of the Earth sciences, although its markedly differs from the preceding ones by its most varied social, environmental, economical and political ramifications.

History of the Super Dual Auroral Radar Network (SuperDARN)-I: pre-SuperDARN developments in high frequency radar technology for ionospheric research and selected scientific results

Part I of this history describes the motivations for developing radars in the high frequency (HF) band to study plasma density irregularities in the F region of the auroral zone and polar cap ionospheres. French and Swedish scientists were the first to use HF frequencies to study the Doppler velocities of HF radar backscatter from F-region plasma density irregularities over northern Sweden. These observations encouraged the author of this paper to pursue similar measurements over northeastern Alaska, and this eventually led to the construction of a large HF-phased-array radar at Goose Bay, Labrador, Canada. This radar utilized frequencies from 8–20 MHz and could be electronically steered over 16 beam directions, covering a 52∘ azimuth sector. Subsequently, similar radars were constructed at Schefferville, Quebec, and Halley Station, Antarctica. Observations with these radars showed that F-region backscatter often exhibited Doppler velocities that were significantly above and below the ion-acoustic velocity. This distinguished HF Doppler measurements from prior measurements of E-region irregularities that were obtained with radars operating at very high frequency (VHF) and ultra-high frequency (UHF). Results obtained with these early HF radars are also presented. They include comparisons of Doppler velocities observed with HF radars and incoherent scatter radars, comparisons of plasma convection patterns observed simultaneously in conjugate hemispheres, and the response of these patterns to changes in the interplanetary magnetic field, transient velocity enhancements in the dayside cusp, preferred frequencies for geomagnetic pulsations, and observations of medium-scale atmospheric gravity waves with HF radars.