The Libros del Saber de Astronomia is a compilation of various Arabic astronomical works translated into Castilian in the second half of the thirteenth century, under the direction of King Alfonso X of Spain. A section describing a mercury clock has been suggested to be of particular significance in view of the likely invention of the mechanical clock around this period, so a new translation into modern technical English has been prepared. The clock is shown to consist essentially of an (...) annulus of mercury-filled chambers separated by narrow partitions, each partition being perforated by a very small hole. This annulus is attached concentrically to a pulley wheel around which a cord is wrapped, and a fixed weight hung upon the cord. The torque raises the mercury on the opposite side, but as the resulting hydrostatic head then causes it to percolate through the holes connecting the chambers the wheel slowly rotates to maintain its equilibrium. The weight therefore gradually descends in a controlled manner. It is claimed that, by suitable adjustment of the driving weight, the wheel could be made to turn once in 4 hours. A 6:1 reduction gear therefore enabled the rete of an astrolabe to be rotated once in 24 hours, modelling the real sky so that the time could be read off directly against the plate.A working model has been constructed on these principles, but utilizing modern materials to contain the mercury. It does work, but the range of rotation periods is quite limited and the reproducibility poor . It is shown that this is a consequence of the compounding of errors in what amounts to a ring of ‘mercury glasses’ joined end-to-end, for a single ‘mercury glass’ has a standard deviation of ±1.7 per cent and five or six are in use at any one time. Errors and omissions in the Castilian account suggest that the translator had never seen the instrument they attempt to describe.The mercury clock of the Libros is not isochronous, and its constant unidirectional rotation contrasts with the oscillators that are the hallmark of all advanced timekeepers. It is concluded that, although an interesting experiment, it had no influence on the evolution of clockwork in the western world. (shrink)

The Royal Society possesses three long-focus simple lenses of diameters 195, 210 and 230 mm, all inscribed with the signature ‘C. Huygens’ and various dates in the year 1686. These prove to have been made by Constantine Huygens, the elder brother of the famous Christiaan Huygens. All three lenses have been examined by a variety of physical and chemical methods, both to define their optical characteristics and to establish the composition of dated samples of late-seventeenth-century Continental glass. The focal lengths (...) of 37·9, 50·1 and 65·2 metres found by combination agree with Huygens' own values of 122, 170 and 210 feet respectively, and are so great that practical employment of the lenses in aerial telescopes has rarely been achieved. All are made from the same very poor glass—a heterogeneous and discoloured potash-rich ‘forest glass’—with a refractive index of 1·516, a costringence of 60, and a density of 2·5 g cm−3. The three lenses were ground with just two concave laps, of radii of curvature 27·11 and 71·15 metres, one lens being plano-convex to a high degree of accuracy. A claim by previous investigators that one lens was a ‘light flint’ glass has been disproved. (shrink)

Diseases caused by Salmonella species are characterized by bacterial invasion of host cells. Salmonella invasion requires a genetic locus (inv) with homology to bacterial systems involved in specific protein export and organelle assembly. Until recently, the actual Salmonella invasion factors exported or assembled by the inv system remained unidentified. It now appears that Salmonella produces novel appendages upon contact with host cells. These appendages are transient, appearing and disappearing rapidly from the bacterial surface. Appendages are altered in strains unable to (...) invade due to mutations within the inv/spa locus. Therefore, a role for the invasion locus has been identified, providing another example of bacterial pathogens responding to signals provided by the host cell surface. (shrink)

The Routledge Handbook of Feminist Bioethics is an outstanding resource for anyone with an interest in feminist bioethics, with chapters covering topics from justice and power to the climate crisis. Comprising 42 chapters by emerging and established scholars, the volume is divided into six parts: Foundations of Feminist Bioethics Identity and Identifications Science, Technology and Research Health and Social Care Reproduction and Making Families Widening the Scope of Feminist Bioethics The volume is essential reading for anyone with an interest in (...) bioethics or feminist philosophy, and will prove an invaluable resource for scholars, teachers, and advanced students. (shrink)

In this work, Mill reflects on the struggle between liberty and authority and defends the view that “the only purpose for which power can be rightfully exercised over any member of a civilized community, against his will, is to prevent harm to others.” He questions the justification for the limits of freedom of conscience and religion, freedom of speech, freedom of action, and the nature of liberalism itself. This new Broadview Edition demonstrates the ways in which Mill’s intellectual landscape differed (...) markedly from our own, while also drawing attention to the reasons why the work remains relevant and essential reading in the present day. Appendices include antecedents to Mill’s work, critical discussions by his contemporaries, and related writings by Mill. Please note: Broadview offers two separate editions of On Liberty. The Kahn edition is particularly relevant to readers who are interested in how the work is situated in the history of political philosophy, whereas the Alexander edition is recommended to those most interested in the work’s Victorian literary and social contexts. (shrink)

This paper empirically examines the financial performance of a UK unit trust that was initially “conventional” and later adopted socially responsible investment (SRI) principles (ethical investment principles). Comparison is made with three similar conventional funds whose investment objectives remained unchanged. Analysis techniques employed in previous studies find similar results: mean risk-adjusted performance is unchanged by the switch to SRI, with no evidence of over-or under-performance relative to the benchmark market index by any of the four funds. More interestingly, changes in (...) variability of returns over time are also modelled using generalised autoregressive conditional heteroscedasticity models, not previously applied to SRI funds so far as is known. Results show a temporary increase in variability of returns, followed by a return to previous levels after around 4 years. Evidence shows the increased variability to be associated with the adoption of SRI rather than with a change in fund management. Possible explanations for the subsequent reduction in variability include the spread of corporate social responsibility activities by firms and learning by fund managers. In addition to reporting on a previously unobserved phenomenon, this paper raises questions for further research. (shrink)

There has recently been a reappraisal of value in UK construction and calls from a wide range of influential individuals, professional institutions and government bodies for the industry to exceed stakeholders’ expectations and develop integrated teams that can deliver world class products and services. As such value is certainly topical, but the importance of values as a separate but related concept is less well understood. Most construction firms have well-defined and well-articulated values, expressed in annual reports and on websites; however, (...) the lack of rigorous and structured approaches published within construction management research and the practical, unsupported advice on construction institution websites may indicate a shortfall in the approaches used. This article reviews and compares the content and␣structure of some of the most widely used values approaches, and discusses their application within the construction sector. One of the most advanced and empirically tested theories of human values is appraised, and subsequently adopted as a suitable approach to eliciting and defining shared organisational values. Three studies within six construction organisations demonstrate the potential application of this individually grounded approach to reveal and align the relative values priorities of individuals and organisations to understand the strength of their similarity and difference. The results of these case studies show that this new universal values structure can be used along with more qualitative elicitation techniques to understand organisational cultures. (shrink)

While the contemporary problem of the criterion raises similar epistemological issues as Agrippa’s Trilemma in ancient Pyrrhonian skepticism, the consideration of such epistemological questions has served two different purposes. On one hand, there is the purely practical purpose of Pyrrhonism, in which such questions are a means to reach suspension of judgment, and on the other hand, there is the theoretical purpose of contemporary epistemologists, in which these issues raise theoretical problems that drive the search for theoretical resolution. In classical (...) India, similar issues arise in Nāgārjuna’s Vigrahavyāvartanī, but it is not entirely clear what Nāgārjuna’s purpose is. Contrary to the theoretical interpretations of several recent scholars such as Jan Westerhoff according to which Nāgārjuna is proffering a contextualist epistemological theory, I argue that Nāgārjuna as well as the later Madhyamaka Candrakīrti, much like Pyrrhonian skeptics, employed concerns about epistemic criteria in service of purely practical purposes. There is no positive epistemological theory to be found in Nāgārjuna’s Vigrahavyāvartanī and Candrakīrti’s Prasannapadā; furthermore a putative thesis of universal emptiness is self-undermining, a conclusion which itself can be seen as part of a therapeutic program. Nonetheless, the historical persistence of these epistemological issues shows that they ought to continue to be areas of theoretical inquiry for epistemologists today. I end with reflections on the wider relevance of my conclusions, particularly with regard to demonstrating the value of philosophy. (shrink)

Altitude sundials do not require knowledge of the N-S direction to quantify time in terms of either seasonal or equal hours. Methods for determining the corresponding dial patterns are reviewed, and accurately computed data for a latitude of 51°N presented as horizontal, vertical, rectangular, and pillar dials on both timekeeping systems.

Canada balsam is secreted by cells in the bark of the balsam fir Abies balsamea, a conifer widely distributed across Canada and northern U.S.A. Collected by an extraordinarily labour-intensive process, it was initially exported to Europe for use in pharmacy. However, it found a much wider application after Brewster showed that the refractive index of 1·54–1·55 characterizing the vitreous mass remaining after heating the natural product exceeded that of most resins, and therefore closely matched the indices of ‘crown’ and ‘light (...) flint’ optical glasses. ‘Cooked’ Canada balsam was therefore very suitable for cementing achromatic lenses for telescopes and microscopes, as well as for mounting specimens for microscopical examination. Canada balsam remained pre-eminent for over a century, but the rise of synthetic adhesives and other substitutes has now relegated the natural balsam to a few specialized niches. (shrink)

This is a major anthropological study of contemporary Tibetan Buddhist monasticism and tantric ritual in the Ladakh region of North-West India and of the role of tantric ritual in the formation and maintenance of traditional forms of state structure and political consciousness in Tibet. Containing detailed descriptions and analyses of monastic ritual, the work builds up a picture of Tibetan tantric traditions as they interact with more localised understandings of bodily identity and territorial cosmology, to produce a substantial re-interpretation of (...) the place of monks as ritual performers and peripheral householders in Ladakh. The work also examines the central and indispensable role of incarnate lamas, such as the Dalai Lama, in the religious life of Tibetan Buddhists. (shrink)

This paper explores two reddit communities that supported Bernie Sanders and Donald Trump, respectively, in the run up to the 2016 US Presidential election campaign. Much of the paper is dedicated to explaining how reddit functions, describing the behaviour of the subreddit communities in question and then asking whether these demonstrated collective intelligence. Subreddit communities submit and vote on content, through their votes they make collective decisions about which content will be broadcast to their community. Large subreddit communities that formed (...) rapidly to support a candidate in an election have not previously been observed on reddit—these offered an interesting context for the consideration of whether subreddit communities demonstrate collective intelligence. Voting is a key determinant of what happens on each subreddit and it is conducted anonymously, it is, therefore, not possible to understand the role that every individual plays in the functioning of the subreddit. The behaviour of these subreddit communities can only be understood as a collective of submitting, commenting, voting and moderating participants. Whether these collectives behave intelligently is a matter of how one defines intelligence—but it is clear that they can be effective in pursuing certain ends. These collectives encounter and sometimes oppose each other on reddit. The community of Trump supporters in particular were in conflict with a number of other high-profile communities on the site, and also the platform’s administrators. (shrink)

During the set-up phase of an international study of genetic influences on outcomes from sepsis, we aimed to characterise potential differences in ethics approval processes and outcomes in participating European countries. Between 2005 and 2007 of the FP6-funded international Genetics Of Sepsis and Septic Shock project, we asked national coordinators to complete a structured survey of research ethic committee approval structures and processes in their countries, and linked these data to outcomes. Survey findings were reconfirmed or modified in 2017. Eighteen (...) countries participated in the study, recruiting 2257 patients from 160 ICUs. National practices differed widely in terms of composition of RECs, procedures and duration of the ethics approval process. Eight countries used a single centralised process for approval, seven required approval by an ethics committee in each participating hospital, and three required both. Outcomes of the application process differed widely between countries because of differences in national legislation, and differed within countries because of interpretation of the ethics of conducting research in patients lacking capacity. The RECs in four countries had no lay representation. The median time from submission to final decision was 1.5 months; in nine approval was received within 1 month; six took over 6 months, and in one 24 months; had all countries been able to match the most efficient approvals processes, an additional 74 months of country or institution-level recruitment would have been available. In three countries, rejection of the application by some local RECs resulted in loss of centres; and one country rejected the application outright. The potential benefits of the single application portal offered by the European Clinical Trials Regulation will not be realised without harmonisation of research ethics committee practices as well as national legislation. (shrink)

This book offers a bold and controversial new thesis regarding the nature of prejudice. The authors' central claim is that prejudice is not simply learned, rather it is predisposed in all human beings and is thus the foundation for ethical valuation. They aim to destroy the illusion that prejudice is merely the result of learned beliefs, socially conditioned attitudes, or pathological states of development. Contrary to traditional accounts, prejudice itself is not a negative attribute of human nature, rather it is (...) the necessary precondition for the self and civilization to emerge. Defined as the preferential self-expression of valuation, prejudice gives rise to greater existential complexities and novelties that elevate selfhood and society to higher states of ethical realization. Rather than offer another contribution that highlights the destructive nature of prejudice, Mills and Polanowski address the ontological, psychological, and dialectical origins of prejudice as it manifests itself in the process of selfhood and culture. They provide an original conceptualization of the phenomenology of prejudice and its dialectical instantiation in the ontology of the individual, worldhood, and the very structures of subjectivity. As a unique synthesis of psychoanalysis, Hegelian idealism, Heideggerian existential ontology, and Whiteheadian process philosophy, prejudice is the indispensable ground for humanity to actualize its highest potentiality-for-Being. The striking result is (1) a revolutionary theory of human nature, (2) a new ethical system, and (3) the elevation of dialectical ethics to the domain of metaphysics. (shrink)

The reliable covariation between numerosity and spatial extent is considered as a strong constraint for inferring the successor principle in numerical cognition. We suggest that children can derive a general number concept from the (experientially) infinite succession of spatial positions during object manipulation.

Classic voltaic batteries of the silver/zinc and copper/zinc types are the ancestors of today's primary cells, and facilitated the development of many aspects of electrical technology. Nevertheless, they appear never to have been studied and evaluated in a quantitative manner, with results recorded in terms of volts, amps, ohms, and watts. Research of this nature is reported here, and has been conducted for the most part with copper/zinc cells. Log–log graphs of voltage versus load and current, and power versus load, (...) are presented for many electrolyte systems. It has been shown that, although the textbook electrolyte of dilute sulphuric acid does work, it is an order of magnitude inferior to a solution containing some additional nitric acid. The latter diminishes the current‐limiting phenomenon of polarization, and was in fact used by Davy, Faraday, and other early investigators. A quantitative consideration of Nicholson and Carlisle's discovery of the electrolysis of water with a silver/zinc voltaic pile is followed by examination of the electrolysis of pure water, trough batteries, and Davy's isolation of potassium and sodium. Every battery gives maximum power when its resistance is adjusted to match the resistance of the load: the maximum output of the ‘Great Battery’ of the Royal Institution is assessed at no more than 3 kW. The paper concludes with a note on the recognized hazard of long‐term exposure to mercury vapour and its possible relevance to the health of Michael Faraday. (shrink)

This paper examines the various types of small, portable heliostat which maintain a beam of sunlight in a constant direction. Used mainly in the second half of the nineteenth century, these instruments were intended for optical demonstrations and the illumination of microscopes and similar apparatus, rather than for astronomical applications. Three basic patterns are distinguished: polar heliostats , biaxial single-mirror heliostats, and coelostats. The theory and geometry of each type is explained, followed by a consideration in chronological order of the (...) corresponding working instruments. Heliostats by Fahrenheit, Meyerstein, 's Gravesande, Gambey, Silbermann, Foucault, Stoney and others are illustrated, and extensive references given. (shrink)

The true form of the seasonal-hour sundial, in both vertical and horizontal planes, has been calculated by spherical trigonometry and displayed with the aid of computer graphics. These grids are presented, and show that the hour lines are in fact shallow curves at sites not on the equator. The curvature becomes very apparent at latitudes exceeding 50°. The true seasonal-hour pattern for a vertical dial at a latitude of 52·6°N is compared with the equiangular scratch dial.

In the early 1800s galvanometers could be constructed with the fine gauges of silk-covered copper or silver wires produced for decorative purposes, but when Faraday was making his classic electrical experiments in 1831 he needed a sturdier gauge of copper wire. Bare copper wire was available in many diameters for mechanical applications, but coils for electromagnetic investigations had to be insulated with string and calico. It was soon realized that the cotton-covered springy iron wire then used to hold out the (...) brims of ladies' bonnets showed how copper wire might be similarly wrapped to provide a flexible insulation. The simple manual machines used by the bonnet-wire makers were readily adapted and improved, and a six-head version was built by William Henley. This craftsman's vision of the growing importance of insulated copper wire was abundantly justified, and he built up a large—but poorly organised—empire in the wire and cable trade. Henley's original multiple-head wrapping machine has been located in the Science Museum, London, and the associated silk-covered copper wire subjected to physical, chemical, and electrical testing. For comparison, the electrical conductivity of the ‘mechanical grade’ copper wire used by Faraday has also been determined. (shrink)

The lodestone is an extremely rare form of the mineral magnetite that occurs naturally as a permanent magnet. It therefore attracts metallic iron as well as fragments of ordinary ‘inert’ magnetite. This ‘magic’ property was known to many ancient cultures, and a powerful lodestone has always commanded a high price. By the eleventh century AD the Chinese had discovered that a freely suspended elongated lodestone would tend to set with its long axis approximately north–south, and utilized this property in the (...) magnetic compass. They also appear to have discovered that this invaluable characteristic could be handed‐on to a steel needle if the latter were contacted with, or stroked by, a lodestone.The magnetism of the lodestone was scientifically investigated by William Gilbert in the sixteenth century, when he defined its ‘poles' and the well‐known rule that ‘like poles repel, unlike attract’. He also studied ‘inclination’ and ‘variation’, and means to aid the preservation of magnetic power. How to concentrate it by ‘arming’ the lodestone with caps or pole‐pieces of soft iron was discovered in the same century. These methods have been repeated, confirmed, and improved. The lodestone occupies a vital place in the history of magnetism, but little beyond Gilbert's work can be reached by historical studies because vastly improved steel or alloy permanent magnets, and electromagnets, replaced it before quantitative measurements were developed. These techniques have therefore been applied retrospectively to both museum specimens and contemporary natural lodestones. A good source of the latter was found to be the igneous complex known as Magnet Cove, Arkansas, and this material has been used as the ‘type example’. All specimens were discrete, well‐rounded, rusty brown pebbles found near the surface. Their unweathered interiors were black titanomagnetite. No significant trace element or crystallographic differences could be found between the lodestones and the magnetically inert material that always accompanied them. The magnetic moment per unit volume of the ‘as‐found’ Magnet Cove lodestones varied between 6.5 and 11.6 emu cm−3, which compares poorly with the hundreds of units characteritzing modern permanent magnets. Hysteresis loops gave a saturation intensity of 27–51 emu cm−3, suggesting that intensity has diminished since formation. This agrees with general experience of magnets, especially in the absence of a ‘keeper’. The initial volume susceptibility of Magnet Cove magnetite was about 0.18 for low fields, and always remained <1. This means that a normal terrestrial magnetic field with a maximum vector <1 Oe is unable to induce even the low magnetic moments we see today, while a field approaching 1000 Oe is required for saturation. These parameters, and the rare occurrence of lodestones as near‐surface fragments, support suggestions that they are the product of a lightning strike upon an exposure of a suitable magnetite. Transient currents averaging 30 000 A have been measured. This would give rise to a zone of potential magnetic saturation at least 12 cm in diameter, to which some of the ejected fragments would be exposed. An attempt to determine the period elapsed since formation of the Magnet Cove lodestone was made by annealing magnetically saturated specimens at temperatures up to 500°C, and measuring J v at weekly intervals for 100 days. The decay curves visually resembled exponential functions, but mathematical tests proved that they were not strictly so. Interpretation was therefore difficult, but a pragmatic procedure involving excessive extrapolation suggested an ‘age’ of about 3500 years. (shrink)

While innovations in modern microscopy, spectroscopy, and nanoscopy techniques have made single molecule observation a standard in many laboratories, the actual design of meaningful fluorescence reporter systems now hinders major scientific breakthroughs. Even though the field of chemical biology is supercharging the fluorescence toolbox, surprisingly few strategies exist that make the transition from model systems to biologically relevant applications. At the same time, the number of microscopy techniques is growing dramatically. We explain our view on how the impact of modern (...) technologies is influenced not only by further hard‐ and software developments, but also by the availability and suitability of protein‐engineering tools. We identify how the largely independent research fields of chemical biology and fluorescence nanoscopy can influence each other to synergistically drive future technology that can visualize the localization, structure, and dynamics of molecular function without constraints. (shrink)

Reprint of the original, first published in 1869.