How Was Edmond Halley’s Map of Magnetic Declination (1701) Constructed?

Edmond Halley made two scientific voyages in the Atlantic Ocean as captain of the HMS Paramore between 1698 and 1700. Following these voyages he published the first map showing lines of equal magnetic declination in 1701. Halley did not reveal how he constructed the map, however, and it remains unknown. In this study, a construction procedure is hypothesized that uses mathematical tools that were available in his day, namely arithmetical averages and Isaac Newton’s method of divided difference for fitting a polynomial curve to data. To enable his map construction, a method is suggested whereby Halley could have created new data to augment the situations where insufficient data were collected.     

中国古代劝学文发展简论

劝学,作为中华民族的古老传统和思想主张,不仅口耳相传,更铭刻在字里行间,那就是一脉相承的劝学类散文.春秋战国时期,学校教育的建立、士阶层的出现以及私学的产生奠定了劝学风气和思想的形成,体现于诸子散文并形成了初步繁盛的局面.秦汉以后直到唐宋,随着儒家思想统治地位的确立和散文的发展,劝学文也日趋成熟和繁荣.元代之后,理学思想和散文创作都从繁荣而走向衰微,劝学文的专门性和系统性有所减弱,文学性也更加淡化,最后随封建社会的终结而完成了自身的使命.     

Geophysics of Lager Wick forced labour camp,Grouville, Jersey,Channel Islands

Abstract

Three seasons of fieldwork at the forced labour camp of Lager Wick, Grouville, Jersey (2014–2016) employed resistivity, ground penetrating radar (GPR) and magnetic susceptibility to investigate areas of the camp. Resistivity and magnetic susceptibility produced the most useful results, whilst the GPR survey only revealed a modern pipe. The resistivity survey was undertaken in the south-west corner of the former camp close to the entrance gate posts, whilst the magnetic susceptibility survey was undertaken over the remains of one of the barrack huts along the Gorey Road frontage which had been burnt to the ground in 1943. The resistivity survey produced some high resistance anomalies that appear to resemble a demolition layer or a surface on which the huts were constructed. Magnetic susceptibility results showed zones of burning which appear to relate to the remains of one of the burnt huts; excavation revealed a stone/brick surface.     

地面核磁共振方法在石质文物保护中的应用

石质文物破坏问题不仅在于人为破坏和表面污染,更多来自自然因素对文物的破坏,例如,日晒雨淋、风沙吹蚀、地表水的冲刷、地震、地下水的侵蚀溶蚀。为对第六批全国重点文物保护单位阳华岩摩崖石刻露天石质文物病害进行探查,采用无损探测的地面核磁共振方法和探地雷达方法,直接找水的地面核磁共振方法成功探测出摩崖石刻依附岩体地层含水分布状况。探地雷达方法探测出依附岩山体内岩溶、裂隙的发育状况。两种方法探测结果发现,石刻依附岩体内岩溶、裂隙发育,部分区域岩溶裂隙带已成为地下水汇聚场所或流通通道,对阳华岩摩崖石刻构成了极为严峻的侵蚀威胁。两种方法解释结果互为验证,研究结果为阳华岩摩崖石刻的病害治理和保护提供了宝贵的基础资料。     

Experimental Heating of Moravian Cherts and its Implication for Palaeolithic Chipped Stone Assemblages

The applicability of colour, magnetic susceptibility and remanent magnetization measurements for the identification of heated or accidentally burned Palaeolithic cherts from Moravia (Czech Republic) is tested in this study. We conclude that all these methods are usable. Colour changes are best detectable in materials heated at between 250–350°C, while magnetic susceptibility and remanent magnetization change at higher temperatures, closer to 600°C. This latter temperature, however, is usually destructive for cherts and is probably evidenced by accidentally burned artefacts. With the use of the three methods, we managed to identify three probably heated chert artefacts from two early Upper Palaeolithic assemblages from Moravia.     

Images of buried graves in Bayat,Afyon (Turkey) from high-resolution magnetic data and their comparison with preliminary excavations

Dedemezari necropolis, the site of our study, is located in the west of Turkey near Afyon. Archaeologists think that it belongs to the Middle Bronze age. A high-resolution magnetic survey identified buried material highly accurately. In particular, anomalies, which are transformed by the analytic signal method, clarify the observed magnetic anomalies. Magnetic surveying was applied in three different areas in this study. The map of analytic signal-transformed anomalies presented good results on preliminary excavation in trenches A and B. Two types of graves are found in the study area. One is made of clay and the second is carved in the rocks. Shapes of the buried graves are mainly cylindrical and elliptical. Most of the magnetic anomalies are elliptical and reflect the shape of the buried materials. Future excavations in Dedemezari necropolis will be able to be carried out more easily due to the known locations of the buried graves.     

转型时期中国海滨度假地衰退研究——以烟台牟平养马岛为例

海滨度假地衰退是国际旅游研究关注的热点之一,然而现有研究形成的两个理论范式——生命周期理论和转型理论都无法完满地解释中国海滨度假地衰退现象。本文以烟台牟平养马岛为案例,对其旅游开发历程进行梳理研究后发现,处于转型时期的中国传统海滨度假地往往遭遇制度性衰退和竞争性衰退的双重困境。中国海滨度假地的复兴必须首先摆脱行政经济的禁锢,走市场化改革的道路。     

Archaeological geophysics of a Bronze Age agricultural landscape: the AROURA Project,central mainland Greece

Between 2010 and 2012, the AROURA project conducted magnetometric prospection in the ancient polder around the Late Bronze Age (ca. 1300–1190 b.c.) fortress of Glas, mainland Greece. As had been hypothesized, the anomalies detected were consistent with a system of agricultural fields. This system appears to have been irrigated and drained through previously identified hydraulic mechanisms in and around the polder. Comparison of soil profiles of anomalies with those of background areas, including their magnetic susceptibilities, corroborated magnetometric data. Anomalies were traced from sampled to unsampled areas through corresponding reclassified satellite bandwidths. Constituent sediments of features discovered were dated to the Late Bronze Age through AMS radiocarbon and OSL analyses. The results validated the use of extensive geophysics to detect and investigate ancient agricultural landscapes.     

Marine Magnetic Survey of a Submerged Roman Harbour, Caesarea Maritima, Israel

A marine geophysical survey was conducted at Caesarea Maritima, Israel, to map the buried structure of King Herod's Roman harbour. Magnetic surveys reveal the presence of an extensive hydraulic concrete foundation below the ruined harbour moles. The magnetic anomaly patterns indicate that the concrete foundation was laid out in header fashion along N-S and W-E trending segments to form two large 'artificial islands'. Magnetic lows within the structure identify baffles that were infilled with sand to stabilise the concrete foundation walls.
© 2004 The Nautical Archaeology Society