Natural and anthropogenic variations in methane sources during the past two millennia.

Methane is an important greenhouse gas that is emitted from multiple natural and anthropogenic sources. Atmospheric methane concentrations have varied on a number of timescales in the past, but what has caused these variations is not always well understood. The different sources and sinks of methane have specific isotopic signatures, and the isotopic composition of methane can therefore help to identify the environmental drivers of variations in atmospheric methane concentrations. Here we present high-resolution carbon isotope data (δ(13)C content) for methane from two ice cores from Greenland for the past two millennia. We find that the δ(13)C content underwent pronounced centennial-scale variations between 100 BC and AD 1600. With the help of two-box model calculations, we show that the centennial-scale variations in isotope ratios can be attributed to changes in pyrogenic and biogenic sources. We find correlations between these source changes and both natural climate variability--such as the Medieval Climate Anomaly and the Little Ice Age--and changes in human population and land use, such as the decline of the Roman empire and the Han dynasty, and the population expansion during the medieval period.

Whence 'zoster'? The convoluted classical origins of a sometimes illogical term.

The term 'zoster' is nowadays associated with 'herpes zoster', the condition resulting from reactivation of the latent varicella-zoster virus which causes shingles. But in antiquity the meaning of 'zoster', a Latin word originating from the Greek for a belt or girdle, was variously associated in men with a form of body armour which could enclose just one half of the body; in women with a garment worn around the waist and sometimes called a 'zona'; and with a place, Zoster, linked mythologically then with the goddess Leto and her zona. Around 48 AD, the Roman physician Scribonius Largus became the first to associate 'zona' with 'herpes', and to attribute a medical meaning to 'zona', here an abbreviation of 'zona ignea' ('fiery girdle'). Although in the past the terms 'zoster' and 'zona' were sometimes used interchangeably, today only 'zoster' remains-even when etymologically illogical in those patients whose zoster rash occurs in body areas other than the trunk.

The nomological image of nature: explaining the tide in the thirteenth century.

The paper examines the relevance of the nomological view of nature to three discussions of tide in the thirteenth century. A nomological conception of nature assumes that the basic explanatory units of natural phenomena are universally binding rules stated in quantitative terms. (1) Robert Grosseteste introduced an account of the tide based on the mechanism of rarefaction and condensation, stimulated by the Moon's rays and their angle of incidence. He considered the Moon's action over the sea an example of the general efficient causality exerted through the universal activity of light or species. (2) Albert the Great posited a plurality of causes which cannot be reduced to a single cause. The connaturality of the Moon and the water is the only principle of explanation which he considered universal. Connaturality, however, renders neither formulation nor quantification possible. While Albert stressed the variety of causes of the tide, (3) Roger Bacon emphasized regularity and reduced the various causes producing tides into forces. He replaced the terminology of 'natures' by one of 'forces'. Force, which in principle can be accurately described and measured, thus becomes a commensurable aspect of a diverse cosmos. When they reasoned why waters return to their place after the tide, Grosseteste argued that waters return in order to prevent a vacuum, Albert claimed that waters 'follow their own nature', while Bacon held that the 'proper force' of the water prevails over the distant force of the first heaven. I exhibit, for the thirteenth century, moments of the move away from the Aristotelian concerns. The basic elements of these concerns were essences and natures which reflect specific phenomena and did not allow for an image of nature as a unified system. In the new perspective of the thirteenth century the key was a causal link between the position of the Moon and the tide cycle, a link which is universal and still qualitative, yet expressed as susceptible to quantification.

Michael Maier--nine newly discovered letters.

The authors provide a transcription, translation, and evaluation of nine newly discovered letters from the alchemist Michael Maier (1568-1622) to Gebhardt Johann von Alvensleben (1576-1631), a noble landholder in the vicinity of Magdeburg. Stemming from the final year of his life, this correspondence casts new light on Maier's biography, detailing his efforts to secure patronage amid the financial crisis of the early Thirty Years' War. While his ill-fated quest to perfect potable gold continued to form the central focus of his patronage suits, Maier also offered his services in several arts that he had condemned in his printed works, namely astrology and "supernatural" magic. Remarks concerning his previously unknown acquaintance with Heinrich Khunrath call for a re-evaluation of Maier's negotiation of the discursive boundaries between Lutheran orthodoxy and Paracelsianism. The letters also reveal Maier's substantial contribution to a work previously ascribed solely to the English alchemist Francis Anthony.

[In process.] / Die kaiserlichen rzte am Hof Leopolds I. (1657-1705) und ihre Beziehungen zur Academia Naturae Curiosorum.

The "Akademie der Naturforscher" (Academy of Natural Scientists) was founded in 1652; in 1687 Emperor LEOPOLD 1. raised it in the rank of an imperial academy (Sacri Romani Imperii Academia Caesareo-Leopoldina Naturae Curiosorum). The president and the editor of the academic periodical (Director Ephemeridum) got the same privileges as imperial physicians. Based on this the duties of the physicians and their status within the court hierarchy are explained. During the reign of LEOPOLD I there were 61 persons who worked as physicians at court. The prosopographical analysis shows their distribution to the households of the members of the imperial family. Other aspects are their origin, their education and their relationship to the University of Vienna. Finally we learn about the imperial physicians as members of the Academy and as mediators between the Academy and the court.

Andreas Vesalius (1514-1564) - an unfinished life.

The fame of Andreas Vesalius (1514-1564) rests on his anatomy text, De humani corporis fabrica, regarded as a seminal book in modern medicine. It was compiled while he taught anatomy at Padua, 1537-1543. Some of his findings challenged Galen's writings of the 2c AD, and caused De fabrica to be rejected immediately by classically trained anatomists. At age 29, Vesalius abandoned his studies and over the next two decades served as physician to Emperor Charles V of the Holy Roman Empire (HRE) and later to King Philip II of Spain in Madrid. In 1564, he sought to resume teaching anatomy in Padua, but release from royal service obliged him first to make a pilgrimage to Palestine. During the return voyage to Venice, he became ill and was put ashore alone on an Ionian island Zakynthos, where he died days later at age 50.